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Diffstat (limited to 'arch/x86/xen/mmu_pv.c')
| -rw-r--r-- | arch/x86/xen/mmu_pv.c | 2677 |
1 files changed, 2677 insertions, 0 deletions
diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c new file mode 100644 index 000000000..73aa0b89a --- /dev/null +++ b/arch/x86/xen/mmu_pv.c @@ -0,0 +1,2677 @@ +/* + * Xen mmu operations + * + * This file contains the various mmu fetch and update operations. + * The most important job they must perform is the mapping between the + * domain's pfn and the overall machine mfns. + * + * Xen allows guests to directly update the pagetable, in a controlled + * fashion. In other words, the guest modifies the same pagetable + * that the CPU actually uses, which eliminates the overhead of having + * a separate shadow pagetable. + * + * In order to allow this, it falls on the guest domain to map its + * notion of a "physical" pfn - which is just a domain-local linear + * address - into a real "machine address" which the CPU's MMU can + * use. + * + * A pgd_t/pmd_t/pte_t will typically contain an mfn, and so can be + * inserted directly into the pagetable. When creating a new + * pte/pmd/pgd, it converts the passed pfn into an mfn. Conversely, + * when reading the content back with __(pgd|pmd|pte)_val, it converts + * the mfn back into a pfn. + * + * The other constraint is that all pages which make up a pagetable + * must be mapped read-only in the guest. This prevents uncontrolled + * guest updates to the pagetable. Xen strictly enforces this, and + * will disallow any pagetable update which will end up mapping a + * pagetable page RW, and will disallow using any writable page as a + * pagetable. + * + * Naively, when loading %cr3 with the base of a new pagetable, Xen + * would need to validate the whole pagetable before going on. + * Naturally, this is quite slow. The solution is to "pin" a + * pagetable, which enforces all the constraints on the pagetable even + * when it is not actively in use. This menas that Xen can be assured + * that it is still valid when you do load it into %cr3, and doesn't + * need to revalidate it. + * + * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007 + */ +#include <linux/sched/mm.h> +#include <linux/highmem.h> +#include <linux/debugfs.h> +#include <linux/bug.h> +#include <linux/vmalloc.h> +#include <linux/export.h> +#include <linux/init.h> +#include <linux/gfp.h> +#include <linux/memblock.h> +#include <linux/seq_file.h> +#include <linux/crash_dump.h> +#ifdef CONFIG_KEXEC_CORE +#include <linux/kexec.h> +#endif + +#include <trace/events/xen.h> + +#include <asm/pgtable.h> +#include <asm/tlbflush.h> +#include <asm/fixmap.h> +#include <asm/mmu_context.h> +#include <asm/setup.h> +#include <asm/paravirt.h> +#include <asm/e820/api.h> +#include <asm/linkage.h> +#include <asm/page.h> +#include <asm/init.h> +#include <asm/pat.h> +#include <asm/smp.h> +#include <asm/tlb.h> + +#include <asm/xen/hypercall.h> +#include <asm/xen/hypervisor.h> + +#include <xen/xen.h> +#include <xen/page.h> +#include <xen/interface/xen.h> +#include <xen/interface/hvm/hvm_op.h> +#include <xen/interface/version.h> +#include <xen/interface/memory.h> +#include <xen/hvc-console.h> + +#include "multicalls.h" +#include "mmu.h" +#include "debugfs.h" + +#ifdef CONFIG_X86_32 +/* + * Identity map, in addition to plain kernel map. This needs to be + * large enough to allocate page table pages to allocate the rest. + * Each page can map 2MB. + */ +#define LEVEL1_IDENT_ENTRIES (PTRS_PER_PTE * 4) +static RESERVE_BRK_ARRAY(pte_t, level1_ident_pgt, LEVEL1_IDENT_ENTRIES); +#endif +#ifdef CONFIG_X86_64 +/* l3 pud for userspace vsyscall mapping */ +static pud_t level3_user_vsyscall[PTRS_PER_PUD] __page_aligned_bss; +#endif /* CONFIG_X86_64 */ + +/* + * Note about cr3 (pagetable base) values: + * + * xen_cr3 contains the current logical cr3 value; it contains the + * last set cr3. This may not be the current effective cr3, because + * its update may be being lazily deferred. However, a vcpu looking + * at its own cr3 can use this value knowing that it everything will + * be self-consistent. + * + * xen_current_cr3 contains the actual vcpu cr3; it is set once the + * hypercall to set the vcpu cr3 is complete (so it may be a little + * out of date, but it will never be set early). If one vcpu is + * looking at another vcpu's cr3 value, it should use this variable. + */ +DEFINE_PER_CPU(unsigned long, xen_cr3); /* cr3 stored as physaddr */ +DEFINE_PER_CPU(unsigned long, xen_current_cr3); /* actual vcpu cr3 */ + +static phys_addr_t xen_pt_base, xen_pt_size __initdata; + +static DEFINE_STATIC_KEY_FALSE(xen_struct_pages_ready); + +/* + * Just beyond the highest usermode address. STACK_TOP_MAX has a + * redzone above it, so round it up to a PGD boundary. + */ +#define USER_LIMIT ((STACK_TOP_MAX + PGDIR_SIZE - 1) & PGDIR_MASK) + +void make_lowmem_page_readonly(void *vaddr) +{ + pte_t *pte, ptev; + unsigned long address = (unsigned long)vaddr; + unsigned int level; + + pte = lookup_address(address, &level); + if (pte == NULL) + return; /* vaddr missing */ + + ptev = pte_wrprotect(*pte); + + if (HYPERVISOR_update_va_mapping(address, ptev, 0)) + BUG(); +} + +void make_lowmem_page_readwrite(void *vaddr) +{ + pte_t *pte, ptev; + unsigned long address = (unsigned long)vaddr; + unsigned int level; + + pte = lookup_address(address, &level); + if (pte == NULL) + return; /* vaddr missing */ + + ptev = pte_mkwrite(*pte); + + if (HYPERVISOR_update_va_mapping(address, ptev, 0)) + BUG(); +} + + +/* + * During early boot all page table pages are pinned, but we do not have struct + * pages, so return true until struct pages are ready. + */ +static bool xen_page_pinned(void *ptr) +{ + if (static_branch_likely(&xen_struct_pages_ready)) { + struct page *page = virt_to_page(ptr); + + return PagePinned(page); + } + return true; +} + +static void xen_extend_mmu_update(const struct mmu_update *update) +{ + struct multicall_space mcs; + struct mmu_update *u; + + mcs = xen_mc_extend_args(__HYPERVISOR_mmu_update, sizeof(*u)); + + if (mcs.mc != NULL) { + mcs.mc->args[1]++; + } else { + mcs = __xen_mc_entry(sizeof(*u)); + MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, DOMID_SELF); + } + + u = mcs.args; + *u = *update; +} + +static void xen_extend_mmuext_op(const struct mmuext_op *op) +{ + struct multicall_space mcs; + struct mmuext_op *u; + + mcs = xen_mc_extend_args(__HYPERVISOR_mmuext_op, sizeof(*u)); + + if (mcs.mc != NULL) { + mcs.mc->args[1]++; + } else { + mcs = __xen_mc_entry(sizeof(*u)); + MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF); + } + + u = mcs.args; + *u = *op; +} + +static void xen_set_pmd_hyper(pmd_t *ptr, pmd_t val) +{ + struct mmu_update u; + + preempt_disable(); + + xen_mc_batch(); + + /* ptr may be ioremapped for 64-bit pagetable setup */ + u.ptr = arbitrary_virt_to_machine(ptr).maddr; + u.val = pmd_val_ma(val); + xen_extend_mmu_update(&u); + + xen_mc_issue(PARAVIRT_LAZY_MMU); + + preempt_enable(); +} + +static void xen_set_pmd(pmd_t *ptr, pmd_t val) +{ + trace_xen_mmu_set_pmd(ptr, val); + + /* If page is not pinned, we can just update the entry + directly */ + if (!xen_page_pinned(ptr)) { + *ptr = val; + return; + } + + xen_set_pmd_hyper(ptr, val); +} + +/* + * Associate a virtual page frame with a given physical page frame + * and protection flags for that frame. + */ +void set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags) +{ + set_pte_vaddr(vaddr, mfn_pte(mfn, flags)); +} + +static bool xen_batched_set_pte(pte_t *ptep, pte_t pteval) +{ + struct mmu_update u; + + if (paravirt_get_lazy_mode() != PARAVIRT_LAZY_MMU) + return false; + + xen_mc_batch(); + + u.ptr = virt_to_machine(ptep).maddr | MMU_NORMAL_PT_UPDATE; + u.val = pte_val_ma(pteval); + xen_extend_mmu_update(&u); + + xen_mc_issue(PARAVIRT_LAZY_MMU); + + return true; +} + +static inline void __xen_set_pte(pte_t *ptep, pte_t pteval) +{ + if (!xen_batched_set_pte(ptep, pteval)) { + /* + * Could call native_set_pte() here and trap and + * emulate the PTE write but with 32-bit guests this + * needs two traps (one for each of the two 32-bit + * words in the PTE) so do one hypercall directly + * instead. + */ + struct mmu_update u; + + u.ptr = virt_to_machine(ptep).maddr | MMU_NORMAL_PT_UPDATE; + u.val = pte_val_ma(pteval); + HYPERVISOR_mmu_update(&u, 1, NULL, DOMID_SELF); + } +} + +static void xen_set_pte(pte_t *ptep, pte_t pteval) +{ + trace_xen_mmu_set_pte(ptep, pteval); + __xen_set_pte(ptep, pteval); +} + +static void xen_set_pte_at(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, pte_t pteval) +{ + trace_xen_mmu_set_pte_at(mm, addr, ptep, pteval); + __xen_set_pte(ptep, pteval); +} + +pte_t xen_ptep_modify_prot_start(struct mm_struct *mm, + unsigned long addr, pte_t *ptep) +{ + /* Just return the pte as-is. We preserve the bits on commit */ + trace_xen_mmu_ptep_modify_prot_start(mm, addr, ptep, *ptep); + return *ptep; +} + +void xen_ptep_modify_prot_commit(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, pte_t pte) +{ + struct mmu_update u; + + trace_xen_mmu_ptep_modify_prot_commit(mm, addr, ptep, pte); + xen_mc_batch(); + + u.ptr = virt_to_machine(ptep).maddr | MMU_PT_UPDATE_PRESERVE_AD; + u.val = pte_val_ma(pte); + xen_extend_mmu_update(&u); + + xen_mc_issue(PARAVIRT_LAZY_MMU); +} + +/* Assume pteval_t is equivalent to all the other *val_t types. */ +static pteval_t pte_mfn_to_pfn(pteval_t val) +{ + if (val & _PAGE_PRESENT) { + unsigned long mfn = (val & XEN_PTE_MFN_MASK) >> PAGE_SHIFT; + unsigned long pfn = mfn_to_pfn(mfn); + + pteval_t flags = val & PTE_FLAGS_MASK; + if (unlikely(pfn == ~0)) + val = flags & ~_PAGE_PRESENT; + else + val = ((pteval_t)pfn << PAGE_SHIFT) | flags; + } + + return val; +} + +static pteval_t pte_pfn_to_mfn(pteval_t val) +{ + if (val & _PAGE_PRESENT) { + unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT; + pteval_t flags = val & PTE_FLAGS_MASK; + unsigned long mfn; + + mfn = __pfn_to_mfn(pfn); + + /* + * If there's no mfn for the pfn, then just create an + * empty non-present pte. Unfortunately this loses + * information about the original pfn, so + * pte_mfn_to_pfn is asymmetric. + */ + if (unlikely(mfn == INVALID_P2M_ENTRY)) { + mfn = 0; + flags = 0; + } else + mfn &= ~(FOREIGN_FRAME_BIT | IDENTITY_FRAME_BIT); + val = ((pteval_t)mfn << PAGE_SHIFT) | flags; + } + + return val; +} + +__visible pteval_t xen_pte_val(pte_t pte) +{ + pteval_t pteval = pte.pte; + + return pte_mfn_to_pfn(pteval); +} +PV_CALLEE_SAVE_REGS_THUNK(xen_pte_val); + +__visible pgdval_t xen_pgd_val(pgd_t pgd) +{ + return pte_mfn_to_pfn(pgd.pgd); +} +PV_CALLEE_SAVE_REGS_THUNK(xen_pgd_val); + +__visible pte_t xen_make_pte(pteval_t pte) +{ + pte = pte_pfn_to_mfn(pte); + + return native_make_pte(pte); +} +PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte); + +__visible pgd_t xen_make_pgd(pgdval_t pgd) +{ + pgd = pte_pfn_to_mfn(pgd); + return native_make_pgd(pgd); +} +PV_CALLEE_SAVE_REGS_THUNK(xen_make_pgd); + +__visible pmdval_t xen_pmd_val(pmd_t pmd) +{ + return pte_mfn_to_pfn(pmd.pmd); +} +PV_CALLEE_SAVE_REGS_THUNK(xen_pmd_val); + +static void xen_set_pud_hyper(pud_t *ptr, pud_t val) +{ + struct mmu_update u; + + preempt_disable(); + + xen_mc_batch(); + + /* ptr may be ioremapped for 64-bit pagetable setup */ + u.ptr = arbitrary_virt_to_machine(ptr).maddr; + u.val = pud_val_ma(val); + xen_extend_mmu_update(&u); + + xen_mc_issue(PARAVIRT_LAZY_MMU); + + preempt_enable(); +} + +static void xen_set_pud(pud_t *ptr, pud_t val) +{ + trace_xen_mmu_set_pud(ptr, val); + + /* If page is not pinned, we can just update the entry + directly */ + if (!xen_page_pinned(ptr)) { + *ptr = val; + return; + } + + xen_set_pud_hyper(ptr, val); +} + +#ifdef CONFIG_X86_PAE +static void xen_set_pte_atomic(pte_t *ptep, pte_t pte) +{ + trace_xen_mmu_set_pte_atomic(ptep, pte); + __xen_set_pte(ptep, pte); +} + +static void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) +{ + trace_xen_mmu_pte_clear(mm, addr, ptep); + __xen_set_pte(ptep, native_make_pte(0)); +} + +static void xen_pmd_clear(pmd_t *pmdp) +{ + trace_xen_mmu_pmd_clear(pmdp); + set_pmd(pmdp, __pmd(0)); +} +#endif /* CONFIG_X86_PAE */ + +__visible pmd_t xen_make_pmd(pmdval_t pmd) +{ + pmd = pte_pfn_to_mfn(pmd); + return native_make_pmd(pmd); +} +PV_CALLEE_SAVE_REGS_THUNK(xen_make_pmd); + +#ifdef CONFIG_X86_64 +__visible pudval_t xen_pud_val(pud_t pud) +{ + return pte_mfn_to_pfn(pud.pud); +} +PV_CALLEE_SAVE_REGS_THUNK(xen_pud_val); + +__visible pud_t xen_make_pud(pudval_t pud) +{ + pud = pte_pfn_to_mfn(pud); + + return native_make_pud(pud); +} +PV_CALLEE_SAVE_REGS_THUNK(xen_make_pud); + +static pgd_t *xen_get_user_pgd(pgd_t *pgd) +{ + pgd_t *pgd_page = (pgd_t *)(((unsigned long)pgd) & PAGE_MASK); + unsigned offset = pgd - pgd_page; + pgd_t *user_ptr = NULL; + + if (offset < pgd_index(USER_LIMIT)) { + struct page *page = virt_to_page(pgd_page); + user_ptr = (pgd_t *)page->private; + if (user_ptr) + user_ptr += offset; + } + + return user_ptr; +} + +static void __xen_set_p4d_hyper(p4d_t *ptr, p4d_t val) +{ + struct mmu_update u; + + u.ptr = virt_to_machine(ptr).maddr; + u.val = p4d_val_ma(val); + xen_extend_mmu_update(&u); +} + +/* + * Raw hypercall-based set_p4d, intended for in early boot before + * there's a page structure. This implies: + * 1. The only existing pagetable is the kernel's + * 2. It is always pinned + * 3. It has no user pagetable attached to it + */ +static void __init xen_set_p4d_hyper(p4d_t *ptr, p4d_t val) +{ + preempt_disable(); + + xen_mc_batch(); + + __xen_set_p4d_hyper(ptr, val); + + xen_mc_issue(PARAVIRT_LAZY_MMU); + + preempt_enable(); +} + +static void xen_set_p4d(p4d_t *ptr, p4d_t val) +{ + pgd_t *user_ptr = xen_get_user_pgd((pgd_t *)ptr); + pgd_t pgd_val; + + trace_xen_mmu_set_p4d(ptr, (p4d_t *)user_ptr, val); + + /* If page is not pinned, we can just update the entry + directly */ + if (!xen_page_pinned(ptr)) { + *ptr = val; + if (user_ptr) { + WARN_ON(xen_page_pinned(user_ptr)); + pgd_val.pgd = p4d_val_ma(val); + *user_ptr = pgd_val; + } + return; + } + + /* If it's pinned, then we can at least batch the kernel and + user updates together. */ + xen_mc_batch(); + + __xen_set_p4d_hyper(ptr, val); + if (user_ptr) + __xen_set_p4d_hyper((p4d_t *)user_ptr, val); + + xen_mc_issue(PARAVIRT_LAZY_MMU); +} + +#if CONFIG_PGTABLE_LEVELS >= 5 +__visible p4dval_t xen_p4d_val(p4d_t p4d) +{ + return pte_mfn_to_pfn(p4d.p4d); +} +PV_CALLEE_SAVE_REGS_THUNK(xen_p4d_val); + +__visible p4d_t xen_make_p4d(p4dval_t p4d) +{ + p4d = pte_pfn_to_mfn(p4d); + + return native_make_p4d(p4d); +} +PV_CALLEE_SAVE_REGS_THUNK(xen_make_p4d); +#endif /* CONFIG_PGTABLE_LEVELS >= 5 */ +#endif /* CONFIG_X86_64 */ + +static int xen_pmd_walk(struct mm_struct *mm, pmd_t *pmd, + int (*func)(struct mm_struct *mm, struct page *, enum pt_level), + bool last, unsigned long limit) +{ + int i, nr, flush = 0; + + nr = last ? pmd_index(limit) + 1 : PTRS_PER_PMD; + for (i = 0; i < nr; i++) { + if (!pmd_none(pmd[i])) + flush |= (*func)(mm, pmd_page(pmd[i]), PT_PTE); + } + return flush; +} + +static int xen_pud_walk(struct mm_struct *mm, pud_t *pud, + int (*func)(struct mm_struct *mm, struct page *, enum pt_level), + bool last, unsigned long limit) +{ + int i, nr, flush = 0; + + nr = last ? pud_index(limit) + 1 : PTRS_PER_PUD; + for (i = 0; i < nr; i++) { + pmd_t *pmd; + + if (pud_none(pud[i])) + continue; + + pmd = pmd_offset(&pud[i], 0); + if (PTRS_PER_PMD > 1) + flush |= (*func)(mm, virt_to_page(pmd), PT_PMD); + flush |= xen_pmd_walk(mm, pmd, func, + last && i == nr - 1, limit); + } + return flush; +} + +static int xen_p4d_walk(struct mm_struct *mm, p4d_t *p4d, + int (*func)(struct mm_struct *mm, struct page *, enum pt_level), + bool last, unsigned long limit) +{ + int flush = 0; + pud_t *pud; + + + if (p4d_none(*p4d)) + return flush; + + pud = pud_offset(p4d, 0); + if (PTRS_PER_PUD > 1) + flush |= (*func)(mm, virt_to_page(pud), PT_PUD); + flush |= xen_pud_walk(mm, pud, func, last, limit); + return flush; +} + +/* + * (Yet another) pagetable walker. This one is intended for pinning a + * pagetable. This means that it walks a pagetable and calls the + * callback function on each page it finds making up the page table, + * at every level. It walks the entire pagetable, but it only bothers + * pinning pte pages which are below limit. In the normal case this + * will be STACK_TOP_MAX, but at boot we need to pin up to + * FIXADDR_TOP. + * + * For 32-bit the important bit is that we don't pin beyond there, + * because then we start getting into Xen's ptes. + * + * For 64-bit, we must skip the Xen hole in the middle of the address + * space, just after the big x86-64 virtual hole. + */ +static int __xen_pgd_walk(struct mm_struct *mm, pgd_t *pgd, + int (*func)(struct mm_struct *mm, struct page *, + enum pt_level), + unsigned long limit) +{ + int i, nr, flush = 0; + unsigned hole_low = 0, hole_high = 0; + + /* The limit is the last byte to be touched */ + limit--; + BUG_ON(limit >= FIXADDR_TOP); + +#ifdef CONFIG_X86_64 + /* + * 64-bit has a great big hole in the middle of the address + * space, which contains the Xen mappings. + */ + hole_low = pgd_index(GUARD_HOLE_BASE_ADDR); + hole_high = pgd_index(GUARD_HOLE_END_ADDR); +#endif + + nr = pgd_index(limit) + 1; + for (i = 0; i < nr; i++) { + p4d_t *p4d; + + if (i >= hole_low && i < hole_high) + continue; + + if (pgd_none(pgd[i])) + continue; + + p4d = p4d_offset(&pgd[i], 0); + flush |= xen_p4d_walk(mm, p4d, func, i == nr - 1, limit); + } + + /* Do the top level last, so that the callbacks can use it as + a cue to do final things like tlb flushes. */ + flush |= (*func)(mm, virt_to_page(pgd), PT_PGD); + + return flush; +} + +static int xen_pgd_walk(struct mm_struct *mm, + int (*func)(struct mm_struct *mm, struct page *, + enum pt_level), + unsigned long limit) +{ + return __xen_pgd_walk(mm, mm->pgd, func, limit); +} + +/* If we're using split pte locks, then take the page's lock and + return a pointer to it. Otherwise return NULL. */ +static spinlock_t *xen_pte_lock(struct page *page, struct mm_struct *mm) +{ + spinlock_t *ptl = NULL; + +#if USE_SPLIT_PTE_PTLOCKS + ptl = ptlock_ptr(page); + spin_lock_nest_lock(ptl, &mm->page_table_lock); +#endif + + return ptl; +} + +static void xen_pte_unlock(void *v) +{ + spinlock_t *ptl = v; + spin_unlock(ptl); +} + +static void xen_do_pin(unsigned level, unsigned long pfn) +{ + struct mmuext_op op; + + op.cmd = level; + op.arg1.mfn = pfn_to_mfn(pfn); + + xen_extend_mmuext_op(&op); +} + +static int xen_pin_page(struct mm_struct *mm, struct page *page, + enum pt_level level) +{ + unsigned pgfl = TestSetPagePinned(page); + int flush; + + if (pgfl) + flush = 0; /* already pinned */ + else if (PageHighMem(page)) + /* kmaps need flushing if we found an unpinned + highpage */ + flush = 1; + else { + void *pt = lowmem_page_address(page); + unsigned long pfn = page_to_pfn(page); + struct multicall_space mcs = __xen_mc_entry(0); + spinlock_t *ptl; + + flush = 0; + + /* + * We need to hold the pagetable lock between the time + * we make the pagetable RO and when we actually pin + * it. If we don't, then other users may come in and + * attempt to update the pagetable by writing it, + * which will fail because the memory is RO but not + * pinned, so Xen won't do the trap'n'emulate. + * + * If we're using split pte locks, we can't hold the + * entire pagetable's worth of locks during the + * traverse, because we may wrap the preempt count (8 + * bits). The solution is to mark RO and pin each PTE + * page while holding the lock. This means the number + * of locks we end up holding is never more than a + * batch size (~32 entries, at present). + * + * If we're not using split pte locks, we needn't pin + * the PTE pages independently, because we're + * protected by the overall pagetable lock. + */ + ptl = NULL; + if (level == PT_PTE) + ptl = xen_pte_lock(page, mm); + + MULTI_update_va_mapping(mcs.mc, (unsigned long)pt, + pfn_pte(pfn, PAGE_KERNEL_RO), + level == PT_PGD ? UVMF_TLB_FLUSH : 0); + + if (ptl) { + xen_do_pin(MMUEXT_PIN_L1_TABLE, pfn); + + /* Queue a deferred unlock for when this batch + is completed. */ + xen_mc_callback(xen_pte_unlock, ptl); + } + } + + return flush; +} + +/* This is called just after a mm has been created, but it has not + been used yet. We need to make sure that its pagetable is all + read-only, and can be pinned. */ +static void __xen_pgd_pin(struct mm_struct *mm, pgd_t *pgd) +{ + trace_xen_mmu_pgd_pin(mm, pgd); + + xen_mc_batch(); + + if (__xen_pgd_walk(mm, pgd, xen_pin_page, USER_LIMIT)) { + /* re-enable interrupts for flushing */ + xen_mc_issue(0); + + kmap_flush_unused(); + + xen_mc_batch(); + } + +#ifdef CONFIG_X86_64 + { + pgd_t *user_pgd = xen_get_user_pgd(pgd); + + xen_do_pin(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa(pgd))); + + if (user_pgd) { + xen_pin_page(mm, virt_to_page(user_pgd), PT_PGD); + xen_do_pin(MMUEXT_PIN_L4_TABLE, + PFN_DOWN(__pa(user_pgd))); + } + } +#else /* CONFIG_X86_32 */ +#ifdef CONFIG_X86_PAE + /* Need to make sure unshared kernel PMD is pinnable */ + xen_pin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]), + PT_PMD); +#endif + xen_do_pin(MMUEXT_PIN_L3_TABLE, PFN_DOWN(__pa(pgd))); +#endif /* CONFIG_X86_64 */ + xen_mc_issue(0); +} + +static void xen_pgd_pin(struct mm_struct *mm) +{ + __xen_pgd_pin(mm, mm->pgd); +} + +/* + * On save, we need to pin all pagetables to make sure they get their + * mfns turned into pfns. Search the list for any unpinned pgds and pin + * them (unpinned pgds are not currently in use, probably because the + * process is under construction or destruction). + * + * Expected to be called in stop_machine() ("equivalent to taking + * every spinlock in the system"), so the locking doesn't really + * matter all that much. + */ +void xen_mm_pin_all(void) +{ + struct page *page; + + spin_lock(&pgd_lock); + + list_for_each_entry(page, &pgd_list, lru) { + if (!PagePinned(page)) { + __xen_pgd_pin(&init_mm, (pgd_t *)page_address(page)); + SetPageSavePinned(page); + } + } + + spin_unlock(&pgd_lock); +} + +static int __init xen_mark_pinned(struct mm_struct *mm, struct page *page, + enum pt_level level) +{ + SetPagePinned(page); + return 0; +} + +/* + * The init_mm pagetable is really pinned as soon as its created, but + * that's before we have page structures to store the bits. So do all + * the book-keeping now once struct pages for allocated pages are + * initialized. This happens only after free_all_bootmem() is called. + */ +static void __init xen_after_bootmem(void) +{ + static_branch_enable(&xen_struct_pages_ready); +#ifdef CONFIG_X86_64 + SetPagePinned(virt_to_page(level3_user_vsyscall)); +#endif + xen_pgd_walk(&init_mm, xen_mark_pinned, FIXADDR_TOP); +} + +static int xen_unpin_page(struct mm_struct *mm, struct page *page, + enum pt_level level) +{ + unsigned pgfl = TestClearPagePinned(page); + + if (pgfl && !PageHighMem(page)) { + void *pt = lowmem_page_address(page); + unsigned long pfn = page_to_pfn(page); + spinlock_t *ptl = NULL; + struct multicall_space mcs; + + /* + * Do the converse to pin_page. If we're using split + * pte locks, we must be holding the lock for while + * the pte page is unpinned but still RO to prevent + * concurrent updates from seeing it in this + * partially-pinned state. + */ + if (level == PT_PTE) { + ptl = xen_pte_lock(page, mm); + + if (ptl) + xen_do_pin(MMUEXT_UNPIN_TABLE, pfn); + } + + mcs = __xen_mc_entry(0); + + MULTI_update_va_mapping(mcs.mc, (unsigned long)pt, + pfn_pte(pfn, PAGE_KERNEL), + level == PT_PGD ? UVMF_TLB_FLUSH : 0); + + if (ptl) { + /* unlock when batch completed */ + xen_mc_callback(xen_pte_unlock, ptl); + } + } + + return 0; /* never need to flush on unpin */ +} + +/* Release a pagetables pages back as normal RW */ +static void __xen_pgd_unpin(struct mm_struct *mm, pgd_t *pgd) +{ + trace_xen_mmu_pgd_unpin(mm, pgd); + + xen_mc_batch(); + + xen_do_pin(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd))); + +#ifdef CONFIG_X86_64 + { + pgd_t *user_pgd = xen_get_user_pgd(pgd); + + if (user_pgd) { + xen_do_pin(MMUEXT_UNPIN_TABLE, + PFN_DOWN(__pa(user_pgd))); + xen_unpin_page(mm, virt_to_page(user_pgd), PT_PGD); + } + } +#endif + +#ifdef CONFIG_X86_PAE + /* Need to make sure unshared kernel PMD is unpinned */ + xen_unpin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]), + PT_PMD); +#endif + + __xen_pgd_walk(mm, pgd, xen_unpin_page, USER_LIMIT); + + xen_mc_issue(0); +} + +static void xen_pgd_unpin(struct mm_struct *mm) +{ + __xen_pgd_unpin(mm, mm->pgd); +} + +/* + * On resume, undo any pinning done at save, so that the rest of the + * kernel doesn't see any unexpected pinned pagetables. + */ +void xen_mm_unpin_all(void) +{ + struct page *page; + + spin_lock(&pgd_lock); + + list_for_each_entry(page, &pgd_list, lru) { + if (PageSavePinned(page)) { + BUG_ON(!PagePinned(page)); + __xen_pgd_unpin(&init_mm, (pgd_t *)page_address(page)); + ClearPageSavePinned(page); + } + } + + spin_unlock(&pgd_lock); +} + +static void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next) +{ + spin_lock(&next->page_table_lock); + xen_pgd_pin(next); + spin_unlock(&next->page_table_lock); +} + +static void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm) +{ + spin_lock(&mm->page_table_lock); + xen_pgd_pin(mm); + spin_unlock(&mm->page_table_lock); +} + +static void drop_mm_ref_this_cpu(void *info) +{ + struct mm_struct *mm = info; + + if (this_cpu_read(cpu_tlbstate.loaded_mm) == mm) + leave_mm(smp_processor_id()); + + /* + * If this cpu still has a stale cr3 reference, then make sure + * it has been flushed. + */ + if (this_cpu_read(xen_current_cr3) == __pa(mm->pgd)) + xen_mc_flush(); +} + +#ifdef CONFIG_SMP +/* + * Another cpu may still have their %cr3 pointing at the pagetable, so + * we need to repoint it somewhere else before we can unpin it. + */ +static void xen_drop_mm_ref(struct mm_struct *mm) +{ + cpumask_var_t mask; + unsigned cpu; + + drop_mm_ref_this_cpu(mm); + + /* Get the "official" set of cpus referring to our pagetable. */ + if (!alloc_cpumask_var(&mask, GFP_ATOMIC)) { + for_each_online_cpu(cpu) { + if (per_cpu(xen_current_cr3, cpu) != __pa(mm->pgd)) + continue; + smp_call_function_single(cpu, drop_mm_ref_this_cpu, mm, 1); + } + return; + } + + /* + * It's possible that a vcpu may have a stale reference to our + * cr3, because its in lazy mode, and it hasn't yet flushed + * its set of pending hypercalls yet. In this case, we can + * look at its actual current cr3 value, and force it to flush + * if needed. + */ + cpumask_clear(mask); + for_each_online_cpu(cpu) { + if (per_cpu(xen_current_cr3, cpu) == __pa(mm->pgd)) + cpumask_set_cpu(cpu, mask); + } + + smp_call_function_many(mask, drop_mm_ref_this_cpu, mm, 1); + free_cpumask_var(mask); +} +#else +static void xen_drop_mm_ref(struct mm_struct *mm) +{ + drop_mm_ref_this_cpu(mm); +} +#endif + +/* + * While a process runs, Xen pins its pagetables, which means that the + * hypervisor forces it to be read-only, and it controls all updates + * to it. This means that all pagetable updates have to go via the + * hypervisor, which is moderately expensive. + * + * Since we're pulling the pagetable down, we switch to use init_mm, + * unpin old process pagetable and mark it all read-write, which + * allows further operations on it to be simple memory accesses. + * + * The only subtle point is that another CPU may be still using the + * pagetable because of lazy tlb flushing. This means we need need to + * switch all CPUs off this pagetable before we can unpin it. + */ +static void xen_exit_mmap(struct mm_struct *mm) +{ + get_cpu(); /* make sure we don't move around */ + xen_drop_mm_ref(mm); + put_cpu(); + + spin_lock(&mm->page_table_lock); + + /* pgd may not be pinned in the error exit path of execve */ + if (xen_page_pinned(mm->pgd)) + xen_pgd_unpin(mm); + + spin_unlock(&mm->page_table_lock); +} + +static void xen_post_allocator_init(void); + +static void __init pin_pagetable_pfn(unsigned cmd, unsigned long pfn) +{ + struct mmuext_op op; + + op.cmd = cmd; + op.arg1.mfn = pfn_to_mfn(pfn); + if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF)) + BUG(); +} + +#ifdef CONFIG_X86_64 +static void __init xen_cleanhighmap(unsigned long vaddr, + unsigned long vaddr_end) +{ + unsigned long kernel_end = roundup((unsigned long)_brk_end, PMD_SIZE) - 1; + pmd_t *pmd = level2_kernel_pgt + pmd_index(vaddr); + + /* NOTE: The loop is more greedy than the cleanup_highmap variant. + * We include the PMD passed in on _both_ boundaries. */ + for (; vaddr <= vaddr_end && (pmd < (level2_kernel_pgt + PTRS_PER_PMD)); + pmd++, vaddr += PMD_SIZE) { + if (pmd_none(*pmd)) + continue; + if (vaddr < (unsigned long) _text || vaddr > kernel_end) + set_pmd(pmd, __pmd(0)); + } + /* In case we did something silly, we should crash in this function + * instead of somewhere later and be confusing. */ + xen_mc_flush(); +} + +/* + * Make a page range writeable and free it. + */ +static void __init xen_free_ro_pages(unsigned long paddr, unsigned long size) +{ + void *vaddr = __va(paddr); + void *vaddr_end = vaddr + size; + + for (; vaddr < vaddr_end; vaddr += PAGE_SIZE) + make_lowmem_page_readwrite(vaddr); + + memblock_free(paddr, size); +} + +static void __init xen_cleanmfnmap_free_pgtbl(void *pgtbl, bool unpin) +{ + unsigned long pa = __pa(pgtbl) & PHYSICAL_PAGE_MASK; + + if (unpin) + pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(pa)); + ClearPagePinned(virt_to_page(__va(pa))); + xen_free_ro_pages(pa, PAGE_SIZE); +} + +static void __init xen_cleanmfnmap_pmd(pmd_t *pmd, bool unpin) +{ + unsigned long pa; + pte_t *pte_tbl; + int i; + + if (pmd_large(*pmd)) { + pa = pmd_val(*pmd) & PHYSICAL_PAGE_MASK; + xen_free_ro_pages(pa, PMD_SIZE); + return; + } + + pte_tbl = pte_offset_kernel(pmd, 0); + for (i = 0; i < PTRS_PER_PTE; i++) { + if (pte_none(pte_tbl[i])) + continue; + pa = pte_pfn(pte_tbl[i]) << PAGE_SHIFT; + xen_free_ro_pages(pa, PAGE_SIZE); + } + set_pmd(pmd, __pmd(0)); + xen_cleanmfnmap_free_pgtbl(pte_tbl, unpin); +} + +static void __init xen_cleanmfnmap_pud(pud_t *pud, bool unpin) +{ + unsigned long pa; + pmd_t *pmd_tbl; + int i; + + if (pud_large(*pud)) { + pa = pud_val(*pud) & PHYSICAL_PAGE_MASK; + xen_free_ro_pages(pa, PUD_SIZE); + return; + } + + pmd_tbl = pmd_offset(pud, 0); + for (i = 0; i < PTRS_PER_PMD; i++) { + if (pmd_none(pmd_tbl[i])) + continue; + xen_cleanmfnmap_pmd(pmd_tbl + i, unpin); + } + set_pud(pud, __pud(0)); + xen_cleanmfnmap_free_pgtbl(pmd_tbl, unpin); +} + +static void __init xen_cleanmfnmap_p4d(p4d_t *p4d, bool unpin) +{ + unsigned long pa; + pud_t *pud_tbl; + int i; + + if (p4d_large(*p4d)) { + pa = p4d_val(*p4d) & PHYSICAL_PAGE_MASK; + xen_free_ro_pages(pa, P4D_SIZE); + return; + } + + pud_tbl = pud_offset(p4d, 0); + for (i = 0; i < PTRS_PER_PUD; i++) { + if (pud_none(pud_tbl[i])) + continue; + xen_cleanmfnmap_pud(pud_tbl + i, unpin); + } + set_p4d(p4d, __p4d(0)); + xen_cleanmfnmap_free_pgtbl(pud_tbl, unpin); +} + +/* + * Since it is well isolated we can (and since it is perhaps large we should) + * also free the page tables mapping the initial P->M table. + */ +static void __init xen_cleanmfnmap(unsigned long vaddr) +{ + pgd_t *pgd; + p4d_t *p4d; + bool unpin; + + unpin = (vaddr == 2 * PGDIR_SIZE); + vaddr &= PMD_MASK; + pgd = pgd_offset_k(vaddr); + p4d = p4d_offset(pgd, 0); + if (!p4d_none(*p4d)) + xen_cleanmfnmap_p4d(p4d, unpin); +} + +static void __init xen_pagetable_p2m_free(void) +{ + unsigned long size; + unsigned long addr; + + size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long)); + + /* No memory or already called. */ + if ((unsigned long)xen_p2m_addr == xen_start_info->mfn_list) + return; + + /* using __ka address and sticking INVALID_P2M_ENTRY! */ + memset((void *)xen_start_info->mfn_list, 0xff, size); + + addr = xen_start_info->mfn_list; + /* + * We could be in __ka space. + * We roundup to the PMD, which means that if anybody at this stage is + * using the __ka address of xen_start_info or + * xen_start_info->shared_info they are in going to crash. Fortunatly + * we have already revectored in xen_setup_kernel_pagetable. + */ + size = roundup(size, PMD_SIZE); + + if (addr >= __START_KERNEL_map) { + xen_cleanhighmap(addr, addr + size); + size = PAGE_ALIGN(xen_start_info->nr_pages * + sizeof(unsigned long)); + memblock_free(__pa(addr), size); + } else { + xen_cleanmfnmap(addr); + } +} + +static void __init xen_pagetable_cleanhighmap(void) +{ + unsigned long size; + unsigned long addr; + + /* At this stage, cleanup_highmap has already cleaned __ka space + * from _brk_limit way up to the max_pfn_mapped (which is the end of + * the ramdisk). We continue on, erasing PMD entries that point to page + * tables - do note that they are accessible at this stage via __va. + * As Xen is aligning the memory end to a 4MB boundary, for good + * measure we also round up to PMD_SIZE * 2 - which means that if + * anybody is using __ka address to the initial boot-stack - and try + * to use it - they are going to crash. The xen_start_info has been + * taken care of already in xen_setup_kernel_pagetable. */ + addr = xen_start_info->pt_base; + size = xen_start_info->nr_pt_frames * PAGE_SIZE; + + xen_cleanhighmap(addr, roundup(addr + size, PMD_SIZE * 2)); + xen_start_info->pt_base = (unsigned long)__va(__pa(xen_start_info->pt_base)); +} +#endif + +static void __init xen_pagetable_p2m_setup(void) +{ + xen_vmalloc_p2m_tree(); + +#ifdef CONFIG_X86_64 + xen_pagetable_p2m_free(); + + xen_pagetable_cleanhighmap(); +#endif + /* And revector! Bye bye old array */ + xen_start_info->mfn_list = (unsigned long)xen_p2m_addr; +} + +static void __init xen_pagetable_init(void) +{ + paging_init(); + xen_post_allocator_init(); + + xen_pagetable_p2m_setup(); + + /* Allocate and initialize top and mid mfn levels for p2m structure */ + xen_build_mfn_list_list(); + + /* Remap memory freed due to conflicts with E820 map */ + xen_remap_memory(); + xen_setup_mfn_list_list(); +} +static void xen_write_cr2(unsigned long cr2) +{ + this_cpu_read(xen_vcpu)->arch.cr2 = cr2; +} + +static unsigned long xen_read_cr2(void) +{ + return this_cpu_read(xen_vcpu)->arch.cr2; +} + +unsigned long xen_read_cr2_direct(void) +{ + return this_cpu_read(xen_vcpu_info.arch.cr2); +} + +static noinline void xen_flush_tlb(void) +{ + struct mmuext_op *op; + struct multicall_space mcs; + + preempt_disable(); + + mcs = xen_mc_entry(sizeof(*op)); + + op = mcs.args; + op->cmd = MMUEXT_TLB_FLUSH_LOCAL; + MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); + + xen_mc_issue(PARAVIRT_LAZY_MMU); + + preempt_enable(); +} + +static void xen_flush_tlb_one_user(unsigned long addr) +{ + struct mmuext_op *op; + struct multicall_space mcs; + + trace_xen_mmu_flush_tlb_one_user(addr); + + preempt_disable(); + + mcs = xen_mc_entry(sizeof(*op)); + op = mcs.args; + op->cmd = MMUEXT_INVLPG_LOCAL; + op->arg1.linear_addr = addr & PAGE_MASK; + MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); + + xen_mc_issue(PARAVIRT_LAZY_MMU); + + preempt_enable(); +} + +static void xen_flush_tlb_others(const struct cpumask *cpus, + const struct flush_tlb_info *info) +{ + struct { + struct mmuext_op op; + DECLARE_BITMAP(mask, NR_CPUS); + } *args; + struct multicall_space mcs; + const size_t mc_entry_size = sizeof(args->op) + + sizeof(args->mask[0]) * BITS_TO_LONGS(num_possible_cpus()); + + trace_xen_mmu_flush_tlb_others(cpus, info->mm, info->start, info->end); + + if (cpumask_empty(cpus)) + return; /* nothing to do */ + + mcs = xen_mc_entry(mc_entry_size); + args = mcs.args; + args->op.arg2.vcpumask = to_cpumask(args->mask); + + /* Remove us, and any offline CPUS. */ + cpumask_and(to_cpumask(args->mask), cpus, cpu_online_mask); + cpumask_clear_cpu(smp_processor_id(), to_cpumask(args->mask)); + + args->op.cmd = MMUEXT_TLB_FLUSH_MULTI; + if (info->end != TLB_FLUSH_ALL && + (info->end - info->start) <= PAGE_SIZE) { + args->op.cmd = MMUEXT_INVLPG_MULTI; + args->op.arg1.linear_addr = info->start; + } + + MULTI_mmuext_op(mcs.mc, &args->op, 1, NULL, DOMID_SELF); + + xen_mc_issue(PARAVIRT_LAZY_MMU); +} + +static unsigned long xen_read_cr3(void) +{ + return this_cpu_read(xen_cr3); +} + +static void set_current_cr3(void *v) +{ + this_cpu_write(xen_current_cr3, (unsigned long)v); +} + +static void __xen_write_cr3(bool kernel, unsigned long cr3) +{ + struct mmuext_op op; + unsigned long mfn; + + trace_xen_mmu_write_cr3(kernel, cr3); + + if (cr3) + mfn = pfn_to_mfn(PFN_DOWN(cr3)); + else + mfn = 0; + + WARN_ON(mfn == 0 && kernel); + + op.cmd = kernel ? MMUEXT_NEW_BASEPTR : MMUEXT_NEW_USER_BASEPTR; + op.arg1.mfn = mfn; + + xen_extend_mmuext_op(&op); + + if (kernel) { + this_cpu_write(xen_cr3, cr3); + + /* Update xen_current_cr3 once the batch has actually + been submitted. */ + xen_mc_callback(set_current_cr3, (void *)cr3); + } +} +static void xen_write_cr3(unsigned long cr3) +{ + BUG_ON(preemptible()); + + xen_mc_batch(); /* disables interrupts */ + + /* Update while interrupts are disabled, so its atomic with + respect to ipis */ + this_cpu_write(xen_cr3, cr3); + + __xen_write_cr3(true, cr3); + +#ifdef CONFIG_X86_64 + { + pgd_t *user_pgd = xen_get_user_pgd(__va(cr3)); + if (user_pgd) + __xen_write_cr3(false, __pa(user_pgd)); + else + __xen_write_cr3(false, 0); + } +#endif + + xen_mc_issue(PARAVIRT_LAZY_CPU); /* interrupts restored */ +} + +#ifdef CONFIG_X86_64 +/* + * At the start of the day - when Xen launches a guest, it has already + * built pagetables for the guest. We diligently look over them + * in xen_setup_kernel_pagetable and graft as appropriate them in the + * init_top_pgt and its friends. Then when we are happy we load + * the new init_top_pgt - and continue on. + * + * The generic code starts (start_kernel) and 'init_mem_mapping' sets + * up the rest of the pagetables. When it has completed it loads the cr3. + * N.B. that baremetal would start at 'start_kernel' (and the early + * #PF handler would create bootstrap pagetables) - so we are running + * with the same assumptions as what to do when write_cr3 is executed + * at this point. + * + * Since there are no user-page tables at all, we have two variants + * of xen_write_cr3 - the early bootup (this one), and the late one + * (xen_write_cr3). The reason we have to do that is that in 64-bit + * the Linux kernel and user-space are both in ring 3 while the + * hypervisor is in ring 0. + */ +static void __init xen_write_cr3_init(unsigned long cr3) +{ + BUG_ON(preemptible()); + + xen_mc_batch(); /* disables interrupts */ + + /* Update while interrupts are disabled, so its atomic with + respect to ipis */ + this_cpu_write(xen_cr3, cr3); + + __xen_write_cr3(true, cr3); + + xen_mc_issue(PARAVIRT_LAZY_CPU); /* interrupts restored */ +} +#endif + +static int xen_pgd_alloc(struct mm_struct *mm) +{ + pgd_t *pgd = mm->pgd; + int ret = 0; + + BUG_ON(PagePinned(virt_to_page(pgd))); + +#ifdef CONFIG_X86_64 + { + struct page *page = virt_to_page(pgd); + pgd_t *user_pgd; + + BUG_ON(page->private != 0); + + ret = -ENOMEM; + + user_pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO); + page->private = (unsigned long)user_pgd; + + if (user_pgd != NULL) { +#ifdef CONFIG_X86_VSYSCALL_EMULATION + user_pgd[pgd_index(VSYSCALL_ADDR)] = + __pgd(__pa(level3_user_vsyscall) | _PAGE_TABLE); +#endif + ret = 0; + } + + BUG_ON(PagePinned(virt_to_page(xen_get_user_pgd(pgd)))); + } +#endif + return ret; +} + +static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd) +{ +#ifdef CONFIG_X86_64 + pgd_t *user_pgd = xen_get_user_pgd(pgd); + + if (user_pgd) + free_page((unsigned long)user_pgd); +#endif +} + +/* + * Init-time set_pte while constructing initial pagetables, which + * doesn't allow RO page table pages to be remapped RW. + * + * If there is no MFN for this PFN then this page is initially + * ballooned out so clear the PTE (as in decrease_reservation() in + * drivers/xen/balloon.c). + * + * Many of these PTE updates are done on unpinned and writable pages + * and doing a hypercall for these is unnecessary and expensive. At + * this point it is not possible to tell if a page is pinned or not, + * so always write the PTE directly and rely on Xen trapping and + * emulating any updates as necessary. + */ +__visible pte_t xen_make_pte_init(pteval_t pte) +{ +#ifdef CONFIG_X86_64 + unsigned long pfn; + + /* + * Pages belonging to the initial p2m list mapped outside the default + * address range must be mapped read-only. This region contains the + * page tables for mapping the p2m list, too, and page tables MUST be + * mapped read-only. + */ + pfn = (pte & PTE_PFN_MASK) >> PAGE_SHIFT; + if (xen_start_info->mfn_list < __START_KERNEL_map && + pfn >= xen_start_info->first_p2m_pfn && + pfn < xen_start_info->first_p2m_pfn + xen_start_info->nr_p2m_frames) + pte &= ~_PAGE_RW; +#endif + pte = pte_pfn_to_mfn(pte); + return native_make_pte(pte); +} +PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte_init); + +static void __init xen_set_pte_init(pte_t *ptep, pte_t pte) +{ +#ifdef CONFIG_X86_32 + /* If there's an existing pte, then don't allow _PAGE_RW to be set */ + if (pte_mfn(pte) != INVALID_P2M_ENTRY + && pte_val_ma(*ptep) & _PAGE_PRESENT) + pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) & + pte_val_ma(pte)); +#endif + __xen_set_pte(ptep, pte); +} + +/* Early in boot, while setting up the initial pagetable, assume + everything is pinned. */ +static void __init xen_alloc_pte_init(struct mm_struct *mm, unsigned long pfn) +{ +#ifdef CONFIG_FLATMEM + BUG_ON(mem_map); /* should only be used early */ +#endif + make_lowmem_page_readonly(__va(PFN_PHYS(pfn))); + pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn); +} + +/* Used for pmd and pud */ +static void __init xen_alloc_pmd_init(struct mm_struct *mm, unsigned long pfn) +{ +#ifdef CONFIG_FLATMEM + BUG_ON(mem_map); /* should only be used early */ +#endif + make_lowmem_page_readonly(__va(PFN_PHYS(pfn))); +} + +/* Early release_pte assumes that all pts are pinned, since there's + only init_mm and anything attached to that is pinned. */ +static void __init xen_release_pte_init(unsigned long pfn) +{ + pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn); + make_lowmem_page_readwrite(__va(PFN_PHYS(pfn))); +} + +static void __init xen_release_pmd_init(unsigned long pfn) +{ + make_lowmem_page_readwrite(__va(PFN_PHYS(pfn))); +} + +static inline void __pin_pagetable_pfn(unsigned cmd, unsigned long pfn) +{ + struct multicall_space mcs; + struct mmuext_op *op; + + mcs = __xen_mc_entry(sizeof(*op)); + op = mcs.args; + op->cmd = cmd; + op->arg1.mfn = pfn_to_mfn(pfn); + + MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF); +} + +static inline void __set_pfn_prot(unsigned long pfn, pgprot_t prot) +{ + struct multicall_space mcs; + unsigned long addr = (unsigned long)__va(pfn << PAGE_SHIFT); + + mcs = __xen_mc_entry(0); + MULTI_update_va_mapping(mcs.mc, (unsigned long)addr, + pfn_pte(pfn, prot), 0); +} + +/* This needs to make sure the new pte page is pinned iff its being + attached to a pinned pagetable. */ +static inline void xen_alloc_ptpage(struct mm_struct *mm, unsigned long pfn, + unsigned level) +{ + bool pinned = xen_page_pinned(mm->pgd); + + trace_xen_mmu_alloc_ptpage(mm, pfn, level, pinned); + + if (pinned) { + struct page *page = pfn_to_page(pfn); + + if (static_branch_likely(&xen_struct_pages_ready)) + SetPagePinned(page); + + if (!PageHighMem(page)) { + xen_mc_batch(); + + __set_pfn_prot(pfn, PAGE_KERNEL_RO); + + if (level == PT_PTE && USE_SPLIT_PTE_PTLOCKS) + __pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn); + + xen_mc_issue(PARAVIRT_LAZY_MMU); + } else { + /* make sure there are no stray mappings of + this page */ + kmap_flush_unused(); + } + } +} + +static void xen_alloc_pte(struct mm_struct *mm, unsigned long pfn) +{ + xen_alloc_ptpage(mm, pfn, PT_PTE); +} + +static void xen_alloc_pmd(struct mm_struct *mm, unsigned long pfn) +{ + xen_alloc_ptpage(mm, pfn, PT_PMD); +} + +/* This should never happen until we're OK to use struct page */ +static inline void xen_release_ptpage(unsigned long pfn, unsigned level) +{ + struct page *page = pfn_to_page(pfn); + bool pinned = PagePinned(page); + + trace_xen_mmu_release_ptpage(pfn, level, pinned); + + if (pinned) { + if (!PageHighMem(page)) { + xen_mc_batch(); + + if (level == PT_PTE && USE_SPLIT_PTE_PTLOCKS) + __pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn); + + __set_pfn_prot(pfn, PAGE_KERNEL); + + xen_mc_issue(PARAVIRT_LAZY_MMU); + } + ClearPagePinned(page); + } +} + +static void xen_release_pte(unsigned long pfn) +{ + xen_release_ptpage(pfn, PT_PTE); +} + +static void xen_release_pmd(unsigned long pfn) +{ + xen_release_ptpage(pfn, PT_PMD); +} + +#ifdef CONFIG_X86_64 +static void xen_alloc_pud(struct mm_struct *mm, unsigned long pfn) +{ + xen_alloc_ptpage(mm, pfn, PT_PUD); +} + +static void xen_release_pud(unsigned long pfn) +{ + xen_release_ptpage(pfn, PT_PUD); +} +#endif + +void __init xen_reserve_top(void) +{ +#ifdef CONFIG_X86_32 + unsigned long top = HYPERVISOR_VIRT_START; + struct xen_platform_parameters pp; + + if (HYPERVISOR_xen_version(XENVER_platform_parameters, &pp) == 0) + top = pp.virt_start; + + reserve_top_address(-top); +#endif /* CONFIG_X86_32 */ +} + +/* + * Like __va(), but returns address in the kernel mapping (which is + * all we have until the physical memory mapping has been set up. + */ +static void * __init __ka(phys_addr_t paddr) +{ +#ifdef CONFIG_X86_64 + return (void *)(paddr + __START_KERNEL_map); +#else + return __va(paddr); +#endif +} + +/* Convert a machine address to physical address */ +static unsigned long __init m2p(phys_addr_t maddr) +{ + phys_addr_t paddr; + + maddr &= XEN_PTE_MFN_MASK; + paddr = mfn_to_pfn(maddr >> PAGE_SHIFT) << PAGE_SHIFT; + + return paddr; +} + +/* Convert a machine address to kernel virtual */ +static void * __init m2v(phys_addr_t maddr) +{ + return __ka(m2p(maddr)); +} + +/* Set the page permissions on an identity-mapped pages */ +static void __init set_page_prot_flags(void *addr, pgprot_t prot, + unsigned long flags) +{ + unsigned long pfn = __pa(addr) >> PAGE_SHIFT; + pte_t pte = pfn_pte(pfn, prot); + + if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, flags)) + BUG(); +} +static void __init set_page_prot(void *addr, pgprot_t prot) +{ + return set_page_prot_flags(addr, prot, UVMF_NONE); +} +#ifdef CONFIG_X86_32 +static void __init xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn) +{ + unsigned pmdidx, pteidx; + unsigned ident_pte; + unsigned long pfn; + + level1_ident_pgt = extend_brk(sizeof(pte_t) * LEVEL1_IDENT_ENTRIES, + PAGE_SIZE); + + ident_pte = 0; + pfn = 0; + for (pmdidx = 0; pmdidx < PTRS_PER_PMD && pfn < max_pfn; pmdidx++) { + pte_t *pte_page; + + /* Reuse or allocate a page of ptes */ + if (pmd_present(pmd[pmdidx])) + pte_page = m2v(pmd[pmdidx].pmd); + else { + /* Check for free pte pages */ + if (ident_pte == LEVEL1_IDENT_ENTRIES) + break; + + pte_page = &level1_ident_pgt[ident_pte]; + ident_pte += PTRS_PER_PTE; + + pmd[pmdidx] = __pmd(__pa(pte_page) | _PAGE_TABLE); + } + + /* Install mappings */ + for (pteidx = 0; pteidx < PTRS_PER_PTE; pteidx++, pfn++) { + pte_t pte; + + if (pfn > max_pfn_mapped) + max_pfn_mapped = pfn; + + if (!pte_none(pte_page[pteidx])) + continue; + + pte = pfn_pte(pfn, PAGE_KERNEL_EXEC); + pte_page[pteidx] = pte; + } + } + + for (pteidx = 0; pteidx < ident_pte; pteidx += PTRS_PER_PTE) + set_page_prot(&level1_ident_pgt[pteidx], PAGE_KERNEL_RO); + + set_page_prot(pmd, PAGE_KERNEL_RO); +} +#endif +void __init xen_setup_machphys_mapping(void) +{ + struct xen_machphys_mapping mapping; + + if (HYPERVISOR_memory_op(XENMEM_machphys_mapping, &mapping) == 0) { + machine_to_phys_mapping = (unsigned long *)mapping.v_start; + machine_to_phys_nr = mapping.max_mfn + 1; + } else { + machine_to_phys_nr = MACH2PHYS_NR_ENTRIES; + } +#ifdef CONFIG_X86_32 + WARN_ON((machine_to_phys_mapping + (machine_to_phys_nr - 1)) + < machine_to_phys_mapping); +#endif +} + +#ifdef CONFIG_X86_64 +static void __init convert_pfn_mfn(void *v) +{ + pte_t *pte = v; + int i; + + /* All levels are converted the same way, so just treat them + as ptes. */ + for (i = 0; i < PTRS_PER_PTE; i++) + pte[i] = xen_make_pte(pte[i].pte); +} +static void __init check_pt_base(unsigned long *pt_base, unsigned long *pt_end, + unsigned long addr) +{ + if (*pt_base == PFN_DOWN(__pa(addr))) { + set_page_prot_flags((void *)addr, PAGE_KERNEL, UVMF_INVLPG); + clear_page((void *)addr); + (*pt_base)++; + } + if (*pt_end == PFN_DOWN(__pa(addr))) { + set_page_prot_flags((void *)addr, PAGE_KERNEL, UVMF_INVLPG); + clear_page((void *)addr); + (*pt_end)--; + } +} +/* + * Set up the initial kernel pagetable. + * + * We can construct this by grafting the Xen provided pagetable into + * head_64.S's preconstructed pagetables. We copy the Xen L2's into + * level2_ident_pgt, and level2_kernel_pgt. This means that only the + * kernel has a physical mapping to start with - but that's enough to + * get __va working. We need to fill in the rest of the physical + * mapping once some sort of allocator has been set up. + */ +void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn) +{ + pud_t *l3; + pmd_t *l2; + unsigned long addr[3]; + unsigned long pt_base, pt_end; + unsigned i; + + /* max_pfn_mapped is the last pfn mapped in the initial memory + * mappings. Considering that on Xen after the kernel mappings we + * have the mappings of some pages that don't exist in pfn space, we + * set max_pfn_mapped to the last real pfn mapped. */ + if (xen_start_info->mfn_list < __START_KERNEL_map) + max_pfn_mapped = xen_start_info->first_p2m_pfn; + else + max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list)); + + pt_base = PFN_DOWN(__pa(xen_start_info->pt_base)); + pt_end = pt_base + xen_start_info->nr_pt_frames; + + /* Zap identity mapping */ + init_top_pgt[0] = __pgd(0); + + /* Pre-constructed entries are in pfn, so convert to mfn */ + /* L4[273] -> level3_ident_pgt */ + /* L4[511] -> level3_kernel_pgt */ + convert_pfn_mfn(init_top_pgt); + + /* L3_i[0] -> level2_ident_pgt */ + convert_pfn_mfn(level3_ident_pgt); + /* L3_k[510] -> level2_kernel_pgt */ + /* L3_k[511] -> level2_fixmap_pgt */ + convert_pfn_mfn(level3_kernel_pgt); + + /* L3_k[511][508-FIXMAP_PMD_NUM ... 507] -> level1_fixmap_pgt */ + convert_pfn_mfn(level2_fixmap_pgt); + + /* We get [511][511] and have Xen's version of level2_kernel_pgt */ + l3 = m2v(pgd[pgd_index(__START_KERNEL_map)].pgd); + l2 = m2v(l3[pud_index(__START_KERNEL_map)].pud); + + addr[0] = (unsigned long)pgd; + addr[1] = (unsigned long)l3; + addr[2] = (unsigned long)l2; + /* Graft it onto L4[273][0]. Note that we creating an aliasing problem: + * Both L4[273][0] and L4[511][510] have entries that point to the same + * L2 (PMD) tables. Meaning that if you modify it in __va space + * it will be also modified in the __ka space! (But if you just + * modify the PMD table to point to other PTE's or none, then you + * are OK - which is what cleanup_highmap does) */ + copy_page(level2_ident_pgt, l2); + /* Graft it onto L4[511][510] */ + copy_page(level2_kernel_pgt, l2); + + /* + * Zap execute permission from the ident map. Due to the sharing of + * L1 entries we need to do this in the L2. + */ + if (__supported_pte_mask & _PAGE_NX) { + for (i = 0; i < PTRS_PER_PMD; ++i) { + if (pmd_none(level2_ident_pgt[i])) + continue; + level2_ident_pgt[i] = pmd_set_flags(level2_ident_pgt[i], _PAGE_NX); + } + } + + /* Copy the initial P->M table mappings if necessary. */ + i = pgd_index(xen_start_info->mfn_list); + if (i && i < pgd_index(__START_KERNEL_map)) + init_top_pgt[i] = ((pgd_t *)xen_start_info->pt_base)[i]; + + /* Make pagetable pieces RO */ + set_page_prot(init_top_pgt, PAGE_KERNEL_RO); + set_page_prot(level3_ident_pgt, PAGE_KERNEL_RO); + set_page_prot(level3_kernel_pgt, PAGE_KERNEL_RO); + set_page_prot(level3_user_vsyscall, PAGE_KERNEL_RO); + set_page_prot(level2_ident_pgt, PAGE_KERNEL_RO); + set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO); + set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO); + + for (i = 0; i < FIXMAP_PMD_NUM; i++) { + set_page_prot(level1_fixmap_pgt + i * PTRS_PER_PTE, + PAGE_KERNEL_RO); + } + + /* Pin down new L4 */ + pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE, + PFN_DOWN(__pa_symbol(init_top_pgt))); + + /* Unpin Xen-provided one */ + pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd))); + + /* + * At this stage there can be no user pgd, and no page structure to + * attach it to, so make sure we just set kernel pgd. + */ + xen_mc_batch(); + __xen_write_cr3(true, __pa(init_top_pgt)); + xen_mc_issue(PARAVIRT_LAZY_CPU); + + /* We can't that easily rip out L3 and L2, as the Xen pagetables are + * set out this way: [L4], [L1], [L2], [L3], [L1], [L1] ... for + * the initial domain. For guests using the toolstack, they are in: + * [L4], [L3], [L2], [L1], [L1], order .. So for dom0 we can only + * rip out the [L4] (pgd), but for guests we shave off three pages. + */ + for (i = 0; i < ARRAY_SIZE(addr); i++) + check_pt_base(&pt_base, &pt_end, addr[i]); + + /* Our (by three pages) smaller Xen pagetable that we are using */ + xen_pt_base = PFN_PHYS(pt_base); + xen_pt_size = (pt_end - pt_base) * PAGE_SIZE; + memblock_reserve(xen_pt_base, xen_pt_size); + + /* Revector the xen_start_info */ + xen_start_info = (struct start_info *)__va(__pa(xen_start_info)); +} + +/* + * Read a value from a physical address. + */ +static unsigned long __init xen_read_phys_ulong(phys_addr_t addr) +{ + unsigned long *vaddr; + unsigned long val; + + vaddr = early_memremap_ro(addr, sizeof(val)); + val = *vaddr; + early_memunmap(vaddr, sizeof(val)); + return val; +} + +/* + * Translate a virtual address to a physical one without relying on mapped + * page tables. Don't rely on big pages being aligned in (guest) physical + * space! + */ +static phys_addr_t __init xen_early_virt_to_phys(unsigned long vaddr) +{ + phys_addr_t pa; + pgd_t pgd; + pud_t pud; + pmd_t pmd; + pte_t pte; + + pa = read_cr3_pa(); + pgd = native_make_pgd(xen_read_phys_ulong(pa + pgd_index(vaddr) * + sizeof(pgd))); + if (!pgd_present(pgd)) + return 0; + + pa = pgd_val(pgd) & PTE_PFN_MASK; + pud = native_make_pud(xen_read_phys_ulong(pa + pud_index(vaddr) * + sizeof(pud))); + if (!pud_present(pud)) + return 0; + pa = pud_val(pud) & PTE_PFN_MASK; + if (pud_large(pud)) + return pa + (vaddr & ~PUD_MASK); + + pmd = native_make_pmd(xen_read_phys_ulong(pa + pmd_index(vaddr) * + sizeof(pmd))); + if (!pmd_present(pmd)) + return 0; + pa = pmd_val(pmd) & PTE_PFN_MASK; + if (pmd_large(pmd)) + return pa + (vaddr & ~PMD_MASK); + + pte = native_make_pte(xen_read_phys_ulong(pa + pte_index(vaddr) * + sizeof(pte))); + if (!pte_present(pte)) + return 0; + pa = pte_pfn(pte) << PAGE_SHIFT; + + return pa | (vaddr & ~PAGE_MASK); +} + +/* + * Find a new area for the hypervisor supplied p2m list and relocate the p2m to + * this area. + */ +void __init xen_relocate_p2m(void) +{ + phys_addr_t size, new_area, pt_phys, pmd_phys, pud_phys; + unsigned long p2m_pfn, p2m_pfn_end, n_frames, pfn, pfn_end; + int n_pte, n_pt, n_pmd, n_pud, idx_pte, idx_pt, idx_pmd, idx_pud; + pte_t *pt; + pmd_t *pmd; + pud_t *pud; + pgd_t *pgd; + unsigned long *new_p2m; + + size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long)); + n_pte = roundup(size, PAGE_SIZE) >> PAGE_SHIFT; + n_pt = roundup(size, PMD_SIZE) >> PMD_SHIFT; + n_pmd = roundup(size, PUD_SIZE) >> PUD_SHIFT; + n_pud = roundup(size, P4D_SIZE) >> P4D_SHIFT; + n_frames = n_pte + n_pt + n_pmd + n_pud; + + new_area = xen_find_free_area(PFN_PHYS(n_frames)); + if (!new_area) { + xen_raw_console_write("Can't find new memory area for p2m needed due to E820 map conflict\n"); + BUG(); + } + + /* + * Setup the page tables for addressing the new p2m list. + * We have asked the hypervisor to map the p2m list at the user address + * PUD_SIZE. It may have done so, or it may have used a kernel space + * address depending on the Xen version. + * To avoid any possible virtual address collision, just use + * 2 * PUD_SIZE for the new area. + */ + pud_phys = new_area; + pmd_phys = pud_phys + PFN_PHYS(n_pud); + pt_phys = pmd_phys + PFN_PHYS(n_pmd); + p2m_pfn = PFN_DOWN(pt_phys) + n_pt; + + pgd = __va(read_cr3_pa()); + new_p2m = (unsigned long *)(2 * PGDIR_SIZE); + for (idx_pud = 0; idx_pud < n_pud; idx_pud++) { + pud = early_memremap(pud_phys, PAGE_SIZE); + clear_page(pud); + for (idx_pmd = 0; idx_pmd < min(n_pmd, PTRS_PER_PUD); + idx_pmd++) { + pmd = early_memremap(pmd_phys, PAGE_SIZE); + clear_page(pmd); + for (idx_pt = 0; idx_pt < min(n_pt, PTRS_PER_PMD); + idx_pt++) { + pt = early_memremap(pt_phys, PAGE_SIZE); + clear_page(pt); + for (idx_pte = 0; + idx_pte < min(n_pte, PTRS_PER_PTE); + idx_pte++) { + pt[idx_pte] = pfn_pte(p2m_pfn, + PAGE_KERNEL); + p2m_pfn++; + } + n_pte -= PTRS_PER_PTE; + early_memunmap(pt, PAGE_SIZE); + make_lowmem_page_readonly(__va(pt_phys)); + pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, + PFN_DOWN(pt_phys)); + pmd[idx_pt] = __pmd(_PAGE_TABLE | pt_phys); + pt_phys += PAGE_SIZE; + } + n_pt -= PTRS_PER_PMD; + early_memunmap(pmd, PAGE_SIZE); + make_lowmem_page_readonly(__va(pmd_phys)); + pin_pagetable_pfn(MMUEXT_PIN_L2_TABLE, + PFN_DOWN(pmd_phys)); + pud[idx_pmd] = __pud(_PAGE_TABLE | pmd_phys); + pmd_phys += PAGE_SIZE; + } + n_pmd -= PTRS_PER_PUD; + early_memunmap(pud, PAGE_SIZE); + make_lowmem_page_readonly(__va(pud_phys)); + pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, PFN_DOWN(pud_phys)); + set_pgd(pgd + 2 + idx_pud, __pgd(_PAGE_TABLE | pud_phys)); + pud_phys += PAGE_SIZE; + } + + /* Now copy the old p2m info to the new area. */ + memcpy(new_p2m, xen_p2m_addr, size); + xen_p2m_addr = new_p2m; + + /* Release the old p2m list and set new list info. */ + p2m_pfn = PFN_DOWN(xen_early_virt_to_phys(xen_start_info->mfn_list)); + BUG_ON(!p2m_pfn); + p2m_pfn_end = p2m_pfn + PFN_DOWN(size); + + if (xen_start_info->mfn_list < __START_KERNEL_map) { + pfn = xen_start_info->first_p2m_pfn; + pfn_end = xen_start_info->first_p2m_pfn + + xen_start_info->nr_p2m_frames; + set_pgd(pgd + 1, __pgd(0)); + } else { + pfn = p2m_pfn; + pfn_end = p2m_pfn_end; + } + + memblock_free(PFN_PHYS(pfn), PAGE_SIZE * (pfn_end - pfn)); + while (pfn < pfn_end) { + if (pfn == p2m_pfn) { + pfn = p2m_pfn_end; + continue; + } + make_lowmem_page_readwrite(__va(PFN_PHYS(pfn))); + pfn++; + } + + xen_start_info->mfn_list = (unsigned long)xen_p2m_addr; + xen_start_info->first_p2m_pfn = PFN_DOWN(new_area); + xen_start_info->nr_p2m_frames = n_frames; +} + +#else /* !CONFIG_X86_64 */ +static RESERVE_BRK_ARRAY(pmd_t, initial_kernel_pmd, PTRS_PER_PMD); +static RESERVE_BRK_ARRAY(pmd_t, swapper_kernel_pmd, PTRS_PER_PMD); +RESERVE_BRK(fixup_kernel_pmd, PAGE_SIZE); +RESERVE_BRK(fixup_kernel_pte, PAGE_SIZE); + +static void __init xen_write_cr3_init(unsigned long cr3) +{ + unsigned long pfn = PFN_DOWN(__pa(swapper_pg_dir)); + + BUG_ON(read_cr3_pa() != __pa(initial_page_table)); + BUG_ON(cr3 != __pa(swapper_pg_dir)); + + /* + * We are switching to swapper_pg_dir for the first time (from + * initial_page_table) and therefore need to mark that page + * read-only and then pin it. + * + * Xen disallows sharing of kernel PMDs for PAE + * guests. Therefore we must copy the kernel PMD from + * initial_page_table into a new kernel PMD to be used in + * swapper_pg_dir. + */ + swapper_kernel_pmd = + extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE); + copy_page(swapper_kernel_pmd, initial_kernel_pmd); + swapper_pg_dir[KERNEL_PGD_BOUNDARY] = + __pgd(__pa(swapper_kernel_pmd) | _PAGE_PRESENT); + set_page_prot(swapper_kernel_pmd, PAGE_KERNEL_RO); + + set_page_prot(swapper_pg_dir, PAGE_KERNEL_RO); + xen_write_cr3(cr3); + pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, pfn); + + pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, + PFN_DOWN(__pa(initial_page_table))); + set_page_prot(initial_page_table, PAGE_KERNEL); + set_page_prot(initial_kernel_pmd, PAGE_KERNEL); + + pv_mmu_ops.write_cr3 = &xen_write_cr3; +} + +/* + * For 32 bit domains xen_start_info->pt_base is the pgd address which might be + * not the first page table in the page table pool. + * Iterate through the initial page tables to find the real page table base. + */ +static phys_addr_t __init xen_find_pt_base(pmd_t *pmd) +{ + phys_addr_t pt_base, paddr; + unsigned pmdidx; + + pt_base = min(__pa(xen_start_info->pt_base), __pa(pmd)); + + for (pmdidx = 0; pmdidx < PTRS_PER_PMD; pmdidx++) + if (pmd_present(pmd[pmdidx]) && !pmd_large(pmd[pmdidx])) { + paddr = m2p(pmd[pmdidx].pmd); + pt_base = min(pt_base, paddr); + } + + return pt_base; +} + +void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn) +{ + pmd_t *kernel_pmd; + + kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd); + + xen_pt_base = xen_find_pt_base(kernel_pmd); + xen_pt_size = xen_start_info->nr_pt_frames * PAGE_SIZE; + + initial_kernel_pmd = + extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE); + + max_pfn_mapped = PFN_DOWN(xen_pt_base + xen_pt_size + 512 * 1024); + + copy_page(initial_kernel_pmd, kernel_pmd); + + xen_map_identity_early(initial_kernel_pmd, max_pfn); + + copy_page(initial_page_table, pgd); + initial_page_table[KERNEL_PGD_BOUNDARY] = + __pgd(__pa(initial_kernel_pmd) | _PAGE_PRESENT); + + set_page_prot(initial_kernel_pmd, PAGE_KERNEL_RO); + set_page_prot(initial_page_table, PAGE_KERNEL_RO); + set_page_prot(empty_zero_page, PAGE_KERNEL_RO); + + pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd))); + + pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, + PFN_DOWN(__pa(initial_page_table))); + xen_write_cr3(__pa(initial_page_table)); + + memblock_reserve(xen_pt_base, xen_pt_size); +} +#endif /* CONFIG_X86_64 */ + +void __init xen_reserve_special_pages(void) +{ + phys_addr_t paddr; + + memblock_reserve(__pa(xen_start_info), PAGE_SIZE); + if (xen_start_info->store_mfn) { + paddr = PFN_PHYS(mfn_to_pfn(xen_start_info->store_mfn)); + memblock_reserve(paddr, PAGE_SIZE); + } + if (!xen_initial_domain()) { + paddr = PFN_PHYS(mfn_to_pfn(xen_start_info->console.domU.mfn)); + memblock_reserve(paddr, PAGE_SIZE); + } +} + +void __init xen_pt_check_e820(void) +{ + if (xen_is_e820_reserved(xen_pt_base, xen_pt_size)) { + xen_raw_console_write("Xen hypervisor allocated page table memory conflicts with E820 map\n"); + BUG(); + } +} + +static unsigned char dummy_mapping[PAGE_SIZE] __page_aligned_bss; + +static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot) +{ + pte_t pte; + + phys >>= PAGE_SHIFT; + + switch (idx) { + case FIX_BTMAP_END ... FIX_BTMAP_BEGIN: +#ifdef CONFIG_X86_32 + case FIX_WP_TEST: +# ifdef CONFIG_HIGHMEM + case FIX_KMAP_BEGIN ... FIX_KMAP_END: +# endif +#elif defined(CONFIG_X86_VSYSCALL_EMULATION) + case VSYSCALL_PAGE: +#endif + case FIX_TEXT_POKE0: + case FIX_TEXT_POKE1: + /* All local page mappings */ + pte = pfn_pte(phys, prot); + break; + +#ifdef CONFIG_X86_LOCAL_APIC + case FIX_APIC_BASE: /* maps dummy local APIC */ + pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL); + break; +#endif + +#ifdef CONFIG_X86_IO_APIC + case FIX_IO_APIC_BASE_0 ... FIX_IO_APIC_BASE_END: + /* + * We just don't map the IO APIC - all access is via + * hypercalls. Keep the address in the pte for reference. + */ + pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL); + break; +#endif + + case FIX_PARAVIRT_BOOTMAP: + /* This is an MFN, but it isn't an IO mapping from the + IO domain */ + pte = mfn_pte(phys, prot); + break; + + default: + /* By default, set_fixmap is used for hardware mappings */ + pte = mfn_pte(phys, prot); + break; + } + + __native_set_fixmap(idx, pte); + +#ifdef CONFIG_X86_VSYSCALL_EMULATION + /* Replicate changes to map the vsyscall page into the user + pagetable vsyscall mapping. */ + if (idx == VSYSCALL_PAGE) { + unsigned long vaddr = __fix_to_virt(idx); + set_pte_vaddr_pud(level3_user_vsyscall, vaddr, pte); + } +#endif +} + +static void __init xen_post_allocator_init(void) +{ + pv_mmu_ops.set_pte = xen_set_pte; + pv_mmu_ops.set_pmd = xen_set_pmd; + pv_mmu_ops.set_pud = xen_set_pud; +#ifdef CONFIG_X86_64 + pv_mmu_ops.set_p4d = xen_set_p4d; +#endif + + /* This will work as long as patching hasn't happened yet + (which it hasn't) */ + pv_mmu_ops.alloc_pte = xen_alloc_pte; + pv_mmu_ops.alloc_pmd = xen_alloc_pmd; + pv_mmu_ops.release_pte = xen_release_pte; + pv_mmu_ops.release_pmd = xen_release_pmd; +#ifdef CONFIG_X86_64 + pv_mmu_ops.alloc_pud = xen_alloc_pud; + pv_mmu_ops.release_pud = xen_release_pud; +#endif + pv_mmu_ops.make_pte = PV_CALLEE_SAVE(xen_make_pte); + +#ifdef CONFIG_X86_64 + pv_mmu_ops.write_cr3 = &xen_write_cr3; +#endif +} + +static void xen_leave_lazy_mmu(void) +{ + preempt_disable(); + xen_mc_flush(); + paravirt_leave_lazy_mmu(); + preempt_enable(); +} + +static const struct pv_mmu_ops xen_mmu_ops __initconst = { + .read_cr2 = xen_read_cr2, + .write_cr2 = xen_write_cr2, + + .read_cr3 = xen_read_cr3, + .write_cr3 = xen_write_cr3_init, + + .flush_tlb_user = xen_flush_tlb, + .flush_tlb_kernel = xen_flush_tlb, + .flush_tlb_one_user = xen_flush_tlb_one_user, + .flush_tlb_others = xen_flush_tlb_others, + .tlb_remove_table = tlb_remove_table, + + .pgd_alloc = xen_pgd_alloc, + .pgd_free = xen_pgd_free, + + .alloc_pte = xen_alloc_pte_init, + .release_pte = xen_release_pte_init, + .alloc_pmd = xen_alloc_pmd_init, + .release_pmd = xen_release_pmd_init, + + .set_pte = xen_set_pte_init, + .set_pte_at = xen_set_pte_at, + .set_pmd = xen_set_pmd_hyper, + + .ptep_modify_prot_start = __ptep_modify_prot_start, + .ptep_modify_prot_commit = __ptep_modify_prot_commit, + + .pte_val = PV_CALLEE_SAVE(xen_pte_val), + .pgd_val = PV_CALLEE_SAVE(xen_pgd_val), + + .make_pte = PV_CALLEE_SAVE(xen_make_pte_init), + .make_pgd = PV_CALLEE_SAVE(xen_make_pgd), + +#ifdef CONFIG_X86_PAE + .set_pte_atomic = xen_set_pte_atomic, + .pte_clear = xen_pte_clear, + .pmd_clear = xen_pmd_clear, +#endif /* CONFIG_X86_PAE */ + .set_pud = xen_set_pud_hyper, + + .make_pmd = PV_CALLEE_SAVE(xen_make_pmd), + .pmd_val = PV_CALLEE_SAVE(xen_pmd_val), + +#ifdef CONFIG_X86_64 + .pud_val = PV_CALLEE_SAVE(xen_pud_val), + .make_pud = PV_CALLEE_SAVE(xen_make_pud), + .set_p4d = xen_set_p4d_hyper, + + .alloc_pud = xen_alloc_pmd_init, + .release_pud = xen_release_pmd_init, + +#if CONFIG_PGTABLE_LEVELS >= 5 + .p4d_val = PV_CALLEE_SAVE(xen_p4d_val), + .make_p4d = PV_CALLEE_SAVE(xen_make_p4d), +#endif +#endif /* CONFIG_X86_64 */ + + .activate_mm = xen_activate_mm, + .dup_mmap = xen_dup_mmap, + .exit_mmap = xen_exit_mmap, + + .lazy_mode = { + .enter = paravirt_enter_lazy_mmu, + .leave = xen_leave_lazy_mmu, + .flush = paravirt_flush_lazy_mmu, + }, + + .set_fixmap = xen_set_fixmap, +}; + +void __init xen_init_mmu_ops(void) +{ + x86_init.paging.pagetable_init = xen_pagetable_init; + x86_init.hyper.init_after_bootmem = xen_after_bootmem; + + pv_mmu_ops = xen_mmu_ops; + + memset(dummy_mapping, 0xff, PAGE_SIZE); +} + +/* Protected by xen_reservation_lock. */ +#define MAX_CONTIG_ORDER 9 /* 2MB */ +static unsigned long discontig_frames[1<<MAX_CONTIG_ORDER]; + +#define VOID_PTE (mfn_pte(0, __pgprot(0))) +static void xen_zap_pfn_range(unsigned long vaddr, unsigned int order, + unsigned long *in_frames, + unsigned long *out_frames) +{ + int i; + struct multicall_space mcs; + + xen_mc_batch(); + for (i = 0; i < (1UL<<order); i++, vaddr += PAGE_SIZE) { + mcs = __xen_mc_entry(0); + + if (in_frames) + in_frames[i] = virt_to_mfn(vaddr); + + MULTI_update_va_mapping(mcs.mc, vaddr, VOID_PTE, 0); + __set_phys_to_machine(virt_to_pfn(vaddr), INVALID_P2M_ENTRY); + + if (out_frames) + out_frames[i] = virt_to_pfn(vaddr); + } + xen_mc_issue(0); +} + +/* + * Update the pfn-to-mfn mappings for a virtual address range, either to + * point to an array of mfns, or contiguously from a single starting + * mfn. + */ +static void xen_remap_exchanged_ptes(unsigned long vaddr, int order, + unsigned long *mfns, + unsigned long first_mfn) +{ + unsigned i, limit; + unsigned long mfn; + + xen_mc_batch(); + + limit = 1u << order; + for (i = 0; i < limit; i++, vaddr += PAGE_SIZE) { + struct multicall_space mcs; + unsigned flags; + + mcs = __xen_mc_entry(0); + if (mfns) + mfn = mfns[i]; + else + mfn = first_mfn + i; + + if (i < (limit - 1)) + flags = 0; + else { + if (order == 0) + flags = UVMF_INVLPG | UVMF_ALL; + else + flags = UVMF_TLB_FLUSH | UVMF_ALL; + } + + MULTI_update_va_mapping(mcs.mc, vaddr, + mfn_pte(mfn, PAGE_KERNEL), flags); + + set_phys_to_machine(virt_to_pfn(vaddr), mfn); + } + + xen_mc_issue(0); +} + +/* + * Perform the hypercall to exchange a region of our pfns to point to + * memory with the required contiguous alignment. Takes the pfns as + * input, and populates mfns as output. + * + * Returns a success code indicating whether the hypervisor was able to + * satisfy the request or not. + */ +static int xen_exchange_memory(unsigned long extents_in, unsigned int order_in, + unsigned long *pfns_in, + unsigned long extents_out, + unsigned int order_out, + unsigned long *mfns_out, + unsigned int address_bits) +{ + long rc; + int success; + + struct xen_memory_exchange exchange = { + .in = { + .nr_extents = extents_in, + .extent_order = order_in, + .extent_start = pfns_in, + .domid = DOMID_SELF + }, + .out = { + .nr_extents = extents_out, + .extent_order = order_out, + .extent_start = mfns_out, + .address_bits = address_bits, + .domid = DOMID_SELF + } + }; + + BUG_ON(extents_in << order_in != extents_out << order_out); + + rc = HYPERVISOR_memory_op(XENMEM_exchange, &exchange); + success = (exchange.nr_exchanged == extents_in); + + BUG_ON(!success && ((exchange.nr_exchanged != 0) || (rc == 0))); + BUG_ON(success && (rc != 0)); + + return success; +} + +int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order, + unsigned int address_bits, + dma_addr_t *dma_handle) +{ + unsigned long *in_frames = discontig_frames, out_frame; + unsigned long flags; + int success; + unsigned long vstart = (unsigned long)phys_to_virt(pstart); + + /* + * Currently an auto-translated guest will not perform I/O, nor will + * it require PAE page directories below 4GB. Therefore any calls to + * this function are redundant and can be ignored. + */ + + if (unlikely(order > MAX_CONTIG_ORDER)) + return -ENOMEM; + + memset((void *) vstart, 0, PAGE_SIZE << order); + + spin_lock_irqsave(&xen_reservation_lock, flags); + + /* 1. Zap current PTEs, remembering MFNs. */ + xen_zap_pfn_range(vstart, order, in_frames, NULL); + + /* 2. Get a new contiguous memory extent. */ + out_frame = virt_to_pfn(vstart); + success = xen_exchange_memory(1UL << order, 0, in_frames, + 1, order, &out_frame, + address_bits); + + /* 3. Map the new extent in place of old pages. */ + if (success) + xen_remap_exchanged_ptes(vstart, order, NULL, out_frame); + else + xen_remap_exchanged_ptes(vstart, order, in_frames, 0); + + spin_unlock_irqrestore(&xen_reservation_lock, flags); + + *dma_handle = virt_to_machine(vstart).maddr; + return success ? 0 : -ENOMEM; +} +EXPORT_SYMBOL_GPL(xen_create_contiguous_region); + +void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order) +{ + unsigned long *out_frames = discontig_frames, in_frame; + unsigned long flags; + int success; + unsigned long vstart; + + if (unlikely(order > MAX_CONTIG_ORDER)) + return; + + vstart = (unsigned long)phys_to_virt(pstart); + memset((void *) vstart, 0, PAGE_SIZE << order); + + spin_lock_irqsave(&xen_reservation_lock, flags); + + /* 1. Find start MFN of contiguous extent. */ + in_frame = virt_to_mfn(vstart); + + /* 2. Zap current PTEs. */ + xen_zap_pfn_range(vstart, order, NULL, out_frames); + + /* 3. Do the exchange for non-contiguous MFNs. */ + success = xen_exchange_memory(1, order, &in_frame, 1UL << order, + 0, out_frames, 0); + + /* 4. Map new pages in place of old pages. */ + if (success) + xen_remap_exchanged_ptes(vstart, order, out_frames, 0); + else + xen_remap_exchanged_ptes(vstart, order, NULL, in_frame); + + spin_unlock_irqrestore(&xen_reservation_lock, flags); +} +EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region); + +#ifdef CONFIG_KEXEC_CORE +phys_addr_t paddr_vmcoreinfo_note(void) +{ + if (xen_pv_domain()) + return virt_to_machine(vmcoreinfo_note).maddr; + else + return __pa(vmcoreinfo_note); +} +#endif /* CONFIG_KEXEC_CORE */ |