// SPDX-License-Identifier: GPL-2.0 /* * Xen leaves the responsibility for maintaining p2m mappings to the * guests themselves, but it must also access and update the p2m array * during suspend/resume when all the pages are reallocated. * * The logical flat p2m table is mapped to a linear kernel memory area. * For accesses by Xen a three-level tree linked via mfns only is set up to * allow the address space to be sparse. * * Xen * | * p2m_top_mfn * / \ * p2m_mid_mfn p2m_mid_mfn * / / * p2m p2m p2m ... * * The p2m_mid_mfn pages are mapped by p2m_top_mfn_p. * * The p2m_top_mfn level is limited to 1 page, so the maximum representable * pseudo-physical address space is: * P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE pages * * P2M_PER_PAGE depends on the architecture, as a mfn is always * unsigned long (8 bytes on 64-bit, 4 bytes on 32), leading to * 512 and 1024 entries respectively. * * In short, these structures contain the Machine Frame Number (MFN) of the PFN. * * However not all entries are filled with MFNs. Specifically for all other * leaf entries, or for the top root, or middle one, for which there is a void * entry, we assume it is "missing". So (for example) * pfn_to_mfn(0x90909090)=INVALID_P2M_ENTRY. * We have a dedicated page p2m_missing with all entries being * INVALID_P2M_ENTRY. This page may be referenced multiple times in the p2m * list/tree in case there are multiple areas with P2M_PER_PAGE invalid pfns. * * We also have the possibility of setting 1-1 mappings on certain regions, so * that: * pfn_to_mfn(0xc0000)=0xc0000 * * The benefit of this is, that we can assume for non-RAM regions (think * PCI BARs, or ACPI spaces), we can create mappings easily because we * get the PFN value to match the MFN. * * For this to work efficiently we have one new page p2m_identity. All entries * in p2m_identity are set to INVALID_P2M_ENTRY type (Xen toolstack only * recognizes that and MFNs, no other fancy value). * * On lookup we spot that the entry points to p2m_identity and return the * identity value instead of dereferencing and returning INVALID_P2M_ENTRY. * If the entry points to an allocated page, we just proceed as before and * return the PFN. If the PFN has IDENTITY_FRAME_BIT set we unmask that in * appropriate functions (pfn_to_mfn). * * The reason for having the IDENTITY_FRAME_BIT instead of just returning the * PFN is that we could find ourselves where pfn_to_mfn(pfn)==pfn for a * non-identity pfn. To protect ourselves against we elect to set (and get) the * IDENTITY_FRAME_BIT on all identity mapped PFNs. */ #include <linux/init.h> #include <linux/export.h> #include <linux/list.h> #include <linux/hash.h> #include <linux/sched.h> #include <linux/seq_file.h> #include <linux/memblock.h> #include <linux/slab.h> #include <linux/vmalloc.h> #include <asm/cache.h> #include <asm/setup.h> #include <linux/uaccess.h> #include <asm/xen/page.h> #include <asm/xen/hypercall.h> #include <asm/xen/hypervisor.h> #include <xen/balloon.h> #include <xen/grant_table.h> #include "multicalls.h" #include "xen-ops.h" #define P2M_MID_PER_PAGE (PAGE_SIZE / sizeof(unsigned long *)) #define P2M_TOP_PER_PAGE (PAGE_SIZE / sizeof(unsigned long **)) #define MAX_P2M_PFN (P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE) #define PMDS_PER_MID_PAGE (P2M_MID_PER_PAGE / PTRS_PER_PTE) unsigned long *xen_p2m_addr __read_mostly; EXPORT_SYMBOL_GPL(xen_p2m_addr); unsigned long xen_p2m_size __read_mostly; EXPORT_SYMBOL_GPL(xen_p2m_size); unsigned long xen_max_p2m_pfn __read_mostly; EXPORT_SYMBOL_GPL(xen_max_p2m_pfn); #ifdef CONFIG_XEN_MEMORY_HOTPLUG_LIMIT #define P2M_LIMIT CONFIG_XEN_MEMORY_HOTPLUG_LIMIT #else #define P2M_LIMIT 0 #endif static DEFINE_SPINLOCK(p2m_update_lock); static unsigned long *p2m_mid_missing_mfn; static unsigned long *p2m_top_mfn; static unsigned long **p2m_top_mfn_p; static unsigned long *p2m_missing; static unsigned long *p2m_identity; static pte_t *p2m_missing_pte; static pte_t *p2m_identity_pte; /* * Hint at last populated PFN. * * Used to set HYPERVISOR_shared_info->arch.max_pfn so the toolstack * can avoid scanning the whole P2M (which may be sized to account for * hotplugged memory). */ static unsigned long xen_p2m_last_pfn; static inline unsigned p2m_top_index(unsigned long pfn) { BUG_ON(pfn >= MAX_P2M_PFN); return pfn / (P2M_MID_PER_PAGE * P2M_PER_PAGE); } static inline unsigned p2m_mid_index(unsigned long pfn) { return (pfn / P2M_PER_PAGE) % P2M_MID_PER_PAGE; } static void p2m_top_mfn_init(unsigned long *top) { unsigned i; for (i = 0; i < P2M_TOP_PER_PAGE; i++) top[i] = virt_to_mfn(p2m_mid_missing_mfn); } static void p2m_top_mfn_p_init(unsigned long **top) { unsigned i; for (i = 0; i < P2M_TOP_PER_PAGE; i++) top[i] = p2m_mid_missing_mfn; } static void p2m_mid_mfn_init(unsigned long *mid, unsigned long *leaf) { unsigned i; for (i = 0; i < P2M_MID_PER_PAGE; i++) mid[i] = virt_to_mfn(leaf); } static void p2m_init(unsigned long *p2m) { unsigned i; for (i = 0; i < P2M_PER_PAGE; i++) p2m[i] = INVALID_P2M_ENTRY; } static void p2m_init_identity(unsigned long *p2m, unsigned long pfn) { unsigned i; for (i = 0; i < P2M_PER_PAGE; i++) p2m[i] = IDENTITY_FRAME(pfn + i); } static void * __ref alloc_p2m_page(void) { if (unlikely(!slab_is_available())) { void *ptr = memblock_alloc(PAGE_SIZE, PAGE_SIZE); if (!ptr) panic("%s: Failed to allocate %lu bytes align=0x%lx\n", __func__, PAGE_SIZE, PAGE_SIZE); return ptr; } return (void *)__get_free_page(GFP_KERNEL); } static void __ref free_p2m_page(void *p) { if (unlikely(!slab_is_available())) { memblock_free(p, PAGE_SIZE); return; } free_page((unsigned long)p); } /* * Build the parallel p2m_top_mfn and p2m_mid_mfn structures * * This is called both at boot time, and after resuming from suspend: * - At boot time we're called rather early, and must use alloc_bootmem*() * to allocate memory. * * - After resume we're called from within stop_machine, but the mfn * tree should already be completely allocated. */ void __ref xen_build_mfn_list_list(void) { unsigned long pfn, mfn; pte_t *ptep; unsigned int level, topidx, mididx; unsigned long *mid_mfn_p; if (xen_start_info->flags & SIF_VIRT_P2M_4TOOLS) return; /* Pre-initialize p2m_top_mfn to be completely missing */ if (p2m_top_mfn == NULL) { p2m_mid_missing_mfn = alloc_p2m_page(); p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing); p2m_top_mfn_p = alloc_p2m_page(); p2m_top_mfn_p_init(p2m_top_mfn_p); p2m_top_mfn = alloc_p2m_page(); p2m_top_mfn_init(p2m_top_mfn); } else { /* Reinitialise, mfn's all change after migration */ p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing); } for (pfn = 0; pfn < xen_max_p2m_pfn && pfn < MAX_P2M_PFN; pfn += P2M_PER_PAGE) { topidx = p2m_top_index(pfn); mididx = p2m_mid_index(pfn); mid_mfn_p = p2m_top_mfn_p[topidx]; ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level); BUG_ON(!ptep || level != PG_LEVEL_4K); mfn = pte_mfn(*ptep); ptep = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1)); /* Don't bother allocating any mfn mid levels if * they're just missing, just update the stored mfn, * since all could have changed over a migrate. */ if (ptep == p2m_missing_pte || ptep == p2m_identity_pte) { BUG_ON(mididx); BUG_ON(mid_mfn_p != p2m_mid_missing_mfn); p2m_top_mfn[topidx] = virt_to_mfn(p2m_mid_missing_mfn); pfn += (P2M_MID_PER_PAGE - 1) * P2M_PER_PAGE; continue; } if (mid_mfn_p == p2m_mid_missing_mfn) { mid_mfn_p = alloc_p2m_page(); p2m_mid_mfn_init(mid_mfn_p, p2m_missing); p2m_top_mfn_p[topidx] = mid_mfn_p; } p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p); mid_mfn_p[mididx] = mfn; } } void xen_setup_mfn_list_list(void) { BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); if (xen_start_info->flags & SIF_VIRT_P2M_4TOOLS) HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list = ~0UL; else HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list = virt_to_mfn(p2m_top_mfn); HYPERVISOR_shared_info->arch.max_pfn = xen_p2m_last_pfn; HYPERVISOR_shared_info->arch.p2m_generation = 0; HYPERVISOR_shared_info->arch.p2m_vaddr = (unsigned long)xen_p2m_addr; HYPERVISOR_shared_info->arch.p2m_cr3 = xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir)); } /* Set up p2m_top to point to the domain-builder provided p2m pages */ void __init xen_build_dynamic_phys_to_machine(void) { unsigned long pfn; xen_p2m_addr = (unsigned long *)xen_start_info->mfn_list; xen_p2m_size = ALIGN(xen_start_info->nr_pages, P2M_PER_PAGE); for (pfn = xen_start_info->nr_pages; pfn < xen_p2m_size; pfn++) xen_p2m_addr[pfn] = INVALID_P2M_ENTRY; xen_max_p2m_pfn = xen_p2m_size; } #define P2M_TYPE_IDENTITY 0 #define P2M_TYPE_MISSING 1 #define P2M_TYPE_PFN 2 #define P2M_TYPE_UNKNOWN 3 static int xen_p2m_elem_type(unsigned long pfn) { unsigned long mfn; if (pfn >= xen_p2m_size) return P2M_TYPE_IDENTITY; mfn = xen_p2m_addr[pfn]; if (mfn == INVALID_P2M_ENTRY) return P2M_TYPE_MISSING; if (mfn & IDENTITY_FRAME_BIT) return P2M_TYPE_IDENTITY; return P2M_TYPE_PFN; } static void __init xen_rebuild_p2m_list(unsigned long *p2m) { unsigned int i, chunk; unsigned long pfn; unsigned long *mfns; pte_t *ptep; pmd_t *pmdp; int type; p2m_missing = alloc_p2m_page(); p2m_init(p2m_missing); p2m_identity = alloc_p2m_page(); p2m_init(p2m_identity); p2m_missing_pte = alloc_p2m_page(); paravirt_alloc_pte(&init_mm, __pa(p2m_missing_pte) >> PAGE_SHIFT); p2m_identity_pte = alloc_p2m_page(); paravirt_alloc_pte(&init_mm, __pa(p2m_identity_pte) >> PAGE_SHIFT); for (i = 0; i < PTRS_PER_PTE; i++) { set_pte(p2m_missing_pte + i, pfn_pte(PFN_DOWN(__pa(p2m_missing)), PAGE_KERNEL_RO)); set_pte(p2m_identity_pte + i, pfn_pte(PFN_DOWN(__pa(p2m_identity)), PAGE_KERNEL_RO)); } for (pfn = 0; pfn < xen_max_p2m_pfn; pfn += chunk) { /* * Try to map missing/identity PMDs or p2m-pages if possible. * We have to respect the structure of the mfn_list_list * which will be built just afterwards. * Chunk size to test is one p2m page if we are in the middle * of a mfn_list_list mid page and the complete mid page area * if we are at index 0 of the mid page. Please note that a * mid page might cover more than one PMD, e.g. on 32 bit PAE * kernels. */ chunk = (pfn & (P2M_PER_PAGE * P2M_MID_PER_PAGE - 1)) ? P2M_PER_PAGE : P2M_PER_PAGE * P2M_MID_PER_PAGE; type = xen_p2m_elem_type(pfn); i = 0; if (type != P2M_TYPE_PFN) for (i = 1; i < chunk; i++) if (xen_p2m_elem_type(pfn + i) != type) break; if (i < chunk) /* Reset to minimal chunk size. */ chunk = P2M_PER_PAGE; if (type == P2M_TYPE_PFN || i < chunk) { /* Use initial p2m page contents. */ mfns = alloc_p2m_page(); copy_page(mfns, xen_p2m_addr + pfn); ptep = populate_extra_pte((unsigned long)(p2m + pfn)); set_pte(ptep, pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL)); continue; } if (chunk == P2M_PER_PAGE) { /* Map complete missing or identity p2m-page. */ mfns = (type == P2M_TYPE_MISSING) ? p2m_missing : p2m_identity; ptep = populate_extra_pte((unsigned long)(p2m + pfn)); set_pte(ptep, pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL_RO)); continue; } /* Complete missing or identity PMD(s) can be mapped. */ ptep = (type == P2M_TYPE_MISSING) ? p2m_missing_pte : p2m_identity_pte; for (i = 0; i < PMDS_PER_MID_PAGE; i++) { pmdp = populate_extra_pmd( (unsigned long)(p2m + pfn) + i * PMD_SIZE); set_pmd(pmdp, __pmd(__pa(ptep) | _KERNPG_TABLE)); } } } void __init xen_vmalloc_p2m_tree(void) { static struct vm_struct vm; unsigned long p2m_limit; xen_p2m_last_pfn = xen_max_p2m_pfn; p2m_limit = (phys_addr_t)P2M_LIMIT * 1024 * 1024 * 1024 / PAGE_SIZE; vm.flags = VM_ALLOC; vm.size = ALIGN(sizeof(unsigned long) * max(xen_max_p2m_pfn, p2m_limit), PMD_SIZE * PMDS_PER_MID_PAGE); vm_area_register_early(&vm, PMD_SIZE * PMDS_PER_MID_PAGE); pr_notice("p2m virtual area at %p, size is %lx\n", vm.addr, vm.size); xen_max_p2m_pfn = vm.size / sizeof(unsigned long); xen_rebuild_p2m_list(vm.addr); xen_p2m_addr = vm.addr; xen_p2m_size = xen_max_p2m_pfn; xen_inv_extra_mem(); } unsigned long get_phys_to_machine(unsigned long pfn) { pte_t *ptep; unsigned int level; if (unlikely(pfn >= xen_p2m_size)) { if (pfn < xen_max_p2m_pfn) return xen_chk_extra_mem(pfn); return IDENTITY_FRAME(pfn); } ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level); BUG_ON(!ptep || level != PG_LEVEL_4K); /* * The INVALID_P2M_ENTRY is filled in both p2m_*identity * and in p2m_*missing, so returning the INVALID_P2M_ENTRY * would be wrong. */ if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity))) return IDENTITY_FRAME(pfn); return xen_p2m_addr[pfn]; } EXPORT_SYMBOL_GPL(get_phys_to_machine); /* * Allocate new pmd(s). It is checked whether the old pmd is still in place. * If not, nothing is changed. This is okay as the only reason for allocating * a new pmd is to replace p2m_missing_pte or p2m_identity_pte by a individual * pmd. */ static pte_t *alloc_p2m_pmd(unsigned long addr, pte_t *pte_pg) { pte_t *ptechk; pte_t *pte_newpg[PMDS_PER_MID_PAGE]; pmd_t *pmdp; unsigned int level; unsigned long flags; unsigned long vaddr; int i; /* Do all allocations first to bail out in error case. */ for (i = 0; i < PMDS_PER_MID_PAGE; i++) { pte_newpg[i] = alloc_p2m_page(); if (!pte_newpg[i]) { for (i--; i >= 0; i--) free_p2m_page(pte_newpg[i]); return NULL; } } vaddr = addr & ~(PMD_SIZE * PMDS_PER_MID_PAGE - 1); for (i = 0; i < PMDS_PER_MID_PAGE; i++) { copy_page(pte_newpg[i], pte_pg); paravirt_alloc_pte(&init_mm, __pa(pte_newpg[i]) >> PAGE_SHIFT); pmdp = lookup_pmd_address(vaddr); BUG_ON(!pmdp); spin_lock_irqsave(&p2m_update_lock, flags); ptechk = lookup_address(vaddr, &level); if (ptechk == pte_pg) { HYPERVISOR_shared_info->arch.p2m_generation++; wmb(); /* Tools are synchronizing via p2m_generation. */ set_pmd(pmdp, __pmd(__pa(pte_newpg[i]) | _KERNPG_TABLE)); wmb(); /* Tools are synchronizing via p2m_generation. */ HYPERVISOR_shared_info->arch.p2m_generation++; pte_newpg[i] = NULL; } spin_unlock_irqrestore(&p2m_update_lock, flags); if (pte_newpg[i]) { paravirt_release_pte(__pa(pte_newpg[i]) >> PAGE_SHIFT); free_p2m_page(pte_newpg[i]); } vaddr += PMD_SIZE; } return lookup_address(addr, &level); } /* * Fully allocate the p2m structure for a given pfn. We need to check * that both the top and mid levels are allocated, and make sure the * parallel mfn tree is kept in sync. We may race with other cpus, so * the new pages are installed with cmpxchg; if we lose the race then * simply free the page we allocated and use the one that's there. */ int xen_alloc_p2m_entry(unsigned long pfn) { unsigned topidx; unsigned long *top_mfn_p, *mid_mfn; pte_t *ptep, *pte_pg; unsigned int level; unsigned long flags; unsigned long addr = (unsigned long)(xen_p2m_addr + pfn); unsigned long p2m_pfn; ptep = lookup_address(addr, &level); BUG_ON(!ptep || level != PG_LEVEL_4K); pte_pg = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1)); if (pte_pg == p2m_missing_pte || pte_pg == p2m_identity_pte) { /* PMD level is missing, allocate a new one */ ptep = alloc_p2m_pmd(addr, pte_pg); if (!ptep) return -ENOMEM; } if (p2m_top_mfn && pfn < MAX_P2M_PFN) { topidx = p2m_top_index(pfn); top_mfn_p = &p2m_top_mfn[topidx]; mid_mfn = READ_ONCE(p2m_top_mfn_p[topidx]); BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p); if (mid_mfn == p2m_mid_missing_mfn) { /* Separately check the mid mfn level */ unsigned long missing_mfn; unsigned long mid_mfn_mfn; mid_mfn = alloc_p2m_page(); if (!mid_mfn) return -ENOMEM; p2m_mid_mfn_init(mid_mfn, p2m_missing); missing_mfn = virt_to_mfn(p2m_mid_missing_mfn); mid_mfn_mfn = virt_to_mfn(mid_mfn); /* try_cmpxchg() updates missing_mfn on failure. */ if (try_cmpxchg(top_mfn_p, &missing_mfn, mid_mfn_mfn)) { p2m_top_mfn_p[topidx] = mid_mfn; } else { free_p2m_page(mid_mfn); mid_mfn = mfn_to_virt(missing_mfn); } } } else { mid_mfn = NULL; } p2m_pfn = pte_pfn(READ_ONCE(*ptep)); if (p2m_pfn == PFN_DOWN(__pa(p2m_identity)) || p2m_pfn == PFN_DOWN(__pa(p2m_missing))) { /* p2m leaf page is missing */ unsigned long *p2m; p2m = alloc_p2m_page(); if (!p2m) return -ENOMEM; if (p2m_pfn == PFN_DOWN(__pa(p2m_missing))) p2m_init(p2m); else p2m_init_identity(p2m, pfn & ~(P2M_PER_PAGE - 1)); spin_lock_irqsave(&p2m_update_lock, flags); if (pte_pfn(*ptep) == p2m_pfn) { HYPERVISOR_shared_info->arch.p2m_generation++; wmb(); /* Tools are synchronizing via p2m_generation. */ set_pte(ptep, pfn_pte(PFN_DOWN(__pa(p2m)), PAGE_KERNEL)); wmb(); /* Tools are synchronizing via p2m_generation. */ HYPERVISOR_shared_info->arch.p2m_generation++; if (mid_mfn) mid_mfn[p2m_mid_index(pfn)] = virt_to_mfn(p2m); p2m = NULL; } spin_unlock_irqrestore(&p2m_update_lock, flags); if (p2m) free_p2m_page(p2m); } /* Expanded the p2m? */ if (pfn >= xen_p2m_last_pfn) { xen_p2m_last_pfn = ALIGN(pfn + 1, P2M_PER_PAGE); HYPERVISOR_shared_info->arch.max_pfn = xen_p2m_last_pfn; } return 0; } EXPORT_SYMBOL(xen_alloc_p2m_entry); unsigned long __init set_phys_range_identity(unsigned long pfn_s, unsigned long pfn_e) { unsigned long pfn; if (unlikely(pfn_s >= xen_p2m_size)) return 0; if (pfn_s > pfn_e) return 0; if (pfn_e > xen_p2m_size) pfn_e = xen_p2m_size; for (pfn = pfn_s; pfn < pfn_e; pfn++) xen_p2m_addr[pfn] = IDENTITY_FRAME(pfn); return pfn - pfn_s; } bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn) { pte_t *ptep; unsigned int level; /* Only invalid entries allowed above the highest p2m covered frame. */ if (unlikely(pfn >= xen_p2m_size)) return mfn == INVALID_P2M_ENTRY; /* * The interface requires atomic updates on p2m elements. * xen_safe_write_ulong() is using an atomic store via asm(). */ if (likely(!xen_safe_write_ulong(xen_p2m_addr + pfn, mfn))) return true; ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level); BUG_ON(!ptep || level != PG_LEVEL_4K); if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_missing))) return mfn == INVALID_P2M_ENTRY; if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity))) return mfn == IDENTITY_FRAME(pfn); return false; } bool set_phys_to_machine(unsigned long pfn, unsigned long mfn) { if (unlikely(!__set_phys_to_machine(pfn, mfn))) { int ret; ret = xen_alloc_p2m_entry(pfn); if (ret < 0) return false; return __set_phys_to_machine(pfn, mfn); } return true; } int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops, struct gnttab_map_grant_ref *kmap_ops, struct page **pages, unsigned int count) { int i, ret = 0; pte_t *pte; if (xen_feature(XENFEAT_auto_translated_physmap)) return 0; if (kmap_ops) { ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, kmap_ops, count); if (ret) goto out; } for (i = 0; i < count; i++) { unsigned long mfn, pfn; struct gnttab_unmap_grant_ref unmap[2]; int rc; /* Do not add to override if the map failed. */ if (map_ops[i].status != GNTST_okay || (kmap_ops && kmap_ops[i].status != GNTST_okay)) continue; if (map_ops[i].flags & GNTMAP_contains_pte) { pte = (pte_t *)(mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) + (map_ops[i].host_addr & ~PAGE_MASK)); mfn = pte_mfn(*pte); } else { mfn = PFN_DOWN(map_ops[i].dev_bus_addr); } pfn = page_to_pfn(pages[i]); WARN(pfn_to_mfn(pfn) != INVALID_P2M_ENTRY, "page must be ballooned"); if (likely(set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) continue; /* * Signal an error for this slot. This in turn requires * immediate unmapping. */ map_ops[i].status = GNTST_general_error; unmap[0].host_addr = map_ops[i].host_addr; unmap[0].handle = map_ops[i].handle; map_ops[i].handle = INVALID_GRANT_HANDLE; if (map_ops[i].flags & GNTMAP_device_map) unmap[0].dev_bus_addr = map_ops[i].dev_bus_addr; else unmap[0].dev_bus_addr = 0; if (kmap_ops) { kmap_ops[i].status = GNTST_general_error; unmap[1].host_addr = kmap_ops[i].host_addr; unmap[1].handle = kmap_ops[i].handle; kmap_ops[i].handle = INVALID_GRANT_HANDLE; if (kmap_ops[i].flags & GNTMAP_device_map) unmap[1].dev_bus_addr = kmap_ops[i].dev_bus_addr; else unmap[1].dev_bus_addr = 0; } /* * Pre-populate both status fields, to be recognizable in * the log message below. */ unmap[0].status = 1; unmap[1].status = 1; rc = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, 1 + !!kmap_ops); if (rc || unmap[0].status != GNTST_okay || unmap[1].status != GNTST_okay) pr_err_once("gnttab unmap failed: rc=%d st0=%d st1=%d\n", rc, unmap[0].status, unmap[1].status); } out: return ret; } int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops, struct gnttab_unmap_grant_ref *kunmap_ops, struct page **pages, unsigned int count) { int i, ret = 0; if (xen_feature(XENFEAT_auto_translated_physmap)) return 0; for (i = 0; i < count; i++) { unsigned long mfn = __pfn_to_mfn(page_to_pfn(pages[i])); unsigned long pfn = page_to_pfn(pages[i]); if (mfn != INVALID_P2M_ENTRY && (mfn & FOREIGN_FRAME_BIT)) set_phys_to_machine(pfn, INVALID_P2M_ENTRY); else ret = -EINVAL; } if (kunmap_ops) ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, kunmap_ops, count) ?: ret; return ret; } #ifdef CONFIG_XEN_DEBUG_FS #include <linux/debugfs.h> #include "debugfs.h" static int p2m_dump_show(struct seq_file *m, void *v) { static const char * const type_name[] = { [P2M_TYPE_IDENTITY] = "identity", [P2M_TYPE_MISSING] = "missing", [P2M_TYPE_PFN] = "pfn", [P2M_TYPE_UNKNOWN] = "abnormal"}; unsigned long pfn, first_pfn; int type, prev_type; prev_type = xen_p2m_elem_type(0); first_pfn = 0; for (pfn = 0; pfn < xen_p2m_size; pfn++) { type = xen_p2m_elem_type(pfn); if (type != prev_type) { seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn, type_name[prev_type]); prev_type = type; first_pfn = pfn; } } seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn, type_name[prev_type]); return 0; } DEFINE_SHOW_ATTRIBUTE(p2m_dump); static struct dentry *d_mmu_debug; static int __init xen_p2m_debugfs(void) { struct dentry *d_xen = xen_init_debugfs(); d_mmu_debug = debugfs_create_dir("mmu", d_xen); debugfs_create_file("p2m", 0600, d_mmu_debug, NULL, &p2m_dump_fops); return 0; } fs_initcall(xen_p2m_debugfs); #endif /* CONFIG_XEN_DEBUG_FS */