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-rw-r--r--arch/x86/xen/p2m.c858
1 files changed, 858 insertions, 0 deletions
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
new file mode 100644
index 000000000..e809f1446
--- /dev/null
+++ b/arch/x86/xen/p2m.c
@@ -0,0 +1,858 @@
+// 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 inline unsigned p2m_index(unsigned long pfn)
+{
+ return pfn % P2M_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((unsigned long)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;
+ unsigned long old_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);
+ old_mfn = cmpxchg(top_mfn_p, missing_mfn, mid_mfn_mfn);
+ if (old_mfn != missing_mfn) {
+ free_p2m_page(mid_mfn);
+ mid_mfn = mfn_to_virt(old_mfn);
+ } else {
+ p2m_top_mfn_p[topidx] = mid_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 = ~0;
+ 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 = ~0;
+ 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;
+}
+EXPORT_SYMBOL_GPL(set_foreign_p2m_mapping);
+
+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;
+}
+EXPORT_SYMBOL_GPL(clear_foreign_p2m_mapping);
+
+#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;
+}
+
+static int p2m_dump_open(struct inode *inode, struct file *filp)
+{
+ return single_open(filp, p2m_dump_show, NULL);
+}
+
+static const struct file_operations p2m_dump_fops = {
+ .open = p2m_dump_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+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 */
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-23 21:48:26 +0000