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-rw-r--r--arch/x86/kvm/mmu.c222
-rw-r--r--arch/x86/kvm/paging_tmpl.h32
-rw-r--r--arch/x86/kvm/x86.c1
3 files changed, 224 insertions, 31 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 103d008dab8b..1932a3aeda1d 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -27,6 +27,7 @@
#include <linux/highmem.h>
#include <linux/module.h>
#include <linux/swap.h>
+#include <linux/hugetlb.h>
#include <asm/page.h>
#include <asm/cmpxchg.h>
@@ -211,6 +212,11 @@ static int is_shadow_present_pte(u64 pte)
&& pte != shadow_notrap_nonpresent_pte;
}
+static int is_large_pte(u64 pte)
+{
+ return pte & PT_PAGE_SIZE_MASK;
+}
+
static int is_writeble_pte(unsigned long pte)
{
return pte & PT_WRITABLE_MASK;
@@ -350,16 +356,100 @@ static void mmu_free_rmap_desc(struct kvm_rmap_desc *rd)
}
/*
+ * Return the pointer to the largepage write count for a given
+ * gfn, handling slots that are not large page aligned.
+ */
+static int *slot_largepage_idx(gfn_t gfn, struct kvm_memory_slot *slot)
+{
+ unsigned long idx;
+
+ idx = (gfn / KVM_PAGES_PER_HPAGE) -
+ (slot->base_gfn / KVM_PAGES_PER_HPAGE);
+ return &slot->lpage_info[idx].write_count;
+}
+
+static void account_shadowed(struct kvm *kvm, gfn_t gfn)
+{
+ int *write_count;
+
+ write_count = slot_largepage_idx(gfn, gfn_to_memslot(kvm, gfn));
+ *write_count += 1;
+ WARN_ON(*write_count > KVM_PAGES_PER_HPAGE);
+}
+
+static void unaccount_shadowed(struct kvm *kvm, gfn_t gfn)
+{
+ int *write_count;
+
+ write_count = slot_largepage_idx(gfn, gfn_to_memslot(kvm, gfn));
+ *write_count -= 1;
+ WARN_ON(*write_count < 0);
+}
+
+static int has_wrprotected_page(struct kvm *kvm, gfn_t gfn)
+{
+ struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
+ int *largepage_idx;
+
+ if (slot) {
+ largepage_idx = slot_largepage_idx(gfn, slot);
+ return *largepage_idx;
+ }
+
+ return 1;
+}
+
+static int host_largepage_backed(struct kvm *kvm, gfn_t gfn)
+{
+ struct vm_area_struct *vma;
+ unsigned long addr;
+
+ addr = gfn_to_hva(kvm, gfn);
+ if (kvm_is_error_hva(addr))
+ return 0;
+
+ vma = find_vma(current->mm, addr);
+ if (vma && is_vm_hugetlb_page(vma))
+ return 1;
+
+ return 0;
+}
+
+static int is_largepage_backed(struct kvm_vcpu *vcpu, gfn_t large_gfn)
+{
+ struct kvm_memory_slot *slot;
+
+ if (has_wrprotected_page(vcpu->kvm, large_gfn))
+ return 0;
+
+ if (!host_largepage_backed(vcpu->kvm, large_gfn))
+ return 0;
+
+ slot = gfn_to_memslot(vcpu->kvm, large_gfn);
+ if (slot && slot->dirty_bitmap)
+ return 0;
+
+ return 1;
+}
+
+/*
* Take gfn and return the reverse mapping to it.
* Note: gfn must be unaliased before this function get called
*/
-static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn)
+static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn, int lpage)
{
struct kvm_memory_slot *slot;
+ unsigned long idx;
slot = gfn_to_memslot(kvm, gfn);
- return &slot->rmap[gfn - slot->base_gfn];
+ if (!lpage)
+ return &slot->rmap[gfn - slot->base_gfn];
+
+ idx = (gfn / KVM_PAGES_PER_HPAGE) -
+ (slot->base_gfn / KVM_PAGES_PER_HPAGE);
+
+ return &slot->lpage_info[idx].rmap_pde;
}
/*
@@ -371,7 +461,7 @@ static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn)
* If rmapp bit zero is one, (then rmap & ~1) points to a struct kvm_rmap_desc
* containing more mappings.
*/
-static void rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
+static void rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn, int lpage)
{
struct kvm_mmu_page *sp;
struct kvm_rmap_desc *desc;
@@ -383,7 +473,7 @@ static void rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
gfn = unalias_gfn(vcpu->kvm, gfn);
sp = page_header(__pa(spte));
sp->gfns[spte - sp->spt] = gfn;
- rmapp = gfn_to_rmap(vcpu->kvm, gfn);
+ rmapp = gfn_to_rmap(vcpu->kvm, gfn, lpage);
if (!*rmapp) {
rmap_printk("rmap_add: %p %llx 0->1\n", spte, *spte);
*rmapp = (unsigned long)spte;
@@ -449,7 +539,7 @@ static void rmap_remove(struct kvm *kvm, u64 *spte)
kvm_release_page_dirty(page);
else
kvm_release_page_clean(page);
- rmapp = gfn_to_rmap(kvm, sp->gfns[spte - sp->spt]);
+ rmapp = gfn_to_rmap(kvm, sp->gfns[spte - sp->spt], is_large_pte(*spte));
if (!*rmapp) {
printk(KERN_ERR "rmap_remove: %p %llx 0->BUG\n", spte, *spte);
BUG();
@@ -515,7 +605,7 @@ static void rmap_write_protect(struct kvm *kvm, u64 gfn)
int write_protected = 0;
gfn = unalias_gfn(kvm, gfn);
- rmapp = gfn_to_rmap(kvm, gfn);
+ rmapp = gfn_to_rmap(kvm, gfn, 0);
spte = rmap_next(kvm, rmapp, NULL);
while (spte) {
@@ -528,8 +618,27 @@ static void rmap_write_protect(struct kvm *kvm, u64 gfn)
}
spte = rmap_next(kvm, rmapp, spte);
}
+ /* check for huge page mappings */
+ rmapp = gfn_to_rmap(kvm, gfn, 1);
+ spte = rmap_next(kvm, rmapp, NULL);
+ while (spte) {
+ BUG_ON(!spte);
+ BUG_ON(!(*spte & PT_PRESENT_MASK));
+ BUG_ON((*spte & (PT_PAGE_SIZE_MASK|PT_PRESENT_MASK)) != (PT_PAGE_SIZE_MASK|PT_PRESENT_MASK));
+ pgprintk("rmap_write_protect(large): spte %p %llx %lld\n", spte, *spte, gfn);
+ if (is_writeble_pte(*spte)) {
+ rmap_remove(kvm, spte);
+ --kvm->stat.lpages;
+ set_shadow_pte(spte, shadow_trap_nonpresent_pte);
+ write_protected = 1;
+ }
+ spte = rmap_next(kvm, rmapp, spte);
+ }
+
if (write_protected)
kvm_flush_remote_tlbs(kvm);
+
+ account_shadowed(kvm, gfn);
}
#ifdef MMU_DEBUG
@@ -747,11 +856,17 @@ static void kvm_mmu_page_unlink_children(struct kvm *kvm,
for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
ent = pt[i];
+ if (is_shadow_present_pte(ent)) {
+ if (!is_large_pte(ent)) {
+ ent &= PT64_BASE_ADDR_MASK;
+ mmu_page_remove_parent_pte(page_header(ent),
+ &pt[i]);
+ } else {
+ --kvm->stat.lpages;
+ rmap_remove(kvm, &pt[i]);
+ }
+ }
pt[i] = shadow_trap_nonpresent_pte;
- if (!is_shadow_present_pte(ent))
- continue;
- ent &= PT64_BASE_ADDR_MASK;
- mmu_page_remove_parent_pte(page_header(ent), &pt[i]);
}
kvm_flush_remote_tlbs(kvm);
}
@@ -791,6 +906,8 @@ static void kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp)
}
kvm_mmu_page_unlink_children(kvm, sp);
if (!sp->root_count) {
+ if (!sp->role.metaphysical)
+ unaccount_shadowed(kvm, sp->gfn);
hlist_del(&sp->hash_link);
kvm_mmu_free_page(kvm, sp);
} else {
@@ -894,7 +1011,8 @@ struct page *gva_to_page(struct kvm_vcpu *vcpu, gva_t gva)
static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
unsigned pt_access, unsigned pte_access,
int user_fault, int write_fault, int dirty,
- int *ptwrite, gfn_t gfn, struct page *page)
+ int *ptwrite, int largepage, gfn_t gfn,
+ struct page *page)
{
u64 spte;
int was_rmapped = 0;
@@ -907,15 +1025,29 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
write_fault, user_fault, gfn);
if (is_rmap_pte(*shadow_pte)) {
- if (host_pfn != page_to_pfn(page)) {
+ /*
+ * If we overwrite a PTE page pointer with a 2MB PMD, unlink
+ * the parent of the now unreachable PTE.
+ */
+ if (largepage && !is_large_pte(*shadow_pte)) {
+ struct kvm_mmu_page *child;
+ u64 pte = *shadow_pte;
+
+ child = page_header(pte & PT64_BASE_ADDR_MASK);
+ mmu_page_remove_parent_pte(child, shadow_pte);
+ } else if (host_pfn != page_to_pfn(page)) {
pgprintk("hfn old %lx new %lx\n",
host_pfn, page_to_pfn(page));
rmap_remove(vcpu->kvm, shadow_pte);
+ } else {
+ if (largepage)
+ was_rmapped = is_large_pte(*shadow_pte);
+ else
+ was_rmapped = 1;
}
- else
- was_rmapped = 1;
}
+
/*
* We don't set the accessed bit, since we sometimes want to see
* whether the guest actually used the pte (in order to detect
@@ -930,6 +1062,8 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
spte |= PT_PRESENT_MASK;
if (pte_access & ACC_USER_MASK)
spte |= PT_USER_MASK;
+ if (largepage)
+ spte |= PT_PAGE_SIZE_MASK;
spte |= page_to_phys(page);
@@ -944,7 +1078,8 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
}
shadow = kvm_mmu_lookup_page(vcpu->kvm, gfn);
- if (shadow) {
+ if (shadow ||
+ (largepage && has_wrprotected_page(vcpu->kvm, gfn))) {
pgprintk("%s: found shadow page for %lx, marking ro\n",
__FUNCTION__, gfn);
pte_access &= ~ACC_WRITE_MASK;
@@ -963,10 +1098,17 @@ unshadowed:
mark_page_dirty(vcpu->kvm, gfn);
pgprintk("%s: setting spte %llx\n", __FUNCTION__, spte);
+ pgprintk("instantiating %s PTE (%s) at %d (%llx) addr %llx\n",
+ (spte&PT_PAGE_SIZE_MASK)? "2MB" : "4kB",
+ (spte&PT_WRITABLE_MASK)?"RW":"R", gfn, spte, shadow_pte);
set_shadow_pte(shadow_pte, spte);
+ if (!was_rmapped && (spte & PT_PAGE_SIZE_MASK)
+ && (spte & PT_PRESENT_MASK))
+ ++vcpu->kvm->stat.lpages;
+
page_header_update_slot(vcpu->kvm, shadow_pte, gfn);
if (!was_rmapped) {
- rmap_add(vcpu, shadow_pte, gfn);
+ rmap_add(vcpu, shadow_pte, gfn, largepage);
if (!is_rmap_pte(*shadow_pte))
kvm_release_page_clean(page);
} else {
@@ -984,7 +1126,8 @@ static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
}
static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
- gfn_t gfn, struct page *page, int level)
+ int largepage, gfn_t gfn, struct page *page,
+ int level)
{
hpa_t table_addr = vcpu->arch.mmu.root_hpa;
int pt_write = 0;
@@ -998,7 +1141,13 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
if (level == 1) {
mmu_set_spte(vcpu, &table[index], ACC_ALL, ACC_ALL,
- 0, write, 1, &pt_write, gfn, page);
+ 0, write, 1, &pt_write, 0, gfn, page);
+ return pt_write;
+ }
+
+ if (largepage && level == 2) {
+ mmu_set_spte(vcpu, &table[index], ACC_ALL, ACC_ALL,
+ 0, write, 1, &pt_write, 1, gfn, page);
return pt_write;
}
@@ -1027,12 +1176,18 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
{
int r;
+ int largepage = 0;
struct page *page;
down_read(&vcpu->kvm->slots_lock);
down_read(&current->mm->mmap_sem);
+ if (is_largepage_backed(vcpu, gfn & ~(KVM_PAGES_PER_HPAGE-1))) {
+ gfn &= ~(KVM_PAGES_PER_HPAGE-1);
+ largepage = 1;
+ }
+
page = gfn_to_page(vcpu->kvm, gfn);
up_read(&current->mm->mmap_sem);
@@ -1045,7 +1200,8 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
spin_lock(&vcpu->kvm->mmu_lock);
kvm_mmu_free_some_pages(vcpu);
- r = __direct_map(vcpu, v, write, gfn, page, PT32E_ROOT_LEVEL);
+ r = __direct_map(vcpu, v, write, largepage, gfn, page,
+ PT32E_ROOT_LEVEL);
spin_unlock(&vcpu->kvm->mmu_lock);
up_read(&vcpu->kvm->slots_lock);
@@ -1180,6 +1336,8 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
{
struct page *page;
int r;
+ int largepage = 0;
+ gfn_t gfn = gpa >> PAGE_SHIFT;
ASSERT(vcpu);
ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
@@ -1189,7 +1347,11 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
return r;
down_read(&current->mm->mmap_sem);
- page = gfn_to_page(vcpu->kvm, gpa >> PAGE_SHIFT);
+ if (is_largepage_backed(vcpu, gfn & ~(KVM_PAGES_PER_HPAGE-1))) {
+ gfn &= ~(KVM_PAGES_PER_HPAGE-1);
+ largepage = 1;
+ }
+ page = gfn_to_page(vcpu->kvm, gfn);
if (is_error_page(page)) {
kvm_release_page_clean(page);
up_read(&current->mm->mmap_sem);
@@ -1198,7 +1360,7 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
spin_lock(&vcpu->kvm->mmu_lock);
kvm_mmu_free_some_pages(vcpu);
r = __direct_map(vcpu, gpa, error_code & PFERR_WRITE_MASK,
- gpa >> PAGE_SHIFT, page, TDP_ROOT_LEVEL);
+ largepage, gfn, page, TDP_ROOT_LEVEL);
spin_unlock(&vcpu->kvm->mmu_lock);
up_read(&current->mm->mmap_sem);
@@ -1397,7 +1559,8 @@ static void mmu_pte_write_zap_pte(struct kvm_vcpu *vcpu,
pte = *spte;
if (is_shadow_present_pte(pte)) {
- if (sp->role.level == PT_PAGE_TABLE_LEVEL)
+ if (sp->role.level == PT_PAGE_TABLE_LEVEL ||
+ is_large_pte(pte))
rmap_remove(vcpu->kvm, spte);
else {
child = page_header(pte & PT64_BASE_ADDR_MASK);
@@ -1405,6 +1568,8 @@ static void mmu_pte_write_zap_pte(struct kvm_vcpu *vcpu,
}
}
set_shadow_pte(spte, shadow_trap_nonpresent_pte);
+ if (is_large_pte(pte))
+ --vcpu->kvm->stat.lpages;
}
static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
@@ -1412,7 +1577,8 @@ static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
u64 *spte,
const void *new)
{
- if (sp->role.level != PT_PAGE_TABLE_LEVEL) {
+ if ((sp->role.level != PT_PAGE_TABLE_LEVEL)
+ && !vcpu->arch.update_pte.largepage) {
++vcpu->kvm->stat.mmu_pde_zapped;
return;
}
@@ -1460,6 +1626,8 @@ static void mmu_guess_page_from_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
u64 gpte = 0;
struct page *page;
+ vcpu->arch.update_pte.largepage = 0;
+
if (bytes != 4 && bytes != 8)
return;
@@ -1487,9 +1655,13 @@ static void mmu_guess_page_from_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
return;
gfn = (gpte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
- down_read(&vcpu->kvm->slots_lock);
+ down_read(&current->mm->mmap_sem);
+ if (is_large_pte(gpte) && is_largepage_backed(vcpu, gfn)) {
+ gfn &= ~(KVM_PAGES_PER_HPAGE-1);
+ vcpu->arch.update_pte.largepage = 1;
+ }
page = gfn_to_page(vcpu->kvm, gfn);
- up_read(&vcpu->kvm->slots_lock);
+ up_read(&current->mm->mmap_sem);
if (is_error_page(page)) {
kvm_release_page_clean(page);
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 4b55f462e2b3..17f9d160ca34 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -248,6 +248,7 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *page,
pt_element_t gpte;
unsigned pte_access;
struct page *npage;
+ int largepage = vcpu->arch.update_pte.largepage;
gpte = *(const pt_element_t *)pte;
if (~gpte & (PT_PRESENT_MASK | PT_ACCESSED_MASK)) {
@@ -264,7 +265,8 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *page,
return;
get_page(npage);
mmu_set_spte(vcpu, spte, page->role.access, pte_access, 0, 0,
- gpte & PT_DIRTY_MASK, NULL, gpte_to_gfn(gpte), npage);
+ gpte & PT_DIRTY_MASK, NULL, largepage, gpte_to_gfn(gpte),
+ npage);
}
/*
@@ -272,8 +274,8 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *page,
*/
static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
struct guest_walker *walker,
- int user_fault, int write_fault, int *ptwrite,
- struct page *page)
+ int user_fault, int write_fault, int largepage,
+ int *ptwrite, struct page *page)
{
hpa_t shadow_addr;
int level;
@@ -301,11 +303,19 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
shadow_ent = ((u64 *)__va(shadow_addr)) + index;
if (level == PT_PAGE_TABLE_LEVEL)
break;
- if (is_shadow_present_pte(*shadow_ent)) {
+
+ if (largepage && level == PT_DIRECTORY_LEVEL)
+ break;
+
+ if (is_shadow_present_pte(*shadow_ent)
+ && !is_large_pte(*shadow_ent)) {
shadow_addr = *shadow_ent & PT64_BASE_ADDR_MASK;
continue;
}
+ if (is_large_pte(*shadow_ent))
+ rmap_remove(vcpu->kvm, shadow_ent);
+
if (level - 1 == PT_PAGE_TABLE_LEVEL
&& walker->level == PT_DIRECTORY_LEVEL) {
metaphysical = 1;
@@ -339,7 +349,7 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
mmu_set_spte(vcpu, shadow_ent, access, walker->pte_access & access,
user_fault, write_fault,
walker->ptes[walker->level-1] & PT_DIRTY_MASK,
- ptwrite, walker->gfn, page);
+ ptwrite, largepage, walker->gfn, page);
return shadow_ent;
}
@@ -369,6 +379,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
int write_pt = 0;
int r;
struct page *page;
+ int largepage = 0;
pgprintk("%s: addr %lx err %x\n", __FUNCTION__, addr, error_code);
kvm_mmu_audit(vcpu, "pre page fault");
@@ -396,6 +407,14 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
}
down_read(&current->mm->mmap_sem);
+ if (walker.level == PT_DIRECTORY_LEVEL) {
+ gfn_t large_gfn;
+ large_gfn = walker.gfn & ~(KVM_PAGES_PER_HPAGE-1);
+ if (is_largepage_backed(vcpu, large_gfn)) {
+ walker.gfn = large_gfn;
+ largepage = 1;
+ }
+ }
page = gfn_to_page(vcpu->kvm, walker.gfn);
up_read(&current->mm->mmap_sem);
@@ -410,7 +429,8 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
spin_lock(&vcpu->kvm->mmu_lock);
kvm_mmu_free_some_pages(vcpu);
shadow_pte = FNAME(fetch)(vcpu, addr, &walker, user_fault, write_fault,
- &write_pt, page);
+ largepage, &write_pt, page);
+
pgprintk("%s: shadow pte %p %llx ptwrite %d\n", __FUNCTION__,
shadow_pte, *shadow_pte, write_pt);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e8e64927bddc..0458bd516185 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -88,6 +88,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
{ "mmu_recycled", VM_STAT(mmu_recycled) },
{ "mmu_cache_miss", VM_STAT(mmu_cache_miss) },
{ "remote_tlb_flush", VM_STAT(remote_tlb_flush) },
+ { "largepages", VM_STAT(lpages) },
{ NULL }
};
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-09 20:47:41 +0000