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-rw-r--r--drivers/kvm/kvm.h1
-rw-r--r--drivers/kvm/kvm_main.c1
-rw-r--r--drivers/kvm/mmu.c152
-rw-r--r--drivers/kvm/paging_tmpl.h1
4 files changed, 142 insertions, 13 deletions
diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index e8fe1039e3b5..b65511ed4388 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -236,6 +236,7 @@ struct kvm {
struct kvm_vcpu vcpus[KVM_MAX_VCPUS];
int memory_config_version;
int busy;
+ unsigned long rmap_overflow;
};
struct kvm_stat {
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index bc88c334664b..f2a6b6f0e929 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -638,6 +638,7 @@ raced:
| __GFP_ZERO);
if (!new.phys_mem[i])
goto out_free;
+ new.phys_mem[i]->private = 0;
}
}
diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c
index 790423c5f23d..0f27beb6c5df 100644
--- a/drivers/kvm/mmu.c
+++ b/drivers/kvm/mmu.c
@@ -27,6 +27,7 @@
#include "kvm.h"
#define pgprintk(x...) do { } while (0)
+#define rmap_printk(x...) do { } while (0)
#define ASSERT(x) \
if (!(x)) { \
@@ -125,6 +126,13 @@
#define PT_DIRECTORY_LEVEL 2
#define PT_PAGE_TABLE_LEVEL 1
+#define RMAP_EXT 4
+
+struct kvm_rmap_desc {
+ u64 *shadow_ptes[RMAP_EXT];
+ struct kvm_rmap_desc *more;
+};
+
static int is_write_protection(struct kvm_vcpu *vcpu)
{
return vcpu->cr0 & CR0_WP_MASK;
@@ -150,6 +158,120 @@ static int is_io_pte(unsigned long pte)
return pte & PT_SHADOW_IO_MARK;
}
+static int is_rmap_pte(u64 pte)
+{
+ return (pte & (PT_WRITABLE_MASK | PT_PRESENT_MASK))
+ == (PT_WRITABLE_MASK | PT_PRESENT_MASK);
+}
+
+/*
+ * Reverse mapping data structures:
+ *
+ * If page->private bit zero is zero, then page->private points to the
+ * shadow page table entry that points to page_address(page).
+ *
+ * If page->private bit zero is one, (then page->private & ~1) points
+ * to a struct kvm_rmap_desc containing more mappings.
+ */
+static void rmap_add(struct kvm *kvm, u64 *spte)
+{
+ struct page *page;
+ struct kvm_rmap_desc *desc;
+ int i;
+
+ if (!is_rmap_pte(*spte))
+ return;
+ page = pfn_to_page((*spte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT);
+ if (!page->private) {
+ rmap_printk("rmap_add: %p %llx 0->1\n", spte, *spte);
+ page->private = (unsigned long)spte;
+ } else if (!(page->private & 1)) {
+ rmap_printk("rmap_add: %p %llx 1->many\n", spte, *spte);
+ desc = kzalloc(sizeof *desc, GFP_NOWAIT);
+ if (!desc)
+ BUG(); /* FIXME: return error */
+ desc->shadow_ptes[0] = (u64 *)page->private;
+ desc->shadow_ptes[1] = spte;
+ page->private = (unsigned long)desc | 1;
+ } else {
+ rmap_printk("rmap_add: %p %llx many->many\n", spte, *spte);
+ desc = (struct kvm_rmap_desc *)(page->private & ~1ul);
+ while (desc->shadow_ptes[RMAP_EXT-1] && desc->more)
+ desc = desc->more;
+ if (desc->shadow_ptes[RMAP_EXT-1]) {
+ desc->more = kzalloc(sizeof *desc->more, GFP_NOWAIT);
+ if (!desc->more)
+ BUG(); /* FIXME: return error */
+ desc = desc->more;
+ }
+ for (i = 0; desc->shadow_ptes[i]; ++i)
+ ;
+ desc->shadow_ptes[i] = spte;
+ }
+}
+
+static void rmap_desc_remove_entry(struct page *page,
+ struct kvm_rmap_desc *desc,
+ int i,
+ struct kvm_rmap_desc *prev_desc)
+{
+ int j;
+
+ for (j = RMAP_EXT - 1; !desc->shadow_ptes[j] && j > i; --j)
+ ;
+ desc->shadow_ptes[i] = desc->shadow_ptes[j];
+ desc->shadow_ptes[j] = 0;
+ if (j != 0)
+ return;
+ if (!prev_desc && !desc->more)
+ page->private = (unsigned long)desc->shadow_ptes[0];
+ else
+ if (prev_desc)
+ prev_desc->more = desc->more;
+ else
+ page->private = (unsigned long)desc->more | 1;
+ kfree(desc);
+}
+
+static void rmap_remove(struct kvm *kvm, u64 *spte)
+{
+ struct page *page;
+ struct kvm_rmap_desc *desc;
+ struct kvm_rmap_desc *prev_desc;
+ int i;
+
+ if (!is_rmap_pte(*spte))
+ return;
+ page = pfn_to_page((*spte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT);
+ if (!page->private) {
+ printk(KERN_ERR "rmap_remove: %p %llx 0->BUG\n", spte, *spte);
+ BUG();
+ } else if (!(page->private & 1)) {
+ rmap_printk("rmap_remove: %p %llx 1->0\n", spte, *spte);
+ if ((u64 *)page->private != spte) {
+ printk(KERN_ERR "rmap_remove: %p %llx 1->BUG\n",
+ spte, *spte);
+ BUG();
+ }
+ page->private = 0;
+ } else {
+ rmap_printk("rmap_remove: %p %llx many->many\n", spte, *spte);
+ desc = (struct kvm_rmap_desc *)(page->private & ~1ul);
+ prev_desc = NULL;
+ while (desc) {
+ for (i = 0; i < RMAP_EXT && desc->shadow_ptes[i]; ++i)
+ if (desc->shadow_ptes[i] == spte) {
+ rmap_desc_remove_entry(page, desc, i,
+ prev_desc);
+ return;
+ }
+ prev_desc = desc;
+ desc = desc->more;
+ }
+ BUG();
+ }
+}
+
static void kvm_mmu_free_page(struct kvm_vcpu *vcpu, hpa_t page_hpa)
{
struct kvm_mmu_page *page_head = page_header(page_hpa);
@@ -229,27 +351,27 @@ hpa_t gva_to_hpa(struct kvm_vcpu *vcpu, gva_t gva)
static void release_pt_page_64(struct kvm_vcpu *vcpu, hpa_t page_hpa,
int level)
{
+ u64 *pos;
+ u64 *end;
+
ASSERT(vcpu);
ASSERT(VALID_PAGE(page_hpa));
ASSERT(level <= PT64_ROOT_LEVEL && level > 0);
- if (level == 1)
- memset(__va(page_hpa), 0, PAGE_SIZE);
- else {
- u64 *pos;
- u64 *end;
+ for (pos = __va(page_hpa), end = pos + PT64_ENT_PER_PAGE;
+ pos != end; pos++) {
+ u64 current_ent = *pos;
- for (pos = __va(page_hpa), end = pos + PT64_ENT_PER_PAGE;
- pos != end; pos++) {
- u64 current_ent = *pos;
-
- *pos = 0;
- if (is_present_pte(current_ent))
+ if (is_present_pte(current_ent)) {
+ if (level != 1)
release_pt_page_64(vcpu,
current_ent &
PT64_BASE_ADDR_MASK,
level - 1);
+ else
+ rmap_remove(vcpu->kvm, pos);
}
+ *pos = 0;
}
kvm_mmu_free_page(vcpu, page_hpa);
}
@@ -275,6 +397,7 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, hpa_t p)
page_header_update_slot(vcpu->kvm, table, v);
table[index] = p | PT_PRESENT_MASK | PT_WRITABLE_MASK |
PT_USER_MASK;
+ rmap_add(vcpu->kvm, &table[index]);
return 0;
}
@@ -437,6 +560,7 @@ static inline void set_pte_common(struct kvm_vcpu *vcpu,
} else {
*shadow_pte |= paddr;
page_header_update_slot(vcpu->kvm, shadow_pte, gaddr);
+ rmap_add(vcpu->kvm, shadow_pte);
}
}
@@ -489,6 +613,7 @@ static void paging_inval_page(struct kvm_vcpu *vcpu, gva_t addr)
u64 *table = __va(page_addr);
if (level == PT_PAGE_TABLE_LEVEL ) {
+ rmap_remove(vcpu->kvm, &table[index]);
table[index] = 0;
return;
}
@@ -679,8 +804,9 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
pt = __va(page->page_hpa);
for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
/* avoid RMW */
- if (pt[i] & PT_WRITABLE_MASK)
+ if (pt[i] & PT_WRITABLE_MASK) {
+ rmap_remove(kvm, &pt[i]);
pt[i] &= ~PT_WRITABLE_MASK;
-
+ }
}
}
diff --git a/drivers/kvm/paging_tmpl.h b/drivers/kvm/paging_tmpl.h
index 09bb9b4ed12d..8c48528a6e89 100644
--- a/drivers/kvm/paging_tmpl.h
+++ b/drivers/kvm/paging_tmpl.h
@@ -261,6 +261,7 @@ static int FNAME(fix_write_pf)(struct kvm_vcpu *vcpu,
mark_page_dirty(vcpu->kvm, gfn);
*shadow_ent |= PT_WRITABLE_MASK;
*guest_ent |= PT_DIRTY_MASK;
+ rmap_add(vcpu->kvm, shadow_ent);
return 1;
}
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