KVM: MMU: Selectively set PageDirty when releasing guest memory

Improve dirty bit setting for pages that kvm release, until now every page
that we released we marked dirty, from now only pages that have potential
to get dirty we mark dirty.

Signed-off-by: Izik Eidus <izike@qumranet.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 15 insertions, 8 deletions

diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c
index 8add4d5c6840..4624f3789b9a 100644
--- a/drivers/kvm/mmu.c
+++ b/drivers/kvm/mmu.c
@@ -420,14 +420,18 @@ static void rmap_remove(struct kvm *kvm, u64 *spte)
         struct kvm_rmap_desc *desc;
         struct kvm_rmap_desc *prev_desc;
         struct kvm_mmu_page *page;
+        struct page *release_page;
         unsigned long *rmapp;
         int i;
 
         if (!is_rmap_pte(*spte))
                 return;
         page = page_header(__pa(spte));
-        kvm_release_page(pfn_to_page((*spte & PT64_BASE_ADDR_MASK) >>
-                         PAGE_SHIFT));
+        release_page = pfn_to_page((*spte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT);
+        if (is_writeble_pte(*spte))
+                kvm_release_page_dirty(release_page);
+        else
+                kvm_release_page_clean(release_page);
         rmapp = gfn_to_rmap(kvm, page->gfns[spte - page->spt]);
         if (!*rmapp) {
                 printk(KERN_ERR "rmap_remove: %p %llx 0->BUG\n", spte, *spte);
@@ -893,7 +897,9 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, hpa_t p)
 {
         int level = PT32E_ROOT_LEVEL;
         hpa_t table_addr = vcpu->mmu.root_hpa;
+        struct page *page;
 
+        page = pfn_to_page(p >> PAGE_SHIFT);
         for (; ; level--) {
                 u32 index = PT64_INDEX(v, level);
                 u64 *table;
@@ -908,7 +914,7 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, hpa_t p)
                         pte = table[index];
                         was_rmapped = is_rmap_pte(pte);
                         if (is_shadow_present_pte(pte) && is_writeble_pte(pte)) {
-                                kvm_release_page(pfn_to_page(p >> PAGE_SHIFT));
+                                kvm_release_page_clean(page);
                                 return 0;
                         }
                         mark_page_dirty(vcpu->kvm, v >> PAGE_SHIFT);
@@ -918,7 +924,8 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, hpa_t p)
                         if (!was_rmapped)
                                 rmap_add(vcpu, &table[index], v >> PAGE_SHIFT);
                         else
-                                kvm_release_page(pfn_to_page(p >> PAGE_SHIFT));
+                                kvm_release_page_clean(page);
+
                         return 0;
                 }
 
@@ -933,7 +940,7 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, hpa_t p)
                                                      1, 3, &table[index]);
                         if (!new_table) {
                                 pgprintk("nonpaging_map: ENOMEM\n");
-                                kvm_release_page(pfn_to_page(p >> PAGE_SHIFT));
+                                kvm_release_page_clean(page);
                                 return -ENOMEM;
                         }
 
@@ -1049,8 +1056,8 @@ static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
         paddr = gpa_to_hpa(vcpu->kvm, addr & PT64_BASE_ADDR_MASK);
 
         if (is_error_hpa(paddr)) {
-                kvm_release_page(pfn_to_page((paddr & PT64_BASE_ADDR_MASK)
-                                 >> PAGE_SHIFT));
+                kvm_release_page_clean(pfn_to_page((paddr & PT64_BASE_ADDR_MASK)
+                                       >> PAGE_SHIFT));
                 return 1;
         }
 
@@ -1580,7 +1587,7 @@ static void audit_mappings_page(struct kvm_vcpu *vcpu, u64 page_pte,
                                        " valid guest gva %lx\n", audit_msg, va);
                         page = pfn_to_page((gpa & PT64_BASE_ADDR_MASK)
                                            >> PAGE_SHIFT);
-                        kvm_release_page(page);
+                        kvm_release_page_clean(page);
 
                 }
         }