KVM: MMU: Use mmu_set_spte() for real-mode shadows

In addition to removing some duplicated code, this also handles the unlikely
case of real-mode code updating a guest page table.  This can happen when
one vcpu (in real mode) touches a second vcpu's (in protected mode) page
tables, or if a vcpu switches to real mode, touches page tables, and switches
back.

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

1 files changed, 10 insertions, 31 deletions

diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c
index b4dd72645853..ba71e8d66761 100644
--- a/drivers/kvm/mmu.c
+++ b/drivers/kvm/mmu.c
@@ -966,40 +966,23 @@ static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
 {
 }
 
-static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, struct page *page)
+static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
 {
         int level = PT32E_ROOT_LEVEL;
         hpa_t table_addr = vcpu->mmu.root_hpa;
+        int pt_write = 0;
 
         for (; ; level--) {
                 u32 index = PT64_INDEX(v, level);
                 u64 *table;
-                u64 pte;
 
                 ASSERT(VALID_PAGE(table_addr));
                 table = __va(table_addr);
 
                 if (level == 1) {
-                        int was_rmapped;
-
-                        pte = table[index];
-                        was_rmapped = is_rmap_pte(pte);
-                        if (is_shadow_present_pte(pte) && is_writeble_pte(pte)) {
-                                kvm_release_page_clean(page);
-                                return 0;
-                        }
-                        mark_page_dirty(vcpu->kvm, v >> PAGE_SHIFT);
-                        page_header_update_slot(vcpu->kvm, table,
-                                                v >> PAGE_SHIFT);
-                        table[index] = page_to_phys(page)
-                                | PT_PRESENT_MASK | PT_WRITABLE_MASK
-                                | PT_USER_MASK;
-                        if (!was_rmapped)
-                                rmap_add(vcpu, &table[index], v >> PAGE_SHIFT);
-                        else
-                                kvm_release_page_clean(page);
-
-                        return 0;
+                        mmu_set_spte(vcpu, &table[index], ACC_ALL, ACC_ALL,
+                                     0, write, 1, &pt_write, gfn);
+                        return pt_write || is_io_pte(table[index]);
                 }
 
                 if (table[index] == shadow_trap_nonpresent_pte) {
@@ -1013,7 +996,6 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, struct page *page)
                                                      1, ACC_ALL, &table[index]);
                         if (!new_table) {
                                 pgprintk("nonpaging_map: ENOMEM\n");
-                                kvm_release_page_clean(page);
                                 return -ENOMEM;
                         }
 
@@ -1114,9 +1096,10 @@ static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr)
 static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
                                 u32 error_code)
 {
-        struct page *page;
+        gfn_t gfn;
         int r;
 
+        pgprintk("%s: gva %lx error %x\n", __FUNCTION__, gva, error_code);
         r = mmu_topup_memory_caches(vcpu);
         if (r)
                 return r;
@@ -1124,14 +1107,10 @@ static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
         ASSERT(vcpu);
         ASSERT(VALID_PAGE(vcpu->mmu.root_hpa));
 
-        page = gfn_to_page(vcpu->kvm, gva >> PAGE_SHIFT);
-
-        if (is_error_page(page)) {
-                kvm_release_page_clean(page);
-                return 1;
-        }
+        gfn = gva >> PAGE_SHIFT;
 
-        return nonpaging_map(vcpu, gva & PAGE_MASK, page);
+        return nonpaging_map(vcpu, gva & PAGE_MASK,
+                             error_code & PFERR_WRITE_MASK, gfn);
 }
 
 static void nonpaging_free(struct kvm_vcpu *vcpu)