KVM: MMU: Fold fix_read_pf() into set_pte_common()

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

1 files changed, 23 insertions, 11 deletions

diff --git a/drivers/kvm/paging_tmpl.h b/drivers/kvm/paging_tmpl.h
index 7e998d193849..869582befaf1 100644
--- a/drivers/kvm/paging_tmpl.h
+++ b/drivers/kvm/paging_tmpl.h
@@ -197,6 +197,7 @@ static void FNAME(set_pte_common)(struct kvm_vcpu *vcpu,
                                   gpa_t gaddr,
                                   pt_element_t *gpte,
                                   u64 access_bits,
+                                  int write_fault,
                                   gfn_t gfn)
 {
         hpa_t paddr;
@@ -219,6 +220,17 @@ static void FNAME(set_pte_common)(struct kvm_vcpu *vcpu,
 
         *shadow_pte |= paddr;
 
+        if (!write_fault && (*shadow_pte & PT_SHADOW_USER_MASK) &&
+            !(*shadow_pte & PT_USER_MASK)) {
+                /*
+                 * If supervisor write protect is disabled, we shadow kernel
+                 * pages as user pages so we can trap the write access.
+                 */
+                *shadow_pte |= PT_USER_MASK;
+                *shadow_pte &= ~PT_WRITABLE_MASK;
+                access_bits &= ~PT_WRITABLE_MASK;
+        }
+
         if (access_bits & PT_WRITABLE_MASK) {
                 struct kvm_mmu_page *shadow;
 
@@ -242,13 +254,14 @@ static void FNAME(set_pte_common)(struct kvm_vcpu *vcpu,
 }
 
 static void FNAME(set_pte)(struct kvm_vcpu *vcpu, pt_element_t *gpte,
-                           u64 *shadow_pte, u64 access_bits, gfn_t gfn)
+                           u64 *shadow_pte, u64 access_bits,
+                           int write_fault, gfn_t gfn)
 {
         ASSERT(*shadow_pte == 0);
         access_bits &= *gpte;
         *shadow_pte = (*gpte & PT_PTE_COPY_MASK);
         FNAME(set_pte_common)(vcpu, shadow_pte, *gpte & PT_BASE_ADDR_MASK,
-                              gpte, access_bits, gfn);
+                              gpte, access_bits, write_fault, gfn);
 }
 
 static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *page,
@@ -262,12 +275,13 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *page,
         if (~gpte & (PT_PRESENT_MASK | PT_ACCESSED_MASK))
                 return;
         pgprintk("%s: gpte %llx spte %p\n", __FUNCTION__, (u64)gpte, spte);
-        FNAME(set_pte)(vcpu, &gpte, spte, PT_USER_MASK | PT_WRITABLE_MASK,
+        FNAME(set_pte)(vcpu, &gpte, spte, PT_USER_MASK | PT_WRITABLE_MASK, 0,
                        (gpte & PT_BASE_ADDR_MASK) >> PAGE_SHIFT);
 }
 
 static void FNAME(set_pde)(struct kvm_vcpu *vcpu, pt_element_t *gpde,
-                           u64 *shadow_pte, u64 access_bits, gfn_t gfn)
+                           u64 *shadow_pte, u64 access_bits, int write_fault,
+                           gfn_t gfn)
 {
         gpa_t gaddr;
 
@@ -279,14 +293,14 @@ static void FNAME(set_pde)(struct kvm_vcpu *vcpu, pt_element_t *gpde,
                         (32 - PT32_DIR_PSE36_SHIFT);
         *shadow_pte = *gpde & PT_PTE_COPY_MASK;
         FNAME(set_pte_common)(vcpu, shadow_pte, gaddr,
-                              gpde, access_bits, gfn);
+                              gpde, access_bits, write_fault, gfn);
 }
 
 /*
  * Fetch a shadow pte for a specific level in the paging hierarchy.
  */
 static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
-                              struct guest_walker *walker)
+                         struct guest_walker *walker, int write_fault)
 {
         hpa_t shadow_addr;
         int level;
@@ -351,12 +365,12 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
                 if (prev_shadow_ent)
                         *prev_shadow_ent |= PT_SHADOW_PS_MARK;
                 FNAME(set_pde)(vcpu, guest_ent, shadow_ent,
-                               walker->inherited_ar, walker->gfn);
+                               walker->inherited_ar, write_fault, walker->gfn);
         } else {
                 ASSERT(walker->level == PT_PAGE_TABLE_LEVEL);
                 FNAME(set_pte)(vcpu, guest_ent, shadow_ent,
                                walker->inherited_ar,
-                               walker->gfn);
+                               write_fault, walker->gfn);
         }
         return shadow_ent;
 }
@@ -489,7 +503,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
                 return 0;
         }
 
-        shadow_pte = FNAME(fetch)(vcpu, addr, &walker);
+        shadow_pte = FNAME(fetch)(vcpu, addr, &walker, write_fault);
         pgprintk("%s: shadow pte %p %llx\n", __FUNCTION__,
                  shadow_pte, *shadow_pte);
 
@@ -499,8 +513,6 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
         if (write_fault)
                 fixed = FNAME(fix_write_pf)(vcpu, shadow_pte, &walker, addr,
                                             user_fault, &write_pt);
-        else
-                fixed = fix_read_pf(shadow_pte);
 
         pgprintk("%s: updated shadow pte %p %llx\n", __FUNCTION__,
                  shadow_pte, *shadow_pte);