3 files changed, 36 insertions, 0 deletions

diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index 58b9deb0bc0e..b7068ecd7765 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -448,6 +448,9 @@ int kvm_write_guest(struct kvm_vcpu *vcpu,
 
 unsigned long segment_base(u16 selector);
 
+void kvm_mmu_pre_write(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes);
+void kvm_mmu_post_write(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes);
+
 static inline struct page *_gfn_to_page(struct kvm *kvm, gfn_t gfn)
 {
         struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 68e121eeccbc..047f6f6ed3f6 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -877,6 +877,27 @@ static int emulator_read_emulated(unsigned long addr,
         }
 }
 
+static int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
+                               unsigned long val, int bytes)
+{
+        struct kvm_memory_slot *m;
+        struct page *page;
+        void *virt;
+
+        if (((gpa + bytes - 1) >> PAGE_SHIFT) != (gpa >> PAGE_SHIFT))
+                return 0;
+        m = gfn_to_memslot(vcpu->kvm, gpa >> PAGE_SHIFT);
+        if (!m)
+                return 0;
+        page = gfn_to_page(m, gpa >> PAGE_SHIFT);
+        kvm_mmu_pre_write(vcpu, gpa, bytes);
+        virt = kmap_atomic(page, KM_USER0);
+        memcpy(virt + offset_in_page(gpa), &val, bytes);
+        kunmap_atomic(virt, KM_USER0);
+        kvm_mmu_post_write(vcpu, gpa, bytes);
+        return 1;
+}
+
 static int emulator_write_emulated(unsigned long addr,
                                    unsigned long val,
                                    unsigned int bytes,
@@ -888,6 +909,9 @@ static int emulator_write_emulated(unsigned long addr,
         if (gpa == UNMAPPED_GVA)
                 return X86EMUL_PROPAGATE_FAULT;
 
+        if (emulator_write_phys(vcpu, gpa, val, bytes))
+                return X86EMUL_CONTINUE;
+
         vcpu->mmio_needed = 1;
         vcpu->mmio_phys_addr = gpa;
         vcpu->mmio_size = bytes;
diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c
index ceae25bfd4b5..bce7eb21f739 100644
--- a/drivers/kvm/mmu.c
+++ b/drivers/kvm/mmu.c
@@ -956,6 +956,15 @@ int kvm_mmu_reset_context(struct kvm_vcpu *vcpu)
         return init_kvm_mmu(vcpu);
 }
 
+void kvm_mmu_pre_write(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes)
+{
+        pgprintk("%s: gpa %llx bytes %d\n", __FUNCTION__, gpa, bytes);
+}
+
+void kvm_mmu_post_write(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes)
+{
+}
+
 static void free_mmu_pages(struct kvm_vcpu *vcpu)
 {
         while (!list_empty(&vcpu->free_pages)) {