KVM: Fetch guest cr3 from hardware on demand

Instead of syncing the guest cr3 every exit, which is expensince on vmx
with ept enabled, sync it only on demand.

[sheng: fix incorrect cr3 seen by Windows XP]

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 6268f6ce6434..95f026be8b5e 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -117,6 +117,7 @@ enum kvm_reg {
 
 enum kvm_reg_ex {
         VCPU_EXREG_PDPTR = NR_VCPU_REGS,
+        VCPU_EXREG_CR3,
 };
 
 enum {
@@ -533,6 +534,7 @@ struct kvm_x86_ops {
                             struct kvm_segment *var, int seg);
         void (*get_cs_db_l_bits)(struct kvm_vcpu *vcpu, int *db, int *l);
         void (*decache_cr0_guest_bits)(struct kvm_vcpu *vcpu);
+        void (*decache_cr3)(struct kvm_vcpu *vcpu);
         void (*decache_cr4_guest_bits)(struct kvm_vcpu *vcpu);
         void (*set_cr0)(struct kvm_vcpu *vcpu, unsigned long cr0);
         void (*set_cr3)(struct kvm_vcpu *vcpu, unsigned long cr3);