[PATCH v2 2/5] KVM: MMU: clear apfs if page state is changed

[Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>]

If CR0.PG is changed, the page fault cann't be avoid when the prefault address
is accessed later

And it also fix a bug: it can retry a page enabled #PF in page disabled context
if mmu is shadow page

This idear is from Gleb Natapov

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
---
 arch/x86/kvm/x86.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index fc29223..c071d73 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -525,6 +525,9 @@ int kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
 
 	kvm_x86_ops->set_cr0(vcpu, cr0);
 
+	if ((cr0 ^ old_cr0) & X86_CR0_PG)
+		kvm_clear_async_pf_completion_queue(vcpu);
+
 	if ((cr0 ^ old_cr0) & update_bits)
 		kvm_mmu_reset_context(vcpu);
 	return 0;
-- 
1.7.0.4