KVM: MMU: fix SMAP virtualization
KVM may turn a user page to a kernel page when kernel writes a readonly
user page if CR0.WP = 1. This shadow page entry will be reused after
SMAP is enabled so that kernel is allowed to access this user page
Fix it by setting SMAP && !CR0.WP into shadow page's role and reset mmu
once CR4.SMAP is updated
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index cdccbe1..cde5d61 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -702,8 +702,9 @@
int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
{
unsigned long old_cr4 = kvm_read_cr4(vcpu);
- unsigned long pdptr_bits = X86_CR4_PGE | X86_CR4_PSE |
- X86_CR4_PAE | X86_CR4_SMEP;
+ unsigned long pdptr_bits = X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PAE |
+ X86_CR4_SMEP | X86_CR4_SMAP;
+
if (cr4 & CR4_RESERVED_BITS)
return 1;
@@ -744,9 +745,6 @@
(!(cr4 & X86_CR4_PCIDE) && (old_cr4 & X86_CR4_PCIDE)))
kvm_mmu_reset_context(vcpu);
- if ((cr4 ^ old_cr4) & X86_CR4_SMAP)
- update_permission_bitmask(vcpu, vcpu->arch.walk_mmu, false);
-
if ((cr4 ^ old_cr4) & X86_CR4_OSXSAVE)
kvm_update_cpuid(vcpu);