From 0be0226f07d14b153a5eedf2bb86e1eb7dcefab5 Mon Sep 17 00:00:00 2001 From: Xiao Guangrong Date: Mon, 11 May 2015 22:55:21 +0800 Subject: 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 Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini --- arch/x86/kvm/x86.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) (limited to 'arch/x86/kvm/x86.c') diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index c73efcd03e29..986b3f5d0523 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -702,8 +702,9 @@ EXPORT_SYMBOL_GPL(kvm_set_xcr); 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 @@ int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) (!(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); -- cgit v1.2.3