linux-kernel - [PATCH 3.12 038/111] KVM: MMU: fix CR4.SMEP=1, CR0.WP=0 with shadow pages

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Date:	Wed, 10 Jun 2015 17:26:27 +0200
From:	Jiri Slaby <jslaby@...e.cz>
To:	stable@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, Paolo Bonzini <pbonzini@...hat.com>,
	Jiri Slaby <jslaby@...e.cz>
Subject: [PATCH 3.12 038/111] KVM: MMU: fix CR4.SMEP=1, CR0.WP=0 with shadow pages

From: Paolo Bonzini <pbonzini@...hat.com>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit 898761158be7682082955e3efa4ad24725305fc7 upstream.

smep_andnot_wp is initialized in kvm_init_shadow_mmu and shadow pages
should not be reused for different values of it.  Thus, it has to be
added to the mask in kvm_mmu_pte_write.

Reviewed-by: Xiao Guangrong <guangrong.xiao@...ux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Jiri Slaby <jslaby@...e.cz>
---
 arch/x86/kvm/mmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 8ad01b4e60cc..b759853d78fe 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -4123,7 +4123,7 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
 	++vcpu->kvm->stat.mmu_pte_write;
 	kvm_mmu_audit(vcpu, AUDIT_PRE_PTE_WRITE);
 
-	mask.cr0_wp = mask.cr4_pae = mask.nxe = 1;
+	mask.cr0_wp = mask.cr4_pae = mask.nxe = mask.smep_andnot_wp = 1;
 	for_each_gfn_indirect_valid_sp(vcpu->kvm, sp, gfn) {
 		if (detect_write_misaligned(sp, gpa, bytes) ||
 		      detect_write_flooding(sp)) {
-- 
2.4.2

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