linux-kernel - [PATCH 3.2 086/164] KVM: MMU: fix CR4.SMEP=1, CR0.WP=0 with shadow pages

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Message-ID: <lsq.1438473757.333474791@decadent.org.uk>
Date:	Sun, 02 Aug 2015 01:02:37 +0100
From:	Ben Hutchings <ben@...adent.org.uk>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:	akpm@...ux-foundation.org, "Paolo Bonzini" <pbonzini@...hat.com>,
	"Xiao Guangrong" <guangrong.xiao@...ux.intel.com>
Subject: [PATCH 3.2 086/164] KVM: MMU: fix CR4.SMEP=1, CR0.WP=0 with
 shadow pages

3.2.70-rc1 review patch.  If anyone has any objections, please let me know.

------------------

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

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>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 arch/x86/kvm/mmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -3609,7 +3609,7 @@ void kvm_mmu_pte_write(struct kvm_vcpu *
 		}
 	}
 
-	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, node) {
 		pte_size = sp->role.cr4_pae ? 8 : 4;
 		misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1);

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