From: Jim Mattson <jmattson@google.com>
Date: Mon, 17 Aug 2020 18:16:55 +0000 (-0700)
Subject: kvm: x86: Toggling CR4.SMAP does not load PDPTEs in PAE mode
X-Git-Tag: v5.7.18~39
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=374c3b5a7775c0dad89a8f7be1515d7c9cda514b;p=thirdparty%2Fkernel%2Fstable.git

kvm: x86: Toggling CR4.SMAP does not load PDPTEs in PAE mode

[ Upstream commit 427890aff8558eb4326e723835e0eae0e6fe3102 ]

See the SDM, volume 3, section 4.4.1:

If PAE paging would be in use following an execution of MOV to CR0 or
MOV to CR4 (see Section 4.1.1) and the instruction is modifying any of
CR0.CD, CR0.NW, CR0.PG, CR4.PAE, CR4.PGE, CR4.PSE, or CR4.SMEP; then
the PDPTEs are loaded from the address in CR3.

Fixes: 0be0226f07d14 ("KVM: MMU: fix SMAP virtualization")
Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Reviewed-by: Oliver Upton <oupton@google.com>
Message-Id: <20200817181655.3716509-2-jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 51ccb4dfaad26..781b5d41663c5 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -956,7 +956,7 @@ 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 | X86_CR4_SMAP | X86_CR4_PKE;
+				   X86_CR4_SMEP | X86_CR4_PKE;
 
 	if (kvm_valid_cr4(vcpu, cr4))
 		return 1;