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Subject[PATCH 5.4 364/388] KVM: x86: Reset MMU context if guest toggles CR4.SMAP or CR4.PKE
Date
From: Sean Christopherson <sean.j.christopherson@intel.com>

[ Upstream commit 8d214c481611b29458a57913bd786f0ac06f0605 ]

Reset the MMU context during kvm_set_cr4() if SMAP or PKE is toggled.
Recent commits to (correctly) not reload PDPTRs when SMAP/PKE are
toggled inadvertantly skipped the MMU context reset due to the mask
of bits that triggers PDPTR loads also being used to trigger MMU context
resets.

Fixes: 427890aff855 ("kvm: x86: Toggling CR4.SMAP does not load PDPTEs in PAE mode")
Fixes: cb957adb4ea4 ("kvm: x86: Toggling CR4.PKE does not load PDPTEs in PAE mode")
Cc: Jim Mattson <jmattson@google.com>
Cc: Peter Shier <pshier@google.com>
Cc: Oliver Upton <oupton@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200923215352.17756-1-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/x86/kvm/x86.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 67ad417a29ca4..12e83297ea020 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -973,6 +973,7 @@ 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;
+ unsigned long mmu_role_bits = pdptr_bits | X86_CR4_SMAP | X86_CR4_PKE;

if (kvm_valid_cr4(vcpu, cr4))
return 1;
@@ -1000,7 +1001,7 @@ int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
if (kvm_x86_ops->set_cr4(vcpu, cr4))
return 1;

- if (((cr4 ^ old_cr4) & pdptr_bits) ||
+ if (((cr4 ^ old_cr4) & mmu_role_bits) ||
(!(cr4 & X86_CR4_PCIDE) && (old_cr4 & X86_CR4_PCIDE)))
kvm_mmu_reset_context(vcpu);

--
2.25.1


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