diff mbox series

[5.10,07/10] KVM: X86: Don't reset mmu context when toggling X86_CR4_PGE

Message ID 20230508154804.30078-8-minipli@grsecurity.net (mailing list archive)
State New, archived
Headers show
Series KVM CR0.WP series backport | expand

Commit Message

Mathias Krause May 8, 2023, 3:48 p.m. UTC 
From: Lai Jiangshan <laijs@linux.alibaba.com>

[ Upstream commit a91a7c7096005113d8e749fd8dfdd3e1eecee263 ]

X86_CR4_PGE doesn't participate in kvm_mmu_role, so the mmu context
doesn't need to be reset.  It is only required to flush all the guest
tlb.

It is also inconsistent that X86_CR4_PGE is in KVM_MMU_CR4_ROLE_BITS
while kvm_mmu_role doesn't use X86_CR4_PGE.  So X86_CR4_PGE is also
removed from KVM_MMU_CR4_ROLE_BITS.

Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210919024246.89230-3-jiangshanlai@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Mathias Krause <minipli@grsecurity.net>	# backport to v5.10.x
---
- no kvm_post_set_cr4() in this kernel yet, it's part of kvm_set_cr4()

 arch/x86/kvm/mmu.h | 5 ++---
 arch/x86/kvm/x86.c | 3 ++-
 2 files changed, 4 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index 0d73e8b45642..a77f6acb46f6 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -44,9 +44,8 @@ 
 #define PT32_ROOT_LEVEL 2
 #define PT32E_ROOT_LEVEL 3
 
-#define KVM_MMU_CR4_ROLE_BITS (X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PAE | \
-			       X86_CR4_SMEP | X86_CR4_SMAP | X86_CR4_PKE | \
-			       X86_CR4_LA57)
+#define KVM_MMU_CR4_ROLE_BITS (X86_CR4_PSE | X86_CR4_PAE | X86_CR4_LA57 | \
+			       X86_CR4_SMEP | X86_CR4_SMAP | X86_CR4_PKE)
 
 #define KVM_MMU_CR0_ROLE_BITS (X86_CR0_PG | X86_CR0_WP)
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 952281f18987..b2378ec80305 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1044,7 +1044,8 @@  int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
 
 	if ((cr4 ^ old_cr4) & KVM_MMU_CR4_ROLE_BITS)
 		kvm_mmu_reset_context(vcpu);
-	else if (!(cr4 & X86_CR4_PCIDE) && (old_cr4 & X86_CR4_PCIDE))
+	else if (((cr4 ^ old_cr4) & X86_CR4_PGE) ||
+		 (!(cr4 & X86_CR4_PCIDE) && (old_cr4 & X86_CR4_PCIDE)))
 		kvm_make_request(KVM_REQ_TLB_FLUSH_GUEST, vcpu);
 
 	if ((cr4 ^ old_cr4) & (X86_CR4_OSXSAVE | X86_CR4_PKE))