diff mbox series

[5.10,06/10] KVM: X86: Don't reset mmu context when X86_CR4_PCIDE 1->0

Message ID 20230508154804.30078-7-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 552617382c197949ff965a3559da8952bf3c1fa5 ]

X86_CR4_PCIDE 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.

Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210919024246.89230-2-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/x86.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d6bb2c300e16..952281f18987 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1042,9 +1042,10 @@  int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
 
 	kvm_x86_ops.set_cr4(vcpu, cr4);
 
-	if (((cr4 ^ old_cr4) & KVM_MMU_CR4_ROLE_BITS) ||
-	    (!(cr4 & X86_CR4_PCIDE) && (old_cr4 & X86_CR4_PCIDE)))
+	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))
+		kvm_make_request(KVM_REQ_TLB_FLUSH_GUEST, vcpu);
 
 	if ((cr4 ^ old_cr4) & (X86_CR4_OSXSAVE | X86_CR4_PKE))
 		kvm_update_cpuid_runtime(vcpu);