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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Lai Jiangshan <laijs@linux.alibaba.com>,
	Sean Christopherson <seanjc@google.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Sasha Levin <sashal@kernel.org>,
	tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
	dave.hansen@linux.intel.com, x86@kernel.org, kvm@vger.kernel.org
Subject: [PATCH MANUALSEL 5.15 2/8] KVM: X86: Don't reset mmu context when X86_CR4_PCIDE 1->0
Date: Tue, 23 Nov 2021 11:36:24 -0500	[thread overview]
Message-ID: <20211123163630.289306-2-sashal@kernel.org> (raw)
In-Reply-To: <20211123163630.289306-1-sashal@kernel.org>

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: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kvm/x86.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 0644f429f848c..98a0f3c28caec 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1042,9 +1042,10 @@ EXPORT_SYMBOL_GPL(kvm_is_valid_cr4);
 
 void kvm_post_set_cr4(struct kvm_vcpu *vcpu, unsigned long old_cr4, unsigned long 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);
 }
 EXPORT_SYMBOL_GPL(kvm_post_set_cr4);
 
-- 
2.33.0


  reply	other threads:[~2021-11-23 16:36 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-23 16:36 [PATCH MANUALSEL 5.15 1/8] KVM: X86: Fix tlb flush for tdp in kvm_invalidate_pcid() Sasha Levin
2021-11-23 16:36 ` Sasha Levin [this message]
2021-11-24  0:24   ` [PATCH MANUALSEL 5.15 2/8] KVM: X86: Don't reset mmu context when X86_CR4_PCIDE 1->0 Lai Jiangshan
2021-11-23 16:36 ` [PATCH MANUALSEL 5.15 3/8] KVM: X86: Don't check unsync if the original spte is writible Sasha Levin
2021-11-23 16:36 ` [PATCH MANUALSEL 5.15 4/8] KVM: selftests: Fix kvm_vm_free() in cr4_cpuid_sync and vmx_tsc_adjust tests Sasha Levin
2021-11-23 16:36 ` [PATCH MANUALSEL 5.15 5/8] KVM: s390: Cap KVM_CAP_NR_VCPUS by num_online_cpus() Sasha Levin
2021-11-23 16:36 ` [PATCH MANUALSEL 5.15 7/8] KVM: MIPS: Cap KVM_CAP_NR_VCPUS by KVM_CAP_MAX_VCPUS Sasha Levin
2021-11-24 18:20 ` [PATCH MANUALSEL 5.15 1/8] KVM: X86: Fix tlb flush for tdp in kvm_invalidate_pcid() Paolo Bonzini

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