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From:   Maxim Levitsky <mlevitsk@redhat.com>
To:     kvm@vger.kernel.org
Cc:     Paolo Bonzini <pbonzini@redhat.com>,
        Ingo Molnar <mingo@redhat.com>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        linux-kernel@vger.kernel.org,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Sandipan Das <sandipan.das@amd.com>,
        Daniel Sneddon <daniel.sneddon@linux.intel.com>,
        Jing Liu <jing2.liu@intel.com>,
        Josh Poimboeuf <jpoimboe@kernel.org>,
        Wyes Karny <wyes.karny@amd.com>,
        Borislav Petkov <bp@alien8.de>,
        Babu Moger <babu.moger@amd.com>,
        Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
        Sean Christopherson <seanjc@google.com>,
        Jim Mattson <jmattson@google.com>, x86@kernel.org,
        Maxim Levitsky <mlevitsk@redhat.com>
Subject: [PATCH 01/13] KVM: nSVM: don't sync back tlb_ctl on nested VM exit
Date:   Thu, 17 Nov 2022 16:32:30 +0200
Message-Id: <20221117143242.102721-2-mlevitsk@redhat.com>
In-Reply-To: <20221117143242.102721-1-mlevitsk@redhat.com>
References: <20221117143242.102721-1-mlevitsk@redhat.com>
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The CPU doesn't change TLB_CTL value as stated in the PRM (15.16.2):

  "The VMRUN instruction reads, but does not change, the
  value of the TLB_CONTROL field"

Therefore the KVM shoudn't do that either.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
---
 arch/x86/kvm/svm/nested.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index b258d6988f5dde..43cc4a5d22e012 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -989,7 +989,6 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
 		vmcb12->control.next_rip  = vmcb02->control.next_rip;
 
 	vmcb12->control.int_ctl           = svm->nested.ctl.int_ctl;
-	vmcb12->control.tlb_ctl           = svm->nested.ctl.tlb_ctl;
 	vmcb12->control.event_inj         = svm->nested.ctl.event_inj;
 	vmcb12->control.event_inj_err     = svm->nested.ctl.event_inj_err;
 
-- 
2.34.3