From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Joerg Roedel" <joro@8bytes.org>,
"Jim Mattson" <jmattson@google.com>
Subject: Re: [PATCH v2 3/5] x86: KVM: clear interrupt shadow on EMULTYPE_SKIP
Date: Tue, 6 Aug 2019 08:45:39 -0700 [thread overview]
Message-ID: <20190806154539.GE27766@linux.intel.com> (raw)
In-Reply-To: <20190806060150.32360-4-vkuznets@redhat.com>
On Tue, Aug 06, 2019 at 08:01:48AM +0200, Vitaly Kuznetsov wrote:
> When doing x86_emulate_instruction(EMULTYPE_SKIP) interrupt shadow has to
> be cleared if and only if the skipping is successful.
>
> There are two immediate issues:
> - In SVM skip_emulated_instruction() we are not zapping interrupt shadow
> in case kvm_emulate_instruction(EMULTYPE_SKIP) is used to advance RIP
> (!nrpip_save).
> - In VMX handle_ept_misconfig() when running as a nested hypervisor we
> (static_cpu_has(X86_FEATURE_HYPERVISOR) case) we forget to clear
Redundant 'we'. Might be worth adding a blurb in the changelog to note
that this intentionally doesn't handle "MOV/POP SS" as skip-emulation of
those instructions can only occur if the guest is doing something silly.
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
> interrupt shadow.
>
> Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> ---
> arch/x86/kvm/x86.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index c6d951cbd76c..eac8253d84d2 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -6537,6 +6537,7 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu,
> kvm_rip_write(vcpu, ctxt->_eip);
> if (ctxt->eflags & X86_EFLAGS_RF)
> kvm_set_rflags(vcpu, ctxt->eflags & ~X86_EFLAGS_RF);
> + kvm_x86_ops->set_interrupt_shadow(vcpu, 0);
> return EMULATE_DONE;
> }
>
> --
> 2.20.1
>
next prev parent reply other threads:[~2019-08-06 15:45 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-06 6:01 [PATCH v2 0/5] x86: KVM: svm: get rid of hardcoded instructions lengths Vitaly Kuznetsov
2019-08-06 6:01 ` [PATCH v2 1/5] x86: KVM: svm: don't pretend to advance RIP in case wrmsr_interception() results in #GP Vitaly Kuznetsov
2019-08-06 15:29 ` Sean Christopherson
2019-08-06 6:01 ` [PATCH v2 2/5] x86: KVM: svm: avoid flooding logs when skip_emulated_instruction() fails Vitaly Kuznetsov
2019-08-06 15:40 ` Sean Christopherson
2019-08-07 11:17 ` Vitaly Kuznetsov
2019-08-06 6:01 ` [PATCH v2 3/5] x86: KVM: clear interrupt shadow on EMULTYPE_SKIP Vitaly Kuznetsov
2019-08-06 15:45 ` Sean Christopherson [this message]
2019-08-06 6:01 ` [PATCH v2 4/5] x86: KVM: add xsetbv to the emulator Vitaly Kuznetsov
2019-08-06 6:01 ` [PATCH v2 5/5] x86: KVM: svm: remove hardcoded instruction length from intercepts Vitaly Kuznetsov
2019-08-06 16:11 ` Sean Christopherson
2019-08-07 11:14 ` Vitaly Kuznetsov
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