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From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: Jim Mattson <jmattson@google.com>
Cc: "kvm list" <kvm@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	"Joerg Roedel" <joro@8bytes.org>
Subject: Re: [PATCH RFC 3/5] x86: KVM: svm: clear interrupt shadow on all paths in skip_emulated_instruction()
Date: Wed, 31 Jul 2019 15:50:32 +0200	[thread overview]
Message-ID: <87ftmm71p3.fsf@vitty.brq.redhat.com> (raw)
In-Reply-To: <CALMp9eQ85h58NMDh-yOYvHN6_2f2T-wu63f+yLnNbwuG+p3Uvw@mail.gmail.com>

Jim Mattson <jmattson@google.com> writes:

> On Thu, Jun 20, 2019 at 4:02 AM Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
>>
>> Regardless of the way how we skip instruction, interrupt shadow needs to be
>> cleared.
>
> This change is definitely an improvement, but the existing code seems
> to assume that we never call skip_emulated_instruction on a
> POP-SS/MOV-to-SS/STI. Is that enforced anywhere?

(before I send v1 of the series) I looked at the current code and I
don't think it is enforced, however, VMX version does the same and
honestly I can't think of a situation when we would be doing 'skip' for
such an instruction.... and there's nothing we can easily enforce from
skip_emulated_instruction() as we have no idea what the instruction
is... 

I can of course be totally wrong and would appreciate if someone more
knowledgeable chimes in :-)

-- 
Vitaly

  parent reply	other threads:[~2019-07-31 13:50 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-20 11:02 [PATCH RFC 0/5] x86/KVM/svm: get rid of hardcoded instructions lengths Vitaly Kuznetsov
2019-06-20 11:02 ` [PATCH RFC 1/5] x86: KVM: svm: don't pretend to advance RIP in case wrmsr_interception() results in #GP Vitaly Kuznetsov
2019-06-20 18:49   ` Jim Mattson
2019-06-21  8:42     ` Vitaly Kuznetsov
2019-06-20 11:02 ` [PATCH RFC 2/5] x86: KVM: svm: avoid flooding logs when skip_emulated_instruction() fails Vitaly Kuznetsov
2019-06-20 18:45   ` Jim Mattson
2019-06-20 11:02 ` [PATCH RFC 3/5] x86: KVM: svm: clear interrupt shadow on all paths in skip_emulated_instruction() Vitaly Kuznetsov
2019-06-20 18:44   ` Jim Mattson
2019-06-21  8:43     ` Vitaly Kuznetsov
2019-07-31 13:50     ` Vitaly Kuznetsov [this message]
2019-07-31 16:37       ` Paolo Bonzini
2019-07-31 20:27         ` Jim Mattson
2019-07-31 23:37           ` Sean Christopherson
2019-07-31 23:45             ` Jim Mattson
2019-07-31 23:56               ` Sean Christopherson
2019-08-01  0:13                 ` Paolo Bonzini
2019-08-01  0:17                   ` Jim Mattson
2019-06-20 11:02 ` [PATCH RFC 4/5] x86: KVM: add xsetbv to the emulator Vitaly Kuznetsov
2019-06-20 12:18   ` Paolo Bonzini
2019-07-31 13:07     ` Vitaly Kuznetsov
2019-07-31 13:14       ` Paolo Bonzini
2019-06-20 11:02 ` [PATCH RFC 5/5] x86: KVM: svm: remove hardcoded instruction length from intercepts Vitaly Kuznetsov
2019-06-20 18:41   ` Jim Mattson
2019-06-20 12:14 ` [PATCH RFC 0/5] x86/KVM/svm: get rid of hardcoded instructions lengths Paolo Bonzini
2019-06-20 12:26   ` Vitaly Kuznetsov

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