From: Andy Lutomirski <luto@amacapital.net>
To: David Laight <David.Laight@aculab.com>
Cc: Xiaoyao Li <xiaoyao.li@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <sean.j.christopherson@intel.com>,
"x86@kernel.org" <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>
Subject: Re: [PATCH 1/2] KVM: x86: Emulate split-lock access as a write
Date: Thu, 30 Jan 2020 07:16:24 -0800 [thread overview]
Message-ID: <777C5046-B9DE-4F8C-B04F-28A546AE4A3F@amacapital.net> (raw)
In-Reply-To: <db3b854fd03745738f46cfce451d9c98@AcuMS.aculab.com>
> On Jan 30, 2020, at 4:31 AM, David Laight <David.Laight@aculab.com> wrote:
>
> From: Xiaoyao Li
>> Sent: 30 January 2020 12:20
>> If split lock detect is enabled (warn/fatal), #AC handler calls die()
>> when split lock happens in kernel.
>>
>> A sane guest should never tigger emulation on a split-lock access, but
>> it cannot prevent malicous guest from doing this. So just emulating the
>> access as a write if it's a split-lock access to avoid malicous guest
>> polluting the kernel log.
>
> That doesn't seem right if, for example, the locked access is addx.
> ISTM it would be better to force an immediate fatal error of some
> kind than just corrupt the guest memory.
>
>
The existing page-spanning case is just as wrong.
next prev parent reply other threads:[~2020-01-30 15:16 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-30 12:19 [PATCH 0/2] kvm: split_lock: Fix emulator and extend #AC handler Xiaoyao Li
2020-01-30 12:19 ` [PATCH 1/2] KVM: x86: Emulate split-lock access as a write Xiaoyao Li
2020-01-30 12:31 ` David Laight
2020-01-30 15:16 ` Andy Lutomirski [this message]
2020-01-31 20:01 ` Sean Christopherson
2020-02-04 14:47 ` Vitaly Kuznetsov
2020-02-10 21:59 ` Sean Christopherson
2020-01-30 12:19 ` [PATCH 2/2] KVM: VMX: Extend VMX's #AC handding Xiaoyao Li
2020-01-30 15:18 ` Andy Lutomirski
2020-01-30 16:29 ` Xiaoyao Li
2020-01-30 17:16 ` Andy Lutomirski
2020-01-31 7:22 ` Xiaoyao Li
2020-01-31 15:37 ` Andy Lutomirski
2020-01-31 17:47 ` Xiaoyao Li
2020-01-31 20:17 ` Sean Christopherson
2020-01-31 20:57 ` Andy Lutomirski
2020-01-31 21:04 ` Sean Christopherson
2020-01-31 21:33 ` Andy Lutomirski
2020-02-01 16:58 ` Xiaoyao Li
2020-02-01 17:56 ` Andy Lutomirski
2020-02-02 4:33 ` Xiaoyao Li
2020-02-03 18:49 ` Andy Lutomirski
2020-02-04 6:03 ` Sean Christopherson
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