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From: Paolo Bonzini <pbonzini@redhat.com>
To: Yang Zhang <yang.zhang.wz@gmail.com>,
	linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Subject: Re: [RFC PATCH 4/4] KVM: vmx: add support for emulating UMIP
Date: Wed, 13 Jul 2016 12:21:52 +0200	[thread overview]
Message-ID: <272876c1-2aea-7401-8221-d62e00e5fcee@redhat.com> (raw)
In-Reply-To: <f4985baa-1694-775f-6a17-4759ad760a87@gmail.com>



On 13/07/2016 12:02, Yang Zhang wrote:
> On 2016/7/13 17:35, Paolo Bonzini wrote:
>>
>>
>> On 13/07/2016 11:21, Yang Zhang wrote:
>>>>
>>>> +static int handle_desc(struct kvm_vcpu *vcpu)
>>>> +{
>>>> +    WARN_ON(!(vcpu->arch.cr4 & X86_CR4_UMIP));
>>>
>>> I think WARN_ON is too heavy since a malicious guest may trigger it
>>> always.
>>
>> I missed this---how so?  Setting the bit is under "if ((cr4 &
>> X86_CR4_UMIP) && !boot_cpu_has(X86_FEATURE_UMIP))".
> 
> Sorry, I consider it under my previous suggestion(setting it
> unconditionally). :(

No problem, thanks for your interest!

Paolo

  reply	other threads:[~2016-07-13 10:22 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-12 19:20 [RFC PATCH 0/4] KVM: Emulate UMIP (or almost do so) Paolo Bonzini
2016-07-12 19:20 ` [RFC PATCH 1/4] x86: add UMIP feature and CR4 bit Paolo Bonzini
2016-07-12 19:20 ` [RFC PATCH 2/4] KVM: x86: emulate sldt and str Paolo Bonzini
2016-07-12 19:20 ` [RFC PATCH 3/4] KVM: x86: add support for emulating UMIP Paolo Bonzini
2016-07-13 20:03   ` Radim Krčmář
2016-07-14  7:00     ` Paolo Bonzini
2016-07-14 12:24       ` Radim Krčmář
2016-07-12 19:20 ` [RFC PATCH 4/4] KVM: vmx: " Paolo Bonzini
2016-07-13  9:21   ` Yang Zhang
2016-07-13  9:35     ` Paolo Bonzini
2016-07-13  9:54       ` Yang Zhang
2016-07-13  9:35     ` Paolo Bonzini
2016-07-13 10:02       ` Yang Zhang
2016-07-13 10:21         ` Paolo Bonzini [this message]
2016-07-13 20:30   ` Radim Krčmář
2016-07-14  8:09     ` Paolo Bonzini
2016-07-14 12:36       ` Radim Krčmář
2016-07-14 12:54         ` Paolo Bonzini
2016-07-31  2:32       ` Wanpeng Li
2016-08-01 15:01         ` Paolo Bonzini
2016-08-02  1:05           ` Wanpeng Li
2016-07-13  8:29 ` [RFC PATCH 0/4] KVM: Emulate UMIP (or almost do so) Yang Zhang
2016-07-13  9:34   ` Paolo Bonzini
2016-12-13  4:03 ` Li, Liang Z
2016-12-13 11:03   ` Paolo Bonzini
2017-03-01  9:04     ` Yu Zhang
2017-03-06 21:07       ` Paolo Bonzini
2017-03-10  8:02       ` Yu Zhang
2017-03-10  8:36         ` Paolo Bonzini
2017-03-10  9:31           ` Yu Zhang
2017-03-10 11:28             ` Yu Zhang
2017-03-10 15:00             ` Paolo Bonzini

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