From: Xiaoyao Li <xiaoyao.li@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
Andy Lutomirski <luto@kernel.org>,
Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Tao Xu <tao3.xu@intel.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>, X86 ML <x86@kernel.org>,
kvm list <kvm@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] KVM: VMX: Enable Notify VM exit
Date: Tue, 3 Nov 2020 14:39:30 +0800 [thread overview]
Message-ID: <06dbea28-4b4a-4f73-2ad2-9b76a8ca4704@intel.com> (raw)
In-Reply-To: <8e41101c-6278-3773-8754-ffe0763eaeea@redhat.com>
On 11/3/2020 2:25 AM, Paolo Bonzini wrote:
> On 02/11/20 19:01, Andy Lutomirski wrote:
>> What's the point? Surely the kernel should reliably mitigate the
>> flaw, and the kernel should decide how to do so.
>
> There is some slowdown in trapping #DB and #AC unconditionally. Though
> for these two cases nobody should care so I agree with keeping the code
> simple and keeping the workaround.
OK.
> Also, why would this trigger after more than a few hundred cycles,
> something like the length of the longest microcode loop? HZ*10 seems
> like a very generous estimate already.
>
As Sean said in another mail, 1/10 tick should be a placeholder.
Glad to see all of you think it should be smaller. We'll come up with
more reasonable candidate once we can test on real silicon.
next prev parent reply other threads:[~2020-11-03 6:39 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-02 6:14 [PATCH] KVM: VMX: Enable Notify VM exit Tao Xu
2020-11-02 16:43 ` Andy Lutomirski
2020-11-02 17:31 ` Sean Christopherson
2020-11-02 18:01 ` Andy Lutomirski
2020-11-02 18:25 ` Paolo Bonzini
2020-11-03 6:39 ` Xiaoyao Li [this message]
2020-11-02 18:33 ` Sean Christopherson
2021-05-17 7:20 ` Xiaoyao Li
2021-05-17 8:55 ` Xiaoyao Li
2020-11-03 5:35 ` Tao Xu
2020-11-03 6:08 ` Tao Xu
2020-11-03 7:29 ` Xiaoyao Li
2020-11-02 17:32 ` Sean Christopherson
2020-11-03 5:36 ` Tao Xu
2020-11-02 22:53 ` Jim Mattson
2020-11-03 6:12 ` Tao Xu
2020-11-03 6:24 ` Xiaoyao Li
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