From: Sean Christopherson <seanjc@google.com>
To: Li Yu <liyu.yukiteru@bytedance.com>
Cc: pbonzini@redhat.com, Jonathan Corbet <corbet@lwn.net>,
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>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
"Paul E. McKenney" <paulmck@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Lu Baolu <baolu.lu@linux.intel.com>,
"Maciej W. Rozycki" <macro@orcam.me.uk>,
Muchun Song <songmuchun@bytedance.com>,
Viresh Kumar <viresh.kumar@linaro.org>,
Robin Murphy <robin.murphy@arm.com>,
Randy Dunlap <rdunlap@infradead.org>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org
Subject: Re: [PATCH v3] KVM: x86/mmu: Warn on iTLB multi-hit for possible problems
Date: Wed, 8 Dec 2021 18:40:40 +0000 [thread overview]
Message-ID: <YbD8KFaY+emLQR+d@google.com> (raw)
In-Reply-To: <20211020043131.1222542-1-liyu.yukiteru@bytedance.com>
On Wed, Oct 20, 2021, Li Yu wrote:
> Warn for guest huge pages split if iTLB multi-hit bug is present
> and CPU mitigations is enabled.
>
> Warn for possible CPU lockup if iTLB multi-hit bug is present but
> CPU mitigations is disabled.
>
> Signed-off-by: Li Yu <liyu.yukiteru@bytedance.com>
> ---
Gah, my last reply in the previous version was offlist. I would like an answer
to the below question before we complicate KVM just to log a message.
On Wed, Oct 20, 2021 at 12:51 PM Sean Christopherson <seanjc@google.com> wrote:
>
> On Wed, Oct 20, 2021, Li Yu wrote:
> > On 2021/10/20 00:23, Sean Christopherson wrote:
> > I think it is necessary to log something when `nx_huge_pages` is `auto` or
> > `off`, and the bug is present.
>
> Why is it necessary? Specifically, what action can be taken based on KVM logging
> that can't reasonably be taken based on all the other information provided by the
> kernel? We should teach userspace to go look at the vulnerabilites info, not to
> scrape the kernel log.
prev parent reply other threads:[~2021-12-08 18:40 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-19 12:18 [PATCH] KVM: x86/mmu: Warn on nx_huge_pages when initializing kvm Li Yu
2021-10-19 12:56 ` Paolo Bonzini
2021-10-19 14:11 ` [PATCH] KVM: x86/mmu: Warn on nx_huge_pages for possible problems Li Yu
2021-10-19 16:23 ` Sean Christopherson
2021-10-20 4:31 ` [PATCH v3] KVM: x86/mmu: Warn on iTLB multi-hit " Li Yu
2021-12-08 18:40 ` Sean Christopherson [this message]
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