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From: Paolo Bonzini <pbonzini@redhat.com>
To: Jinpu Wang <jinpuwang@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
	"KVM-ML (kvm@vger.kernel.org)" <kvm@vger.kernel.org>
Subject: Re: [FYI PATCH 0/7] Mitigation for CVE-2018-12207
Date: Wed, 13 Nov 2019 15:44:08 +0100	[thread overview]
Message-ID: <6cb5e680-86f1-108d-92db-62e904dccb7c@redhat.com> (raw)
In-Reply-To: <CAD9gYJ+9sDYh+8RkbaaRrMEbJ1EJrkMdJFCa6HVPUE4_FA13ag@mail.gmail.com>

On 13/11/19 14:00, Jinpu Wang wrote:
> Hi Paolo, hi list,
> 
> Thanks for info, do we need qemu patch for full mitigation?
> Debian mentioned:
> https://linuxsecurity.com/advisories/debian/debian-dsa-4566-1-qemu-security-update-17-10-10
> "
>     A qemu update adding support for the PSCHANGE_MC_NO feature, which
>     allows to disable iTLB Multihit mitigations in nested hypervisors
>     will be provided via DSA 4566-1.
> 
> "
> But It's not yet available  publicly.

I will send it today, but it's not needed for full mitigation.  It just
provides a knob to turn it on and off in nested hypervisors.

> About the performance hit, do you know any number? probably the answer
> is workload dependent.

We generally measured 0-4%.  There can be latency spikes for RT, which I
will send a patch for soon.

Paolo


  reply	other threads:[~2019-11-13 14:44 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-12 21:21 [FYI PATCH 0/7] Mitigation for CVE-2018-12207 Paolo Bonzini
2019-11-12 21:21 ` [PATCH 1/7] x86/bugs: Add ITLB_MULTIHIT bug infrastructure Paolo Bonzini
2019-11-12 21:21 ` [PATCH 2/7] x86/cpu: Add Tremont to the cpu vulnerability whitelist Paolo Bonzini
2019-11-12 21:21 ` [PATCH 3/7] cpu/speculation: Uninline and export CPU mitigations helpers Paolo Bonzini
2019-11-12 21:21 ` [PATCH 4/7] kvm: mmu: ITLB_MULTIHIT mitigation Paolo Bonzini
2019-11-12 21:21 ` [PATCH 5/7] kvm: Add helper function for creating VM worker threads Paolo Bonzini
2019-11-12 21:21 ` [PATCH 6/7] kvm: x86: mmu: Recovery of shattered NX large pages Paolo Bonzini
2019-11-12 21:21 ` [PATCH 7/7] Documentation: Add ITLB_MULTIHIT documentation Paolo Bonzini
2019-11-13  6:38 ` [FYI PATCH 0/7] Mitigation for CVE-2018-12207 Jan Kiszka
2019-11-13  8:23   ` Paolo Bonzini
2019-11-13 21:24     ` Dave Hansen
2019-11-14  1:17       ` Nadav Amit
2019-11-14  5:26         ` Dave Hansen
2019-11-14  6:02           ` Nadav Amit
2019-11-15  2:11           ` Pawan Gupta
2019-11-14  8:09       ` Jan Kiszka
2019-11-18 13:58         ` Ralf Ramsauer
2020-01-21 18:08           ` Jan Kiszka
2020-01-21 18:25             ` Dave Hansen
2019-11-13 23:25     ` Pawan Gupta
2019-11-14  8:13       ` Jan Kiszka
2019-11-15  2:23         ` Pawan Gupta
2019-11-13 13:00 ` Jinpu Wang
2019-11-13 14:44   ` Paolo Bonzini [this message]
2019-11-13 18:10 ` Nadav Amit
2019-11-13 18:33   ` Paolo Bonzini

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