From: Paolo Bonzini <pbonzini@redhat.com>
To: Eduardo Habkost <ehabkost@redhat.com>, qemu-devel@nongnu.org
Cc: Jiri Denemark <jdenemar@redhat.com>,
Kashyap Chamarthy <kchamart@redhat.com>,
Richard Henderson <rth@twiddle.net>
Subject: Re: [PATCH for-4.2 1/2] i386: Add new versions of Skylake/Cascadelake/Icelake without TSX
Date: Wed, 20 Nov 2019 18:40:06 +0100 [thread overview]
Message-ID: <b1d8c3ef-646a-85c7-176b-c4429f36d384@redhat.com> (raw)
In-Reply-To: <20191120164912.32384-2-ehabkost@redhat.com>
On 20/11/19 17:49, Eduardo Habkost wrote:
> One of the mitigation methods for TAA[1] is to disable TSX
> support on the host system. Linux added a mechanism to disable
> TSX globally through the kernel command line, and many Linux
> distributions now default to tsx=off. This makes existing CPU
> models that have HLE and RTM enabled not usable anymore.
>
> Add new versions of all CPU models that have the HLE and RTM
> features enabled, that can be used when TSX is disabled in the
> host system.
What is the effect of this when using "-cpu CascadeLake-Server" and
upgrading QEMU? Would it automatically switch to the new version? If
so, would it be better to include a duplicate of the models (and if so,
that would conflict with my VMX features patch, which is also for 4.2).
Paolo
next prev parent reply other threads:[~2019-11-20 17:41 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-20 16:49 [PATCH for-4.2 0/2] i386: Add new versions of Skylake/Cascadelake/Icelake without TSX Eduardo Habkost
2019-11-20 16:49 ` [PATCH for-4.2 1/2] " Eduardo Habkost
2019-11-20 17:40 ` Paolo Bonzini [this message]
2019-11-20 18:42 ` Eduardo Habkost
2019-11-21 9:16 ` Paolo Bonzini
2019-11-21 11:41 ` Kashyap Chamarthy
2019-11-20 16:49 ` [PATCH for-4.2 2/2] i386: Add -noTSX aliases for hle=off, rtm=off CPU models Eduardo Habkost
2019-11-21 14:12 ` Kashyap Chamarthy
2019-11-25 14:21 ` Eduardo Habkost
2019-11-25 17:06 ` Kashyap Chamarthy
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