From: Paolo Bonzini <pbonzini@redhat.com>
To: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
David Woodhouse <dwmw@amazon.co.uk>,
KarimAllah Ahmed <karahmed@amazon.de>
Subject: Re: [PATCH] KVM: VMX: expose the host's ARCH_CAPABILITIES MSR to userspace
Date: Wed, 7 Mar 2018 16:10:11 +0100 [thread overview]
Message-ID: <37a89c09-e933-9256-1b7a-3a9df846a672@redhat.com> (raw)
In-Reply-To: <20180307145628.GA12299@flask>
On 07/03/2018 15:56, Radim Krčmář wrote:
> The MSR_F10H_DECFG default is questionable -- MSR_F10H_DECFG is an
> architectural MSR, so we'd be changing the guest under the sight of
> existing userspaces.
> A potential security risk if they migrate the guest to a CPU that
> doesn't serialize LFENCE. ARCH_CAPABILITIES are at least hidden by a
> new CPUID bit.
Good point. Perhaps we should add a KVM-specific CPUID bit for
serializing LFENCE.
> The feature MSR defaults are going to be a mess anyway: we have
> MSR_IA32_UCODE_REV that is tightly coupled with CPUID. Not a good
> candidate for passing by default and currently also has a default value.
Yeah, ucode revision is out of question.
Paolo
next prev parent reply other threads:[~2018-03-07 15:10 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-24 0:52 [PATCH] KVM: VMX: expose the host's ARCH_CAPABILITIES MSR to userspace Paolo Bonzini
2018-02-26 22:13 ` Konrad Rzeszutek Wilk
2018-02-26 22:23 ` Konrad Rzeszutek Wilk
2018-03-01 21:39 ` Radim Krčmář
2018-03-02 9:36 ` Paolo Bonzini
2018-03-02 21:42 ` Radim Krčmář
2018-03-07 11:53 ` Paolo Bonzini
2018-03-07 14:56 ` Radim Krčmář
2018-03-07 15:10 ` Paolo Bonzini [this message]
2018-03-07 15:39 ` Radim Krčmář
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=37a89c09-e933-9256-1b7a-3a9df846a672@redhat.com \
--to=pbonzini@redhat.com \
--cc=dwmw@amazon.co.uk \
--cc=karahmed@amazon.de \
--cc=konrad.wilk@oracle.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=rkrcmar@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).