lkml.org 
[lkml]   [2018]   [Mar]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] KVM: VMX: expose the host's ARCH_CAPABILITIES MSR to userspace
From
Date
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

\
 
 \ /
  Last update: 2018-03-07 16:10    [W:0.051 / U:7.624 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site