lkml.org 
[lkml]   [2020]   [Jan]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 2/2] KVM: VMX: Extend VMX's #AC handding
On Fri, Jan 31, 2020 at 12:57:51PM -0800, Andy Lutomirski wrote:
>
> > On Jan 31, 2020, at 12:18 PM, Sean Christopherson <sean.j.christopherson@intel.com> wrote:
> >
> > This is essentially what I proposed a while back. KVM would allow enabling
> > split-lock #AC in the guest if and only if SMT is disabled or the enable bit
> > is per-thread, *or* the host is in "warn" mode (can live with split-lock #AC
> > being randomly disabled/enabled) and userspace has communicated to KVM that
> > it is pinning vCPUs.
>
> How about covering the actual sensible case: host is set to fatal? In this
> mode, the guest gets split lock detection whether it wants it or not. How do
> we communicate this to the guest?

KVM doesn't advertise split-lock #AC to the guest and returns -EFAULT to the
userspace VMM if the guest triggers a split-lock #AC.

Effectively the same behavior as any other userspace process, just that KVM
explicitly returns -EFAULT instead of the process getting a SIGBUS.

\
 
 \ /
  Last update: 2020-01-31 22:05    [W:1.489 / U:0.000 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site