Re: Avoid speculative indirect calls in kernel

From: Andrew Cooper
Date: Thu Jan 04 2018 - 11:04:52 EST


On 04/01/18 15:32, Paolo Bonzini wrote:
> On 04/01/2018 16:29, Woodhouse, David wrote:
>> Adding that for KVM is in the Linux IBRS patch set that I've seen.
>> Didn't we already have a conversation about how the Linux patch set
>> does it as an atomically-switched MSR while you've done it manually in
>> Xen because it's faster?
> I'm also doing it manually in the RHEL versions of the KVM patches, for
> what it's worth.

Actually, I did it manually in Xen because I was expecting IBRS on AMD,
and there are no MSR load/save lists for PV or SVM guests. (Also yes,
I've been reliably informed that manually is much faster than VT-x
load/save lists.)

~Andrew