Re: [Xen-devel] [XEN PATCH for-4.13 3/3] libxl: Set shadow_memkb for stub device model domains

[Ian Jackson <ian.jackson@xxxxxxxxxx>]

Andrew Cooper writes ("Re: [XEN PATCH for-4.13 3/3] libxl: Set shadow_memkb for 
stub device model domains"):
> On 28/10/2019 15:29, Ian Jackson wrote:
> > Previously we did not do this.  Indeed we have never done so.  Stub
> > domains have had no memory allowance for shadow memory.  This seems to
> > be an existing bug which we fix.
> >
> > x86 maintainers: please comment.
> 
> PV guests need a shadow allocation to migrate, or if they trip over the
> PV L1TF safety checks.
> 
> The former is not applicable to stubdoms, and the latter is arguably
> better left with a shadow allocation of 0.
> 
> These are infrastructure VMs rather than customer VMs, and there is no
> excuse really to be running an L1TF-vulnerable stubdom which is taking
> the 20% perf hit.

Thanks for the review.

I think this means I should drop this patch.  The other two were
reviewed and release-acked (thanks Jürgen and Anthony) so I have just
pushed them to staging.

Ian.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel