Re: [Xen-devel] [PATCH linux v2 0/9] xen: pvhvm: support bootup on secondary vCPUs

From: Julien Grall
Date: Mon Jul 25 2016 - 09:17:44 EST


Hi David,

On 25/07/16 13:38, David Vrabel wrote:
On 30/06/16 16:56, Vitaly Kuznetsov wrote:
It may happen that Xen's and Linux's ideas of vCPU id diverge. In
particular, when we crash on a secondary vCPU we may want to do kdump
and unlike plain kexec where we do migrate_to_reboot_cpu() we try booting
on the vCPU which crashed. This doesn't work very well for PVHVM guests as
we have a number of hypercalls where we pass vCPU id as a parameter. These
hypercalls either fail or do something unexpected. To solve the issue we
need to have a mapping between Linux's and Xen's vCPU ids.

This series solves the issue for x86 PVHVM guests. PV guests don't (and
probably won't) support kdump so I always assume Xen's vCPU id == Linux's
vCPU id. ARM guests will probably need to get proper mapping once we start
supporting kexec/kdump there.

Applied to for-linus-4.8, thanks.

It would have been nice to send a ping before applying. This patch series is containing Xen ARM code which has not been acked by Stefano, nor had feedback from ARM side.

For instance given that all the hypercalls are representing a "vcpu id" using "uint32_t" it is a bit weird to use "int" to define xen_vcpu_id (see patch #3).

Regards,

--
Julien Grall