Re: [PATCH Part2 v5 00/45] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support

Dr. David Alan Gilbert
2021-11-15T15:33:09Z

* Joerg Roedel (jroedel@suse.de) wrote:
> On Mon, Nov 15, 2021 at 12:30:59PM +0000, Dr. David Alan Gilbert wrote:
> > Still; I wonder if it's best to kill the guest - maybe it's best for
> > the host to kill the guest and leave behind diagnostics of what
> > happened; for someone debugging the crash, it's going to be less useful
> > to know that page X was wrongly accessed (which is what the guest would
> > see), and more useful to know that it was the kernel's vhost-... driver
> > that accessed it.
>
> I is best to let the guest #VC on the page when this happens. If it
> happened because of a guest bug all necessary debugging data is in the
> guest and only the guest owner can obtain it.
>
> Then the guest owner can do a kdump on this unexpected #VC and collect
> the data to debug the issue. With just killing the guest from the host
> side this data would be lost.

How would you debug an unexpected access by the host kernel using a
guests kdump?

Dave

> Regards,
>
> Joerg
>
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK