Re: [PATCH v4 0/4] x86/pvh: fix unbootable VMs again (PVH + KASAN)

[Mauricio Faria de Oliveira <mfo@igalia.com>]

On 2026-05-30 20:01, Mauricio Faria de Oliveira wrote:
> On 2026-05-30 19:04, Borislav Petkov wrote:
>> On Sat, May 30, 2026 at 03:25:25PM -0300, Mauricio Faria de Oliveira wrote:
>>> In this instance, the use case is to speed up the dev-test cycle when
>>> debugging on VMs: PVH allows booting directly from vmlinux, avoiding the
>>> need to build/compress and decompress bzImage, while KASAN helps detect
>>> issues early.
>> 
>> Makes sense in itself. And you can't do your use case with KVM? It has to be
>> Xen?
> 
> It uses KVM, actually. 
> 
> IIUIC, the PVH entry point was originally developed for Xen, but later
> QEMU support was added for KVM as well.
> (found this blog post [1] with a nice summary and links about it.)

[1]
https://stefano-garzarella.github.io/posts/2019-08-23-qemu-linux-kernel-pvh/

>>> Briefly, this is a side effect of reusing code from 'boot/string.c'
>>> through <asm/string.h>, which introduces additional complications;
>>> please see patch 1 for details.
>>> 
>>> These complications could be avoided by not reusing that code and
>>> instead adding slightly duplicated code [1] directly to <asm/string.h>,
>>> if that is preferred.
>> 
>> I'll take a look.
> 
> Ok, thanks!
> 
>> 
>> Thx.

-- 
Mauricio