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Peter Anvin" , Juergen Gross , Alexey Dobriyan , Boris Ostrovsky , kernel-dev@igalia.com, linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, kernel test robot Subject: Re: [PATCH v4 0/4] x86/pvh: fix unbootable VMs again (PVH + KASAN) In-Reply-To: <7f1af7169b4f8c90abae28cebd3e377f@igalia.com> References: <20260526-pvh-kasan-inline-v4-0-a310e6a25ecd@igalia.com> <20260527204736.GBahdYaKk6kAkIUYE3@fat_crate.local> <274609541a0c7c6b49b386001967dd2b@igalia.com> <20260530220453.GAahtfBVv2hydidbnW@fat_crate.local> <7f1af7169b4f8c90abae28cebd3e377f@igalia.com> Message-ID: <28155e57d75407a645d57e4a6f99859c@igalia.com> X-Sender: mfo@igalia.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Spam-Report: NO, Score=-4.7, Tests=ALL_TRUSTED=-3,AWL=-2.551,BAYES_50=0.8,URIBL_BLOCKED=0.001,URIBL_DBL_BLOCKED_OPENDNS=0.001,URIBL_ZEN_BLOCKED_OPENDNS=0.001 X-Spam-Score: -46 X-Spam-Bar: ---- 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 , 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 , >>> if that is preferred. >> >> I'll take a look. > > Ok, thanks! > >> >> Thx. -- Mauricio