Re: [PATCH 1/3] xen, pvh: fix unbootable VMs (PVH + KASAN)

[Jürgen Groß]

On 01.08.24 21:16, Alexey Dobriyan wrote:
> Uninstrument arch/x86/platform/pvh/enlighten.c: KASAN is not setup
> _this_ early in the boot process.
>
> Steps to reproduce:
>
> 	make allnoconfig
> 	make sure CONFIG_AMD_MEM_ENCRYPT is disabled
> 		AMD_MEM_ENCRYPT independently uninstruments lib/string.o
> 		so PVH boot code calls into uninstrumented memset() and
> 		memcmp() which can make the bug disappear depending on
> 		the compiler.
> 	enable CONFIG_PVH
> 	enable CONFIG_KASAN
> 	enable serial console
> 		this is fun exercise if you never done it from nothing :^)
>
> 	make
>
> 	qemu-system-x86_64	\
> 		-enable-kvm	\
> 		-cpu host	\
> 		-smp cpus=1	\
> 		-m 4096		\
> 		-serial stdio	\
> 		-kernel vmlinux \
> 		-append 'console=ttyS0 ignore_loglevel'
>
> Messages on serial console will easily tell OK kernel from unbootable
> kernel. In bad case qemu hangs in an infinite loop stroboscoping
> "SeaBIOS" message.
>
> Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx>

Acked-by: Juergen Gross <jgross@xxxxxxxx>


Juergen