Re: [PATCH v2] xen/arm: p2m don't fall over on FEAT_LPA enabled hw

[Alex Bennée <alex.bennee@xxxxxxxxxx>]

Julien Grall <julien@xxxxxxx> writes:

> Hi Alex,
>
> On 28/04/2022 11:34, Alex Bennée wrote:
>> When we introduced FEAT_LPA to QEMU's -cpu max we discovered older
>> kernels had a bug where the physical address was copied directly from
>> ID_AA64MMFR0_EL1.PARange field. The early cpu_init code of Xen commits
>> the same error by blindly copying across the max supported range.
>> Unsurprisingly when the page tables aren't set up for these greater
>> ranges hilarity ensues and the hypervisor crashes fairly early on in
>> the boot-up sequence. This happens when we write to the control
>> register in enable_mmu().
>> Attempt to fix this the same way as the Linux kernel does by gating
>> PARange to the maximum the hypervisor can handle. I also had to fix up
>> code in p2m which panics when it sees an "invalid" entry in PARange.
>> Signed-off-by: Alex Bennée <alex.bennee@xxxxxxxxxx>
>> Cc: Richard Henderson <richard.henderson@xxxxxxxxxx>
>> Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
>> Cc: Julien Grall <julien@xxxxxxx>
>> Cc: Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>
>> Cc: Bertrand Marquis <bertrand.marquis@xxxxxxx>
>
> Acked-by: Julien Grall <jgrall@xxxxxxxxxx>

Will you pick this up via your tree or do I need to do something else to
get it upstreamed? I guess it needs to go on master and last stable?

-- 
Alex Bennée