[PATCH 0/2] KVM: arm64: Make AArch64 support sticky

[Ganapatrao Kulkarni]

On 4/29/2025 5:11 PM, Marc Zyngier wrote:
> It's been recently reported[1] that our sorry excuse for a test suite
> is writing a bunch of zeroes to ID_AA64PFR0_EL1.EL{0,1,2,3},
> effectively removing the advertised support for AArch64 to the guest.
> 
> This leads to an interesting interaction with the NV code which reacts
> in a slightly overzealous way and inject an UNDEF at the earliest
> opportunity.
> 
> This small series fixes KVM by bluntly refusing to disable AArch64,
> and the test to stop being so lame. I'm also fixing the NV code
> separately, since it isn't upstream.
> 
> [1] https://lore.kernel.org/r/4e63a13f-c5dc-4f97-879a-26b5548da07f@os.amperecomputing.com
> 
> Marc Zyngier (2):
>    KVM: arm64: Prevent userspace from disabling AArch64 support at any
>      virtualisable EL
>    KVM: arm64: selftest: Don't try to disable AArch64 support
> 
>   arch/arm64/kvm/sys_regs.c                       | 6 ++++++
>   tools/testing/selftests/kvm/arm64/set_id_regs.c | 8 ++++----
>   2 files changed, 10 insertions(+), 4 deletions(-)
> 

Please feel free to add,
Reviewed-by: Ganapatrao Kulkarni <gankulkarni at os.amperecomputing.com>

-- 
Thanks,
Gk