Re: [PATCH 01/12] KVM: arm64: Make ICC_*SGI*_EL1 undef in the absence of a vGICv3

On Tue, Aug 20, 2024 at 11:03:38AM +0100, Marc Zyngier wrote:

On a system with a GICv3, if a guest hasn't been configured with GICv3 and that the host is not capable of GICv2 emulation, a write to any of the ICC_*SGI*_EL1 registers is trapped to EL2.

We therefore try to emulate the SGI access, only to hit a NULL pointer as no private interrupt is allocated (no GIC, remember?).

The obvious fix is to give the guest what it deserves, in the shape of a UNDEF exception.

Reported-by: Alexander Potapenko glider@google.com Signed-off-by: Marc Zyngier maz@kernel.org Cc: stable@vger.kernel.org

LGTM, and just as an FYI I do plan on grabbing this for 6.11