Commit b10d86fb authored by Oliver Upton's avatar Oliver Upton Committed by Marc Zyngier
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KVM: arm64: Reject 32bit user PSTATE on asymmetric systems 



KVM does not support AArch32 EL0 on asymmetric systems. To that end,
prevent userspace from configuring a vCPU in such a state through
setting PSTATE.

It is already ABI that KVM rejects such a write on a system where
AArch32 EL0 is unsupported. Though the kernel's definition of a 32bit
system changed in commit 2122a833 ("arm64: Allow mismatched
32-bit EL0 support"), KVM's did not.

Fixes: 2122a833 ("arm64: Allow mismatched 32-bit EL0 support")
Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220816192554.1455559-3-oliver.upton@linux.dev
parent f3c6efc7

arch/arm64/kvm/guest.c

+1 −1
Original line number Diff line number Diff line
@@ -242,7 +242,7 @@ static int set_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) 
		u64 mode = (*(u64 *)valp) & PSR_AA32_MODE_MASK;

		switch (mode) {

		case PSR_AA32_MODE_USR:

			if (!system_supports_32bit_el0())

			if (!kvm_supports_32bit_el0())

				return -EINVAL;

			break;

		case PSR_AA32_MODE_FIQ: