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 6a9c7b920970 ("arm64: Allow mismatched
32-bit EL0 support"), KVM's did not.

Fixes: 6a9c7b920970 ("arm64: Allow mismatched 32-bit EL0 support")
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220816192554.1455559-3-oliver.upton@linux.dev

diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 8c607199cad14d4dee8320d8847dc3ab9dab52ce..f802a3b3f8dbc86664d280601b1180ff2da0378f 100644 (file)
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -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: