KVM: arm64: nv: Allow userspace to set PSR_MODE_EL2x

We were not allowing userspace to set a more privileged mode for the VCPU
than EL1, but we should allow this when nested virtualization is enabled
for the VCPU.

Reviewed-by: Russell King (Oracle) <[e-mail]>
Signed-off-by: Christoffer Dall <[e-mail]>
Signed-off-by: Marc Zyngier <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Oliver Upton <[e-mail]>

arch/arm64/kvm/guest.c

···
 #include <asm/fpsimd.h>
 #include <asm/kvm.h>
 #include <asm/kvm_emulate.h>
+#include <asm/kvm_nested.h>
 #include <asm/sigcontext.h>
 
 #include "trace.h"
···
 			if (!vcpu_el1_is_32bit(vcpu))
 				return -EINVAL;
 			break;
+		case PSR_MODE_EL2h:
+		case PSR_MODE_EL2t:
+			if (!vcpu_has_nv(vcpu))
+				return -EINVAL;
+			fallthrough;
 		case PSR_MODE_EL0t:
 		case PSR_MODE_EL1t:
 		case PSR_MODE_EL1h: