kvm: selftests: aarch64: use a tighter assert in vgic_poke_irq()

vgic_poke_irq() checks that the attr argument passed to the vgic device
ioctl is sane. Make this check tighter by moving it to after the last
attr update.
Signed-off-by: Ricardo Koller <ricarkol@google.com>
Reported-by: Reiji Watanabe <reijiw@google.com>
Cc: Andrew Jones <drjones@redhat.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220127030858.3269036-6-ricarkol@google.com

tools/testing/selftests/kvm/lib/aarch64/vgic.c

@@ -138,9 +138,6 @@ static void vgic_poke_irq(int gic_fd, uint32_t intid,
 	uint64_t val;
 	bool intid_is_private = INTID_IS_SGI(intid) || INTID_IS_PPI(intid);
 
-	/* Check that the addr part of the attr is within 32 bits. */
-	assert(attr <= KVM_DEV_ARM_VGIC_OFFSET_MASK);
-
 	uint32_t group = intid_is_private ? KVM_DEV_ARM_VGIC_GRP_REDIST_REGS
 					  : KVM_DEV_ARM_VGIC_GRP_DIST_REGS;
 
@@ -150,6 +147,9 @@ static void vgic_poke_irq(int gic_fd, uint32_t intid,
 		attr += SZ_64K;
 	}
 
+	/* Check that the addr part of the attr is within 32 bits. */
+	assert((attr & ~KVM_DEV_ARM_VGIC_OFFSET_MASK) == 0);
+
 	/*
 	 * All calls will succeed, even with invalid intid's, as long as the
 	 * addr part of the attr is within 32 bits (checked above). An invalid