KVM: s390: reverse bit ordering of irqs in pending mask

This patch prepares a simplification of bit operations between the irq
pending mask for emulated interrupts and the Interruption Pending Mask
(IPM) which is part of the Guest Interruption State Area (GISA), a feature
that allows interrupt delivery to guests by means of the SIE instruction.

Without that change, a bit-wise *or* operation on parts of these two masks
would either require a look-up table of size 256 bytes to map the IPM
to the emulated irq pending mask bit orientation (all bits mirrored at half
byte) or a sequence of up to 8 condidional branches to perform tests of
single bit positions. Both options are to be rejected either by performance
or space utilization reasons.

Beyond that this change will be transparent.

Signed-off-by: Michael Mueller <mimu@linux.vnet.ibm.com>
Reviewed-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

1 files changed, 27 insertions, 27 deletions

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 029e8144c6ec..d2351d63afa3 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -422,35 +422,35 @@ struct kvm_vcpu_stat {
 #define PGM_PER                         0x80
 #define PGM_CRYPTO_OPERATION            0x119
 
-/* irq types in order of priority */
+/* irq types in ascend order of priorities */
 enum irq_types {
-        IRQ_PEND_MCHK_EX = 0,
-        IRQ_PEND_SVC,
-        IRQ_PEND_PROG,
-        IRQ_PEND_MCHK_REP,
-        IRQ_PEND_EXT_IRQ_KEY,
-        IRQ_PEND_EXT_MALFUNC,
-        IRQ_PEND_EXT_EMERGENCY,
-        IRQ_PEND_EXT_EXTERNAL,
-        IRQ_PEND_EXT_CLOCK_COMP,
-        IRQ_PEND_EXT_CPU_TIMER,
-        IRQ_PEND_EXT_TIMING,
-        IRQ_PEND_EXT_SERVICE,
-        IRQ_PEND_EXT_HOST,
-        IRQ_PEND_PFAULT_INIT,
-        IRQ_PEND_PFAULT_DONE,
-        IRQ_PEND_VIRTIO,
-        IRQ_PEND_IO_ISC_0,
-        IRQ_PEND_IO_ISC_1,
-        IRQ_PEND_IO_ISC_2,
-        IRQ_PEND_IO_ISC_3,
-        IRQ_PEND_IO_ISC_4,
-        IRQ_PEND_IO_ISC_5,
-        IRQ_PEND_IO_ISC_6,
-        IRQ_PEND_IO_ISC_7,
-        IRQ_PEND_SIGP_STOP,
+        IRQ_PEND_SET_PREFIX = 0,
         IRQ_PEND_RESTART,
-        IRQ_PEND_SET_PREFIX,
+        IRQ_PEND_SIGP_STOP,
+        IRQ_PEND_IO_ISC_7,
+        IRQ_PEND_IO_ISC_6,
+        IRQ_PEND_IO_ISC_5,
+        IRQ_PEND_IO_ISC_4,
+        IRQ_PEND_IO_ISC_3,
+        IRQ_PEND_IO_ISC_2,
+        IRQ_PEND_IO_ISC_1,
+        IRQ_PEND_IO_ISC_0,
+        IRQ_PEND_VIRTIO,
+        IRQ_PEND_PFAULT_DONE,
+        IRQ_PEND_PFAULT_INIT,
+        IRQ_PEND_EXT_HOST,
+        IRQ_PEND_EXT_SERVICE,
+        IRQ_PEND_EXT_TIMING,
+        IRQ_PEND_EXT_CPU_TIMER,
+        IRQ_PEND_EXT_CLOCK_COMP,
+        IRQ_PEND_EXT_EXTERNAL,
+        IRQ_PEND_EXT_EMERGENCY,
+        IRQ_PEND_EXT_MALFUNC,
+        IRQ_PEND_EXT_IRQ_KEY,
+        IRQ_PEND_MCHK_REP,
+        IRQ_PEND_PROG,
+        IRQ_PEND_SVC,
+        IRQ_PEND_MCHK_EX,
         IRQ_PEND_COUNT
 };