linux_dsm_epyc7002/arch/s390/kvm
Michael Mueller c7901a6ebe 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>
2018-01-26 09:49:09 +01:00
..
diag.c KVM: s390: add vcpu stat counters for many instruction 2018-01-24 16:49:02 +01:00
gaccess.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
gaccess.h KVM: s390: Remove redundant license text 2017-12-06 09:18:42 +01:00
guestdbg.c KVM: s390: Remove redundant license text 2017-12-06 09:18:42 +01:00
intercept.c KVM: s390: Remove redundant license text 2017-12-06 09:18:42 +01:00
interrupt.c KVM: s390: reverse bit ordering of irqs in pending mask 2018-01-26 09:49:09 +01:00
irq.h KVM: s390: Remove redundant license text 2017-12-06 09:18:42 +01:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kvm-s390.c KVM: s390: introduce and use kvm_s390_test_cpuflags() 2018-01-24 17:46:42 +01:00
kvm-s390.h KVM: s390: introduce and use kvm_s390_test_cpuflags() 2018-01-24 17:46:42 +01:00
Makefile KVM: s390: Remove redundant license text 2017-12-06 09:18:42 +01:00
priv.c KVM: s390: introduce and use kvm_s390_test_cpuflags() 2018-01-24 17:46:42 +01:00
sigp.c KVM: s390: introduce and use kvm_s390_test_cpuflags() 2018-01-24 17:46:42 +01:00
trace-s390.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
trace.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
vsie.c KVM: s390: introduce and use kvm_s390_clear_cpuflags() 2018-01-24 17:46:42 +01:00