ESSA emulation in migration mode silently dropped addressing exceptions
when the guest page-table walk failed, so the guest never received the
expected PGM_ADDRESSING interrupt during live migration.
Patch 1 fixes dat_perform_essa() to return PGM_ADDRESSING on a walk
failure, and __do_essa() to inject the program interrupt when it sees
that return value.
Patch 2 adds a regression test integrated into the existing cmma_test
selftest.
Changes since v1:
- dat_perform_essa() now returns +PGM_ADDRESSING instead of
-PGM_ADDRESSING; kvm_s390_inject_program_int() takes an unsigned u16
so passing -5 would have wrapped to 0xFFFB and injected a bogus PIC.
__do_essa() comparison and inject call updated accordingly. The
kernel-doc return-value entry is corrected to %PGM_ADDRESSING.
- Selftest: pgm_handler_c() now reads the actual PIC from lowcore
(__LC_PGM_INT_CODE) instead of hard-coding PGM_ADDRESSING, so the
test would have caught the sign error above had it been in v1.
- Selftest: virt_map(vm, 0, 0, 1) added so the DAT-on guest can
access the lowcore to read the PIC.
- Selftest: PGM_ADDRESSING, __LC_PGM_INT_CODE and __LC_PGM_NEW_PSW
constants moved to the shared s390/processor.h header.
- Selftest: SIGALRM/alarm() timeout wrapper removed.
Gautam Gala (2):
KVM: s390: fix ESSA addressing exception injection in migration mode
KVM: s390: selftests: add ESSA migration mode PGM_ADDRESSING
regression test
arch/s390/kvm/gmap/dat.c | 5 +-
arch/s390/kvm/s390/priv.c | 2 +
.../selftests/kvm/include/s390/processor.h | 7 ++
tools/testing/selftests/kvm/s390/cmma_test.c | 69 +++++++++++++++++++
4 files changed, 82 insertions(+), 1 deletion(-)
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2.55.0
