The DIAGNOSE 0x0318 instruction, unique to s390x, is a privileged call
that must be intercepted via SIE, handled in userspace, and the
information set by the instruction is communicated back to KVM.
To test the instruction interception, an ad-hoc handler is defined which
simply has a VM execute the instruction and then userspace will extract
the necessary info. The handler is defined such that the instruction
invocation occurs only once. It is up to the caller to determine how the
info returned by this handler should be used.
The diag318 info is communicated from userspace to KVM via a sync_regs
call. This is tested during a sync_regs test, where the diag318 info is
requested via the handler, then the info is stored in the appropriate
register in KVM via a sync registers call.
If KVM does not support diag318, then the tests will print a message
stating that diag318 was skipped, and the asserts will simply test
against a value of 0.
Signed-off-by: Collin Walling <walling@linux.ibm.com>
Link: https://lore.kernel.org/r/20201207154125.10322-1-walling@linux.ibm.com
Acked-by: Janosch Frank <frankja@linux.ibm.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
similar to commit 2c57da356800 ("selftests: kvm: fix sync_regs_test with
newer gccs") and commit 204c91eff7 ("KVM: selftests: do not blindly
clobber registers in guest asm") we better do not rely on gcc leaving
r11 untouched. We can write the simple ucall inline and have the guest
code completely as small assembler function.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
The test is an adaption of the same test for x86. Note that there
are some differences in the way how s390x deals with the kvm_valid_regs
in struct kvm_run, so some of the tests had to be removed. Also this
test is not using the ucall() interface on s390x yet (which would need
some work to be usable on s390x), so it simply drops out of the VM with
a diag 0x501 breakpoint instead.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20190523164309.13345-8-thuth@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
