Commit Graph

3 Commits

Author SHA1 Message Date
David Matlack
a10453c038 KVM: selftests: Fix hang in hardware_disable_test
If /dev/kvm is not available then hardware_disable_test will hang
indefinitely because the child process exits before posting to the
semaphore for which the parent is waiting.

Fix this by making the parent periodically check if the child has
exited. We have to be careful to forward the child's exit status to
preserve a KSFT_SKIP status.

I considered just checking for /dev/kvm before creating the child
process, but there are so many other reasons why the child could exit
early that it seemed better to handle that as general case.

Tested:

$ ./hardware_disable_test
/dev/kvm not available, skipping test
$ echo $?
4
$ modprobe kvm_intel
$ ./hardware_disable_test
$ echo $?
0

Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20210514230521.2608768-1-dmatlack@google.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-05-27 07:45:55 -04:00
Vitaly Kuznetsov
f982fb62a3 selftests: kvm: make hardware_disable_test less verbose
hardware_disable_test produces 512 snippets like
...
 main: [511] waiting semaphore
 run_test: [511] start vcpus
 run_test: [511] all threads launched
 main: [511] waiting 368us
 main: [511] killing child

and this doesn't have much value, let's print this info with pr_debug().

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20210323104331.1354800-1-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-30 13:07:10 -04:00
Ignacio Alvarado
1838b06bf0 selftests: kvm: add hardware_disable test
This test launches 512 VMs in serial and kills them after a random
amount of time.

The test was original written to exercise KVM user notifiers in
the context of1650b4ebc99d:
- KVM: Disable irq while unregistering user notifier
- https://lore.kernel.org/kvm/CACXrx53vkO=HKfwWwk+fVpvxcNjPrYmtDZ10qWxFvVX_PTGp3g@mail.gmail.com/

Recently, this test piqued my interest because it proved useful to
for AMD SNP in exercising the "in-use" pages, described in APM section
15.36.12, "Running SNP-Active Virtual Machines".

Signed-off-by: Ignacio Alvarado <ikalvarado@google.com>
Signed-off-by: Marc Orr <marcorr@google.com>
Message-Id: <20210213001452.1719001-1-marcorr@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-15 11:42:36 -05:00