diff options
| author | Sean Christopherson <seanjc@google.com> | 2023-08-18 02:34:30 +0300 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2023-08-25 19:04:11 +0300 |
| commit | 02dc2543e3795867260826983bf3f20b282c8fc3 (patch) | |
| tree | dbc5f0db61c68faeb39231b10255491fc912d566 /tools | |
| parent | 5002b112a5ad23579b7c3a36c9748740bcdfc88e (diff) | |
| download | linux-02dc2543e3795867260826983bf3f20b282c8fc3.tar.xz | |
KVM: selftests: Explicit set #UD when *potentially* injecting exception
Explicitly set the exception vector to #UD when potentially injecting an
exception in sync_regs_test's subtests that try to detect TOCTOU bugs
in KVM's handling of exceptions injected by userspace. A side effect of
the original KVM bug was that KVM would clear the vector, but relying on
KVM to clear the vector (i.e. make it #DE) makes it less likely that the
test would ever find *new* KVM bugs, e.g. because only the first iteration
would run with a legal vector to start.
Explicitly inject #UD for race_events_inj_pen() as well, e.g. so that it
doesn't inherit the illegal 255 vector from race_events_exc(), which
currently runs first.
Link: https://lore.kernel.org/r/20230817233430.1416463-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/testing/selftests/kvm/x86_64/sync_regs_test.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/x86_64/sync_regs_test.c b/tools/testing/selftests/kvm/x86_64/sync_regs_test.c index 21e99dae2ff2..00965ba33f73 100644 --- a/tools/testing/selftests/kvm/x86_64/sync_regs_test.c +++ b/tools/testing/selftests/kvm/x86_64/sync_regs_test.c @@ -91,6 +91,8 @@ static void *race_events_inj_pen(void *arg) struct kvm_run *run = (struct kvm_run *)arg; struct kvm_vcpu_events *events = &run->s.regs.events; + WRITE_ONCE(events->exception.nr, UD_VECTOR); + for (;;) { WRITE_ONCE(run->kvm_dirty_regs, KVM_SYNC_X86_EVENTS); WRITE_ONCE(events->flags, 0); @@ -115,6 +117,7 @@ static void *race_events_exc(void *arg) for (;;) { WRITE_ONCE(run->kvm_dirty_regs, KVM_SYNC_X86_EVENTS); WRITE_ONCE(events->flags, 0); + WRITE_ONCE(events->exception.nr, UD_VECTOR); WRITE_ONCE(events->exception.pending, 1); WRITE_ONCE(events->exception.nr, 255); |