On Thu, Oct 20, 2022, Maxim Levitsky wrote:
> On Thu, 2022-10-20 at 18:23 +0300, Maxim Levitsky wrote:
> > +static void svm_shutdown_intercept_test(void)
> > +{
> > + void* unmapped_address = alloc_vpage();
> > +
> > + /*
> > + * Test that shutdown vm exit doesn't crash L0
> > + *
> > + * Test both native and emulated triple fault
> > + * (due to exception merging)
> > + */
> > +
> > +
> > + /*
> > + * This will usually cause native SVM_EXIT_SHUTDOWN
> > + * (KVM usually doesn't intercept #PF)
> > + * */
> > + test_set_guest(shutdown_intercept_test_guest);
> > + vmcb->save.idtr.base = (u64)unmapped_address;
> > + vmcb->control.intercept |= (1ULL << INTERCEPT_SHUTDOWN);
> > + svm_vmrun();
> > + report (vmcb->control.exit_code == SVM_EXIT_SHUTDOWN, "shutdown (BP->PF->DF->TRIPLE_FAULT) test passed");
> > +
> > + /*
> > + * This will usually cause emulated SVM_EXIT_SHUTDOWN
> > + * (KVM usually intercepts #UD)
> > + */
> > + test_set_guest(shutdown_intercept_test_guest2);
> > + vmcb_ident(vmcb);
> > + vmcb->save.idtr.limit = 0;
> > + vmcb->control.intercept |= (1ULL << INTERCEPT_SHUTDOWN);
> > + svm_vmrun();
> > + report (vmcb->control.exit_code == SVM_EXIT_SHUTDOWN, "shutdown (UD->DF->TRIPLE_FAULT) test passed");
> > +}
> > +
> > struct svm_test svm_tests[] = {
> > { "null", default_supported, default_prepare,
> > default_prepare_gif_clear, null_test,
> > @@ -3382,6 +3432,7 @@ struct svm_test svm_tests[] = {
> > TEST(svm_intr_intercept_mix_smi),
> > TEST(svm_tsc_scale_test),
> > TEST(pause_filter_test),
> > + TEST(svm_shutdown_intercept_test),
> > { NULL, NULL, NULL, NULL, NULL, NULL, NULL }
> > };
>
> Note that on unpatched KVM, this test will cause a kernel panic on the host
> if run.
>
> I sent a patch today with a fix for this.
I'm confused. The KVM patches address a bug where KVM screws up if the SHUTDOWN
(or INIT) is _not_ intercepted by L1, but the test here does intercept SHUTDOWN.
Are there more bugs lurking in KVM, or am I missing something?
