On Thu, 2022-10-20 at 18:23 +0300, Maxim Levitsky wrote:
> Test that if L2 triggers a shutdown, this VM exits to L1
> and doesn't crash the host.
>
> Signed-off-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
> ---
> x86/svm_tests.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 51 insertions(+)
>
> diff --git a/x86/svm_tests.c b/x86/svm_tests.c
> index 19b35e95..2c29c2b0 100644
> --- a/x86/svm_tests.c
> +++ b/x86/svm_tests.c
> @@ -10,6 +10,7 @@
> #include "isr.h"
> #include "apic.h"
> #include "delay.h"
> +#include "vmalloc.h"
>
> #define SVM_EXIT_MAX_DR_INTERCEPT 0x3f
>
> @@ -3270,6 +3271,55 @@ static void svm_intr_intercept_mix_smi(void)
> svm_intr_intercept_mix_run_guest(NULL, SVM_EXIT_SMI);
> }
>
> +
> +static void shutdown_intercept_test_guest(struct svm_test *test)
> +{
> + asm volatile ("int3");
> + report_fail("should not reach here\n");
> +
> +}
> +
> +static void shutdown_intercept_test_guest2(struct svm_test *test)
> +{
> + asm volatile ("ud2");
> + report_fail("should not reach here\n");
> +
> +}
> +
> +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.
Best regards,
MaxiM Levitsky
