Re: [PATCH 06/10] KVM: selftests: Add "delete" testcase to set_memory_region_test

From: Andrew Jones
Date: Tue Apr 14 2020 - 12:19:39 EST


On Fri, Apr 10, 2020 at 04:17:03PM -0700, Sean Christopherson wrote:
> Add a testcase for deleting memslots while the guest is running.
> Like the "move" testcase, this is x86_64-only as it relies on MMIO
> happening when a non-existent memslot is encountered.
>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
> ---
> .../kvm/x86_64/set_memory_region_test.c | 91 +++++++++++++++++++
> 1 file changed, 91 insertions(+)
>
> diff --git a/tools/testing/selftests/kvm/x86_64/set_memory_region_test.c b/tools/testing/selftests/kvm/x86_64/set_memory_region_test.c
> index 629dd8579b73..b556024af683 100644
> --- a/tools/testing/selftests/kvm/x86_64/set_memory_region_test.c
> +++ b/tools/testing/selftests/kvm/x86_64/set_memory_region_test.c
> @@ -29,6 +29,9 @@
>
> static const uint64_t MMIO_VAL = 0xbeefull;
>
> +extern const uint64_t final_rip_start;
> +extern const uint64_t final_rip_end;
> +
> static sem_t vcpu_ready;
>
> static inline uint64_t guest_spin_on_val(uint64_t spin_val)

We don't have guest_spin_on_val(), so it looks like this patch applies
on the older version of this series? But I don't know where
wait_for_vcpu() called below comes from.

Thanks,
drew


> @@ -203,6 +206,89 @@ static void test_move_memory_region(void)
> kvm_vm_free(vm);
> }
>
> +static void guest_code_delete_memory_region(void)
> +{
> + uint64_t val;
> +
> + GUEST_SYNC(0);
> +
> + /* Spin until the memory region is deleted. */
> + val = guest_spin_on_val(0);
> + GUEST_ASSERT_1(val == MMIO_VAL, val);
> +
> + /* Spin until the memory region is recreated. */
> + val = guest_spin_on_val(MMIO_VAL);
> + GUEST_ASSERT_1(val == 0, val);
> +
> + /* Spin until the memory region is deleted. */
> + val = guest_spin_on_val(0);
> + GUEST_ASSERT_1(val == MMIO_VAL, val);
> +
> + asm("1:\n\t"
> + ".pushsection .rodata\n\t"
> + ".global final_rip_start\n\t"
> + "final_rip_start: .quad 1b\n\t"
> + ".popsection");
> +
> + /* Spin indefinitely (until the code memslot is deleted). */
> + guest_spin_on_val(MMIO_VAL);
> +
> + asm("1:\n\t"
> + ".pushsection .rodata\n\t"
> + ".global final_rip_end\n\t"
> + "final_rip_end: .quad 1b\n\t"
> + ".popsection");
> +
> + GUEST_ASSERT_1(0, 0);
> +}
> +
> +static void test_delete_memory_region(void)
> +{
> + pthread_t vcpu_thread;
> + struct kvm_regs regs;
> + struct kvm_run *run;
> + struct kvm_vm *vm;
> +
> + vm = spawn_vm(&vcpu_thread, guest_code_delete_memory_region);
> +
> + /* Delete the memory region, the guest should not die. */
> + vm_mem_region_delete(vm, MEM_REGION_SLOT);
> + wait_for_vcpu();
> +
> + /* Recreate the memory region. The guest should see "0". */
> + vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS_THP,
> + MEM_REGION_GPA, MEM_REGION_SLOT,
> + MEM_REGION_SIZE / getpagesize(), 0);
> + wait_for_vcpu();
> +
> + /* Delete the region again so that there's only one memslot left. */
> + vm_mem_region_delete(vm, MEM_REGION_SLOT);
> + wait_for_vcpu();
> +
> + /*
> + * Delete the primary memslot. This should cause an emulation error or
> + * shutdown due to the page tables getting nuked.
> + */
> + vm_mem_region_delete(vm, 0);
> +
> + pthread_join(vcpu_thread, NULL);
> +
> + run = vcpu_state(vm, VCPU_ID);
> +
> + TEST_ASSERT(run->exit_reason == KVM_EXIT_SHUTDOWN ||
> + run->exit_reason == KVM_EXIT_INTERNAL_ERROR,
> + "Unexpected exit reason = %d", run->exit_reason);
> +
> + vcpu_regs_get(vm, VCPU_ID, &regs);
> +
> + TEST_ASSERT(regs.rip >= final_rip_start &&
> + regs.rip < final_rip_end,
> + "Bad rip, expected 0x%lx - 0x%lx, got 0x%llx\n",
> + final_rip_start, final_rip_end, regs.rip);
> +
> + kvm_vm_free(vm);
> +}
> +
> int main(int argc, char *argv[])
> {
> int i, loops;
> @@ -215,8 +301,13 @@ int main(int argc, char *argv[])
> else
> loops = 10;
>
> + pr_info("Testing MOVE of in-use region, %d loops\n", loops);
> for (i = 0; i < loops; i++)
> test_move_memory_region();
>
> + pr_info("Testing DELETE of in-use region, %d loops\n", loops);
> + for (i = 0; i < loops; i++)
> + test_delete_memory_region();
> +
> return 0;
> }
> --
> 2.26.0
>