Re: [PATCH v4 3/3] selftests: KVM: SVM: Add vmcall test

From: Auger Eric
Date: Fri Feb 07 2020 - 05:16:06 EST


Hi Wei,

On 2/6/20 6:39 PM, Wei Huang wrote:
> On 02/06 11:47, Eric Auger wrote:
>> L2 guest calls vmcall and L1 checks the exit status does
>> correspond.
>>
>> Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
>> Reviewed-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
>> Reviewed-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
>
> I verified this patch with my AMD box, both with nested=1 and nested=0. I
> also intentionally changed the assertion of exit_code to a different
> value (0x082) and the test complained about it. So the test is good.
>
> # selftests: kvm: svm_vmcall_test
> # ==== Test Assertion Failure ====
> # x86_64/svm_vmcall_test.c:64: false
> # pid=2485656 tid=2485656 - Interrupted system call
> # 1 0x0000000000401387: main at svm_vmcall_test.c:72
> # 2 0x00007fd0978d71a2: ?? ??:0
> # 3 0x00000000004013ed: _start at ??:?
> # Failed guest assert: vmcb->control.exit_code == SVM_EXIT_VMMCALL
> # Testing guest mode: PA-bits:ANY, VA-bits:48, 4K pages
> # Guest physical address width detected: 48
> not ok 15 selftests: kvm: svm_vmcall_test # exit=254

thank you for testing! May I include your T-b then?
>
>>
>> ---
>>
>> v3 -> v4:
>> - remove useless includes
>> - collected Lin's R-b
>>
>> v2 -> v3:
>> - remove useless comment and add Vitaly's R-b
>> ---
>> tools/testing/selftests/kvm/Makefile | 1 +
>> .../selftests/kvm/x86_64/svm_vmcall_test.c | 79 +++++++++++++++++++
>> 2 files changed, 80 insertions(+)
>> create mode 100644 tools/testing/selftests/kvm/x86_64/svm_vmcall_test.c
>>
>> diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
>> index 2e770f554cae..b529d3b42c02 100644
>> --- a/tools/testing/selftests/kvm/Makefile
>> +++ b/tools/testing/selftests/kvm/Makefile
>> @@ -26,6 +26,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/vmx_dirty_log_test
>> TEST_GEN_PROGS_x86_64 += x86_64/vmx_set_nested_state_test
>> TEST_GEN_PROGS_x86_64 += x86_64/vmx_tsc_adjust_test
>> TEST_GEN_PROGS_x86_64 += x86_64/xss_msr_test
>> +TEST_GEN_PROGS_x86_64 += x86_64/svm_vmcall_test
>> TEST_GEN_PROGS_x86_64 += clear_dirty_log_test
>> TEST_GEN_PROGS_x86_64 += dirty_log_test
>> TEST_GEN_PROGS_x86_64 += kvm_create_max_vcpus
>> diff --git a/tools/testing/selftests/kvm/x86_64/svm_vmcall_test.c b/tools/testing/selftests/kvm/x86_64/svm_vmcall_test.c
>> new file mode 100644
>> index 000000000000..6d3565aab94e
>> --- /dev/null
>> +++ b/tools/testing/selftests/kvm/x86_64/svm_vmcall_test.c
>
> Probably rename the file to svm_nested_vmcall_test.c. This matches with
> the naming convention of VMX's nested tests. Otherwise people might not know
> it is a nested one.

>From what I understand, all the vmx_* (including vmx_tsc_adjust_test for
instance) are related to nested. So I'd rather leave svm_ prefix for
nested SVM.

Thanks

Eric
>
> Everything else looks good.
>
>> @@ -0,0 +1,79 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * svm_vmcall_test
>> + *
>> + * Copyright (C) 2020, Red Hat, Inc.
>> + *
>> + * Nested SVM testing: VMCALL
>> + */
>> +
>> +#include "test_util.h"
>> +#include "kvm_util.h"
>> +#include "processor.h"
>> +#include "svm_util.h"
>> +
>> +#define VCPU_ID 5
>> +
>> +static struct kvm_vm *vm;
>> +
>> +static inline void l2_vmcall(struct svm_test_data *svm)
>> +{
>> + __asm__ __volatile__("vmcall");
>> +}
>> +
>> +static void l1_guest_code(struct svm_test_data *svm)
>> +{
>> + #define L2_GUEST_STACK_SIZE 64
>> + unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
>> + struct vmcb *vmcb = svm->vmcb;
>> +
>> + /* Prepare for L2 execution. */
>> + generic_svm_setup(svm, l2_vmcall,
>> + &l2_guest_stack[L2_GUEST_STACK_SIZE]);
>> +
>> + run_guest(vmcb, svm->vmcb_gpa);
>> +
>> + GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
>> + GUEST_DONE();
>> +}
>> +
>> +int main(int argc, char *argv[])
>> +{
>> + vm_vaddr_t svm_gva;
>> +
>> + nested_svm_check_supported();
>> +
>> + vm = vm_create_default(VCPU_ID, 0, (void *) l1_guest_code);
>> + vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
>> +
>> + vcpu_alloc_svm(vm, &svm_gva);
>> + vcpu_args_set(vm, VCPU_ID, 1, svm_gva);
>> +
>> + for (;;) {
>> + volatile struct kvm_run *run = vcpu_state(vm, VCPU_ID);
>> + struct ucall uc;
>> +
>> + vcpu_run(vm, VCPU_ID);
>> + TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
>> + "Got exit_reason other than KVM_EXIT_IO: %u (%s)\n",
>> + run->exit_reason,
>> + exit_reason_str(run->exit_reason));
>> +
>> + switch (get_ucall(vm, VCPU_ID, &uc)) {
>> + case UCALL_ABORT:
>> + TEST_ASSERT(false, "%s",
>> + (const char *)uc.args[0]);
>> + /* NOT REACHED */
>> + case UCALL_SYNC:
>> + break;
>> + case UCALL_DONE:
>> + goto done;
>> + default:
>> + TEST_ASSERT(false,
>> + "Unknown ucall 0x%x.", uc.cmd);
>> + }
>> + }
>> +done:
>> + kvm_vm_free(vm);
>> + return 0;
>> +}
>
>