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

[Auger Eric]

Hi Krish,
On 2/6/20 8:08 PM, Krish Sadhukhan wrote:
> 
> On 2/6/20 9:39 AM, 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 ====
>> #ÂÂ x86_64/svm_vmcall_test.c:64: false
>> #ÂÂ pid=2485656 tid=2485656 - Interrupted system call
>> #ÂÂÂÂÂ 1ÂÂÂÂÂÂÂ 0x0000000000401387: main at svm_vmcall_test.c:72
>> #ÂÂÂÂÂ 2ÂÂÂÂÂÂÂ 0x00007fd0978d71a2: ?? ??:0
>> #ÂÂÂÂÂ 3ÂÂÂÂÂÂÂ 0x00000000004013ed: _start at ??:?
>> #ÂÂ 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
>>
>>> ---
>>>
>>> v3 -> v4:
>>> - remove useless includes
>>> - collected Lin's R-b
>>>
>>> v2 -> v3:
>>> - remove useless comment and add Vitaly's R-b
>>> ---
>>> Â tools/testing/selftests/kvm/MakefileÂÂÂÂÂÂÂÂÂ |Â 1 +
>>> Â .../selftests/kvm/x86_64/svm_vmcall_test.cÂÂÂ | 79 +++++++++++++++++++
>>> Â 2 files changed, 80 insertions(+)
>>> Â 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
>>> Â TEST_GEN_PROGS_x86_64 += x86_64/vmx_set_nested_state_test
>>> Â TEST_GEN_PROGS_x86_64 += x86_64/vmx_tsc_adjust_test
>>> Â TEST_GEN_PROGS_x86_64 += x86_64/xss_msr_test
>>> +TEST_GEN_PROGS_x86_64 += x86_64/svm_vmcall_test
>>> Â TEST_GEN_PROGS_x86_64 += clear_dirty_log_test
>>> Â TEST_GEN_PROGS_x86_64 += dirty_log_test
>>> Â 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.
> 
> Is it better to give this file a generic name, say, nsvm_tests or
> something like that, and place all future nested SVM tests in it, rather
> than creating a separate file for each nested test ?
We had this discussion earlier. See https://lkml.org/lkml/2020/1/21/429

In v1 I proposed a similar framework as kut with sub-tests but it looks
we do not target such kind of tests in kselftests. vmcall test is just a
first dummy test that paves the way for more involved API tests.

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_IDÂÂÂÂÂÂÂ 5
>>> +
>>> +static struct kvm_vm *vm;
>>> +
>>> +static inline void l2_vmcall(struct svm_test_data *svm)
>>> +{
>>> +ÂÂÂ __asm__ __volatile__("vmcall");
>>> +}
>>> +
>>> +static void l1_guest_code(struct svm_test_data *svm)
>>> +{
>>> +ÂÂÂ #define L2_GUEST_STACK_SIZE 64
>>> +ÂÂÂ unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
>>> +ÂÂÂ struct vmcb *vmcb = svm->vmcb;
>>> +
>>> +ÂÂÂ /* Prepare for L2 execution. */
>>> +ÂÂÂ generic_svm_setup(svm, l2_vmcall,
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂ &l2_guest_stack[L2_GUEST_STACK_SIZE]);
>>> +
>>> +ÂÂÂ run_guest(vmcb, svm->vmcb_gpa);
>>> +
>>> +ÂÂÂ GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
>>> +ÂÂÂ GUEST_DONE();
>>> +}
>>> +
>>> +int main(int argc, char *argv[])
>>> +{
>>> +ÂÂÂ vm_vaddr_t svm_gva;
>>> +
>>> +ÂÂÂ nested_svm_check_supported();
>>> +
>>> +ÂÂÂ vm = vm_create_default(VCPU_ID, 0, (void *) l1_guest_code);
>>> +ÂÂÂ vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
>>> +
>>> +ÂÂÂ vcpu_alloc_svm(vm, &svm_gva);
>>> +ÂÂÂ vcpu_args_set(vm, VCPU_ID, 1, svm_gva);
>>> +
>>> +ÂÂÂ for (;;) {
>>> +ÂÂÂÂÂÂÂ volatile struct kvm_run *run = vcpu_state(vm, VCPU_ID);
>>> +ÂÂÂÂÂÂÂ struct ucall uc;
>>> +
>>> +ÂÂÂÂÂÂÂ vcpu_run(vm, VCPU_ID);
>>> +ÂÂÂÂÂÂÂ TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ "Got exit_reason other than KVM_EXIT_IO: %u (%s)\n",
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ run->exit_reason,
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ exit_reason_str(run->exit_reason));
>>> +
>>> +ÂÂÂÂÂÂÂ switch (get_ucall(vm, VCPU_ID, &uc)) {
>>> +ÂÂÂÂÂÂÂ case UCALL_ABORT:
>>> +ÂÂÂÂÂÂÂÂÂÂÂ TEST_ASSERT(false, "%s",
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ (const char *)uc.args[0]);
>>> +ÂÂÂÂÂÂÂÂÂÂÂ /* NOT REACHED */
>>> +ÂÂÂÂÂÂÂ case UCALL_SYNC:
>>> +ÂÂÂÂÂÂÂÂÂÂÂ break;
>>> +ÂÂÂÂÂÂÂ case UCALL_DONE:
>>> +ÂÂÂÂÂÂÂÂÂÂÂ goto done;
>>> +ÂÂÂÂÂÂÂ default:
>>> +ÂÂÂÂÂÂÂÂÂÂÂ TEST_ASSERT(false,
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ "Unknown ucall 0x%x.", uc.cmd);
>>> +ÂÂÂÂÂÂÂ }
>>> +ÂÂÂ }
>>> +done:
>>> +ÂÂÂ kvm_vm_free(vm);
>>> +ÂÂÂ return 0;
>>> +}
>>
>