linux-kernel - Re: [PATCH v2 8/9] KVM: selftests: add svm part to triple_fault

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Message-ID: <a1fc425b-4c59-090b-f475-caf7d6074042@oracle.com>
Date:   Mon, 21 Nov 2022 16:34:22 +0000
From:   Liam Merwick <liam.merwick@...cle.com>
To:     Maxim Levitsky <mlevitsk@...hat.com>, kvm@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-kernel@...r.kernel.org,
        Chenyi Qiang <chenyi.qiang@...el.com>,
        Yang Zhong <yang.zhong@...el.com>, x86@...nel.org,
        Shuah Khan <shuah@...nel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        Colton Lewis <coltonlewis@...gle.com>,
        Borislav Petkov <bp@...en8.de>, Peter Xu <peterx@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Jim Mattson <jmattson@...gle.com>,
        linux-kselftest@...r.kernel.org, Ingo Molnar <mingo@...hat.com>,
        Wei Wang <wei.w.wang@...el.com>,
        David Matlack <dmatlack@...gle.com>,
        Liam Merwick <liam.merwick@...cle.com>
Subject: Re: [PATCH v2 8/9] KVM: selftests: add svm part to triple_fault_test

On 03/11/2022 14:13, Maxim Levitsky wrote:
> Add a SVM implementation to triple_fault_test to test that
> emulated/injected shutdown works.
> 
> Since instead of the VMX, the SVM allows the hypervisor to avoid

maybe "instead of the VMX, the SVM" -> ", unlike VMX, SVM" ?

> intercepting shutdown in guest, don't intercept shutdown to test that
> KVM suports this correctly.

typo: suports

> 
> Signed-off-by: Maxim Levitsky <mlevitsk@...hat.com>


Reviewed-by: Liam Merwick <liam.merwick@...cle.com>


> ---
>   .../kvm/x86_64/triple_fault_event_test.c      | 73 ++++++++++++++-----
>   1 file changed, 56 insertions(+), 17 deletions(-)
> 
> diff --git a/tools/testing/selftests/kvm/x86_64/triple_fault_event_test.c b/tools/testing/selftests/kvm/x86_64/triple_fault_event_test.c
> index 70b44f0b52fef2..ead5d878a71c45 100644
> --- a/tools/testing/selftests/kvm/x86_64/triple_fault_event_test.c
> +++ b/tools/testing/selftests/kvm/x86_64/triple_fault_event_test.c
> @@ -3,6 +3,7 @@
>   #include "kvm_util.h"
>   #include "processor.h"
>   #include "vmx.h"
> +#include "svm_util.h"
>   
>   #include <string.h>
>   #include <sys/ioctl.h>
> @@ -20,10 +21,11 @@ static void l2_guest_code(void)
>   		     : : [port] "d" (ARBITRARY_IO_PORT) : "rax");
>   }
>   
> -void l1_guest_code(struct vmx_pages *vmx)
> -{
>   #define L2_GUEST_STACK_SIZE 64
> -	unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
> +unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
> +
> +void l1_guest_code_vmx(struct vmx_pages *vmx)
> +{
>   
>   	GUEST_ASSERT(vmx->vmcs_gpa);
>   	GUEST_ASSERT(prepare_for_vmx_operation(vmx));
> @@ -38,24 +40,53 @@ void l1_guest_code(struct vmx_pages *vmx)
>   	GUEST_DONE();
>   }
>   
> +void l1_guest_code_svm(struct svm_test_data *svm)
> +{
> +	struct vmcb *vmcb = svm->vmcb;
> +
> +	generic_svm_setup(svm, l2_guest_code,
> +			&l2_guest_stack[L2_GUEST_STACK_SIZE]);
> +
> +	/* don't intercept shutdown to test the case of SVM allowing to do so */
> +	vmcb->control.intercept &= ~(BIT(INTERCEPT_SHUTDOWN));
> +
> +	run_guest(vmcb, svm->vmcb_gpa);
> +
> +	/* should not reach here, L1 should crash  */
> +	GUEST_ASSERT(0);
> +}
> +
>   int main(void)
>   {
>   	struct kvm_vcpu *vcpu;
>   	struct kvm_run *run;
>   	struct kvm_vcpu_events events;
> -	vm_vaddr_t vmx_pages_gva;
>   	struct ucall uc;
>   
> -	TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_VMX));
> +	bool has_vmx = kvm_cpu_has(X86_FEATURE_VMX);
> +	bool has_svm = kvm_cpu_has(X86_FEATURE_SVM);
> +
> +	TEST_REQUIRE(has_vmx || has_svm);
>   
>   	TEST_REQUIRE(kvm_has_cap(KVM_CAP_X86_TRIPLE_FAULT_EVENT));
>   
> -	vm = vm_create_with_one_vcpu(&vcpu, l1_guest_code);
> -	vm_enable_cap(vm, KVM_CAP_X86_TRIPLE_FAULT_EVENT, 1);
>   
> +	if (has_vmx) {
> +		vm_vaddr_t vmx_pages_gva;
> +
> +		vm = vm_create_with_one_vcpu(&vcpu, l1_guest_code_vmx);
> +		vcpu_alloc_vmx(vm, &vmx_pages_gva);
> +		vcpu_args_set(vcpu, 1, vmx_pages_gva);
> +	} else {
> +		vm_vaddr_t svm_gva;
> +
> +		vm = vm_create_with_one_vcpu(&vcpu, l1_guest_code_svm);
> +		vcpu_alloc_svm(vm, &svm_gva);
> +		vcpu_args_set(vcpu, 1, svm_gva);
> +	}
> +
> +	vm_enable_cap(vm, KVM_CAP_X86_TRIPLE_FAULT_EVENT, 1);
>   	run = vcpu->run;
> -	vcpu_alloc_vmx(vm, &vmx_pages_gva);
> -	vcpu_args_set(vcpu, 1, vmx_pages_gva);
>   	vcpu_run(vcpu);
>   
>   	TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
> @@ -78,13 +109,21 @@ int main(void)
>   		    "No triple fault pending");
>   	vcpu_run(vcpu);
>   
> -	switch (get_ucall(vcpu, &uc)) {
> -	case UCALL_DONE:
> -		break;
> -	case UCALL_ABORT:
> -		REPORT_GUEST_ASSERT(uc);
> -	default:
> -		TEST_FAIL("Unexpected ucall: %lu", uc.cmd);
> -	}
>   
> +	if (has_svm) {
> +		TEST_ASSERT(run->exit_reason == KVM_EXIT_SHUTDOWN,
> +			    "Got exit_reason other than KVM_EXIT_SHUTDOWN: %u (%s)\n",
> +			    run->exit_reason,
> +			    exit_reason_str(run->exit_reason));
> +	} else {
> +		switch (get_ucall(vcpu, &uc)) {
> +		case UCALL_DONE:
> +			break;
> +		case UCALL_ABORT:
> +			REPORT_GUEST_ASSERT(uc);
> +		default:
> +			TEST_FAIL("Unexpected ucall: %lu", uc.cmd);
> +		}
> +	}
> +	return 0;
>   }