[PATCH 1/2] selftests: kvm: introduce cpu_has_svm() check

[PATCH 1/2] selftests: kvm: introduce cpu_has_svm() check

[Vitaly Kuznetsov]

More tests may want to check if the CPU is Intel or AMD in
guest code, separate cpu_has_svm() and put it as static
inline to svm_util.h.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 tools/testing/selftests/kvm/include/x86_64/svm_util.h | 10 ++++++++++
 tools/testing/selftests/kvm/x86_64/state_test.c       |  9 +--------
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/x86_64/svm_util.h b/tools/testing/selftests/kvm/include/x86_64/svm_util.h
index cd037917fece..b1057773206a 100644
--- a/tools/testing/selftests/kvm/include/x86_64/svm_util.h
+++ b/tools/testing/selftests/kvm/include/x86_64/svm_util.h
@@ -35,4 +35,14 @@ void generic_svm_setup(struct svm_test_data *svm, void *guest_rip, void *guest_r
 void run_guest(struct vmcb *vmcb, uint64_t vmcb_gpa);
 void nested_svm_check_supported(void);
 
+static inline bool cpu_has_svm(void)
+{
+	u32 eax = 0x80000001, ecx;
+
+	asm volatile("cpuid" :
+		     "=a" (eax), "=c" (ecx) : "0" (eax) : "ebx", "edx");
+
+	return ecx & CPUID_SVM;
+}
+
 #endif /* SELFTEST_KVM_SVM_UTILS_H */
diff --git a/tools/testing/selftests/kvm/x86_64/state_test.c b/tools/testing/selftests/kvm/x86_64/state_test.c
index af8b6df6a13e..d43b6f99b66c 100644
--- a/tools/testing/selftests/kvm/x86_64/state_test.c
+++ b/tools/testing/selftests/kvm/x86_64/state_test.c
@@ -137,20 +137,13 @@ static void vmx_l1_guest_code(struct vmx_pages *vmx_pages)
 	GUEST_ASSERT(vmresume());
 }
 
-static u32 cpuid_ecx(u32 eax)
-{
-	u32 ecx;
-	asm volatile("cpuid" : "=a" (eax), "=c" (ecx) : "0" (eax) : "ebx", "edx");
-	return ecx;
-}
-
 static void __attribute__((__flatten__)) guest_code(void *arg)
 {
 	GUEST_SYNC(1);
 	GUEST_SYNC(2);
 
 	if (arg) {
-		if (cpuid_ecx(0x80000001) & CPUID_SVM)
+		if (cpu_has_svm())
 			svm_l1_guest_code(arg);
 		else
 			vmx_l1_guest_code(arg);
-- 
2.25.4

[PATCH 2/2] selftests: kvm: fix smm test on SVM

[Vitaly Kuznetsov]

KVM_CAP_NESTED_STATE is now supported for AMD too but smm test acts like
it is still Intel only.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 tools/testing/selftests/kvm/x86_64/smm_test.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/kvm/x86_64/smm_test.c b/tools/testing/selftests/kvm/x86_64/smm_test.c
index 8230b6bc6b8f..6f8f478b3ceb 100644
--- a/tools/testing/selftests/kvm/x86_64/smm_test.c
+++ b/tools/testing/selftests/kvm/x86_64/smm_test.c
@@ -17,6 +17,7 @@
 #include "kvm_util.h"
 
 #include "vmx.h"
+#include "svm_util.h"
 
 #define VCPU_ID	      1
 
@@ -58,7 +59,7 @@ void self_smi(void)
 	      APIC_DEST_SELF | APIC_INT_ASSERT | APIC_DM_SMI);
 }
 
-void guest_code(struct vmx_pages *vmx_pages)
+void guest_code(void *arg)
 {
 	uint64_t apicbase = rdmsr(MSR_IA32_APICBASE);
 
@@ -72,8 +73,11 @@ void guest_code(struct vmx_pages *vmx_pages)
 
 	sync_with_host(4);
 
-	if (vmx_pages) {
-		GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages));
+	if (arg) {
+		if (cpu_has_svm())
+			generic_svm_setup(arg, NULL, NULL);
+		else
+			GUEST_ASSERT(prepare_for_vmx_operation(arg));
 
 		sync_with_host(5);
 
@@ -87,7 +91,7 @@ void guest_code(struct vmx_pages *vmx_pages)
 
 int main(int argc, char *argv[])
 {
-	vm_vaddr_t vmx_pages_gva = 0;
+	vm_vaddr_t nested_gva = 0;
 
 	struct kvm_regs regs;
 	struct kvm_vm *vm;
@@ -114,8 +118,11 @@ int main(int argc, char *argv[])
 	vcpu_set_msr(vm, VCPU_ID, MSR_IA32_SMBASE, SMRAM_GPA);
 
 	if (kvm_check_cap(KVM_CAP_NESTED_STATE)) {
-		vcpu_alloc_vmx(vm, &vmx_pages_gva);
-		vcpu_args_set(vm, VCPU_ID, 1, vmx_pages_gva);
+		if (kvm_get_supported_cpuid_entry(0x80000001)->ecx & CPUID_SVM)
+			vcpu_alloc_svm(vm, &nested_gva);
+		else
+			vcpu_alloc_vmx(vm, &nested_gva);
+		vcpu_args_set(vm, VCPU_ID, 1, nested_gva);
 	} else {
 		pr_info("will skip SMM test with VMX enabled\n");
 		vcpu_args_set(vm, VCPU_ID, 1, 0);
-- 
2.25.4

Re: [PATCH 1/2] selftests: kvm: introduce cpu_has_svm() check

[Sean Christopherson]

On Fri, May 29, 2020 at 03:04:06PM +0200, Vitaly Kuznetsov wrote:
> More tests may want to check if the CPU is Intel or AMD in
> guest code, separate cpu_has_svm() and put it as static
> inline to svm_util.h.
> 
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> ---
>  tools/testing/selftests/kvm/include/x86_64/svm_util.h | 10 ++++++++++
>  tools/testing/selftests/kvm/x86_64/state_test.c       |  9 +--------
>  2 files changed, 11 insertions(+), 8 deletions(-)
> 
> diff --git a/tools/testing/selftests/kvm/include/x86_64/svm_util.h b/tools/testing/selftests/kvm/include/x86_64/svm_util.h
> index cd037917fece..b1057773206a 100644
> --- a/tools/testing/selftests/kvm/include/x86_64/svm_util.h
> +++ b/tools/testing/selftests/kvm/include/x86_64/svm_util.h
> @@ -35,4 +35,14 @@ void generic_svm_setup(struct svm_test_data *svm, void *guest_rip, void *guest_r
>  void run_guest(struct vmcb *vmcb, uint64_t vmcb_gpa);
>  void nested_svm_check_supported(void);
>  
> +static inline bool cpu_has_svm(void)
> +{
> +	u32 eax = 0x80000001, ecx;
> +
> +	asm volatile("cpuid" :
> +		     "=a" (eax), "=c" (ecx) : "0" (eax) : "ebx", "edx");

	u32 eax, ecx;

	asm("cpuid" : "=a" (eax), "=c" (ecx) : "a" (0x80000001) : "ebx", "edx");

The volatile shouldn't be needed, e.g. no one should be using this purely
for its seralization properties, and I don't see any reason to put the leaf
number into a variable.

Alternatively, adding a proper cpuid framework to processor.h would likely
be useful in the long run.

> +
> +	return ecx & CPUID_SVM;
> +}
> +

Re: [PATCH 2/2] selftests: kvm: fix smm test on SVM

[Paolo Bonzini]

On 29/05/20 15:04, Vitaly Kuznetsov wrote:
> KVM_CAP_NESTED_STATE is now supported for AMD too but smm test acts like
> it is still Intel only.
> 
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> ---
>  tools/testing/selftests/kvm/x86_64/smm_test.c | 19 +++++++++++++------
>  1 file changed, 13 insertions(+), 6 deletions(-)
> 
> diff --git a/tools/testing/selftests/kvm/x86_64/smm_test.c b/tools/testing/selftests/kvm/x86_64/smm_test.c
> index 8230b6bc6b8f..6f8f478b3ceb 100644
> --- a/tools/testing/selftests/kvm/x86_64/smm_test.c
> +++ b/tools/testing/selftests/kvm/x86_64/smm_test.c
> @@ -17,6 +17,7 @@
>  #include "kvm_util.h"
>  
>  #include "vmx.h"
> +#include "svm_util.h"
>  
>  #define VCPU_ID	      1
>  
> @@ -58,7 +59,7 @@ void self_smi(void)
>  	      APIC_DEST_SELF | APIC_INT_ASSERT | APIC_DM_SMI);
>  }
>  
> -void guest_code(struct vmx_pages *vmx_pages)
> +void guest_code(void *arg)
>  {
>  	uint64_t apicbase = rdmsr(MSR_IA32_APICBASE);
>  
> @@ -72,8 +73,11 @@ void guest_code(struct vmx_pages *vmx_pages)
>  
>  	sync_with_host(4);
>  
> -	if (vmx_pages) {
> -		GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages));
> +	if (arg) {
> +		if (cpu_has_svm())
> +			generic_svm_setup(arg, NULL, NULL);
> +		else
> +			GUEST_ASSERT(prepare_for_vmx_operation(arg));
>  
>  		sync_with_host(5);
>  
> @@ -87,7 +91,7 @@ void guest_code(struct vmx_pages *vmx_pages)
>  
>  int main(int argc, char *argv[])
>  {
> -	vm_vaddr_t vmx_pages_gva = 0;
> +	vm_vaddr_t nested_gva = 0;
>  
>  	struct kvm_regs regs;
>  	struct kvm_vm *vm;
> @@ -114,8 +118,11 @@ int main(int argc, char *argv[])
>  	vcpu_set_msr(vm, VCPU_ID, MSR_IA32_SMBASE, SMRAM_GPA);
>  
>  	if (kvm_check_cap(KVM_CAP_NESTED_STATE)) {
> -		vcpu_alloc_vmx(vm, &vmx_pages_gva);
> -		vcpu_args_set(vm, VCPU_ID, 1, vmx_pages_gva);
> +		if (kvm_get_supported_cpuid_entry(0x80000001)->ecx & CPUID_SVM)
> +			vcpu_alloc_svm(vm, &nested_gva);
> +		else
> +			vcpu_alloc_vmx(vm, &nested_gva);
> +		vcpu_args_set(vm, VCPU_ID, 1, nested_gva);
>  	} else {
>  		pr_info("will skip SMM test with VMX enabled\n");
>  		vcpu_args_set(vm, VCPU_ID, 1, 0);
> 

Thanks, I'll include this in v3 of the nSVM series.

Paolo

Re: [PATCH 1/2] selftests: kvm: introduce cpu_has_svm() check

[Vitaly Kuznetsov]

Sean Christopherson <sean.j.christopherson@intel.com> writes:

> On Fri, May 29, 2020 at 03:04:06PM +0200, Vitaly Kuznetsov wrote:
>> More tests may want to check if the CPU is Intel or AMD in
>> guest code, separate cpu_has_svm() and put it as static
>> inline to svm_util.h.
>> 
>> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
>> ---
>>  tools/testing/selftests/kvm/include/x86_64/svm_util.h | 10 ++++++++++
>>  tools/testing/selftests/kvm/x86_64/state_test.c       |  9 +--------
>>  2 files changed, 11 insertions(+), 8 deletions(-)
>> 
>> diff --git a/tools/testing/selftests/kvm/include/x86_64/svm_util.h b/tools/testing/selftests/kvm/include/x86_64/svm_util.h
>> index cd037917fece..b1057773206a 100644
>> --- a/tools/testing/selftests/kvm/include/x86_64/svm_util.h
>> +++ b/tools/testing/selftests/kvm/include/x86_64/svm_util.h
>> @@ -35,4 +35,14 @@ void generic_svm_setup(struct svm_test_data *svm, void *guest_rip, void *guest_r
>>  void run_guest(struct vmcb *vmcb, uint64_t vmcb_gpa);
>>  void nested_svm_check_supported(void);
>>  
>> +static inline bool cpu_has_svm(void)
>> +{
>> +	u32 eax = 0x80000001, ecx;
>> +
>> +	asm volatile("cpuid" :
>> +		     "=a" (eax), "=c" (ecx) : "0" (eax) : "ebx", "edx");
>
> 	u32 eax, ecx;
>
> 	asm("cpuid" : "=a" (eax), "=c" (ecx) : "a" (0x80000001) : "ebx", "edx");
>
> The volatile shouldn't be needed, e.g. no one should be using this purely
> for its seralization properties, and I don't see any reason to put the leaf
> number into a variable.
>
> Alternatively, adding a proper cpuid framework to processor.h would likely
> be useful in the long run.
>

All true, even better would be to find a way to include the definition
of native_cpuid*() from arch/x86/include/asm/processor.h but I didn't
explore these options yet, was trying to address the immediate issue
with Paolo's SVM series. It can probably be done when there is a second
user of cpuid in tests which needs to check something different from SVM
bit.

-- 
Vitaly