[RFC,v5,15/29] KVM: selftests: TDX: Add TDX MSR read/write tests

Message ID 20231212204647.2170650-16-sagis@google.com
State New
Headers
Series TDX KVM selftests |

Commit Message

Sagi Shahar Dec. 12, 2023, 8:46 p.m. UTC
  The test verifies reads and writes for MSR registers with different access
level.

Signed-off-by: Sagi Shahar <sagis@google.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
Signed-off-by: Ryan Afranji <afranji@google.com>
---
 .../selftests/kvm/include/x86_64/tdx/tdx.h    |   5 +
 .../selftests/kvm/lib/x86_64/tdx/tdx.c        |  27 +++
 .../selftests/kvm/x86_64/tdx_vm_tests.c       | 209 ++++++++++++++++++
 3 files changed, 241 insertions(+)
  

Comments

Binbin Wu March 1, 2024, noon UTC | #1
On 12/13/2023 4:46 AM, Sagi Shahar wrote:
> The test verifies reads and writes for MSR registers with different access
> level.
>
> Signed-off-by: Sagi Shahar <sagis@google.com>
> Signed-off-by: Ackerley Tng <ackerleytng@google.com>
> Signed-off-by: Ryan Afranji <afranji@google.com>
> ---
>   .../selftests/kvm/include/x86_64/tdx/tdx.h    |   5 +
>   .../selftests/kvm/lib/x86_64/tdx/tdx.c        |  27 +++
>   .../selftests/kvm/x86_64/tdx_vm_tests.c       | 209 ++++++++++++++++++
>   3 files changed, 241 insertions(+)
>
> diff --git a/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h b/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
> index 63788012bf94..85ba6aab79a7 100644
> --- a/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
> +++ b/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
> @@ -9,11 +9,16 @@
>   #define TDG_VP_VMCALL_REPORT_FATAL_ERROR 0x10003
>   
>   #define TDG_VP_VMCALL_INSTRUCTION_IO 30
> +#define TDG_VP_VMCALL_INSTRUCTION_RDMSR 31
> +#define TDG_VP_VMCALL_INSTRUCTION_WRMSR 32
> +
>   void handle_userspace_tdg_vp_vmcall_exit(struct kvm_vcpu *vcpu);
>   uint64_t tdg_vp_vmcall_instruction_io(uint64_t port, uint64_t size,
>   				      uint64_t write, uint64_t *data);
>   void tdg_vp_vmcall_report_fatal_error(uint64_t error_code, uint64_t data_gpa);
>   uint64_t tdg_vp_vmcall_get_td_vmcall_info(uint64_t *r11, uint64_t *r12,
>   					uint64_t *r13, uint64_t *r14);
> +uint64_t tdg_vp_vmcall_instruction_rdmsr(uint64_t index, uint64_t *ret_value);
> +uint64_t tdg_vp_vmcall_instruction_wrmsr(uint64_t index, uint64_t value);
>   
>   #endif // SELFTEST_TDX_TDX_H
> diff --git a/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
> index e5a9e13c62e2..88ea6f2a6469 100644
> --- a/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
> +++ b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
> @@ -87,3 +87,30 @@ uint64_t tdg_vp_vmcall_get_td_vmcall_info(uint64_t *r11, uint64_t *r12,
>   
>   	return ret;
>   }
> +
> +uint64_t tdg_vp_vmcall_instruction_rdmsr(uint64_t index, uint64_t *ret_value)
> +{
> +	uint64_t ret;
> +	struct tdx_hypercall_args args = {
> +		.r11 = TDG_VP_VMCALL_INSTRUCTION_RDMSR,
> +		.r12 = index,
> +	};
> +
> +	ret = __tdx_hypercall(&args, TDX_HCALL_HAS_OUTPUT);
> +
> +	if (ret_value)
> +		*ret_value = args.r11;
> +
> +	return ret;
> +}
> +
> +uint64_t tdg_vp_vmcall_instruction_wrmsr(uint64_t index, uint64_t value)
> +{
> +	struct tdx_hypercall_args args = {
> +		.r11 = TDG_VP_VMCALL_INSTRUCTION_WRMSR,
> +		.r12 = index,
> +		.r13 = value,
> +	};
> +
> +	return __tdx_hypercall(&args, 0);
> +}
> diff --git a/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c b/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
> index 699cba36e9ce..5db3701cc6d9 100644
> --- a/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
> +++ b/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
> @@ -515,6 +515,213 @@ void verify_guest_reads(void)
>   	printf("\t ... PASSED\n");
>   }
>   
> +/*
> + * Define a filter which denies all MSR access except the following:
> + * MSR_X2APIC_APIC_ICR: Allow read/write access (allowed by default)

The default filtering behavior of tdx_msr_test_filter is
KVM_MSR_FILTER_DEFAULT_DENY, and MSR_X2APIC_APIC_ICR is not covered
by any specific range, shouldn't MSR_X2APIC_APIC_ICR be denied by default?

> + * MSR_IA32_MISC_ENABLE: Allow read access
> + * MSR_IA32_POWER_CTL: Allow write access
> + */
> +#define MSR_X2APIC_APIC_ICR 0x830
> +static u64 tdx_msr_test_allow_bits = 0xFFFFFFFFFFFFFFFF;
> +struct kvm_msr_filter tdx_msr_test_filter = {
> +	.flags = KVM_MSR_FILTER_DEFAULT_DENY,
> +	.ranges = {
> +		{
> +			.flags = KVM_MSR_FILTER_READ,
> +			.nmsrs = 1,
> +			.base = MSR_IA32_MISC_ENABLE,
> +			.bitmap = (uint8_t *)&tdx_msr_test_allow_bits,
> +		}, {
> +			.flags = KVM_MSR_FILTER_WRITE,
> +			.nmsrs = 1,
> +			.base = MSR_IA32_POWER_CTL,
> +			.bitmap = (uint8_t *)&tdx_msr_test_allow_bits,
> +		},
> +	},
> +};
> +
> +/*
> + * Verifies MSR read functionality.
> + */
> +void guest_msr_read(void)
> +{
> +	uint64_t data;
> +	uint64_t ret;
> +
> +	ret = tdg_vp_vmcall_instruction_rdmsr(MSR_X2APIC_APIC_ICR, &data);
> +	if (ret)
> +		tdx_test_fatal(ret);
> +
> +	ret = tdx_test_report_64bit_to_user_space(data);
> +	if (ret)
> +		tdx_test_fatal(ret);
> +
> +	ret = tdg_vp_vmcall_instruction_rdmsr(MSR_IA32_MISC_ENABLE, &data);
> +	if (ret)
> +		tdx_test_fatal(ret);
> +
> +	ret = tdx_test_report_64bit_to_user_space(data);
> +	if (ret)
> +		tdx_test_fatal(ret);
> +
> +	/* We expect this call to fail since MSR_IA32_POWER_CTL is write only */
> +	ret = tdg_vp_vmcall_instruction_rdmsr(MSR_IA32_POWER_CTL, &data);
> +	if (ret) {
> +		ret = tdx_test_report_64bit_to_user_space(ret);
> +		if (ret)
> +			tdx_test_fatal(ret);
> +	} else {
> +		tdx_test_fatal(-99);
> +	}
> +
> +	tdx_test_success();
> +}
> +
> +void verify_guest_msr_reads(void)
> +{
> +	struct kvm_vm *vm;
> +	struct kvm_vcpu *vcpu;
> +
> +	uint64_t data;
> +	int ret;
> +
> +	vm = td_create();
> +	td_initialize(vm, VM_MEM_SRC_ANONYMOUS, 0);
> +
> +	/*
> +	 * Set explicit MSR filter map to control access to the MSR registers
> +	 * used in the test.
> +	 */
> +	printf("\t ... Setting test MSR filter\n");
> +	ret = kvm_check_cap(KVM_CAP_X86_USER_SPACE_MSR);
> +	TEST_ASSERT(ret, "KVM_CAP_X86_USER_SPACE_MSR is unavailable");
> +	vm_enable_cap(vm, KVM_CAP_X86_USER_SPACE_MSR, KVM_MSR_EXIT_REASON_FILTER);
> +
> +	ret = kvm_check_cap(KVM_CAP_X86_MSR_FILTER);
> +	TEST_ASSERT(ret, "KVM_CAP_X86_MSR_FILTER is unavailable");
> +
> +	ret = ioctl(vm->fd, KVM_X86_SET_MSR_FILTER, &tdx_msr_test_filter);
> +	TEST_ASSERT(ret == 0,
> +		    "KVM_X86_SET_MSR_FILTER failed, ret: %i errno: %i (%s)",
> +		    ret, errno, strerror(errno));
> +
> +	vcpu = td_vcpu_add(vm, 0, guest_msr_read);
> +	td_finalize(vm);
> +
> +	printf("Verifying guest msr reads:\n");
> +
> +	printf("\t ... Setting test MSR values\n");
> +	/* Write arbitrary to the MSRs. */
> +	vcpu_set_msr(vcpu, MSR_X2APIC_APIC_ICR, 4);
> +	vcpu_set_msr(vcpu, MSR_IA32_MISC_ENABLE, 5);
> +	vcpu_set_msr(vcpu, MSR_IA32_POWER_CTL, 6);
> +
> +	printf("\t ... Running guest\n");
> +	td_vcpu_run(vcpu);
> +	TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
> +	data = tdx_test_read_64bit_report_from_guest(vcpu);
> +	TEST_ASSERT_EQ(data, 4);
> +
> +	td_vcpu_run(vcpu);
> +	TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
> +	data = tdx_test_read_64bit_report_from_guest(vcpu);
> +	TEST_ASSERT_EQ(data, 5);
> +
> +	td_vcpu_run(vcpu);
> +	TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
> +	data = tdx_test_read_64bit_report_from_guest(vcpu);
> +	TEST_ASSERT_EQ(data, TDG_VP_VMCALL_INVALID_OPERAND);
> +
> +	td_vcpu_run(vcpu);
> +	TDX_TEST_ASSERT_SUCCESS(vcpu);
> +
> +	kvm_vm_free(vm);
> +	printf("\t ... PASSED\n");
> +}
> +
> +/*
> + * Verifies MSR write functionality.
> + */
> +void guest_msr_write(void)
> +{
> +	uint64_t ret;
> +
> +	ret = tdg_vp_vmcall_instruction_wrmsr(MSR_X2APIC_APIC_ICR, 4);
> +	if (ret)
> +		tdx_test_fatal(ret);
> +
> +	/* We expect this call to fail since MSR_IA32_MISC_ENABLE is read only */
> +	ret = tdg_vp_vmcall_instruction_wrmsr(MSR_IA32_MISC_ENABLE, 5);
> +	if (ret) {
> +		ret = tdx_test_report_64bit_to_user_space(ret);
> +		if (ret)
> +			tdx_test_fatal(ret);
> +	} else {
> +		tdx_test_fatal(-99);
> +	}
> +
> +
> +	ret = tdg_vp_vmcall_instruction_wrmsr(MSR_IA32_POWER_CTL, 6);
> +	if (ret)
> +		tdx_test_fatal(ret);
> +
> +	tdx_test_success();
> +}
> +
> +void verify_guest_msr_writes(void)
> +{
> +	struct kvm_vcpu *vcpu;
> +	struct kvm_vm *vm;
> +
> +	uint64_t data;
> +	int ret;
> +
> +	vm = td_create();
> +	td_initialize(vm, VM_MEM_SRC_ANONYMOUS, 0);
> +
> +	/*
> +	 * Set explicit MSR filter map to control access to the MSR registers
> +	 * used in the test.
> +	 */
> +	printf("\t ... Setting test MSR filter\n");
> +	ret = kvm_check_cap(KVM_CAP_X86_USER_SPACE_MSR);
> +	TEST_ASSERT(ret, "KVM_CAP_X86_USER_SPACE_MSR is unavailable");
> +	vm_enable_cap(vm, KVM_CAP_X86_USER_SPACE_MSR, KVM_MSR_EXIT_REASON_FILTER);
> +
> +	ret = kvm_check_cap(KVM_CAP_X86_MSR_FILTER);
> +	TEST_ASSERT(ret, "KVM_CAP_X86_MSR_FILTER is unavailable");
> +
> +	ret = ioctl(vm->fd, KVM_X86_SET_MSR_FILTER, &tdx_msr_test_filter);
> +	TEST_ASSERT(ret == 0,
> +		    "KVM_X86_SET_MSR_FILTER failed, ret: %i errno: %i (%s)",
> +		    ret, errno, strerror(errno));
> +
> +	vcpu = td_vcpu_add(vm, 0, guest_msr_write);
> +	td_finalize(vm);
> +
> +	printf("Verifying guest msr writes:\n");
> +
> +	printf("\t ... Running guest\n");
> +	/* Only the write to MSR_IA32_MISC_ENABLE should trigger an exit */
> +	td_vcpu_run(vcpu);
> +	TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
> +	data = tdx_test_read_64bit_report_from_guest(vcpu);
> +	TEST_ASSERT_EQ(data, TDG_VP_VMCALL_INVALID_OPERAND);
> +
> +	td_vcpu_run(vcpu);
> +	TDX_TEST_ASSERT_SUCCESS(vcpu);
> +
> +	printf("\t ... Verifying MSR values writen by guest\n");
> +
> +	TEST_ASSERT_EQ(vcpu_get_msr(vcpu, MSR_X2APIC_APIC_ICR), 4);
> +	TEST_ASSERT_EQ(vcpu_get_msr(vcpu, MSR_IA32_MISC_ENABLE), 0x1800);
> +	TEST_ASSERT_EQ(vcpu_get_msr(vcpu, MSR_IA32_POWER_CTL), 6);
> +
> +	kvm_vm_free(vm);
> +	printf("\t ... PASSED\n");
> +}
> +
> +
>   int main(int argc, char **argv)
>   {
>   	setbuf(stdout, NULL);
> @@ -531,6 +738,8 @@ int main(int argc, char **argv)
>   	run_in_new_process(&verify_get_td_vmcall_info);
>   	run_in_new_process(&verify_guest_writes);
>   	run_in_new_process(&verify_guest_reads);
> +	run_in_new_process(&verify_guest_msr_writes);
> +	run_in_new_process(&verify_guest_msr_reads);
>   
>   	return 0;
>   }
  
Binbin Wu March 1, 2024, 12:09 p.m. UTC | #2
On 3/1/2024 8:00 PM, Binbin Wu wrote:
>
>
> On 12/13/2023 4:46 AM, Sagi Shahar wrote:
>> The test verifies reads and writes for MSR registers with different 
>> access
>> level.
>>
>> Signed-off-by: Sagi Shahar <sagis@google.com>
>> Signed-off-by: Ackerley Tng <ackerleytng@google.com>
>> Signed-off-by: Ryan Afranji <afranji@google.com>
>> ---
>>   .../selftests/kvm/include/x86_64/tdx/tdx.h    |   5 +
>>   .../selftests/kvm/lib/x86_64/tdx/tdx.c        |  27 +++
>>   .../selftests/kvm/x86_64/tdx_vm_tests.c       | 209 ++++++++++++++++++
>>   3 files changed, 241 insertions(+)
>>
>> diff --git a/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h 
>> b/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
>> index 63788012bf94..85ba6aab79a7 100644
>> --- a/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
>> +++ b/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
>> @@ -9,11 +9,16 @@
>>   #define TDG_VP_VMCALL_REPORT_FATAL_ERROR 0x10003
>>     #define TDG_VP_VMCALL_INSTRUCTION_IO 30
>> +#define TDG_VP_VMCALL_INSTRUCTION_RDMSR 31
>> +#define TDG_VP_VMCALL_INSTRUCTION_WRMSR 32
>> +
>>   void handle_userspace_tdg_vp_vmcall_exit(struct kvm_vcpu *vcpu);
>>   uint64_t tdg_vp_vmcall_instruction_io(uint64_t port, uint64_t size,
>>                         uint64_t write, uint64_t *data);
>>   void tdg_vp_vmcall_report_fatal_error(uint64_t error_code, uint64_t 
>> data_gpa);
>>   uint64_t tdg_vp_vmcall_get_td_vmcall_info(uint64_t *r11, uint64_t 
>> *r12,
>>                       uint64_t *r13, uint64_t *r14);
>> +uint64_t tdg_vp_vmcall_instruction_rdmsr(uint64_t index, uint64_t 
>> *ret_value);
>> +uint64_t tdg_vp_vmcall_instruction_wrmsr(uint64_t index, uint64_t 
>> value);
>>     #endif // SELFTEST_TDX_TDX_H
>> diff --git a/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c 
>> b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
>> index e5a9e13c62e2..88ea6f2a6469 100644
>> --- a/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
>> +++ b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
>> @@ -87,3 +87,30 @@ uint64_t tdg_vp_vmcall_get_td_vmcall_info(uint64_t 
>> *r11, uint64_t *r12,
>>         return ret;
>>   }
>> +
>> +uint64_t tdg_vp_vmcall_instruction_rdmsr(uint64_t index, uint64_t 
>> *ret_value)
>> +{
>> +    uint64_t ret;
>> +    struct tdx_hypercall_args args = {
>> +        .r11 = TDG_VP_VMCALL_INSTRUCTION_RDMSR,
>> +        .r12 = index,
>> +    };
>> +
>> +    ret = __tdx_hypercall(&args, TDX_HCALL_HAS_OUTPUT);
>> +
>> +    if (ret_value)
>> +        *ret_value = args.r11;
>> +
>> +    return ret;
>> +}
>> +
>> +uint64_t tdg_vp_vmcall_instruction_wrmsr(uint64_t index, uint64_t 
>> value)
>> +{
>> +    struct tdx_hypercall_args args = {
>> +        .r11 = TDG_VP_VMCALL_INSTRUCTION_WRMSR,
>> +        .r12 = index,
>> +        .r13 = value,
>> +    };
>> +
>> +    return __tdx_hypercall(&args, 0);
>> +}
>> diff --git a/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c 
>> b/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
>> index 699cba36e9ce..5db3701cc6d9 100644
>> --- a/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
>> +++ b/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
>> @@ -515,6 +515,213 @@ void verify_guest_reads(void)
>>       printf("\t ... PASSED\n");
>>   }
>>   +/*
>> + * Define a filter which denies all MSR access except the following:
>> + * MSR_X2APIC_APIC_ICR: Allow read/write access (allowed by default)
>
> The default filtering behavior of tdx_msr_test_filter is
> KVM_MSR_FILTER_DEFAULT_DENY, and MSR_X2APIC_APIC_ICR is not covered
> by any specific range, shouldn't MSR_X2APIC_APIC_ICR be denied by 
> default?

Sorry, please ignore this comment.

I see the description from the KVM document later:
"x2APIC MSR accesses cannot be filtered (KVM silently ignores filters 
that cover any x2APIC MSRs)."

>
>> + * MSR_IA32_MISC_ENABLE: Allow read access
>> + * MSR_IA32_POWER_CTL: Allow write access
>> + */
>> +#define MSR_X2APIC_APIC_ICR 0x830
>> +static u64 tdx_msr_test_allow_bits = 0xFFFFFFFFFFFFFFFF;
>> +struct kvm_msr_filter tdx_msr_test_filter = {
>> +    .flags = KVM_MSR_FILTER_DEFAULT_DENY,
>> +    .ranges = {
>> +        {
>> +            .flags = KVM_MSR_FILTER_READ,
>> +            .nmsrs = 1,
>> +            .base = MSR_IA32_MISC_ENABLE,
>> +            .bitmap = (uint8_t *)&tdx_msr_test_allow_bits,
>> +        }, {
>> +            .flags = KVM_MSR_FILTER_WRITE,
>> +            .nmsrs = 1,
>> +            .base = MSR_IA32_POWER_CTL,
>> +            .bitmap = (uint8_t *)&tdx_msr_test_allow_bits,
>> +        },
>> +    },
>> +};
>> +
>> +/*
>> + * Verifies MSR read functionality.
>> + */
>> +void guest_msr_read(void)
>> +{
>> +    uint64_t data;
>> +    uint64_t ret;
>> +
>> +    ret = tdg_vp_vmcall_instruction_rdmsr(MSR_X2APIC_APIC_ICR, &data);
>> +    if (ret)
>> +        tdx_test_fatal(ret);
>> +
>> +    ret = tdx_test_report_64bit_to_user_space(data);
>> +    if (ret)
>> +        tdx_test_fatal(ret);
>> +
>> +    ret = tdg_vp_vmcall_instruction_rdmsr(MSR_IA32_MISC_ENABLE, &data);
>> +    if (ret)
>> +        tdx_test_fatal(ret);
>> +
>> +    ret = tdx_test_report_64bit_to_user_space(data);
>> +    if (ret)
>> +        tdx_test_fatal(ret);
>> +
>> +    /* We expect this call to fail since MSR_IA32_POWER_CTL is write 
>> only */
>> +    ret = tdg_vp_vmcall_instruction_rdmsr(MSR_IA32_POWER_CTL, &data);
>> +    if (ret) {
>> +        ret = tdx_test_report_64bit_to_user_space(ret);
>> +        if (ret)
>> +            tdx_test_fatal(ret);
>> +    } else {
>> +        tdx_test_fatal(-99);
>> +    }
>> +
>> +    tdx_test_success();
>> +}
>> +
>> +void verify_guest_msr_reads(void)
>> +{
>> +    struct kvm_vm *vm;
>> +    struct kvm_vcpu *vcpu;
>> +
>> +    uint64_t data;
>> +    int ret;
>> +
>> +    vm = td_create();
>> +    td_initialize(vm, VM_MEM_SRC_ANONYMOUS, 0);
>> +
>> +    /*
>> +     * Set explicit MSR filter map to control access to the MSR 
>> registers
>> +     * used in the test.
>> +     */
>> +    printf("\t ... Setting test MSR filter\n");
>> +    ret = kvm_check_cap(KVM_CAP_X86_USER_SPACE_MSR);
>> +    TEST_ASSERT(ret, "KVM_CAP_X86_USER_SPACE_MSR is unavailable");
>> +    vm_enable_cap(vm, KVM_CAP_X86_USER_SPACE_MSR, 
>> KVM_MSR_EXIT_REASON_FILTER);
>> +
>> +    ret = kvm_check_cap(KVM_CAP_X86_MSR_FILTER);
>> +    TEST_ASSERT(ret, "KVM_CAP_X86_MSR_FILTER is unavailable");
>> +
>> +    ret = ioctl(vm->fd, KVM_X86_SET_MSR_FILTER, &tdx_msr_test_filter);
>> +    TEST_ASSERT(ret == 0,
>> +            "KVM_X86_SET_MSR_FILTER failed, ret: %i errno: %i (%s)",
>> +            ret, errno, strerror(errno));
>> +
>> +    vcpu = td_vcpu_add(vm, 0, guest_msr_read);
>> +    td_finalize(vm);
>> +
>> +    printf("Verifying guest msr reads:\n");
>> +
>> +    printf("\t ... Setting test MSR values\n");
>> +    /* Write arbitrary to the MSRs. */
>> +    vcpu_set_msr(vcpu, MSR_X2APIC_APIC_ICR, 4);
>> +    vcpu_set_msr(vcpu, MSR_IA32_MISC_ENABLE, 5);
>> +    vcpu_set_msr(vcpu, MSR_IA32_POWER_CTL, 6);
>> +
>> +    printf("\t ... Running guest\n");
>> +    td_vcpu_run(vcpu);
>> +    TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
>> +    data = tdx_test_read_64bit_report_from_guest(vcpu);
>> +    TEST_ASSERT_EQ(data, 4);
>> +
>> +    td_vcpu_run(vcpu);
>> +    TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
>> +    data = tdx_test_read_64bit_report_from_guest(vcpu);
>> +    TEST_ASSERT_EQ(data, 5);
>> +
>> +    td_vcpu_run(vcpu);
>> +    TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
>> +    data = tdx_test_read_64bit_report_from_guest(vcpu);
>> +    TEST_ASSERT_EQ(data, TDG_VP_VMCALL_INVALID_OPERAND);
>> +
>> +    td_vcpu_run(vcpu);
>> +    TDX_TEST_ASSERT_SUCCESS(vcpu);
>> +
>> +    kvm_vm_free(vm);
>> +    printf("\t ... PASSED\n");
>> +}
>> +
>> +/*
>> + * Verifies MSR write functionality.
>> + */
>> +void guest_msr_write(void)
>> +{
>> +    uint64_t ret;
>> +
>> +    ret = tdg_vp_vmcall_instruction_wrmsr(MSR_X2APIC_APIC_ICR, 4);
>> +    if (ret)
>> +        tdx_test_fatal(ret);
>> +
>> +    /* We expect this call to fail since MSR_IA32_MISC_ENABLE is 
>> read only */
>> +    ret = tdg_vp_vmcall_instruction_wrmsr(MSR_IA32_MISC_ENABLE, 5);
>> +    if (ret) {
>> +        ret = tdx_test_report_64bit_to_user_space(ret);
>> +        if (ret)
>> +            tdx_test_fatal(ret);
>> +    } else {
>> +        tdx_test_fatal(-99);
>> +    }
>> +
>> +
>> +    ret = tdg_vp_vmcall_instruction_wrmsr(MSR_IA32_POWER_CTL, 6);
>> +    if (ret)
>> +        tdx_test_fatal(ret);
>> +
>> +    tdx_test_success();
>> +}
>> +
>> +void verify_guest_msr_writes(void)
>> +{
>> +    struct kvm_vcpu *vcpu;
>> +    struct kvm_vm *vm;
>> +
>> +    uint64_t data;
>> +    int ret;
>> +
>> +    vm = td_create();
>> +    td_initialize(vm, VM_MEM_SRC_ANONYMOUS, 0);
>> +
>> +    /*
>> +     * Set explicit MSR filter map to control access to the MSR 
>> registers
>> +     * used in the test.
>> +     */
>> +    printf("\t ... Setting test MSR filter\n");
>> +    ret = kvm_check_cap(KVM_CAP_X86_USER_SPACE_MSR);
>> +    TEST_ASSERT(ret, "KVM_CAP_X86_USER_SPACE_MSR is unavailable");
>> +    vm_enable_cap(vm, KVM_CAP_X86_USER_SPACE_MSR, 
>> KVM_MSR_EXIT_REASON_FILTER);
>> +
>> +    ret = kvm_check_cap(KVM_CAP_X86_MSR_FILTER);
>> +    TEST_ASSERT(ret, "KVM_CAP_X86_MSR_FILTER is unavailable");
>> +
>> +    ret = ioctl(vm->fd, KVM_X86_SET_MSR_FILTER, &tdx_msr_test_filter);
>> +    TEST_ASSERT(ret == 0,
>> +            "KVM_X86_SET_MSR_FILTER failed, ret: %i errno: %i (%s)",
>> +            ret, errno, strerror(errno));
>> +
>> +    vcpu = td_vcpu_add(vm, 0, guest_msr_write);
>> +    td_finalize(vm);
>> +
>> +    printf("Verifying guest msr writes:\n");
>> +
>> +    printf("\t ... Running guest\n");
>> +    /* Only the write to MSR_IA32_MISC_ENABLE should trigger an exit */
>> +    td_vcpu_run(vcpu);
>> +    TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
>> +    data = tdx_test_read_64bit_report_from_guest(vcpu);
>> +    TEST_ASSERT_EQ(data, TDG_VP_VMCALL_INVALID_OPERAND);
>> +
>> +    td_vcpu_run(vcpu);
>> +    TDX_TEST_ASSERT_SUCCESS(vcpu);
>> +
>> +    printf("\t ... Verifying MSR values writen by guest\n");
>> +
>> +    TEST_ASSERT_EQ(vcpu_get_msr(vcpu, MSR_X2APIC_APIC_ICR), 4);
>> +    TEST_ASSERT_EQ(vcpu_get_msr(vcpu, MSR_IA32_MISC_ENABLE), 0x1800);
>> +    TEST_ASSERT_EQ(vcpu_get_msr(vcpu, MSR_IA32_POWER_CTL), 6);
>> +
>> +    kvm_vm_free(vm);
>> +    printf("\t ... PASSED\n");
>> +}
>> +
>> +
>>   int main(int argc, char **argv)
>>   {
>>       setbuf(stdout, NULL);
>> @@ -531,6 +738,8 @@ int main(int argc, char **argv)
>>       run_in_new_process(&verify_get_td_vmcall_info);
>>       run_in_new_process(&verify_guest_writes);
>>       run_in_new_process(&verify_guest_reads);
>> +    run_in_new_process(&verify_guest_msr_writes);
>> +    run_in_new_process(&verify_guest_msr_reads);
>>         return 0;
>>   }
>
>
  

Patch

diff --git a/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h b/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
index 63788012bf94..85ba6aab79a7 100644
--- a/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
+++ b/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
@@ -9,11 +9,16 @@ 
 #define TDG_VP_VMCALL_REPORT_FATAL_ERROR 0x10003
 
 #define TDG_VP_VMCALL_INSTRUCTION_IO 30
+#define TDG_VP_VMCALL_INSTRUCTION_RDMSR 31
+#define TDG_VP_VMCALL_INSTRUCTION_WRMSR 32
+
 void handle_userspace_tdg_vp_vmcall_exit(struct kvm_vcpu *vcpu);
 uint64_t tdg_vp_vmcall_instruction_io(uint64_t port, uint64_t size,
 				      uint64_t write, uint64_t *data);
 void tdg_vp_vmcall_report_fatal_error(uint64_t error_code, uint64_t data_gpa);
 uint64_t tdg_vp_vmcall_get_td_vmcall_info(uint64_t *r11, uint64_t *r12,
 					uint64_t *r13, uint64_t *r14);
+uint64_t tdg_vp_vmcall_instruction_rdmsr(uint64_t index, uint64_t *ret_value);
+uint64_t tdg_vp_vmcall_instruction_wrmsr(uint64_t index, uint64_t value);
 
 #endif // SELFTEST_TDX_TDX_H
diff --git a/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
index e5a9e13c62e2..88ea6f2a6469 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
@@ -87,3 +87,30 @@  uint64_t tdg_vp_vmcall_get_td_vmcall_info(uint64_t *r11, uint64_t *r12,
 
 	return ret;
 }
+
+uint64_t tdg_vp_vmcall_instruction_rdmsr(uint64_t index, uint64_t *ret_value)
+{
+	uint64_t ret;
+	struct tdx_hypercall_args args = {
+		.r11 = TDG_VP_VMCALL_INSTRUCTION_RDMSR,
+		.r12 = index,
+	};
+
+	ret = __tdx_hypercall(&args, TDX_HCALL_HAS_OUTPUT);
+
+	if (ret_value)
+		*ret_value = args.r11;
+
+	return ret;
+}
+
+uint64_t tdg_vp_vmcall_instruction_wrmsr(uint64_t index, uint64_t value)
+{
+	struct tdx_hypercall_args args = {
+		.r11 = TDG_VP_VMCALL_INSTRUCTION_WRMSR,
+		.r12 = index,
+		.r13 = value,
+	};
+
+	return __tdx_hypercall(&args, 0);
+}
diff --git a/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c b/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
index 699cba36e9ce..5db3701cc6d9 100644
--- a/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
+++ b/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
@@ -515,6 +515,213 @@  void verify_guest_reads(void)
 	printf("\t ... PASSED\n");
 }
 
+/*
+ * Define a filter which denies all MSR access except the following:
+ * MSR_X2APIC_APIC_ICR: Allow read/write access (allowed by default)
+ * MSR_IA32_MISC_ENABLE: Allow read access
+ * MSR_IA32_POWER_CTL: Allow write access
+ */
+#define MSR_X2APIC_APIC_ICR 0x830
+static u64 tdx_msr_test_allow_bits = 0xFFFFFFFFFFFFFFFF;
+struct kvm_msr_filter tdx_msr_test_filter = {
+	.flags = KVM_MSR_FILTER_DEFAULT_DENY,
+	.ranges = {
+		{
+			.flags = KVM_MSR_FILTER_READ,
+			.nmsrs = 1,
+			.base = MSR_IA32_MISC_ENABLE,
+			.bitmap = (uint8_t *)&tdx_msr_test_allow_bits,
+		}, {
+			.flags = KVM_MSR_FILTER_WRITE,
+			.nmsrs = 1,
+			.base = MSR_IA32_POWER_CTL,
+			.bitmap = (uint8_t *)&tdx_msr_test_allow_bits,
+		},
+	},
+};
+
+/*
+ * Verifies MSR read functionality.
+ */
+void guest_msr_read(void)
+{
+	uint64_t data;
+	uint64_t ret;
+
+	ret = tdg_vp_vmcall_instruction_rdmsr(MSR_X2APIC_APIC_ICR, &data);
+	if (ret)
+		tdx_test_fatal(ret);
+
+	ret = tdx_test_report_64bit_to_user_space(data);
+	if (ret)
+		tdx_test_fatal(ret);
+
+	ret = tdg_vp_vmcall_instruction_rdmsr(MSR_IA32_MISC_ENABLE, &data);
+	if (ret)
+		tdx_test_fatal(ret);
+
+	ret = tdx_test_report_64bit_to_user_space(data);
+	if (ret)
+		tdx_test_fatal(ret);
+
+	/* We expect this call to fail since MSR_IA32_POWER_CTL is write only */
+	ret = tdg_vp_vmcall_instruction_rdmsr(MSR_IA32_POWER_CTL, &data);
+	if (ret) {
+		ret = tdx_test_report_64bit_to_user_space(ret);
+		if (ret)
+			tdx_test_fatal(ret);
+	} else {
+		tdx_test_fatal(-99);
+	}
+
+	tdx_test_success();
+}
+
+void verify_guest_msr_reads(void)
+{
+	struct kvm_vm *vm;
+	struct kvm_vcpu *vcpu;
+
+	uint64_t data;
+	int ret;
+
+	vm = td_create();
+	td_initialize(vm, VM_MEM_SRC_ANONYMOUS, 0);
+
+	/*
+	 * Set explicit MSR filter map to control access to the MSR registers
+	 * used in the test.
+	 */
+	printf("\t ... Setting test MSR filter\n");
+	ret = kvm_check_cap(KVM_CAP_X86_USER_SPACE_MSR);
+	TEST_ASSERT(ret, "KVM_CAP_X86_USER_SPACE_MSR is unavailable");
+	vm_enable_cap(vm, KVM_CAP_X86_USER_SPACE_MSR, KVM_MSR_EXIT_REASON_FILTER);
+
+	ret = kvm_check_cap(KVM_CAP_X86_MSR_FILTER);
+	TEST_ASSERT(ret, "KVM_CAP_X86_MSR_FILTER is unavailable");
+
+	ret = ioctl(vm->fd, KVM_X86_SET_MSR_FILTER, &tdx_msr_test_filter);
+	TEST_ASSERT(ret == 0,
+		    "KVM_X86_SET_MSR_FILTER failed, ret: %i errno: %i (%s)",
+		    ret, errno, strerror(errno));
+
+	vcpu = td_vcpu_add(vm, 0, guest_msr_read);
+	td_finalize(vm);
+
+	printf("Verifying guest msr reads:\n");
+
+	printf("\t ... Setting test MSR values\n");
+	/* Write arbitrary to the MSRs. */
+	vcpu_set_msr(vcpu, MSR_X2APIC_APIC_ICR, 4);
+	vcpu_set_msr(vcpu, MSR_IA32_MISC_ENABLE, 5);
+	vcpu_set_msr(vcpu, MSR_IA32_POWER_CTL, 6);
+
+	printf("\t ... Running guest\n");
+	td_vcpu_run(vcpu);
+	TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
+	data = tdx_test_read_64bit_report_from_guest(vcpu);
+	TEST_ASSERT_EQ(data, 4);
+
+	td_vcpu_run(vcpu);
+	TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
+	data = tdx_test_read_64bit_report_from_guest(vcpu);
+	TEST_ASSERT_EQ(data, 5);
+
+	td_vcpu_run(vcpu);
+	TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
+	data = tdx_test_read_64bit_report_from_guest(vcpu);
+	TEST_ASSERT_EQ(data, TDG_VP_VMCALL_INVALID_OPERAND);
+
+	td_vcpu_run(vcpu);
+	TDX_TEST_ASSERT_SUCCESS(vcpu);
+
+	kvm_vm_free(vm);
+	printf("\t ... PASSED\n");
+}
+
+/*
+ * Verifies MSR write functionality.
+ */
+void guest_msr_write(void)
+{
+	uint64_t ret;
+
+	ret = tdg_vp_vmcall_instruction_wrmsr(MSR_X2APIC_APIC_ICR, 4);
+	if (ret)
+		tdx_test_fatal(ret);
+
+	/* We expect this call to fail since MSR_IA32_MISC_ENABLE is read only */
+	ret = tdg_vp_vmcall_instruction_wrmsr(MSR_IA32_MISC_ENABLE, 5);
+	if (ret) {
+		ret = tdx_test_report_64bit_to_user_space(ret);
+		if (ret)
+			tdx_test_fatal(ret);
+	} else {
+		tdx_test_fatal(-99);
+	}
+
+
+	ret = tdg_vp_vmcall_instruction_wrmsr(MSR_IA32_POWER_CTL, 6);
+	if (ret)
+		tdx_test_fatal(ret);
+
+	tdx_test_success();
+}
+
+void verify_guest_msr_writes(void)
+{
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm;
+
+	uint64_t data;
+	int ret;
+
+	vm = td_create();
+	td_initialize(vm, VM_MEM_SRC_ANONYMOUS, 0);
+
+	/*
+	 * Set explicit MSR filter map to control access to the MSR registers
+	 * used in the test.
+	 */
+	printf("\t ... Setting test MSR filter\n");
+	ret = kvm_check_cap(KVM_CAP_X86_USER_SPACE_MSR);
+	TEST_ASSERT(ret, "KVM_CAP_X86_USER_SPACE_MSR is unavailable");
+	vm_enable_cap(vm, KVM_CAP_X86_USER_SPACE_MSR, KVM_MSR_EXIT_REASON_FILTER);
+
+	ret = kvm_check_cap(KVM_CAP_X86_MSR_FILTER);
+	TEST_ASSERT(ret, "KVM_CAP_X86_MSR_FILTER is unavailable");
+
+	ret = ioctl(vm->fd, KVM_X86_SET_MSR_FILTER, &tdx_msr_test_filter);
+	TEST_ASSERT(ret == 0,
+		    "KVM_X86_SET_MSR_FILTER failed, ret: %i errno: %i (%s)",
+		    ret, errno, strerror(errno));
+
+	vcpu = td_vcpu_add(vm, 0, guest_msr_write);
+	td_finalize(vm);
+
+	printf("Verifying guest msr writes:\n");
+
+	printf("\t ... Running guest\n");
+	/* Only the write to MSR_IA32_MISC_ENABLE should trigger an exit */
+	td_vcpu_run(vcpu);
+	TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
+	data = tdx_test_read_64bit_report_from_guest(vcpu);
+	TEST_ASSERT_EQ(data, TDG_VP_VMCALL_INVALID_OPERAND);
+
+	td_vcpu_run(vcpu);
+	TDX_TEST_ASSERT_SUCCESS(vcpu);
+
+	printf("\t ... Verifying MSR values writen by guest\n");
+
+	TEST_ASSERT_EQ(vcpu_get_msr(vcpu, MSR_X2APIC_APIC_ICR), 4);
+	TEST_ASSERT_EQ(vcpu_get_msr(vcpu, MSR_IA32_MISC_ENABLE), 0x1800);
+	TEST_ASSERT_EQ(vcpu_get_msr(vcpu, MSR_IA32_POWER_CTL), 6);
+
+	kvm_vm_free(vm);
+	printf("\t ... PASSED\n");
+}
+
+
 int main(int argc, char **argv)
 {
 	setbuf(stdout, NULL);
@@ -531,6 +738,8 @@  int main(int argc, char **argv)
 	run_in_new_process(&verify_get_td_vmcall_info);
 	run_in_new_process(&verify_guest_writes);
 	run_in_new_process(&verify_guest_reads);
+	run_in_new_process(&verify_guest_msr_writes);
+	run_in_new_process(&verify_guest_msr_reads);
 
 	return 0;
 }