Re: [RFC PATCH v5 17/29] KVM: selftests: TDX: Add TDX MMIO reads test

From: Zhang, Dongsheng X
Date: Thu Mar 21 2024 - 19:46:00 EST




On 12/12/2023 12:46 PM, Sagi Shahar wrote:
> The test verifies MMIO reads of various sizes from the host to the guest.
>
> Signed-off-by: Sagi Shahar <sagis@xxxxxxxxxx>
> Signed-off-by: Ackerley Tng <ackerleytng@xxxxxxxxxx>
> Signed-off-by: Ryan Afranji <afranji@xxxxxxxxxx>
> ---
> .../selftests/kvm/include/x86_64/tdx/tdcall.h | 2 +
> .../selftests/kvm/include/x86_64/tdx/tdx.h | 3 +
> .../kvm/include/x86_64/tdx/test_util.h | 23 +++++
> .../selftests/kvm/lib/x86_64/tdx/tdx.c | 19 ++++
> .../selftests/kvm/x86_64/tdx_vm_tests.c | 87 +++++++++++++++++++
> 5 files changed, 134 insertions(+)
>
> diff --git a/tools/testing/selftests/kvm/include/x86_64/tdx/tdcall.h b/tools/testing/selftests/kvm/include/x86_64/tdx/tdcall.h
> index b5e94b7c48fa..95fcdbd8404e 100644
> --- a/tools/testing/selftests/kvm/include/x86_64/tdx/tdcall.h
> +++ b/tools/testing/selftests/kvm/include/x86_64/tdx/tdcall.h
> @@ -9,6 +9,8 @@
>
> #define TDG_VP_VMCALL_INSTRUCTION_IO_READ 0
> #define TDG_VP_VMCALL_INSTRUCTION_IO_WRITE 1
> +#define TDG_VP_VMCALL_VE_REQUEST_MMIO_READ 0
> +#define TDG_VP_VMCALL_VE_REQUEST_MMIO_WRITE 1
>
> #define TDG_VP_VMCALL_SUCCESS 0x0000000000000000
> #define TDG_VP_VMCALL_INVALID_OPERAND 0x8000000000000000
> 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 b18e39d20498..13ce60df5684 100644
> --- a/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
> +++ b/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
> @@ -12,6 +12,7 @@
> #define TDG_VP_VMCALL_INSTRUCTION_IO 30
> #define TDG_VP_VMCALL_INSTRUCTION_RDMSR 31
> #define TDG_VP_VMCALL_INSTRUCTION_WRMSR 32
> +#define TDG_VP_VMCALL_VE_REQUEST_MMIO 48
>
> void handle_userspace_tdg_vp_vmcall_exit(struct kvm_vcpu *vcpu);
> uint64_t tdg_vp_vmcall_instruction_io(uint64_t port, uint64_t size,
> @@ -22,5 +23,7 @@ uint64_t tdg_vp_vmcall_get_td_vmcall_info(uint64_t *r11, uint64_t *r12,
> 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);
> uint64_t tdg_vp_vmcall_instruction_hlt(uint64_t interrupt_blocked_flag);
> +uint64_t tdg_vp_vmcall_ve_request_mmio_read(uint64_t address, uint64_t size,
> + uint64_t *data_out);
>
> #endif // SELFTEST_TDX_TDX_H
> diff --git a/tools/testing/selftests/kvm/include/x86_64/tdx/test_util.h b/tools/testing/selftests/kvm/include/x86_64/tdx/test_util.h
> index 8a9b6a1bec3e..af412b764604 100644
> --- a/tools/testing/selftests/kvm/include/x86_64/tdx/test_util.h
> +++ b/tools/testing/selftests/kvm/include/x86_64/tdx/test_util.h
> @@ -35,6 +35,29 @@
> (VCPU)->run->io.direction); \
> } while (0)
>
> +
> +/**
> + * Assert that some MMIO operation involving TDG.VP.VMCALL <#VERequestMMIO> was
> + * called in the guest.
> + */
> +#define TDX_TEST_ASSERT_MMIO(VCPU, ADDR, SIZE, DIR) \
> + do { \
> + TEST_ASSERT((VCPU)->run->exit_reason == KVM_EXIT_MMIO, \
> + "Got exit_reason other than KVM_EXIT_MMIO: %u (%s)\n", \
> + (VCPU)->run->exit_reason, \
> + exit_reason_str((VCPU)->run->exit_reason)); \
> + \
> + TEST_ASSERT(((VCPU)->run->exit_reason == KVM_EXIT_MMIO) && \
> + ((VCPU)->run->mmio.phys_addr == (ADDR)) && \
> + ((VCPU)->run->mmio.len == (SIZE)) && \
> + ((VCPU)->run->mmio.is_write == (DIR)), \
> + "Got an unexpected MMIO exit values: %u (%s) %llu %d %d\n", \
> + (VCPU)->run->exit_reason, \
> + exit_reason_str((VCPU)->run->exit_reason), \
> + (VCPU)->run->mmio.phys_addr, (VCPU)->run->mmio.len, \
> + (VCPU)->run->mmio.is_write); \
> + } while (0)
> +
> /**
> * Check and report if there was some failure in the guest, either an exception
> * like a triple fault, or if a tdx_test_fatal() was hit.
> 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 9485bafedc38..b19f07ebc0e7 100644
> --- a/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
> +++ b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
> @@ -124,3 +124,22 @@ uint64_t tdg_vp_vmcall_instruction_hlt(uint64_t interrupt_blocked_flag)
>
> return __tdx_hypercall(&args, 0);
> }
> +
> +uint64_t tdg_vp_vmcall_ve_request_mmio_read(uint64_t address, uint64_t size,
> + uint64_t *data_out)
> +{
> + uint64_t ret;
> + struct tdx_hypercall_args args = {
> + .r11 = TDG_VP_VMCALL_VE_REQUEST_MMIO,
> + .r12 = size,
> + .r13 = TDG_VP_VMCALL_VE_REQUEST_MMIO_READ,
> + .r14 = address,
> + };
> +
> + ret = __tdx_hypercall(&args, TDX_HCALL_HAS_OUTPUT);
> +
> + if (data_out)
> + *data_out = args.r11;
> +
> + return ret;
> +}
> 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 5fae4c6e5f95..48902b69d13e 100644
> --- a/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
> +++ b/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
> @@ -799,6 +799,92 @@ void verify_guest_hlt(void)
> _verify_guest_hlt(0);
> }
>
> +/* Pick any address that was not mapped into the guest to test MMIO */
> +#define TDX_MMIO_TEST_ADDR 0x200000000
> +
> +void guest_mmio_reads(void)
> +{
> + uint64_t data;
> + uint64_t ret;
> +
> + ret = tdg_vp_vmcall_ve_request_mmio_read(TDX_MMIO_TEST_ADDR, 1, &data);
> + if (ret)
> + tdx_test_fatal(ret);
> + if (data != 0x12)
> + tdx_test_fatal(1);
> +
> + ret = tdg_vp_vmcall_ve_request_mmio_read(TDX_MMIO_TEST_ADDR, 2, &data);
> + if (ret)
> + tdx_test_fatal(ret);
> + if (data != 0x1234)
> + tdx_test_fatal(2);
> +
> + ret = tdg_vp_vmcall_ve_request_mmio_read(TDX_MMIO_TEST_ADDR, 4, &data);
> + if (ret)
> + tdx_test_fatal(ret);
> + if (data != 0x12345678)
> + tdx_test_fatal(4);
> +
> + ret = tdg_vp_vmcall_ve_request_mmio_read(TDX_MMIO_TEST_ADDR, 8, &data);
> + if (ret)
> + tdx_test_fatal(ret);
> + if (data != 0x1234567890ABCDEF)
> + tdx_test_fatal(8);
> +
> + // Read an invalid number of bytes.
> + ret = tdg_vp_vmcall_ve_request_mmio_read(TDX_MMIO_TEST_ADDR, 10, &data);
> + if (ret)
> + tdx_test_fatal(ret);
> +
> + tdx_test_success();
> +}
> +
> +/*
> + * Varifies guest MMIO reads.

Nit: typo? Varifies ==> Verifies

> + */
> +void verify_mmio_reads(void)
> +{
> + struct kvm_vm *vm;
> + struct kvm_vcpu *vcpu;
> +
> + vm = td_create();
> + td_initialize(vm, VM_MEM_SRC_ANONYMOUS, 0);
> + vcpu = td_vcpu_add(vm, 0, guest_mmio_reads);
> + td_finalize(vm);
> +
> + printf("Verifying TD MMIO reads:\n");
> +
> + td_vcpu_run(vcpu);
> + TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
> + TDX_TEST_ASSERT_MMIO(vcpu, TDX_MMIO_TEST_ADDR, 1, TDG_VP_VMCALL_VE_REQUEST_MMIO_READ);
> + *(uint8_t *)vcpu->run->mmio.data = 0x12;
> +
> + td_vcpu_run(vcpu);
> + TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
> + TDX_TEST_ASSERT_MMIO(vcpu, TDX_MMIO_TEST_ADDR, 2, TDG_VP_VMCALL_VE_REQUEST_MMIO_READ);
> + *(uint16_t *)vcpu->run->mmio.data = 0x1234;
> +
> + td_vcpu_run(vcpu);
> + TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
> + TDX_TEST_ASSERT_MMIO(vcpu, TDX_MMIO_TEST_ADDR, 4, TDG_VP_VMCALL_VE_REQUEST_MMIO_READ);
> + *(uint32_t *)vcpu->run->mmio.data = 0x12345678;
> +
> + td_vcpu_run(vcpu);
> + TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
> + TDX_TEST_ASSERT_MMIO(vcpu, TDX_MMIO_TEST_ADDR, 8, TDG_VP_VMCALL_VE_REQUEST_MMIO_READ);
> + *(uint64_t *)vcpu->run->mmio.data = 0x1234567890ABCDEF;
> +
> + td_vcpu_run(vcpu);
> + TEST_ASSERT_EQ(vcpu->run->exit_reason, KVM_EXIT_SYSTEM_EVENT);
> + TEST_ASSERT_EQ(vcpu->run->system_event.data[1], TDG_VP_VMCALL_INVALID_OPERAND);
> +
> + td_vcpu_run(vcpu);
> + TDX_TEST_ASSERT_SUCCESS(vcpu);
> +
> + kvm_vm_free(vm);
> + printf("\t ... PASSED\n");
> +}
> +
> int main(int argc, char **argv)
> {
> setbuf(stdout, NULL);
> @@ -818,6 +904,7 @@ int main(int argc, char **argv)
> run_in_new_process(&verify_guest_msr_writes);
> run_in_new_process(&verify_guest_msr_reads);
> run_in_new_process(&verify_guest_hlt);
> + run_in_new_process(&verify_mmio_reads);
>
> return 0;
> }