Re: [RFC PATCH v5 23/29] KVM: selftests: TDX: Add shared memory test

From: Chen, Zide
Date: Sat Mar 16 2024 - 02:25:18 EST

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On 12/12/2023 12:47 PM, Sagi Shahar wrote:
>
>
> -----Original Message-----
> From: Sagi Shahar <sagis@xxxxxxxxxx>
> Sent: Tuesday, December 12, 2023 12:47 PM
> To: linux-kselftest@xxxxxxxxxxxxxxx; Ackerley Tng <ackerleytng@xxxxxxxxxx>; Afranji, Ryan <afranji@xxxxxxxxxx>; Aktas, Erdem <erdemaktas@xxxxxxxxxx>; Sagi Shahar <sagis@xxxxxxxxxx>; Yamahata, Isaku <isaku.yamahata@xxxxxxxxx>
> Cc: Sean Christopherson <seanjc@xxxxxxxxxx>; Paolo Bonzini <pbonzini@xxxxxxxxxx>; Shuah Khan <shuah@xxxxxxxxxx>; Peter Gonda <pgonda@xxxxxxxxxx>; Xu, Haibo1 <haibo1.xu@xxxxxxxxx>; Chao Peng <chao.p.peng@xxxxxxxxxxxxxxx>; Annapurve, Vishal <vannapurve@xxxxxxxxxx>; Roger Wang <runanwang@xxxxxxxxxx>; Vipin Sharma <vipinsh@xxxxxxxxxx>; jmattson@xxxxxxxxxx; dmatlack@xxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; kvm@xxxxxxxxxxxxxxx; linux-mm@xxxxxxxxx
> Subject: [RFC PATCH v5 23/29] KVM: selftests: TDX: Add shared memory test
>
> From: Ryan Afranji <afranji@xxxxxxxxxx>
>
> Adds a test that sets up shared memory between the host and guest.
>
> Signed-off-by: Ryan Afranji <afranji@xxxxxxxxxx>
> Signed-off-by: Sagi Shahar <sagis@xxxxxxxxxx>
> Signed-off-by: Ackerley Tng <ackerleytng@xxxxxxxxxx>
> ---
> tools/testing/selftests/kvm/Makefile | 1 +
> .../selftests/kvm/include/x86_64/tdx/tdx.h | 2 +
> .../kvm/include/x86_64/tdx/tdx_util.h | 2 +
> .../selftests/kvm/lib/x86_64/tdx/tdx.c | 26 ++++
> .../selftests/kvm/lib/x86_64/tdx/tdx_util.c | 25 ++++
> .../kvm/x86_64/tdx_shared_mem_test.c | 135 ++++++++++++++++++
> 6 files changed, 191 insertions(+)
> create mode 100644 tools/testing/selftests/kvm/x86_64/tdx_shared_mem_test.c
>
> diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
> index 80d4a50eeb9f..8c0a6b395ee5 100644
> --- a/tools/testing/selftests/kvm/Makefile
> +++ b/tools/testing/selftests/kvm/Makefile
> @@ -156,6 +156,7 @@ TEST_GEN_PROGS_x86_64 += steal_time
> TEST_GEN_PROGS_x86_64 += kvm_binary_stats_test
> TEST_GEN_PROGS_x86_64 += system_counter_offset_test
> TEST_GEN_PROGS_x86_64 += x86_64/tdx_vm_tests
> +TEST_GEN_PROGS_x86_64 += x86_64/tdx_shared_mem_test
>
> # Compiled outputs used by test targets
> TEST_GEN_PROGS_EXTENDED_x86_64 += x86_64/nx_huge_pages_test 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 6b176de1e795..db4cc62abb5d 100644
> --- a/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
> +++ b/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
> @@ -8,6 +8,7 @@
> #define TDG_VP_INFO 1
>
> #define TDG_VP_VMCALL_GET_TD_VM_CALL_INFO 0x10000
> +#define TDG_VP_VMCALL_MAP_GPA 0x10001
> #define TDG_VP_VMCALL_REPORT_FATAL_ERROR 0x10003
>
> #define TDG_VP_VMCALL_INSTRUCTION_CPUID 10 @@ -36,5 +37,6 @@ uint64_t tdg_vp_vmcall_instruction_cpuid(uint32_t eax, uint32_t ecx, uint64_t tdg_vp_info(uint64_t *rcx, uint64_t *rdx,
> uint64_t *r8, uint64_t *r9,
> uint64_t *r10, uint64_t *r11);
> +uint64_t tdg_vp_vmcall_map_gpa(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/tdx_util.h b/tools/testing/selftests/kvm/include/x86_64/tdx/tdx_util.h
> index 32dd6b8fda46..3e850ecb85a6 100644
> --- a/tools/testing/selftests/kvm/include/x86_64/tdx/tdx_util.h
> +++ b/tools/testing/selftests/kvm/include/x86_64/tdx/tdx_util.h
> @@ -13,5 +13,7 @@ void td_initialize(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type,
> uint64_t attributes);
> void td_finalize(struct kvm_vm *vm);
> void td_vcpu_run(struct kvm_vcpu *vcpu);
> +void handle_memory_conversion(struct kvm_vm *vm, uint64_t gpa, uint64_t size,
> + bool shared_to_private);
>
> #endif // SELFTESTS_TDX_KVM_UTIL_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 bcd9cceb3372..061a5c0bef34 100644
> --- a/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
> +++ b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
> @@ -4,9 +4,11 @@
>
> #include "tdx/tdcall.h"
> #include "tdx/tdx.h"
> +#include "tdx/tdx_util.h"
>
> void handle_userspace_tdg_vp_vmcall_exit(struct kvm_vcpu *vcpu) {
> + struct kvm_vm *vm = vcpu->vm;
> struct kvm_tdx_vmcall *vmcall_info = &vcpu->run->tdx.u.vmcall;
> uint64_t vmcall_subfunction = vmcall_info->subfunction;
>
> @@ -20,6 +22,14 @@ void handle_userspace_tdg_vp_vmcall_exit(struct kvm_vcpu *vcpu)
> vcpu->run->system_event.data[2] = vmcall_info->in_r13;
> vmcall_info->status_code = 0;
> break;
> + case TDG_VP_VMCALL_MAP_GPA:
> + uint64_t gpa = vmcall_info->in_r12 & ~vm->arch.s_bit;
> + bool shared_to_private = !(vm->arch.s_bit &
> + vmcall_info->in_r12);
> + handle_memory_conversion(vm, gpa, vmcall_info->in_r13,
> + shared_to_private);
> + vmcall_info->status_code = 0;
> + break;
> default:
> TEST_FAIL("TD VMCALL subfunction %lu is unsupported.\n",
> vmcall_subfunction);
> @@ -210,3 +220,19 @@ uint64_t tdg_vp_info(uint64_t *rcx, uint64_t *rdx,
>
> return ret;
> }
> +
> +uint64_t tdg_vp_vmcall_map_gpa(uint64_t address, uint64_t size,
> +uint64_t *data_out) {
> + uint64_t ret;
> + struct tdx_hypercall_args args = {
> + .r11 = TDG_VP_VMCALL_MAP_GPA,
> + .r12 = address,
> + .r13 = size
> + };
> +
> + ret = __tdx_hypercall(&args, TDX_HCALL_HAS_OUTPUT);
> +
> + if (data_out)
> + *data_out = args.r11;
> + return ret;
> +}
> diff --git a/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx_util.c b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx_util.c
> index d745bb6287c1..92fa6bd13229 100644
> --- a/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx_util.c
> +++ b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx_util.c
> @@ -531,3 +531,28 @@ void td_vcpu_run(struct kvm_vcpu *vcpu)
> handle_userspace_tdg_vp_vmcall_exit(vcpu);
> }
> }
> +
> +/**
> + * Handle conversion of memory with @size beginning @gpa for @vm. Set
> + * @shared_to_private to true for shared to private conversions and
> +false
> + * otherwise.
> + *
> + * Since this is just for selftests, we will just keep both pieces of
> +backing
> + * memory allocated and not deallocate/allocate memory; we'll just do
> +the
> + * minimum of calling KVM_MEMORY_ENCRYPT_REG_REGION and
> + * KVM_MEMORY_ENCRYPT_UNREG_REGION.
> + */
> +void handle_memory_conversion(struct kvm_vm *vm, uint64_t gpa, uint64_t size,
> + bool shared_to_private)
> +{
> + struct kvm_memory_attributes range;
> +
> + range.address = gpa;
> + range.size = size;
> + range.attributes = shared_to_private ? KVM_MEMORY_ATTRIBUTE_PRIVATE : 0;
> + range.flags = 0;
> +
> + printf("\t ... calling KVM_SET_MEMORY_ATTRIBUTES ioctl with gpa=%#lx,
> +size=%#lx, attributes=%#llx\n", gpa, size, range.attributes);
> +
> + vm_ioctl(vm, KVM_SET_MEMORY_ATTRIBUTES, &range); }
> diff --git a/tools/testing/selftests/kvm/x86_64/tdx_shared_mem_test.c b/tools/testing/selftests/kvm/x86_64/tdx_shared_mem_test.c
> new file mode 100644
> index 000000000000..ba6bdc470270
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/x86_64/tdx_shared_mem_test.c
> @@ -0,0 +1,135 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +
> +#include <linux/kvm.h>
> +#include <stdint.h>
> +
> +#include "kvm_util_base.h"
> +#include "processor.h"
> +#include "tdx/tdcall.h"
> +#include "tdx/tdx.h"
> +#include "tdx/tdx_util.h"
> +#include "tdx/test_util.h"
> +#include "test_util.h"
> +
> +#define TDX_SHARED_MEM_TEST_PRIVATE_GVA (0x80000000) #define
> +TDX_SHARED_MEM_TEST_VADDR_SHARED_MASK BIT_ULL(30)
> +#define TDX_SHARED_MEM_TEST_SHARED_GVA \
> + (TDX_SHARED_MEM_TEST_PRIVATE_GVA | \
> + TDX_SHARED_MEM_TEST_VADDR_SHARED_MASK)
> +
> +#define TDX_SHARED_MEM_TEST_GUEST_WRITE_VALUE (0xcafecafe) #define
> +TDX_SHARED_MEM_TEST_HOST_WRITE_VALUE (0xabcdabcd)
> +
> +#define TDX_SHARED_MEM_TEST_INFO_PORT 0x87
> +
> +/*
> + * Shared variables between guest and host */ static uint64_t
> +test_mem_private_gpa; static uint64_t test_mem_shared_gpa;
> +
> +void guest_shared_mem(void)
> +{
> + uint32_t *test_mem_shared_gva =
> + (uint32_t *)TDX_SHARED_MEM_TEST_SHARED_GVA;
> +
> + uint64_t placeholder;
> + uint64_t ret;
> +
> + /* Map gpa as shared */
> + ret = tdg_vp_vmcall_map_gpa(test_mem_shared_gpa, PAGE_SIZE,
> + &placeholder);
> + if (ret)
> + tdx_test_fatal_with_data(ret, __LINE__);
> +
> + *test_mem_shared_gva = TDX_SHARED_MEM_TEST_GUEST_WRITE_VALUE;
> +
> + /* Exit so host can read shared value */
> + ret = tdg_vp_vmcall_instruction_io(TDX_SHARED_MEM_TEST_INFO_PORT, 4,
> + TDG_VP_VMCALL_INSTRUCTION_IO_WRITE,
> + &placeholder);
> + if (ret)
> + tdx_test_fatal_with_data(ret, __LINE__);
> +
> + /* Read value written by host and send it back out for verification */
> + ret = tdg_vp_vmcall_instruction_io(TDX_SHARED_MEM_TEST_INFO_PORT, 4,
> + TDG_VP_VMCALL_INSTRUCTION_IO_WRITE,
> + (uint64_t *)test_mem_shared_gva);
> + if (ret)
> + tdx_test_fatal_with_data(ret, __LINE__); }
> +
> +int verify_shared_mem(void)
> +{
> + struct kvm_vm *vm;
> + struct kvm_vcpu *vcpu;
> +
> + vm_vaddr_t test_mem_private_gva;
> + uint32_t *test_mem_hva;
> +
> + vm = td_create();
> + td_initialize(vm, VM_MEM_SRC_ANONYMOUS, 0);
> + vcpu = td_vcpu_add(vm, 0, guest_shared_mem);
> +
> + /*
> + * Set up shared memory page for testing by first allocating as private
> + * and then mapping the same GPA again as shared. This way, the TD does
> + * not have to remap its page tables at runtime.
> + */
> + test_mem_private_gva = vm_vaddr_alloc(vm, vm->page_size,
> + TDX_SHARED_MEM_TEST_PRIVATE_GVA);
> + TEST_ASSERT_EQ(test_mem_private_gva, TDX_SHARED_MEM_TEST_PRIVATE_GVA);
> +
> + test_mem_hva = addr_gva2hva(vm, test_mem_private_gva);
> + TEST_ASSERT(test_mem_hva != NULL,
> + "Guest address not found in guest memory regions\n");
> +
> + test_mem_private_gpa = addr_gva2gpa(vm, test_mem_private_gva);
> + virt_pg_map_shared(vm, TDX_SHARED_MEM_TEST_SHARED_GVA,
> + test_mem_private_gpa);

As mentioned in the comments in [PATCH 22/29], how about replacing
virt_pg_map_shared() with the following?

vm_phy_pages_conversion(); // new API to update protected_phy_pages
virt_pg_map(); // set s_bit according to protected_phy_pages
> +
> + test_mem_shared_gpa = test_mem_private_gpa | BIT_ULL(vm->pa_bits - 1);
> + sync_global_to_guest(vm, test_mem_private_gpa);
> + sync_global_to_guest(vm, test_mem_shared_gpa);
> +
> + td_finalize(vm);
> +
> + printf("Verifying shared memory accesses for TDX\n");
> +
> + /* Begin guest execution; guest writes to shared memory. */
> + printf("\t ... Starting guest execution\n");
> +
> + /* Handle map gpa as shared */
> + td_vcpu_run(vcpu);
> + TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
> +
> + td_vcpu_run(vcpu);
> + TDX_TEST_ASSERT_IO(vcpu, TDX_SHARED_MEM_TEST_INFO_PORT, 4,
> + TDG_VP_VMCALL_INSTRUCTION_IO_WRITE);
> + TEST_ASSERT_EQ(*test_mem_hva, TDX_SHARED_MEM_TEST_GUEST_WRITE_VALUE);
> +
> + *test_mem_hva = TDX_SHARED_MEM_TEST_HOST_WRITE_VALUE;
> + td_vcpu_run(vcpu);
> + TDX_TEST_ASSERT_IO(vcpu, TDX_SHARED_MEM_TEST_INFO_PORT, 4,
> + TDG_VP_VMCALL_INSTRUCTION_IO_WRITE);
> + TEST_ASSERT_EQ(
> + *(uint32_t *)((void *)vcpu->run + vcpu->run->io.data_offset),
> + TDX_SHARED_MEM_TEST_HOST_WRITE_VALUE);
> +
> + printf("\t ... PASSED\n");
> +
> + kvm_vm_free(vm);
> +
> + return 0;
> +}
> +
> +int main(int argc, char **argv)
> +{
> + if (!is_tdx_enabled()) {
> + printf("TDX is not supported by the KVM\n"
> + "Skipping the TDX tests.\n");
> + return 0;
> + }
> +
> + return verify_shared_mem();
> +}
> --
> 2.43.0.472.g3155946c3a-goog
>

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Previous message: Chen, Zide: "Re: [RFC PATCH v5 22/29] KVM: selftests: Add functions to allow mapping as shared"
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