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

On 12/12/2023 12:47 PM, Sagi Shahar wrote:

-----Original Message----- From: Sagi Shahar sagis@google.com Sent: Tuesday, December 12, 2023 12:47 PM To: linux-kselftest@vger.kernel.org; Ackerley Tng ackerleytng@google.com; Afranji, Ryan afranji@google.com; Aktas, Erdem erdemaktas@google.com; Sagi Shahar sagis@google.com; Yamahata, Isaku isaku.yamahata@intel.com Cc: Sean Christopherson seanjc@google.com; Paolo Bonzini pbonzini@redhat.com; Shuah Khan shuah@kernel.org; Peter Gonda pgonda@google.com; Xu, Haibo1 haibo1.xu@intel.com; Chao Peng chao.p.peng@linux.intel.com; Annapurve, Vishal vannapurve@google.com; Roger Wang runanwang@google.com; Vipin Sharma vipinsh@google.com; jmattson@google.com; dmatlack@google.com; linux-kernel@vger.kernel.org; kvm@vger.kernel.org; linux-mm@kvack.org Subject: [RFC PATCH v5 23/29] KVM: selftests: TDX: Add shared memory test

From: Ryan Afranji afranji@google.com

Adds a test that sets up shared memory between the host and guest.

Signed-off-by: Ryan Afranji afranji@google.com Signed-off-by: Sagi Shahar sagis@google.com Signed-off-by: Ackerley Tng ackerleytng@google.com

---

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