On 7/23/2026 7:13 AM, Lisa Wang wrote:
From: Sagi Shahar <[email protected]>
Allocate memory for TDX boot parameters and define the utility functions
necessary to fill this memory with the boot parameters.
Co-developed-by: Ackerley Tng <[email protected]>
Signed-off-by: Ackerley Tng <[email protected]>
Signed-off-by: Sagi Shahar <[email protected]>
Signed-off-by: Lisa Wang <[email protected]>
Reviewed-by: Xiaoyao Li <[email protected]>
2 nits below. I think you can keep the code as-is unless maintainers ask
you to change.
---
.../selftests/kvm/include/x86/tdx/tdx_util.h | 2 +
tools/testing/selftests/kvm/lib/x86/processor.c | 2 +
tools/testing/selftests/kvm/lib/x86/tdx/tdx_util.c | 51 ++++++++++++++++++++++
3 files changed, 55 insertions(+)
diff --git a/tools/testing/selftests/kvm/include/x86/tdx/tdx_util.h
b/tools/testing/selftests/kvm/include/x86/tdx/tdx_util.h
index 642ffa010da3..f5003cbaa106 100644
--- a/tools/testing/selftests/kvm/include/x86/tdx/tdx_util.h
+++ b/tools/testing/selftests/kvm/include/x86/tdx/tdx_util.h
@@ -46,5 +46,7 @@ static inline bool is_tdx_vm(struct kvm_vm *vm)
void tdx_init_vm(struct kvm_vm *vm, u64 attributes);
void tdx_vm_setup_boot_code_region(struct kvm_vm *vm);
+void tdx_vm_setup_boot_parameters_region(struct kvm_vm *vm, u32
nr_runnable_vcpus);
+void tdx_vm_load_common_boot_parameters(struct kvm_vm *vm);
#endif /* SELFTESTS_TDX_TDX_UTIL_H */
diff --git a/tools/testing/selftests/kvm/lib/x86/processor.c
b/tools/testing/selftests/kvm/lib/x86/processor.c
index f93953777ca1..748c6041f8bf 100644
--- a/tools/testing/selftests/kvm/lib/x86/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86/processor.c
@@ -794,6 +794,8 @@ void kvm_arch_vm_post_create(struct kvm_vm *vm, unsigned
int nr_vcpus)
if (is_tdx_vm(vm)) {
tdx_init_vm(vm, 0);
tdx_vm_setup_boot_code_region(vm);
+ tdx_vm_setup_boot_parameters_region(vm, nr_vcpus);
+ tdx_vm_load_common_boot_parameters(vm);
}
r = __vm_ioctl(vm, KVM_GET_TSC_KHZ, NULL);
diff --git a/tools/testing/selftests/kvm/lib/x86/tdx/tdx_util.c
b/tools/testing/selftests/kvm/lib/x86/tdx/tdx_util.c
index d64d153d19e2..2ce8c297f7ed 100644
--- a/tools/testing/selftests/kvm/lib/x86/tdx/tdx_util.c
+++ b/tools/testing/selftests/kvm/lib/x86/tdx/tdx_util.c
@@ -6,6 +6,7 @@
/* Arbitrarily selected to avoid overlaps with anything else */
#define TD_BOOT_CODE_SLOT 20
+#define TD_BOOT_PARAMETERS_SLOT 21
#define X86_RESET_VECTOR 0xfffffff0ul
#define X86_RESET_VECTOR_SIZE 16
@@ -49,6 +50,56 @@ void tdx_vm_setup_boot_code_region(struct kvm_vm *vm)
hva[2] = 0xcc;
}
+void tdx_vm_setup_boot_parameters_region(struct kvm_vm *vm, u32 nr_runnable_vcpus)
+{
+ size_t boot_params_size =
+ sizeof(struct td_boot_parameters) +
+ nr_runnable_vcpus * sizeof(struct td_per_vcpu_parameters);
Nit: I'm not sure if the style is acceptable to selftest or not. From
KVM coding style, it's not common.
+ int npages = DIV_ROUND_UP(boot_params_size, PAGE_SIZE);
+ const u64 gmem_flags = 0;
+ gpa_t gpa;
+
+ vm_mem_add(vm, VM_MEM_SRC_SHMEM, TD_BOOT_PARAMETERS_GPA,
+ TD_BOOT_PARAMETERS_SLOT, npages,
+ KVM_MEM_GUEST_MEMFD, -1, 0, gmem_flags);
+ gpa = vm_phy_pages_alloc(vm, npages, TD_BOOT_PARAMETERS_GPA,
TD_BOOT_PARAMETERS_SLOT);
+ TEST_ASSERT(gpa == TD_BOOT_PARAMETERS_GPA, "Failed
vm_phy_pages_alloc\n");
+
+ virt_map(vm, TD_BOOT_PARAMETERS_GPA, TD_BOOT_PARAMETERS_GPA, npages);
+}
+
+void tdx_vm_load_common_boot_parameters(struct kvm_vm *vm)
+{
+ struct td_boot_parameters *params =
+ addr_gpa2hva(vm, TD_BOOT_PARAMETERS_GPA);
Nit: I think it's OK to make it just one line.
+ u32 cr4;
+
+ cr4 = kvm_get_default_cr4(vm->mmu.pgtable_levels);
+
+ /* TDX spec 11.6.2: CR4 bit MCE is fixed to 1 */
+ cr4 |= X86_CR4_MCE;
+
+ /* TDX spec 11.6.2: CR4 bit VMXE and SMXE are fixed to 0 */
+ cr4 &= ~(X86_CR4_VMXE | X86_CR4_SMXE);
+
+ /* Set parameters! */
+ params->cr0 = kvm_get_default_cr0();
+ TEST_ASSERT(vm->mmu.pgd < (1ULL << 32),
+ "PGD must be within 32-bit address space for 32-bit boot
code");
+ params->cr3 = vm->mmu.pgd;
+ params->cr4 = cr4;
+ params->idtr.base = vm->arch.idt;
+ params->idtr.limit = kvm_get_default_idt_limit();
+ params->gdtr.base = vm->arch.gdt;
+ params->gdtr.limit = kvm_get_default_gdt_limit();
+
+ TEST_ASSERT(params->cr0 != 0, "cr0 should not be 0");
+ TEST_ASSERT(params->cr3 != 0, "cr3 should not be 0");
+ TEST_ASSERT(params->cr4 != 0, "cr4 should not be 0");
+ TEST_ASSERT(params->gdtr.base != 0, "gdt base address should not be 0");
+ TEST_ASSERT(params->idtr.base != 0, "idt base address should not be 0");
+}
+
static struct kvm_tdx_capabilities *tdx_read_capabilities(struct kvm_vm *vm)
{
static struct kvm_tdx_capabilities *tdx_cap;
