linux-kernel - [PATCH v9 11/19] KVM: selftests: Set up TDX boot parameters region

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Message-ID: <20250821042915.3712925-12-sagis@google.com>
Date: Wed, 20 Aug 2025 21:29:04 -0700
From: Sagi Shahar <sagis@...gle.com>
To: linux-kselftest@...r.kernel.org, Paolo Bonzini <pbonzini@...hat.com>, 
	Shuah Khan <shuah@...nel.org>, Sean Christopherson <seanjc@...gle.com>, 
	Ackerley Tng <ackerleytng@...gle.com>, Ryan Afranji <afranji@...gle.com>, 
	Andrew Jones <ajones@...tanamicro.com>, Isaku Yamahata <isaku.yamahata@...el.com>, 
	Erdem Aktas <erdemaktas@...gle.com>, Rick Edgecombe <rick.p.edgecombe@...el.com>, 
	Sagi Shahar <sagis@...gle.com>, Roger Wang <runanwang@...gle.com>, 
	Binbin Wu <binbin.wu@...ux.intel.com>, Oliver Upton <oliver.upton@...ux.dev>, 
	"Pratik R. Sampat" <pratikrajesh.sampat@....com>, Reinette Chatre <reinette.chatre@...el.com>, 
	Ira Weiny <ira.weiny@...el.com>, Chao Gao <chao.gao@...el.com>, 
	Chenyi Qiang <chenyi.qiang@...el.com>
Cc: linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: [PATCH v9 11/19] KVM: selftests: Set up TDX boot parameters region

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 <ackerleytng@...gle.com>
Signed-off-by: Ackerley Tng <ackerleytng@...gle.com>
Signed-off-by: Sagi Shahar <sagis@...gle.com>
---
 .../selftests/kvm/include/x86/tdx/tdx_util.h  |  4 +
 .../selftests/kvm/lib/x86/tdx/tdx_util.c      | 73 +++++++++++++++++++
 2 files changed, 77 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 ec05bcd59145..dafdc7e46abe 100644
--- a/tools/testing/selftests/kvm/include/x86/tdx/tdx_util.h
+++ b/tools/testing/selftests/kvm/include/x86/tdx/tdx_util.h
@@ -12,5 +12,9 @@ static inline bool is_tdx_vm(struct kvm_vm *vm)
 }
 
 void vm_tdx_setup_boot_code_region(struct kvm_vm *vm);
+void vm_tdx_setup_boot_parameters_region(struct kvm_vm *vm, uint32_t nr_runnable_vcpus);
+void vm_tdx_load_common_boot_parameters(struct kvm_vm *vm);
+void vm_tdx_load_vcpu_boot_parameters(struct kvm_vm *vm, struct kvm_vcpu *vcpu);
+void vm_tdx_set_vcpu_entry_point(struct kvm_vcpu *vcpu, void *guest_code);
 
 #endif // SELFTESTS_TDX_TDX_UTIL_H
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 15833b9eb5d5..52dc25e0cce4 100644
--- a/tools/testing/selftests/kvm/lib/x86/tdx/tdx_util.c
+++ b/tools/testing/selftests/kvm/lib/x86/tdx/tdx_util.c
@@ -5,10 +5,12 @@
 #include "kvm_util.h"
 #include "processor.h"
 #include "tdx/td_boot.h"
+#include "tdx/td_boot_asm.h"
 #include "tdx/tdx_util.h"
 
 /* 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
@@ -52,3 +54,74 @@ void vm_tdx_setup_boot_code_region(struct kvm_vm *vm)
 	hva[1] = 256 - 2 - TD_BOOT_CODE_SIZE;
 	hva[2] = 0xcc;
 }
+
+void vm_tdx_setup_boot_parameters_region(struct kvm_vm *vm, uint32_t nr_runnable_vcpus)
+{
+	size_t boot_params_size =
+		sizeof(struct td_boot_parameters) +
+		nr_runnable_vcpus * sizeof(struct td_per_vcpu_parameters);
+	int npages = DIV_ROUND_UP(boot_params_size, PAGE_SIZE);
+	vm_paddr_t gpa;
+
+	vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
+				    TD_BOOT_PARAMETERS_GPA,
+				    TD_BOOT_PARAMETERS_SLOT, npages,
+				    KVM_MEM_GUEST_MEMFD);
+	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 vm_tdx_load_common_boot_parameters(struct kvm_vm *vm)
+{
+	struct td_boot_parameters *params =
+		addr_gpa2hva(vm, TD_BOOT_PARAMETERS_GPA);
+	uint32_t cr4;
+
+	TEST_ASSERT_EQ(vm->mode, VM_MODE_PXXV48_4K);
+
+	cr4 = kvm_get_default_cr4();
+
+	/* TDX spec 11.6.2: CR4 bit MCE is fixed to 1 */
+	cr4 |= X86_CR4_MCE;
+
+	/* Set this because UEFI also sets this up, to handle XMM exceptions */
+	cr4 |= X86_CR4_OSXMMEXCPT;
+
+	/* 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();
+	params->cr3 = vm->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");
+}
+
+void vm_tdx_load_vcpu_boot_parameters(struct kvm_vm *vm, struct kvm_vcpu *vcpu)
+{
+	struct td_boot_parameters *params =
+		addr_gpa2hva(vm, TD_BOOT_PARAMETERS_GPA);
+	struct td_per_vcpu_parameters *vcpu_params =
+		&params->per_vcpu[vcpu->id];
+
+	vcpu_params->esp_gva = kvm_allocate_vcpu_stack(vm);
+}
+
+void vm_tdx_set_vcpu_entry_point(struct kvm_vcpu *vcpu, void *guest_code)
+{
+	struct td_boot_parameters *params = addr_gpa2hva(vcpu->vm, TD_BOOT_PARAMETERS_GPA);
+	struct td_per_vcpu_parameters *vcpu_params = &params->per_vcpu[vcpu->id];
+
+	vcpu_params->guest_code = (uint64_t)guest_code;
+}
-- 
2.51.0.rc1.193.gad69d77794-goog