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From: Lisa Wang <wyihan@google.com>
To: Andrew Jones <ajones@ventanamicro.com>,
	Ackerley Tng <ackerleytng@google.com>,
	 Binbin Wu <binbin.wu@linux.intel.com>,
	Chao Gao <chao.gao@intel.com>,
	 Chenyi Qiang <chenyi.qiang@intel.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	 Erdem Aktas <erdemaktas@google.com>,
	Ira Weiny <ira.weiny@intel.com>,
	 Isaku Yamahata <isaku.yamahata@intel.com>,
	Kiryl Shutsemau <kas@kernel.org>,
	 linux-kselftest@vger.kernel.org,
	Paolo Bonzini <pbonzini@redhat.com>,
	 "Pratik R. Sampat" <pratikrajesh.sampat@amd.com>,
	Reinette Chatre <reinette.chatre@intel.com>,
	 Rick Edgecombe <rick.p.edgecombe@intel.com>,
	Roger Wang <runanwang@google.com>,
	 Ryan Afranji <afranji@google.com>,
	Sagi Shahar <sagis@google.com>,
	 Sean Christopherson <seanjc@google.com>,
	Shuah Khan <shuah@kernel.org>, Xiaoyao Li <xiaoyao.li@intel.com>,
	 Oliver Upton <oupton@kernel.org>
Cc: Jeremiah McReynolds <jmcrey@google.com>,
	kvm@vger.kernel.org, linux-coco@lists.linux.dev,
	 linux-kernel@vger.kernel.org, x86@kernel.org,
	Lisa Wang <wyihan@google.com>
Subject: [PATCH v14 07/22] KVM: selftests: Introduce structures for TDX guest boot parameters
Date: Wed, 22 Jul 2026 23:13:12 +0000	[thread overview]
Message-ID: <20260722-tdx-selftests-v14-7-15ad654a50db@google.com> (raw)
In-Reply-To: <20260722-tdx-selftests-v14-0-15ad654a50db@google.com>

From: Sagi Shahar <sagis@google.com>

Introduce `td_boot_parameters` and `td_per_vcpu_parameters`, and export
their offsets to assembly via the kbuild infrastructure.

TDX guest registers are private and must be initialized by guest-side
assembly. These structures allow the assembly code to retrieve boot
parameters and index into per-vCPU data based on the vCPU ID, while
keeping host and guest definitions synchronized.

Use kbuild.h to expose the offsets into the structs from c code to
assembly code.

Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com>
Co-developed-by: Ackerley Tng <ackerleytng@google.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
Signed-off-by: Sagi Shahar <sagis@google.com>
Co-developed-by: Lisa Wang <wyihan@google.com>
Signed-off-by: Lisa Wang <wyihan@google.com>
---
 tools/testing/selftests/kvm/.gitignore             |  3 +-
 tools/testing/selftests/kvm/Makefile.kvm           | 29 +++++++++-
 .../selftests/kvm/include/x86/tdx/td_boot.h        | 66 ++++++++++++++++++++++
 .../selftests/kvm/lib/x86/tdx/td_boot_offsets.c    | 21 +++++++
 4 files changed, 116 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
index 1d41a046a7bf..eef6055242b2 100644
--- a/tools/testing/selftests/kvm/.gitignore
+++ b/tools/testing/selftests/kvm/.gitignore
@@ -9,4 +9,5 @@
 !config
 !settings
 !Makefile
-!Makefile.kvm
\ No newline at end of file
+!Makefile.kvm
+include/x86/**/*_offsets.h
\ No newline at end of file
diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm
index 3f98d1c6488c..397afebbb34b 100644
--- a/tools/testing/selftests/kvm/Makefile.kvm
+++ b/tools/testing/selftests/kvm/Makefile.kvm
@@ -19,6 +19,8 @@ LIBKVM += lib/userfaultfd_util.c
 
 LIBKVM_STRING += lib/string_override.c
 
+LIBKVM_ASM_DEFS += lib/x86/tdx/td_boot_offsets.c
+
 LIBKVM_x86 += lib/x86/apic.c
 LIBKVM_x86 += lib/x86/handlers.S
 LIBKVM_x86 += lib/x86/hyperv.c
@@ -261,6 +263,10 @@ OVERRIDE_TARGETS = 1
 include ../lib.mk
 include ../cgroup/lib/libcgroup.mk
 
+# Enable Kbuild tools.
+include $(top_srcdir)/scripts/Kbuild.include
+include $(top_srcdir)/scripts/Makefile.lib
+
 INSTALL_HDR_PATH = $(top_srcdir)/usr
 LINUX_HDR_PATH = $(INSTALL_HDR_PATH)/include/
 LINUX_TOOL_INCLUDE = $(top_srcdir)/tools/include
@@ -273,15 +279,24 @@ CFLAGS += -Wall -Wstrict-prototypes -Wuninitialized -O2 -g -std=gnu99 \
 	-fno-stack-protector -fno-PIE -fno-strict-aliasing \
 	-I$(LINUX_TOOL_INCLUDE) -I$(LINUX_TOOL_ARCH_INCLUDE) \
 	-I$(LINUX_HDR_PATH) -Iinclude -I$(<D) -Iinclude/$(ARCH) \
-	-I ../rseq -I.. $(EXTRA_CFLAGS) $(KHDR_INCLUDES)
+	-I ../rseq -I.. -I$(OUTPUT)/include/$(ARCH) $(EXTRA_CFLAGS) $(KHDR_INCLUDES)
 ifeq ($(ARCH),s390)
 	CFLAGS += -march=z10
 endif
+
 ifeq ($(ARCH),x86)
+
 ifeq ($(shell echo "void foo(void) { }" | $(CC) -march=x86-64-v2 -x c - -c -o /dev/null 2>/dev/null; echo "$$?"),0)
 	CFLAGS += -march=x86-64-v2
 endif
+
+KVM_GEN_HDRS := $(patsubst lib/x86/%.c, $(OUTPUT)/include/x86/%.h, $(filter lib/x86/%, $(LIBKVM_ASM_DEFS)))
+$(shell mkdir -p $(sort $(dir $(KVM_GEN_HDRS))))
+$(KVM_GEN_HDRS): GUARD = $(shell echo $(*F) | tr a-z A-Z | tr '.' '_')
+$(KVM_GEN_HDRS): $(OUTPUT)/include/x86/%.h: $(OUTPUT)/lib/x86/%.s FORCE
+	$(call filechk,offsets,__$(GUARD)_H__)
 endif
+
 ifeq ($(ARCH),arm64)
 tools_dir := $(top_srcdir)/tools
 arm64_tools_dir := $(tools_dir)/arch/arm64/tools/
@@ -314,6 +329,7 @@ LIBKVM_S := $(filter %.S,$(LIBKVM))
 LIBKVM_C_OBJ := $(patsubst %.c, $(OUTPUT)/%.o, $(LIBKVM_C))
 LIBKVM_S_OBJ := $(patsubst %.S, $(OUTPUT)/%.o, $(LIBKVM_S))
 LIBKVM_STRING_OBJ := $(patsubst %.c, $(OUTPUT)/%.o, $(LIBKVM_STRING))
+LIBKVM_ASM_DEFS_OBJ += $(patsubst %.c, $(OUTPUT)/%.s, $(LIBKVM_ASM_DEFS))
 LIBKVM_OBJS = $(LIBKVM_C_OBJ) $(LIBKVM_S_OBJ) $(LIBKVM_STRING_OBJ) $(LIBCGROUP_O)
 SPLIT_TEST_GEN_PROGS := $(patsubst %, $(OUTPUT)/%, $(SPLIT_TESTS))
 SPLIT_TEST_GEN_OBJ := $(patsubst %, $(OUTPUT)/$(ARCH)/%.o, $(SPLIT_TESTS))
@@ -339,7 +355,9 @@ $(SPLIT_TEST_GEN_OBJ): $(OUTPUT)/$(ARCH)/%.o: $(ARCH)/%.c
 	$(CC) $(CFLAGS) $(CPPFLAGS) $(TARGET_ARCH) -c $< -o $@
 
 EXTRA_CLEAN += $(GEN_HDRS) \
+	       $(KVM_GEN_HDRS) \
 	       $(LIBKVM_OBJS) \
+	       $(LIBKVM_ASM_DEFS_OBJ) \
 	       $(SPLIT_TEST_GEN_OBJ) \
 	       $(TEST_DEP_FILES) \
 	       $(TEST_GEN_OBJ) \
@@ -351,6 +369,9 @@ $(LIBKVM_C_OBJ): $(OUTPUT)/%.o: %.c $(GEN_HDRS)
 $(LIBKVM_S_OBJ): $(OUTPUT)/%.o: %.S $(GEN_HDRS)
 	$(CC) $(CFLAGS) $(CPPFLAGS) $(TARGET_ARCH) -c $< -o $@
 
+$(LIBKVM_ASM_DEFS_OBJ): $(OUTPUT)/%.s: %.c FORCE
+	$(CC) $(CFLAGS) $(CPPFLAGS) $(TARGET_ARCH) -S $< -o $@
+
 # Compile the string overrides as freestanding to prevent the compiler from
 # generating self-referential code, e.g. without "freestanding" the compiler may
 # "optimize" memcmp() by invoking memcmp(), thus causing infinite recursion.
@@ -359,11 +380,15 @@ $(LIBKVM_STRING_OBJ): $(OUTPUT)/%.o: %.c
 
 $(shell mkdir -p $(sort $(dir $(TEST_GEN_PROGS))))
 $(SPLIT_TEST_GEN_OBJ): $(GEN_HDRS)
+$(LIBKVM_OBJS): $(KVM_GEN_HDRS)
 $(TEST_GEN_PROGS): $(LIBKVM_OBJS)
 $(TEST_GEN_PROGS_EXTENDED): $(LIBKVM_OBJS)
 $(TEST_GEN_OBJ): $(GEN_HDRS)
 
-cscope: include_paths = $(LINUX_TOOL_INCLUDE) $(LINUX_HDR_PATH) include lib ..
+FORCE:
+
+cscope: include_paths = $(LINUX_TOOL_INCLUDE) $(LINUX_HDR_PATH) include lib .. \
+			$(wildcard $(sort $(dir $(KVM_GEN_HDRS))))
 cscope:
 	$(RM) cscope.*
 	(find $(include_paths) -name '*.h' \
diff --git a/tools/testing/selftests/kvm/include/x86/tdx/td_boot.h b/tools/testing/selftests/kvm/include/x86/tdx/td_boot.h
new file mode 100644
index 000000000000..bf2282931d49
--- /dev/null
+++ b/tools/testing/selftests/kvm/include/x86/tdx/td_boot.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef SELFTEST_TDX_TD_BOOT_H
+#define SELFTEST_TDX_TD_BOOT_H
+
+#include <linux/compiler.h>
+#include <linux/types.h>
+
+/*
+ * Layout for boot section (not to scale)
+ *
+ *                                   GPA
+ * _________________________________ 0x1_0000_0000 (4GB)
+ * |   Boot code trampoline    |
+ * |___________________________|____ 0x0_ffff_fff0: Reset vector (16B below 4GB)
+ * |   Boot code               |
+ * |___________________________|____ td_boot will be copied here, so that the
+ * |                           |     jmp to td_boot is exactly at the reset vector
+ * |   Empty space             |
+ * |                           |
+ * |───────────────────────────|
+ * |                           |
+ * |                           |
+ * |   Boot parameters         |
+ * |                           |
+ * |                           |
+ * |___________________________|____ 0x0_ffff_0000: TD_BOOT_PARAMETERS_GPA
+ */
+
+/*
+ * The exact memory layout for LGDT or LIDT instructions.
+ */
+struct __packed td_boot_parameters_dtr {
+	u16 limit;
+	u32 base;
+};
+
+/*
+ * Allows each vCPU to be initialized with different rip and esp.
+ */
+struct td_per_vcpu_parameters {
+	u32 esp_gva;
+	u64 guest_code;
+};
+
+/*
+ * Boot parameters for the TD.
+ *
+ * Unlike a regular VM, KVM cannot set registers such as esp, eip, etc
+ * before boot, so to run selftests, these registers' values have to be
+ * initialized by the TD.
+ *
+ * This struct is loaded in TD private memory at TD_BOOT_PARAMETERS_GPA.
+ *
+ * The TD boot code will read off parameters from this struct and set up the
+ * vCPU for executing selftests.
+ */
+struct td_boot_parameters {
+	u32 cr0;
+	u32 cr3;
+	u32 cr4;
+	struct td_boot_parameters_dtr gdtr;
+	struct td_boot_parameters_dtr idtr;
+	struct td_per_vcpu_parameters per_vcpu[];
+};
+
+#endif /* SELFTEST_TDX_TD_BOOT_H */
diff --git a/tools/testing/selftests/kvm/lib/x86/tdx/td_boot_offsets.c b/tools/testing/selftests/kvm/lib/x86/tdx/td_boot_offsets.c
new file mode 100644
index 000000000000..7f76a3585b99
--- /dev/null
+++ b/tools/testing/selftests/kvm/lib/x86/tdx/td_boot_offsets.c
@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0
+#define COMPILE_OFFSETS
+
+#include <linux/kbuild.h>
+
+#include "tdx/td_boot.h"
+
+static void __attribute__((used)) common(void)
+{
+	OFFSET(TD_BOOT_PARAMETERS_CR0, td_boot_parameters, cr0);
+	OFFSET(TD_BOOT_PARAMETERS_CR3, td_boot_parameters, cr3);
+	OFFSET(TD_BOOT_PARAMETERS_CR4, td_boot_parameters, cr4);
+	OFFSET(TD_BOOT_PARAMETERS_GDT, td_boot_parameters, gdtr);
+	OFFSET(TD_BOOT_PARAMETERS_IDT, td_boot_parameters, idtr);
+	OFFSET(TD_BOOT_PARAMETERS_PER_VCPU, td_boot_parameters, per_vcpu);
+	OFFSET(TD_PER_VCPU_PARAMETERS_ESP_GVA, td_per_vcpu_parameters, esp_gva);
+	OFFSET(TD_PER_VCPU_PARAMETERS_GUEST_CODE, td_per_vcpu_parameters,
+	       guest_code);
+	DEFINE(SIZEOF_TD_PER_VCPU_PARAMETERS,
+	       sizeof(struct td_per_vcpu_parameters));
+}

-- 
2.55.0.229.g6434b31f56-goog


  parent reply	other threads:[~2026-07-22 23:14 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-22 23:13 [PATCH v14 00/22] TDX KVM selftests Lisa Wang
2026-07-22 23:13 ` [PATCH v14 01/22] KVM: selftests: Add macros to simplify creating VM shapes for non-default types Lisa Wang
2026-07-22 23:13 ` [PATCH v14 02/22] KVM: selftests: Update kvm_init_vm_address_properties() for TDX Lisa Wang
2026-07-22 23:13 ` [PATCH v14 03/22] KVM: selftests: Initialize the TDX VM Lisa Wang
2026-07-23  8:44   ` Xiaoyao Li
2026-07-22 23:13 ` [PATCH v14 04/22] KVM: selftests: TDX: Use KVM_TDX_CAPABILITIES to validate TDs' attribute configuration Lisa Wang
2026-07-22 23:13 ` [PATCH v14 05/22] KVM: selftests: Expose segment definitions to assembly files Lisa Wang
2026-07-22 23:13 ` [PATCH v14 06/22] tools: include: Add kbuild.h for assembly structure offsets Lisa Wang
2026-07-22 23:13 ` Lisa Wang [this message]
2026-07-22 23:13 ` [PATCH v14 08/22] KVM: selftests: Add TDX boot code Lisa Wang
2026-07-22 23:13 ` [PATCH v14 09/22] KVM: selftests: Expose functions to get default sregs values Lisa Wang
2026-07-22 23:13 ` [PATCH v14 10/22] KVM: selftests: Set up TDX boot code region Lisa Wang
2026-07-22 23:13 ` [PATCH v14 11/22] KVM: selftests: Set up TDX boot parameters region Lisa Wang
2026-07-22 23:13 ` [PATCH v14 12/22] KVM: selftests: Require guest_memfd for TDX VMs Lisa Wang
2026-07-22 23:13 ` [PATCH v14 13/22] KVM: selftests: Support guest_memfd in-place conversion Lisa Wang
2026-07-22 23:13 ` [PATCH v14 14/22] KVM: selftests: Expose function to allocate vCPU stack Lisa Wang
2026-07-22 23:13 ` [PATCH v14 15/22] KVM: selftests: Call KVM_TDX_INIT_VCPU when creating a new TDX vcpu Lisa Wang
2026-07-22 23:13 ` [PATCH v14 16/22] KVM: selftests: Load per-vCPU guest stack in TDX boot parameters Lisa Wang
2026-07-22 23:13 ` [PATCH v14 17/22] KVM: selftests: Set entry point for TDX guest code Lisa Wang
2026-07-22 23:13 ` [PATCH v14 18/22] KVM: selftests: Add helpers to init TDX memory and finalize VM Lisa Wang
2026-07-22 23:13 ` [PATCH v14 19/22] KVM: selftests: Finalize TD memory as part of kvm_arch_vm_finalize_vcpus Lisa Wang
2026-07-22 23:13 ` [PATCH v14 20/22] KVM: selftests: Implement MMIO WRITE for the TDX VM Lisa Wang
2026-07-28 22:56   ` Ackerley Tng
2026-07-22 23:13 ` [PATCH v14 21/22] KVM: selftests: Add ucall support for TDX Lisa Wang
2026-07-22 23:13 ` [PATCH v14 22/22] KVM: selftests: Add TDX lifecycle test Lisa Wang

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