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Sampat" , Reinette Chatre , Rick Edgecombe , Roger Wang , Ryan Afranji , Sagi Shahar , Sean Christopherson , Shuah Khan , Xiaoyao Li , Oliver Upton Cc: Jeremiah McReynolds , kvm@vger.kernel.org, linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org, x86@kernel.org, Lisa Wang Content-Type: text/plain; charset="utf-8" From: Erdem Aktas Add code to boot a TDX test VM. Since TDX registers are inaccessible to KVM, the boot code loads the relevant values from memory into the registers before jumping to the guest code. Co-developed-by: Ackerley Tng Signed-off-by: Ackerley Tng Co-developed-by: Sagi Shahar Signed-off-by: Sagi Shahar Co-developed-by: Lisa Wang Signed-off-by: Lisa Wang Signed-off-by: Erdem Aktas Reviewed-by: Binbin Wu Reviewed-by: Xiaoyao Li --- tools/testing/selftests/kvm/Makefile.kvm | 1 + .../selftests/kvm/include/x86/tdx/td_boot.h | 21 ++++++- tools/testing/selftests/kvm/lib/x86/tdx/td_boot.S | 65 ++++++++++++++++++++++ 3 files changed, 84 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm index 8fc38a93a725..9464168e361a 100644 --- a/tools/testing/selftests/kvm/Makefile.kvm +++ b/tools/testing/selftests/kvm/Makefile.kvm @@ -33,6 +33,7 @@ LIBKVM_x86 += lib/x86/svm.c LIBKVM_x86 += lib/x86/tdx/tdx_util.c LIBKVM_x86 += lib/x86/ucall.c LIBKVM_x86 += lib/x86/vmx.c +LIBKVM_x86 += lib/x86/tdx/td_boot.S LIBKVM_arm64 += lib/arm64/gic.c LIBKVM_arm64 += lib/arm64/gic_v3.c diff --git a/tools/testing/selftests/kvm/include/x86/tdx/td_boot.h b/tools/testing/selftests/kvm/include/x86/tdx/td_boot.h index bf2282931d49..577e7b23c51c 100644 --- a/tools/testing/selftests/kvm/include/x86/tdx/td_boot.h +++ b/tools/testing/selftests/kvm/include/x86/tdx/td_boot.h @@ -2,9 +2,6 @@ #ifndef SELFTEST_TDX_TD_BOOT_H #define SELFTEST_TDX_TD_BOOT_H -#include -#include - /* * Layout for boot section (not to scale) * @@ -24,7 +21,19 @@ * | | * | | * |___________________________|____ 0x0_ffff_0000: TD_BOOT_PARAMETERS_GPA + * + * TD_BOOT_PARAMETERS_GPA is arbitrarily chosen to + * + * + be within the 4GB address space + * + provide enough contiguous memory for the struct td_boot_parameters such + * that there is one struct td_per_vcpu_parameters for KVM_MAX_VCPUS */ +#define TD_BOOT_PARAMETERS_GPA 0xffff0000 + +#ifndef __ASSEMBLER__ + +#include +#include /* * The exact memory layout for LGDT or LIDT instructions. @@ -63,4 +72,10 @@ struct td_boot_parameters { struct td_per_vcpu_parameters per_vcpu[]; }; +extern u8 td_boot[], td_boot_code_end[]; + +#define TD_BOOT_CODE_SIZE (td_boot_code_end - td_boot) + +#endif /* #ifndef __ASSEMBLER__ */ + #endif /* SELFTEST_TDX_TD_BOOT_H */ diff --git a/tools/testing/selftests/kvm/lib/x86/tdx/td_boot.S b/tools/testing/selftests/kvm/lib/x86/tdx/td_boot.S new file mode 100644 index 000000000000..726ec51e040e --- /dev/null +++ b/tools/testing/selftests/kvm/lib/x86/tdx/td_boot.S @@ -0,0 +1,65 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#include "tdx/td_boot.h" +#include "tdx/td_boot_offsets.h" +#include "processor_asm.h" + +.code32 + +.globl td_boot +td_boot: + /* + * Paging is turned off. + * + * Register usage throughout td_boot: + * ebx: Address of global boot parameters (Must be preserved) + * eax: Address of per-vCPU parameters (Must be preserved) + * edi, edx: Temporary scratch registers + */ + cli + + movl $TD_BOOT_PARAMETERS_GPA, %ebx + + /* + * Find the address of struct td_per_vcpu_parameters for this + * vCPU based on esi (TDX spec: initialized with vCPU id). Put + * struct address into eax for indirect addressing. + */ + movl $SIZEOF_TD_PER_VCPU_PARAMETERS, %eax + mul %esi + leal TD_BOOT_PARAMETERS_PER_VCPU(%ebx), %edi + addl %edi, %eax + + /* Setup stack. */ + movl TD_PER_VCPU_PARAMETERS_ESP_GVA(%eax), %esp + + /* Setup GDT. */ + leal TD_BOOT_PARAMETERS_GDT(%ebx), %edi + lgdt (%edi) + + /* Setup IDT. */ + leal TD_BOOT_PARAMETERS_IDT(%ebx), %edi + lidt (%edi) + + /* + * Set up control registers (x86 does not support moving memory + * directly to a control register). + */ + movl TD_BOOT_PARAMETERS_CR4(%ebx), %edi + movl %edi, %cr4 + movl TD_BOOT_PARAMETERS_CR3(%ebx), %edi + movl %edi, %cr3 + movl TD_BOOT_PARAMETERS_CR0(%ebx), %edi + movl %edi, %cr0 + + /* Switching to 64bit mode after ljmp and then jump to guest code */ + ljmp $(KERNEL_CS),$1f +1: + jmp *TD_PER_VCPU_PARAMETERS_GUEST_CODE(%eax) + +/* Leave marker so size of td_boot code can be computed. */ +.globl td_boot_code_end +td_boot_code_end: + +/* Disable executable stack. */ +.section .note.GNU-stack,"",%progbits -- 2.56.0.rc1.315.gc6ed9934b7-goog