diff options
| -rw-r--r-- | arch/x86/Kconfig | 12 | ||||
| -rw-r--r-- | arch/x86/Makefile | 2 | ||||
| -rw-r--r-- | arch/x86/boot/compressed/tdx.c | 6 | ||||
| -rw-r--r-- | arch/x86/coco/tdx/tdcall.S | 234 | ||||
| -rw-r--r-- | arch/x86/coco/tdx/tdx-shared.c | 28 | ||||
| -rw-r--r-- | arch/x86/coco/tdx/tdx.c | 138 | ||||
| -rw-r--r-- | arch/x86/hyperv/ivm.c | 10 | ||||
| -rw-r--r-- | arch/x86/include/asm/shared/tdx.h | 89 | ||||
| -rw-r--r-- | arch/x86/include/asm/tdx.h | 11 | ||||
| -rw-r--r-- | arch/x86/kernel/asm-offsets.c | 33 | ||||
| -rw-r--r-- | arch/x86/virt/Makefile | 2 | ||||
| -rw-r--r-- | arch/x86/virt/vmx/Makefile | 2 | ||||
| -rw-r--r-- | arch/x86/virt/vmx/tdx/Makefile | 2 | ||||
| -rw-r--r-- | arch/x86/virt/vmx/tdx/seamcall.S | 61 | ||||
| -rw-r--r-- | arch/x86/virt/vmx/tdx/tdxcall.S | 226 | ||||
| -rw-r--r-- | tools/objtool/noreturns.h | 1 |
16 files changed, 491 insertions, 366 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index ad478a2b49e2..433f5e1906d1 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1940,6 +1940,18 @@ config X86_USER_SHADOW_STACK If unsure, say N. +config INTEL_TDX_HOST + bool "Intel Trust Domain Extensions (TDX) host support" + depends on CPU_SUP_INTEL + depends on X86_64 + depends on KVM_INTEL + help + Intel Trust Domain Extensions (TDX) protects guest VMs from malicious + host and certain physical attacks. This option enables necessary TDX + support in the host kernel to run confidential VMs. + + If unsure, say N. + config EFI bool "EFI runtime service support" depends on ACPI diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 76da1e8b3eb0..4de6ddaf4b84 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -253,6 +253,8 @@ archheaders: libs-y += arch/x86/lib/ +core-y += arch/x86/virt/ + # drivers-y are linked after core-y drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/ drivers-$(CONFIG_PCI) += arch/x86/pci/ diff --git a/arch/x86/boot/compressed/tdx.c b/arch/x86/boot/compressed/tdx.c index 8841b945a1e2..8451d6a1030c 100644 --- a/arch/x86/boot/compressed/tdx.c +++ b/arch/x86/boot/compressed/tdx.c @@ -18,7 +18,7 @@ void __tdx_hypercall_failed(void) static inline unsigned int tdx_io_in(int size, u16 port) { - struct tdx_hypercall_args args = { + struct tdx_module_args args = { .r10 = TDX_HYPERCALL_STANDARD, .r11 = hcall_func(EXIT_REASON_IO_INSTRUCTION), .r12 = size, @@ -26,7 +26,7 @@ static inline unsigned int tdx_io_in(int size, u16 port) .r14 = port, }; - if (__tdx_hypercall_ret(&args)) + if (__tdx_hypercall(&args)) return UINT_MAX; return args.r11; @@ -34,7 +34,7 @@ static inline unsigned int tdx_io_in(int size, u16 port) static inline void tdx_io_out(int size, u16 port, u32 value) { - struct tdx_hypercall_args args = { + struct tdx_module_args args = { .r10 = TDX_HYPERCALL_STANDARD, .r11 = hcall_func(EXIT_REASON_IO_INSTRUCTION), .r12 = size, diff --git a/arch/x86/coco/tdx/tdcall.S b/arch/x86/coco/tdx/tdcall.S index b193c0a1d8db..52d9786da308 100644 --- a/arch/x86/coco/tdx/tdcall.S +++ b/arch/x86/coco/tdx/tdcall.S @@ -1,239 +1,63 @@ /* SPDX-License-Identifier: GPL-2.0 */ #include <asm/asm-offsets.h> #include <asm/asm.h> -#include <asm/frame.h> -#include <asm/unwind_hints.h> #include <linux/linkage.h> -#include <linux/bits.h> #include <linux/errno.h> #include "../../virt/vmx/tdx/tdxcall.S" -/* - * Bitmasks of exposed registers (with VMM). - */ -#define TDX_RDX BIT(2) -#define TDX_RBX BIT(3) -#define TDX_RSI BIT(6) -#define TDX_RDI BIT(7) -#define TDX_R8 BIT(8) -#define TDX_R9 BIT(9) -#define TDX_R10 BIT(10) -#define TDX_R11 BIT(11) -#define TDX_R12 BIT(12) -#define TDX_R13 BIT(13) -#define TDX_R14 BIT(14) -#define TDX_R15 BIT(15) - -/* - * These registers are clobbered to hold arguments for each - * TDVMCALL. They are safe to expose to the VMM. - * Each bit in this mask represents a register ID. Bit field - * details can be found in TDX GHCI specification, section - * titled "TDCALL [TDG.VP.VMCALL] leaf". - */ -#define TDVMCALL_EXPOSE_REGS_MASK \ - ( TDX_RDX | TDX_RBX | TDX_RSI | TDX_RDI | TDX_R8 | TDX_R9 | \ - TDX_R10 | TDX_R11 | TDX_R12 | TDX_R13 | TDX_R14 | TDX_R15 ) - .section .noinstr.text, "ax" /* - * __tdx_module_call() - Used by TDX guests to request services from - * the TDX module (does not include VMM services) using TDCALL instruction. - * - * Transforms function call register arguments into the TDCALL register ABI. - * After TDCALL operation, TDX module output is saved in @out (if it is - * provided by the user). - * - *------------------------------------------------------------------------- - * TDCALL ABI: - *------------------------------------------------------------------------- - * Input Registers: - * - * RAX - TDCALL Leaf number. - * RCX,RDX,R8-R9 - TDCALL Leaf specific input registers. - * - * Output Registers: + * __tdcall() - Used by TDX guests to request services from the TDX + * module (does not include VMM services) using TDCALL instruction. * - * RAX - TDCALL instruction error code. - * RCX,RDX,R8-R11 - TDCALL Leaf specific output registers. + * __tdcall() function ABI: * - *------------------------------------------------------------------------- + * @fn (RDI) - TDCALL Leaf ID, moved to RAX + * @args (RSI) - struct tdx_module_args for input * - * __tdx_module_call() function ABI: - * - * @fn (RDI) - TDCALL Leaf ID, moved to RAX - * @rcx (RSI) - Input parameter 1, moved to RCX - * @rdx (RDX) - Input parameter 2, moved to RDX - * @r8 (RCX) - Input parameter 3, moved to R8 - * @r9 (R8) - Input parameter 4, moved to R9 - * - * @out (R9) - struct tdx_module_output pointer - * stored temporarily in R12 (not - * shared with the TDX module). It - * can be NULL. + * Only RCX/RDX/R8-R11 are used as input registers. * * Return status of TDCALL via RAX. */ -SYM_FUNC_START(__tdx_module_call) - FRAME_BEGIN +SYM_FUNC_START(__tdcall) TDX_MODULE_CALL host=0 - FRAME_END - RET -SYM_FUNC_END(__tdx_module_call) +SYM_FUNC_END(__tdcall) /* - * TDX_HYPERCALL - Make hypercalls to a TDX VMM using TDVMCALL leaf of TDCALL - * instruction - * - * Transforms values in function call argument struct tdx_hypercall_args @args - * into the TDCALL register ABI. After TDCALL operation, VMM output is saved - * back in @args, if \ret is 1. - * - *------------------------------------------------------------------------- - * TD VMCALL ABI: - *------------------------------------------------------------------------- - * - * Input Registers: + * __tdcall_ret() - Used by TDX guests to request services from the TDX + * module (does not include VMM services) using TDCALL instruction, with + * saving output registers to the 'struct tdx_module_args' used as input. * - * RAX - TDCALL instruction leaf number (0 - TDG.VP.VMCALL) - * RCX - BITMAP which controls which part of TD Guest GPR - * is passed as-is to the VMM and back. - * R10 - Set 0 to indicate TDCALL follows standard TDX ABI - * specification. Non zero value indicates vendor - * specific ABI. - * R11 - VMCALL sub function number - * RBX, RDX, RDI, RSI - Used to pass VMCALL sub function specific arguments. - * R8-R9, R12-R15 - Same as above. + * __tdcall_ret() function ABI: * - * Output Registers: + * @fn (RDI) - TDCALL Leaf ID, moved to RAX + * @args (RSI) - struct tdx_module_args for input and output * - * RAX - TDCALL instruction status (Not related to hypercall - * output). - * RBX, RDX, RDI, RSI - Hypercall sub function specific output values. - * R8-R15 - Same as above. + * Only RCX/RDX/R8-R11 are used as input/output registers. * + * Return status of TDCALL via RAX. */ -.macro TDX_HYPERCALL ret:req - FRAME_BEGIN - - /* Save callee-saved GPRs as mandated by the x86_64 ABI */ - push %r15 - push %r14 - push %r13 - push %r12 - push %rbx - - /* Free RDI to be used as TDVMCALL arguments */ - movq %rdi, %rax - - /* Copy hypercall registers from arg struct: */ - movq TDX_HYPERCALL_r8(%rax), %r8 - movq TDX_HYPERCALL_r9(%rax), %r9 - movq TDX_HYPERCALL_r10(%rax), %r10 - movq TDX_HYPERCALL_r11(%rax), %r11 - movq TDX_HYPERCALL_r12(%rax), %r12 - movq TDX_HYPERCALL_r13(%rax), %r13 - movq TDX_HYPERCALL_r14(%rax), %r14 - movq TDX_HYPERCALL_r15(%rax), %r15 - movq TDX_HYPERCALL_rdi(%rax), %rdi - movq TDX_HYPERCALL_rsi(%rax), %rsi - movq TDX_HYPERCALL_rbx(%rax), %rbx - movq TDX_HYPERCALL_rdx(%rax), %rdx - - push %rax - - /* Mangle function call ABI into TDCALL ABI: */ - /* Set TDCALL leaf ID (TDVMCALL (0)) in RAX */ - xor %eax, %eax - - movl $TDVMCALL_EXPOSE_REGS_MASK, %ecx - - tdcall - - /* - * RAX!=0 indicates a failure of the TDVMCALL mechanism itself and that - * something has gone horribly wrong with the TDX module. - * - * The return status of the hypercall operation is in a separate - * register (in R10). Hypercall errors are a part of normal operation - * and are handled by callers. - */ - testq %rax, %rax - jne .Lpanic\@ - - pop %rax - - .if \ret - movq %r8, TDX_HYPERCALL_r8(%rax) - movq %r9, TDX_HYPERCALL_r9(%rax) - movq %r10, TDX_HYPERCALL_r10(%rax) - movq %r11, TDX_HYPERCALL_r11(%rax) - movq %r12, TDX_HYPERCALL_r12(%rax) - movq %r13, TDX_HYPERCALL_r13(%rax) - movq %r14, TDX_HYPERCALL_r14(%rax) - movq %r15, TDX_HYPERCALL_r15(%rax) - movq %rdi, TDX_HYPERCALL_rdi(%rax) - movq %rsi, TDX_HYPERCALL_rsi(%rax) - movq %rbx, TDX_HYPERCALL_rbx(%rax) - movq %rdx, TDX_HYPERCALL_rdx(%rax) - .endif - - /* TDVMCALL leaf return code is in R10 */ - movq %r10, %rax - - /* - * Zero out registers exposed to the VMM to avoid speculative execution - * with VMM-controlled values. This needs to include all registers - * present in TDVMCALL_EXPOSE_REGS_MASK, except RBX, and R12-R15 which - * will be restored. - */ - xor %r8d, %r8d - xor %r9d, %r9d - xor %r10d, %r10d - xor %r11d, %r11d - xor %rdi, %rdi - xor %rdx, %rdx - - /* Restore callee-saved GPRs as mandated by the x86_64 ABI */ - pop %rbx - pop %r12 - pop %r13 - pop %r14 - pop %r15 - - FRAME_END - - RET -.Lpanic\@: - call __tdx_hypercall_failed - /* __tdx_hypercall_failed never returns */ - REACHABLE - jmp .Lpanic\@ -.endm +SYM_FUNC_START(__tdcall_ret) + TDX_MODULE_CALL host=0 ret=1 +SYM_FUNC_END(__tdcall_ret) /* + * __tdcall_saved_ret() - Used by TDX guests to request services from the + * TDX module (including VMM services) using TDCALL instruction, with + * saving output registers to the 'struct tdx_module_args' used as input. * - * __tdx_hypercall() function ABI: - * - * @args (RDI) - struct tdx_hypercall_args for input - * - * On successful completion, return the hypercall error code. - */ -SYM_FUNC_START(__tdx_hypercall) - TDX_HYPERCALL ret=0 -SYM_FUNC_END(__tdx_hypercall) - -/* + * __tdcall_saved_ret() function ABI: * - * __tdx_hypercall_ret() function ABI: + * @fn (RDI) - TDCALL leaf ID, moved to RAX + * @args (RSI) - struct tdx_module_args for input/output * - * @args (RDI) - struct tdx_hypercall_args for input and output + * All registers in @args are used as input/output registers. * * On successful completion, return the hypercall error code. */ -SYM_FUNC_START(__tdx_hypercall_ret) - TDX_HYPERCALL ret=1 -SYM_FUNC_END(__tdx_hypercall_ret) +SYM_FUNC_START(__tdcall_saved_ret) + TDX_MODULE_CALL host=0 ret=1 saved=1 +SYM_FUNC_END(__tdcall_saved_ret) diff --git a/arch/x86/coco/tdx/tdx-shared.c b/arch/x86/coco/tdx/tdx-shared.c index ef20ddc37b58..78e413269791 100644 --- a/arch/x86/coco/tdx/tdx-shared.c +++ b/arch/x86/coco/tdx/tdx-shared.c @@ -5,7 +5,7 @@ static unsigned long try_accept_one(phys_addr_t start, unsigned long len, enum pg_level pg_level) { unsigned long accept_size = page_level_size(pg_level); - u64 tdcall_rcx; + struct tdx_module_args args = {}; u8 page_size; if (!IS_ALIGNED(start, accept_size)) @@ -34,8 +34,8 @@ static unsigned long try_accept_one(phys_addr_t start, unsigned long len, return 0; } - tdcall_rcx = start | page_size; - if (__tdx_module_call(TDX_ACCEPT_PAGE, tdcall_rcx, 0, 0, 0, NULL)) + args.rcx = start | page_size; + if (__tdcall(TDG_MEM_PAGE_ACCEPT, &args)) return 0; return accept_size; @@ -45,7 +45,7 @@ bool tdx_accept_memory(phys_addr_t start, phys_addr_t end) { /* * For shared->private conversion, accept the page using - * TDX_ACCEPT_PAGE TDX module call. + * TDG_MEM_PAGE_ACCEPT TDX module call. */ while (start < end) { unsigned long len = end - start; @@ -69,3 +69,23 @@ bool tdx_accept_memory(phys_addr_t start, phys_addr_t end) return true; } + +noinstr u64 __tdx_hypercall(struct tdx_module_args *args) +{ + /* + * For TDVMCALL explicitly set RCX to the bitmap of shared registers. + * The caller isn't expected to set @args->rcx anyway. + */ + args->rcx = TDVMCALL_EXPOSE_REGS_MASK; + + /* + * Failure of __tdcall_saved_ret() indicates a failure of the TDVMCALL + * mechanism itself and that something has gone horribly wrong with + * the TDX module. __tdx_hypercall_failed() never returns. + */ + if (__tdcall_saved_ret(TDG_VP_VMCALL, args)) + __tdx_hypercall_failed(); + + /* TDVMCALL leaf return code is in R10 */ + return args->r10; +} diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c index 2e1be592c220..d11206ceff3b 100644 --- a/arch/x86/coco/tdx/tdx.c +++ b/arch/x86/coco/tdx/tdx.c @@ -38,7 +38,7 @@ #define TDREPORT_SUBTYPE_0 0 /* Called from __tdx_hypercall() for unrecoverable failure */ -noinstr void __tdx_hypercall_failed(void) +noinstr void __noreturn __tdx_hypercall_failed(void) { instrumentation_begin(); panic("TDVMCALL failed. TDX module bug?"); @@ -48,7 +48,7 @@ noinstr void __tdx_hypercall_failed(void) long tdx_kvm_hypercall(unsigned int nr, unsigned long p1, unsigned long p2, unsigned long p3, unsigned long p4) { - struct tdx_hypercall_args args = { + struct tdx_module_args args = { .r10 = nr, .r11 = p1, .r12 = p2, @@ -66,10 +66,9 @@ EXPORT_SYMBOL_GPL(tdx_kvm_hypercall); * should only be used for calls that have no legitimate reason to fail * or where the kernel can not survive the call failing. */ -static inline void tdx_module_call(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r9, - struct tdx_module_output *out) +static inline void tdcall(u64 fn, struct tdx_module_args *args) { - if (__tdx_module_call(fn, rcx, rdx, r8, r9, out)) + if (__tdcall_ret(fn, args)) panic("TDCALL %lld failed (Buggy TDX module!)\n", fn); } @@ -89,11 +88,14 @@ static inline void tdx_module_call(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r9, */ int tdx_mcall_get_report0(u8 *reportdata, u8 *tdreport) { + struct tdx_module_args args = { + .rcx = virt_to_phys(tdreport), + .rdx = virt_to_phys(reportdata), + .r8 = TDREPORT_SUBTYPE_0, + }; u64 ret; - ret = __tdx_module_call(TDX_GET_REPORT, virt_to_phys(tdreport), - virt_to_phys(reportdata), TDREPORT_SUBTYPE_0, - 0, NULL); + ret = __tdcall(TDG_MR_REPORT, &args); if (ret) { if (TDCALL_RETURN_CODE(ret) == TDCALL_INVALID_OPERAND) return -EINVAL; @@ -106,7 +108,7 @@ EXPORT_SYMBOL_GPL(tdx_mcall_get_report0); static void __noreturn tdx_panic(const char *msg) { - struct tdx_hypercall_args args = { + struct tdx_module_args args = { .r10 = TDX_HYPERCALL_STANDARD, .r11 = TDVMCALL_REPORT_FATAL_ERROR, .r12 = 0, /* Error code: 0 is Panic */ @@ -141,7 +143,7 @@ static void __noreturn tdx_panic(const char *msg) static void tdx_parse_tdinfo(u64 *cc_mask) { - struct tdx_module_output out; + struct tdx_module_args args = {}; unsigned int gpa_width; u64 td_attr; @@ -152,7 +154,7 @@ static void tdx_parse_tdinfo(u64 *cc_mask) * Guest-Host-Communication Interface (GHCI), section 2.4.2 TDCALL * [TDG.VP.INFO]. */ - tdx_module_call(TDX_GET_INFO, 0, 0, 0, 0, &out); + tdcall(TDG_VP_INFO, &args); /* * The highest bit of a guest physical address is the "sharing" bit. @@ -161,7 +163,7 @@ static void tdx_parse_tdinfo(u64 *cc_mask) * The GPA width that comes out of this call is critical. TDX guests * can not meaningfully run without it. */ - gpa_width = out.rcx & GENMASK(5, 0); + gpa_width = args.rcx & GENMASK(5, 0); *cc_mask = BIT_ULL(gpa_width - 1); /* @@ -169,7 +171,7 @@ static void tdx_parse_tdinfo(u64 *cc_mask) * memory. Ensure that no #VE will be delivered for accesses to * TD-private memory. Only VMM-shared memory (MMIO) will #VE. */ - td_attr = out.rdx; + td_attr = args.rdx; if (!(td_attr & ATTR_SEPT_VE_DISABLE)) { const char *msg = "TD misconfiguration: SEPT_VE_DISABLE attribute must be set."; @@ -228,7 +230,7 @@ static int ve_instr_len(struct ve_info *ve) static u64 __cpuidle __halt(const bool irq_disabled) { - struct tdx_hypercall_args args = { + struct tdx_module_args args = { .r10 = TDX_HYPERCALL_STANDARD, .r11 = hcall_func(EXIT_REASON_HLT), .r12 = irq_disabled, @@ -272,7 +274,7 @@ void __cpuidle tdx_safe_halt(void) static int read_msr(struct pt_regs *regs, struct ve_info *ve) { - struct tdx_hypercall_args args = { + struct tdx_module_args args = { .r10 = TDX_HYPERCALL_STANDARD, .r11 = hcall_func(EXIT_REASON_MSR_READ), .r12 = regs->cx, @@ -283,7 +285,7 @@ static int read_msr(struct pt_regs *regs, struct ve_info *ve) * can be found in TDX Guest-Host-Communication Interface * (GHCI), section titled "TDG.VP.VMCALL<Instruction.RDMSR>". */ - if (__tdx_hypercall_ret(&args)) + if (__tdx_hypercall(&args)) return -EIO; regs->ax = lower_32_bits(args.r11); @@ -293,7 +295,7 @@ static int read_msr(struct pt_regs *regs, struct ve_info *ve) static int write_msr(struct pt_regs *regs, struct ve_info *ve) { - struct tdx_hypercall_args args = { + struct tdx_module_args args = { .r10 = TDX_HYPERCALL_STANDARD, .r11 = hcall_func(EXIT_REASON_MSR_WRITE), .r12 = regs->cx, @@ -313,7 +315,7 @@ static int write_msr(struct pt_regs *regs, struct ve_info *ve) static int handle_cpuid(struct pt_regs *regs, struct ve_info *ve) { - struct tdx_hypercall_args args = { + struct tdx_module_args args = { .r10 = TDX_HYPERCALL_STANDARD, .r11 = hcall_func(EXIT_REASON_CPUID), .r12 = regs->ax, @@ -337,7 +339,7 @@ static int handle_cpuid(struct pt_regs *regs, struct ve_info *ve) * ABI can be found in TDX Guest-Host-Communication Interface * (GHCI), section titled "VP.VMCALL<Instruction.CPUID>". */ - if (__tdx_hypercall_ret(&args)) + if (__tdx_hypercall(&args)) return -EIO; /* @@ -355,7 +357,7 @@ static int handle_cpuid(struct pt_regs *regs, struct ve_info *ve) static bool mmio_read(int size, unsigned long addr, unsigned long *val) { - struct tdx_hypercall_args args = { + struct tdx_module_args args = { .r10 = TDX_HYPERCALL_STANDARD, .r11 = hcall_func(EXIT_REASON_EPT_VIOLATION), .r12 = size, @@ -364,8 +366,9 @@ static bool mmio_read(int size, unsigned long addr, unsigned long *val) .r15 = *val, }; - if (__tdx_hypercall_ret(&args)) + if (__tdx_hypercall(&args)) return false; + *val = args.r11; return true; } @@ -483,7 +486,7 @@ static int handle_mmio(struct pt_regs *regs, struct ve_info *ve) static bool handle_in(struct pt_regs *regs, int size, int port) { - struct tdx_hypercall_args args = { + struct tdx_module_args args = { .r10 = TDX_HYPERCALL_STANDARD, .r11 = hcall_func(EXIT_REASON_IO_INSTRUCTION), .r12 = size, @@ -498,7 +501,7 @@ static bool handle_in(struct pt_regs *regs, int size, int port) * in TDX Guest-Host-Communication Interface (GHCI) section titled * "TDG.VP.VMCALL<Instruction.IO>". */ - success = !__tdx_hypercall_ret(&args); + success = !__tdx_hypercall(&args); /* Update part of the register affected by the emulated instruction */ regs->ax &= ~mask; @@ -577,7 +580,7 @@ __init bool tdx_early_handle_ve(struct pt_regs *regs) void tdx_get_ve_info(struct ve_info *ve) { - struct tdx_module_output out; + struct tdx_module_args args = {}; /* * Called during #VE handling to retrieve the #VE info from the @@ -594,15 +597,15 @@ void tdx_get_ve_info(struct ve_info *ve) * Note, the TDX module treats virtual NMIs as inhibited if the #VE * valid flag is set. It means that NMI=>#VE will not result in a #DF. */ - tdx_module_call(TDX_GET_VEINFO, 0, 0, 0, 0, &out); + tdcall(TDG_VP_VEINFO_GET, &args); /* Transfer the output parameters */ - ve->exit_reason = out.rcx; - ve->exit_qual = out.rdx; - ve->gla = out.r8; - ve->gpa = out.r9; - ve->instr_len = lower_32_bits(out.r10); - ve->instr_info = upper_32_bits(out.r10); + ve->exit_reason = args.rcx; + ve->exit_qual = args.rdx; + ve->gla = args.r8; + ve->gpa = args.r9; + ve->instr_len = lower_32_bits(args.r10); + ve->instr_info = upper_32_bits(args.r10); } /* @@ -703,14 +706,15 @@ static bool tdx_cache_flush_required(void) } /* - * Inform the VMM of the guest's intent for this physical page: shared with - * the VMM or private to the guest. The VMM is expected to change its mapping - * of the page in response. + * Notify the VMM about page mapping conversion. More info about ABI + * can be found in TDX Guest-Host-Communication Interface (GHCI), + * section "TDG.VP.VMCALL<MapGPA>". */ -static bool tdx_enc_status_changed(unsigned long vaddr, int numpages, bool enc) +static bool tdx_map_gpa(phys_addr_t start, phys_addr_t end, bool enc) { - phys_addr_t start = __pa(vaddr); - phys_addr_t end = __pa(vaddr + numpages * PAGE_SIZE); + /* Retrying the hypercall a second time should succeed; use 3 just in case */ + const int max_retries_per_page = 3; + int retry_count = 0; if (!enc) { /* Set the shared (decrypted) bits: */ @@ -718,12 +722,51 @@ static bool tdx_enc_status_changed(unsigned long vaddr, int numpages, bool enc) end |= cc_mkdec(0); } - /* - * Notify the VMM about page mapping conversion. More info about ABI - * can be found in TDX Guest-Host-Communication Interface (GHCI), - * section "TDG.VP.VMCALL<MapGPA>" - */ - if (_tdx_hypercall(TDVMCALL_MAP_GPA, start, end - start, 0, 0)) + while (retry_count < max_retries_per_page) { + struct tdx_module_args args = { + .r10 = TDX_HYPERCALL_STANDARD, + .r11 = TDVMCALL_MAP_GPA, + .r12 = start, + .r13 = end - start }; + + u64 map_fail_paddr; + u64 ret = __tdx_hypercall(&args); + + if (ret != TDVMCALL_STATUS_RETRY) + return !ret; + /* + * The guest must retry the operation for the pages in the + * region starting at the GPA specified in R11. R11 comes + * from the untrusted VMM. Sanity check it. + */ + map_fail_paddr = args.r11; + if (map_fail_paddr < start || map_fail_paddr >= end) + return false; + + /* "Consume" a retry without forward progress */ + if (map_fail_paddr == start) { + retry_count++; + continue; + } + + start = map_fail_paddr; + retry_count = 0; + } + + return false; +} + +/* + * Inform the VMM of the guest's intent for this physical page: shared with + * the VMM or private to the guest. The VMM is expected to change its mapping + * of the page in response. + */ +static bool tdx_enc_status_changed(unsigned long vaddr, int numpages, bool enc) +{ + phys_addr_t start = __pa(vaddr); + phys_addr_t end = __pa(vaddr + numpages * PAGE_SIZE); + + if (!tdx_map_gpa(start, end, enc)) return false; /* shared->private conversion requires memory to be accepted before use */ @@ -759,6 +802,10 @@ static bool tdx_enc_status_change_finish(unsigned long vaddr, int numpages, void __init tdx_early_init(void) { + struct tdx_module_args args = { + .rdx = TDCS_NOTIFY_ENABLES, + .r9 = -1ULL, + }; u64 cc_mask; u32 eax, sig[3]; @@ -769,12 +816,15 @@ void __init tdx_early_init(void) setup_force_cpu_cap(X86_FEATURE_TDX_GUEST); + /* TSC is the only reliable clock in TDX guest */ + setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE); + cc_vendor = CC_VENDOR_INTEL; tdx_parse_tdinfo(&cc_mask); cc_set_mask(cc_mask); /* Kernel does not use NOTIFY_ENABLES and does not need random #VEs */ - tdx_module_call(TDX_WR, 0, TDCS_NOTIFY_ENABLES, 0, -1ULL, NULL); + tdcall(TDG_VM_WR, &args); /* * All bits above GPA width are reserved and kernel treats shared bit diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c index c6edde1a1dec..02e55237d919 100644 --- a/arch/x86/hyperv/ivm.c +++ b/arch/x86/hyperv/ivm.c @@ -384,7 +384,7 @@ static inline void hv_ghcb_msr_read(u64 msr, u64 *value) {} #ifdef CONFIG_INTEL_TDX_GUEST static void hv_tdx_msr_write(u64 msr, u64 val) { - struct tdx_hypercall_args args = { + struct tdx_module_args args = { .r10 = TDX_HYPERCALL_STANDARD, .r11 = EXIT_REASON_MSR_WRITE, .r12 = msr, @@ -398,13 +398,13 @@ static void hv_tdx_msr_write(u64 msr, u64 val) static void hv_tdx_msr_read(u64 msr, u64 *val) { - struct tdx_hypercall_args args = { + struct tdx_module_args args = { .r10 = TDX_HYPERCALL_STANDARD, .r11 = EXIT_REASON_MSR_READ, .r12 = msr, }; - u64 ret = __tdx_hypercall_ret(&args); + u64 ret = __tdx_hypercall(&args); if (WARN_ONCE(ret, "Failed to emulate MSR read: %lld\n", ret)) *val = 0; @@ -414,13 +414,13 @@ static void hv_tdx_msr_read(u64 msr, u64 *val) u64 hv_tdx_hypercall(u64 control, u64 param1, u64 param2) { - struct tdx_hypercall_args args = { }; + struct tdx_module_args args = { }; args.r10 = control; args.rdx = param1; args.r8 = param2; - (void)__tdx_hypercall_ret(&args); + (void)__tdx_hypercall(&args); return args.r11; } diff --git a/arch/x86/include/asm/shared/tdx.h b/arch/x86/include/asm/shared/tdx.h index 7513b3bb69b7..f74695dea217 100644 --- a/arch/x86/include/asm/shared/tdx.h +++ b/arch/x86/include/asm/shared/tdx.h @@ -11,11 +11,12 @@ #define TDX_IDENT "IntelTDX " /* TDX module Call Leaf IDs */ -#define TDX_GET_INFO 1 -#define TDX_GET_VEINFO 3 -#define TDX_GET_REPORT 4 -#define TDX_ACCEPT_PAGE 6 -#define TDX_WR 8 +#define TDG_VP_VMCALL 0 +#define TDG_VP_INFO 1 +#define TDG_VP_VEINFO_GET 3 +#define TDG_MR_REPORT 4 +#define TDG_MEM_PAGE_ACCEPT 6 +#define TDG_VM_WR 8 /* TDCS fields. To be used by TDG.VM.WR and TDG.VM.RD module calls */ #define TDCS_NOTIFY_ENABLES 0x9100000000000010 @@ -24,32 +25,70 @@ #define TDVMCALL_MAP_GPA 0x10001 #define TDVMCALL_REPORT_FATAL_ERROR 0x10003 +#define TDVMCALL_STATUS_RETRY 1 + +/* + * Bitmasks of exposed registers (with VMM). + */ +#define TDX_RDX BIT(2) +#define TDX_RBX BIT(3) +#define TDX_RSI BIT(6) +#define TDX_RDI BIT(7) +#define TDX_R8 BIT(8) +#define TDX_R9 BIT(9) +#define TDX_R10 BIT(10) +#define TDX_R11 BIT(11) +#define TDX_R12 BIT(12) +#define TDX_R13 BIT(13) +#define TDX_R14 BIT(14) +#define TDX_R15 BIT(15) + +/* + * These registers are clobbered to hold arguments for each + * TDVMCALL. They are safe to expose to the VMM. + * Each bit in this mask represents a register ID. Bit field + * details can be found in TDX GHCI specification, section + * titled "TDCALL [TDG.VP.VMCALL] leaf". + */ +#define TDVMCALL_EXPOSE_REGS_MASK \ + (TDX_RDX | TDX_RBX | TDX_RSI | TDX_RDI | TDX_R8 | TDX_R9 | \ + TDX_R10 | TDX_R11 | TDX_R12 | TDX_R13 | TDX_R14 | TDX_R15) + #ifndef __ASSEMBLY__ +#include <linux/compiler_attributes.h> + /* - * Used in __tdx_hypercall() to pass down and get back registers' values of - * the TDCALL instruction when requesting services from the VMM. - * - * This is a software only structure and not part of the TDX module/VMM ABI. + * Used in __tdcall*() to gather the input/output registers' values of the + * TDCALL instruction when requesting services from the TDX module. This is a + * software only structure and not part of the TDX module/VMM ABI */ -struct tdx_hypercall_args { +struct tdx_module_args { + /* callee-clobbered */ + u64 rcx; + u64 rdx; u64 r8; u64 r9; + /* extra callee-clobbered */ u64 r10; u64 r11; + /* callee-saved + rdi/rsi */ u64 r12; u64 r13; u64 r14; u64 r15; + u64 rbx; u64 rdi; u64 rsi; - u64 rbx; - u64 rdx; }; +/* Used to communicate with the TDX module */ +u64 __tdcall(u64 fn, struct tdx_module_args *args); +u64 __tdcall_ret(u64 fn, struct tdx_module_args *args); +u64 __tdcall_saved_ret(u64 fn, struct tdx_module_args *args); + /* Used to request services from the VMM */ -u64 __tdx_hypercall(struct tdx_hypercall_args *args); -u64 __tdx_hypercall_ret(struct tdx_hypercall_args *args); +u64 __tdx_hypercall(struct tdx_module_args *args); /* * Wrapper for standard use of __tdx_hypercall with no output aside from @@ -57,7 +96,7 @@ u64 __tdx_hypercall_ret(struct tdx_hypercall_args *args); */ static inline u64 _tdx_hypercall(u64 fn, u64 r12, u64 r13, u64 r14, u64 r15) { - struct tdx_hypercall_args args = { + struct tdx_module_args args = { .r10 = TDX_HYPERCALL_STANDARD, .r11 = fn, .r12 = r12, @@ -71,25 +110,7 @@ static inline u64 _tdx_hypercall(u64 fn, u64 r12, u64 r13, u64 r14, u64 r15) /* Called from __tdx_hypercall() for unrecoverable failure */ -void __tdx_hypercall_failed(void); - -/* - * Used in __tdx_module_call() to gather the output registers' values of the - * TDCALL instruction when requesting services from the TDX module. This is a - * software only structure and not part of the TDX module/VMM ABI - */ -struct tdx_module_output { - u64 rcx; - u64 rdx; - u64 r8; - u64 r9; - u64 r10; - u64 r11; -}; - -/* Used to communicate with the TDX module */ -u64 __tdx_module_call(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r9, - struct tdx_module_output *out); +void __noreturn __tdx_hypercall_failed(void); bool tdx_accept_memory(phys_addr_t start, phys_addr_t end); diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h index 603e6d1e9d4a..adcbe3f1de30 100644 --- a/arch/x86/include/asm/tdx.h +++ b/arch/x86/include/asm/tdx.h @@ -8,6 +8,7 @@ #include <asm/errno.h> #include <asm/ptrace.h> +#include <asm/trapnr.h> #include <asm/shared/tdx.h> /* @@ -20,6 +21,9 @@ #define TDX_SW_ERROR (TDX_ERROR | GENMASK_ULL(47, 40)) #define TDX_SEAMCALL_VMFAILINVALID (TDX_SW_ERROR | _UL(0xFFFF0000)) +#define TDX_SEAMCALL_GP (TDX_SW_ERROR | X86_TRAP_GP) +#define TDX_SEAMCALL_UD (TDX_SW_ERROR | X86_TRAP_UD) + #ifndef __ASSEMBLY__ /* @@ -72,5 +76,12 @@ static inline long tdx_kvm_hypercall(unsigned int nr, unsigned long p1, return -ENODEV; } #endif /* CONFIG_INTEL_TDX_GUEST && CONFIG_KVM_GUEST */ + +#ifdef CONFIG_INTEL_TDX_HOST +u64 __seamcall(u64 fn, struct tdx_module_args *args); +u64 __seamcall_ret(u64 fn, struct tdx_module_args *args); +u64 __seamcall_saved_ret(u64 fn, struct tdx_module_args *args); +#endif /* CONFIG_INTEL_TDX_HOST */ + #endif /* !__ASSEMBLY__ */ #endif /* _ASM_X86_TDX_H */ diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c index dc3576303f1a..6913b372ccf7 100644 --- a/arch/x86/kernel/asm-offsets.c +++ b/arch/x86/kernel/asm-offsets.c @@ -68,26 +68,19 @@ static void __used common(void) #endif BLANK(); - OFFSET(TDX_MODULE_rcx, tdx_module_output, rcx); - OFFSET(TDX_MODULE_rdx, tdx_module_output, rdx); - OFFSET(TDX_MODULE_r8, tdx_module_output, r8); - OFFSET(TDX_MODULE_r9, tdx_module_output, r9); - OFFSET(TDX_MODULE_r10, tdx_module_output, r10); - OFFSET(TDX_MODULE_r11, tdx_module_output, r11); - - BLANK(); - OFFSET(TDX_HYPERCALL_r8, tdx_hypercall_args, r8); - OFFSET(TDX_HYPERCALL_r9, tdx_hypercall_args, r9); - OFFSET(TDX_HYPERCALL_r10, tdx_hypercall_args, r10); - OFFSET(TDX_HYPERCALL_r11, tdx_hypercall_args, r11); - OFFSET(TDX_HYPERCALL_r12, tdx_hypercall_args, r12); - OFFSET(TDX_HYPERCALL_r13, tdx_hypercall_args, r13); - OFFSET(TDX_HYPERCALL_r14, tdx_hypercall_args, r14); - OFFSET(TDX_HYPERCALL_r15, tdx_hypercall_args, r15); - OFFSET(TDX_HYPERCALL_rdi, tdx_hypercall_args, rdi); - OFFSET(TDX_HYPERCALL_rsi, tdx_hypercall_args, rsi); - OFFSET(TDX_HYPERCALL_rbx, tdx_hypercall_args, rbx); - OFFSET(TDX_HYPERCALL_rdx, tdx_hypercall_args, rdx); + OFFSET(TDX_MODULE_rcx, tdx_module_args, rcx); + OFFSET(TDX_MODULE_rdx, tdx_module_args, rdx); + OFFSET(TDX_MODULE_r8, tdx_module_args, r8); + OFFSET(TDX_MODULE_r9, tdx_module_args, r9); + OFFSET(TDX_MODULE_r10, tdx_module_args, r10); + OFFSET(TDX_MODULE_r11, tdx_module_args, r11); + OFFSET(TDX_MODULE_r12, tdx_module_args, r12); + OFFSET(TDX_MODULE_r13, tdx_module_args, r13); + OFFSET(TDX_MODULE_r14, tdx_module_args, r14); + OFFSET(TDX_MODULE_r15, tdx_module_args, r15); + OFFSET(TDX_MODULE_rbx, tdx_module_args, rbx); + OFFSET(TDX_MODULE_rdi, tdx_module_args, rdi); + OFFSET(TDX_MODULE_rsi, tdx_module_args, rsi); BLANK(); OFFSET(BP_scratch, boot_params, scratch); diff --git a/arch/x86/virt/Makefile b/arch/x86/virt/Makefile new file mode 100644 index 000000000000..1e36502cd738 --- /dev/null +++ b/arch/x86/virt/Makefile @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +obj-y += vmx/ diff --git a/arch/x86/virt/vmx/Makefile b/arch/x86/virt/vmx/Makefile new file mode 100644 index 000000000000..feebda21d793 --- /dev/null +++ b/arch/x86/virt/vmx/Makefile @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +obj-$(CONFIG_INTEL_TDX_HOST) += tdx/ diff --git a/arch/x86/virt/vmx/tdx/Makefile b/arch/x86/virt/vmx/tdx/Makefile new file mode 100644 index 000000000000..46ef8f73aebb --- /dev/null +++ b/arch/x86/virt/vmx/tdx/Makefile @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +obj-y += seamcall.o diff --git a/arch/x86/virt/vmx/tdx/seamcall.S b/arch/x86/virt/vmx/tdx/seamcall.S new file mode 100644 index 000000000000..5b1f2286aea9 --- /dev/null +++ b/arch/x86/virt/vmx/tdx/seamcall.S @@ -0,0 +1,61 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#include <linux/linkage.h> +#include <asm/frame.h> + +#include "tdxcall.S" + +/* + * __seamcall() - Host-side interface functions to SEAM software + * (the P-SEAMLDR or the TDX module). + * + * __seamcall() function ABI: + * + * @fn (RDI) - SEAMCALL Leaf number, moved to RAX + * @args (RSI) - struct tdx_module_args for input + * + * Only RCX/RDX/R8-R11 are used as input registers. + * + * Return (via RAX) TDX_SEAMCALL_VMFAILINVALID if the SEAMCALL itself + * fails, or the completion status of the SEAMCALL leaf function. + */ +SYM_FUNC_START(__seamcall) + TDX_MODULE_CALL host=1 +SYM_FUNC_END(__seamcall) + +/* + * __seamcall_ret() - Host-side interface functions to SEAM software + * (the P-SEAMLDR or the TDX module), with saving output registers to + * the 'struct tdx_module_args' used as input. + * + * __seamcall_ret() function ABI: + * + * @fn (RDI) - SEAMCALL Leaf number, moved to RAX + * @args (RSI) - struct tdx_module_args for input and output + * + * Only RCX/RDX/R8-R11 are used as input/output registers. + * + * Return (via RAX) TDX_SEAMCALL_VMFAILINVALID if the SEAMCALL itself + * fails, or the completion status of the SEAMCALL leaf function. + */ +SYM_FUNC_START(__seamcall_ret) + TDX_MODULE_CALL host=1 ret=1 +SYM_FUNC_END(__seamcall_ret) + +/* + * __seamcall_saved_ret() - Host-side interface functions to SEAM software + * (the P-SEAMLDR or the TDX module), with saving output registers to the + * 'struct tdx_module_args' used as input. + * + * __seamcall_saved_ret() function ABI: + * + * @fn (RDI) - SEAMCALL Leaf number, moved to RAX + * @args (RSI) - struct tdx_module_args for input and output + * + * All registers in @args are used as input/output registers. + * + * Return (via RAX) TDX_SEAMCALL_VMFAILINVALID if the SEAMCALL itself + * fails, or the completion status of the SEAMCALL leaf function. + */ +SYM_FUNC_START(__seamcall_saved_ret) + TDX_MODULE_CALL host=1 ret=1 saved=1 +SYM_FUNC_END(__seamcall_saved_ret) diff --git a/arch/x86/virt/vmx/tdx/tdxcall.S b/arch/x86/virt/vmx/tdx/tdxcall.S index 49a54356ae99..016a2a1ec1d6 100644 --- a/arch/x86/virt/vmx/tdx/tdxcall.S +++ b/arch/x86/virt/vmx/tdx/tdxcall.S @@ -1,5 +1,7 @@ /* SPDX-License-Identifier: GPL-2.0 */ #include <asm/asm-offsets.h> +#include <asm/frame.h> +#include <asm/asm.h> #include <asm/tdx.h> /* @@ -16,35 +18,75 @@ * TDX module and hypercalls to the VMM. * SEAMCALL - used by TDX hosts to make requests to the * TDX module. + * + *------------------------------------------------------------------------- + * TDCALL/SEAMCALL ABI: + *------------------------------------------------------------------------- + * Input Registers: + * + * RAX - TDCALL/SEAMCALL Leaf number. + * RCX,RDX,RDI,RSI,RBX,R8-R15 - TDCALL/SEAMCALL Leaf specific input registers. + * + * Output Registers: + * + * RAX - TDCALL/SEAMCALL instruction error code. + * RCX,RDX,RDI,RSI,RBX,R8-R15 - TDCALL/SEAMCALL Leaf specific output registers. + * + *------------------------------------------------------------------------- + * + * So while the common core (RAX,RCX,RDX,R8-R11) fits nicely in the + * callee-clobbered registers and even leaves RDI,RSI free to act as a + * base pointer, some leafs (e.g., VP.ENTER) make a giant mess of things. + * + * For simplicity, assume that anything that needs the callee-saved regs + * also tramples on RDI,RSI. This isn't strictly true, see for example + * TDH.EXPORT.MEM. */ -.macro TDX_MODULE_CALL host:req - /* - * R12 will be used as temporary storage for struct tdx_module_output - * pointer. Since R12-R15 registers are not used by TDCALL/SEAMCALL - * services supported by this function, it can be reused. - */ +.macro TDX_MODULE_CALL host:req ret=0 saved=0 + FRAME_BEGIN - /* Callee saved, so preserve it */ - push %r12 + /* Move Leaf ID to RAX */ + mov %rdi, %rax + + /* Move other input regs from 'struct tdx_module_args' */ + movq TDX_MODULE_rcx(%rsi), %rcx + movq TDX_MODULE_rdx(%rsi), %rdx + movq TDX_MODULE_r8(%rsi), %r8 + movq TDX_MODULE_r9(%rsi), %r9 + movq TDX_MODULE_r10(%rsi), %r10 + movq TDX_MODULE_r11(%rsi), %r11 +.if \saved /* - * Push output pointer to stack. - * After the operation, it will be fetched into R12 register. + * Move additional input regs from the structure. For simplicity + * assume that anything needs the callee-saved regs also tramples + * on RDI/RSI (see VP.ENTER). */ - push %r9 + /* Save those callee-saved GPRs as mandated by the x86_64 ABI */ + pushq %rbx + pushq %r12 + pushq %r13 + pushq %r14 + pushq %r15 - /* Mangle function call ABI into TDCALL/SEAMCALL ABI: */ - /* Move Leaf ID to RAX */ - mov %rdi, %rax - /* Move input 4 to R9 */ - mov %r8, %r9 - /* Move input 3 to R8 */ - mov %rcx, %r8 - /* Move input 1 to RCX */ - mov %rsi, %rcx - /* Leave input param 2 in RDX */ - - .if \host + movq TDX_MODULE_r12(%rsi), %r12 + movq TDX_MODULE_r13(%rsi), %r13 + movq TDX_MODULE_r14(%rsi), %r14 + movq TDX_MODULE_r15(%rsi), %r15 + movq TDX_MODULE_rbx(%rsi), %rbx + +.if \ret + /* Save the structure pointer as RSI is about to be clobbered */ + pushq %rsi +.endif + + movq TDX_MODULE_rdi(%rsi), %rdi + /* RSI needs to be done at last */ + movq TDX_MODULE_rsi(%rsi), %rsi +.endif /* \saved */ + +.if \host +.Lseamcall\@: seamcall /* * SEAMCALL instruction is essentially a VMExit from VMX root @@ -57,40 +99,122 @@ * This value will never be used as actual SEAMCALL error code as * it is from the Reserved status code class. */ - jnc .Lno_vmfailinvalid - mov $TDX_SEAMCALL_VMFAILINVALID, %rax -.Lno_vmfailinvalid: - - .else + jc .Lseamcall_vmfailinvalid\@ +.else tdcall - .endif +.endif +.if \ret +.if \saved /* - * Fetch output pointer from stack to R12 (It is used - * as temporary storage) + * Restore the structure from stack to save the output registers + * + * In case of VP.ENTER returns due to TDVMCALL, all registers are + * valid thus no register can be used as spare to restore the + * structure from the stack (see "TDH.VP.ENTER Output Operands + * Definition on TDCALL(TDG.VP.VMCALL) Following a TD Entry"). + * For this case, need to make one register as spare by saving it + * to the stack and then manually load the structure pointer to + * the spare register. + * + * Note for other TDCALLs/SEAMCALLs there are spare registers + * thus no need for such hack but just use this for all. */ - pop %r12 + pushq %rax /* save the TDCALL/SEAMCALL return code */ + movq 8(%rsp), %rax /* restore the structure pointer */ + movq %rsi, TDX_MODULE_rsi(%rax) /* save RSI */ + popq %rax /* restore the return code */ + popq %rsi /* pop the structure pointer */ + + /* Copy additional output regs to the structure */ + movq %r12, TDX_MODULE_r12(%rsi) + movq %r13, TDX_MODULE_r13(%rsi) + movq %r14, TDX_MODULE_r14(%rsi) + movq %r15, TDX_MODULE_r15(%rsi) + movq %rbx, TDX_MODULE_rbx(%rsi) + movq %rdi, TDX_MODULE_rdi(%rsi) +.endif /* \saved */ + /* Copy output registers to the structure */ + movq %rcx, TDX_MODULE_rcx(%rsi) + movq %rdx, TDX_MODULE_rdx(%rsi) + movq %r8, TDX_MODULE_r8(%rsi) + movq %r9, TDX_MODULE_r9(%rsi) + movq %r10, TDX_MODULE_r10(%rsi) + movq %r11, TDX_MODULE_r11(%rsi) +.endif /* \ret */ + +.if \saved && \ret /* - * Since this macro can be invoked with NULL as an output pointer, - * check if caller provided an output struct before storing output - * registers. + * Clear registers shared by guest for VP.VMCALL/VP.ENTER to prevent + * speculative use of guest's/VMM's values, including those are + * restored from the stack. + * + * See arch/x86/kvm/vmx/vmenter.S: * - * Update output registers, even if the call failed (RAX != 0). - * Other registers may contain details of the failure. + * In theory, a L1 cache miss when restoring register from stack + * could lead to speculative execution with guest's values. + * + * Note: RBP/RSP are not used as shared register. RSI has been + * restored already. + * + * XOR is cheap, thus unconditionally do for all leafs. */ - test %r12, %r12 - jz .Lno_output_struct - - /* Copy result registers to output struct: */ - movq %rcx, TDX_MODULE_rcx(%r12) - movq %rdx, TDX_MODULE_rdx(%r12) - movq %r8, TDX_MODULE_r8(%r12) - movq %r9, TDX_MODULE_r9(%r12) - movq %r10, TDX_MODULE_r10(%r12) - movq %r11, TDX_MODULE_r11(%r12) - -.Lno_output_struct: - /* Restore the state of R12 register */ - pop %r12 + xorl %ecx, %ecx + xorl %edx, %edx + xorl %r8d, %r8d + xorl %r9d, %r9d + xorl %r10d, %r10d + xorl %r11d, %r11d + xorl %r12d, %r12d + xorl %r13d, %r13d + xorl %r14d, %r14d + xorl %r15d, %r15d + xorl %ebx, %ebx + xorl %edi, %edi +.endif /* \ret && \host */ + +.if \host +.Lout\@: +.endif + +.if \saved + /* Restore callee-saved GPRs as mandated by the x86_64 ABI */ + popq %r15 + popq %r14 + popq %r13 + popq %r12 + popq %rbx +.endif /* \saved */ + + FRAME_END + RET + +.if \host +.Lseamcall_vmfailinvalid\@: + mov $TDX_SEAMCALL_VMFAILINVALID, %rax + jmp .Lseamcall_fail\@ + +.Lseamcall_trap\@: + /* + * SEAMCALL caused #GP or #UD. By reaching here RAX contains + * the trap number. Convert the trap number to the TDX error + * code by setting TDX_SW_ERROR to the high 32-bits of RAX. + * + * Note cannot OR TDX_SW_ERROR directly to RAX as OR instruction + * only accepts 32-bit immediate at most. + */ + movq $TDX_SW_ERROR, %rdi + orq %rdi, %rax + +.Lseamcall_fail\@: +.if \ret && \saved + /* pop the unused structure pointer back to RSI */ + popq %rsi +.endif + jmp .Lout\@ + + _ASM_EXTABLE_FAULT(.Lseamcall\@, .Lseamcall_trap\@) +.endif /* \host */ + .endm diff --git a/tools/objtool/noreturns.h b/tools/objtool/noreturns.h index e92f67383dde..649ebdef9c3f 100644 --- a/tools/objtool/noreturns.h +++ b/tools/objtool/noreturns.h @@ -11,6 +11,7 @@ NORETURN(__kunit_abort) NORETURN(__module_put_and_kthread_exit) NORETURN(__reiserfs_panic) NORETURN(__stack_chk_fail) +NORETURN(__tdx_hypercall_failed) NORETURN(__ubsan_handle_builtin_unreachable) NORETURN(arch_call_rest_init) NORETURN(arch_cpu_idle_dead) |