diff options
Diffstat (limited to 'arch/x86/coco/tdx/tdx.c')
| -rw-r--r-- | arch/x86/coco/tdx/tdx.c | 161 |
1 files changed, 116 insertions, 45 deletions
diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c index f3c75809fe..cf1f13c821 100644 --- a/arch/x86/coco/tdx/tdx.c +++ b/arch/x86/coco/tdx/tdx.c @@ -39,7 +39,7 @@ #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?"); @@ -49,7 +49,7 @@ 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, @@ -67,10 +67,9 @@ 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); } @@ -90,11 +89,14 @@ 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; @@ -105,9 +107,30 @@ int tdx_mcall_get_report0(u8 *reportdata, u8 *tdreport) } EXPORT_SYMBOL_GPL(tdx_mcall_get_report0); +/** + * tdx_hcall_get_quote() - Wrapper to request TD Quote using GetQuote + * hypercall. + * @buf: Address of the directly mapped shared kernel buffer which + * contains TDREPORT. The same buffer will be used by VMM to + * store the generated TD Quote output. + * @size: size of the tdquote buffer (4KB-aligned). + * + * Refer to section titled "TDG.VP.VMCALL<GetQuote>" in the TDX GHCI + * v1.0 specification for more information on GetQuote hypercall. + * It is used in the TDX guest driver module to get the TD Quote. + * + * Return 0 on success or error code on failure. + */ +u64 tdx_hcall_get_quote(u8 *buf, size_t size) +{ + /* Since buf is a shared memory, set the shared (decrypted) bits */ + return _tdx_hypercall(TDVMCALL_GET_QUOTE, cc_mkdec(virt_to_phys(buf)), size, 0, 0); +} +EXPORT_SYMBOL_GPL(tdx_hcall_get_quote); + 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 */ @@ -120,7 +143,7 @@ static void __noreturn tdx_panic(const char *msg) } message; /* VMM assumes '\0' in byte 65, if the message took all 64 bytes */ - strncpy(message.str, msg, 64); + strtomem_pad(message.str, msg, '\0'); args.r8 = message.r8; args.r9 = message.r9; @@ -142,7 +165,7 @@ 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; @@ -153,7 +176,7 @@ 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. @@ -162,7 +185,7 @@ 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); /* @@ -170,7 +193,7 @@ 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."; @@ -229,7 +252,7 @@ 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, @@ -273,7 +296,7 @@ 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, @@ -284,7 +307,7 @@ 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); @@ -294,7 +317,7 @@ 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, @@ -314,7 +337,7 @@ 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, @@ -338,7 +361,7 @@ 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; /* @@ -356,7 +379,7 @@ 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, @@ -365,8 +388,9 @@ 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; } @@ -484,7 +508,7 @@ 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, @@ -499,7 +523,7 @@ 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; @@ -578,7 +602,7 @@ __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 @@ -595,15 +619,15 @@ 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); } /* @@ -704,14 +728,15 @@ 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: */ @@ -719,12 +744,51 @@ 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 */ @@ -760,6 +824,10 @@ 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]; @@ -770,12 +838,15 @@ 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 |