6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Kai Huang kai.huang@intel.com
[ Upstream commit 57a420bb8186d1d0178b857e5dd5026093641654 ]
Currently, the TDX_MODULE_CALL asm macro, which handles both TDCALL and SEAMCALL, takes one parameter for each input register and an optional 'struct tdx_module_output' (a collection of output registers) as output. This is different from the TDX_HYPERCALL macro which uses a single 'struct tdx_hypercall_args' to carry all input/output registers.
The newer TDX versions introduce more TDCALLs/SEAMCALLs which use more input/output registers. Also, the TDH.VP.ENTER (which isn't covered by the current TDX_MODULE_CALL macro) basically can use all registers that the TDX_HYPERCALL does. The current TDX_MODULE_CALL macro isn't extendible to cover those cases.
Similar to the TDX_HYPERCALL macro, simplify the TDX_MODULE_CALL macro to use a single structure 'struct tdx_module_args' to carry all the input/output registers. Currently, R10/R11 are only used as output register but not as input by any TDCALL/SEAMCALL. Change to also use R10/R11 as input register to make input/output registers symmetric.
Currently, the TDX_MODULE_CALL macro depends on the caller to pass a non-NULL 'struct tdx_module_output' to get additional output registers. Similar to the TDX_HYPERCALL macro, change the TDX_MODULE_CALL macro to take a new 'ret' macro argument to indicate whether to save the output registers to the 'struct tdx_module_args'. Also introduce a new __tdcall_ret() for that purpose, similar to the __tdx_hypercall_ret().
Note the tdcall(), which is a wrapper of __tdcall(), is called by three callers: tdx_parse_tdinfo(), tdx_get_ve_info() and tdx_early_init(). The former two need the additional output but the last one doesn't. For simplicity, make tdcall() always call __tdcall_ret() to avoid another "_ret()" wrapper. The last caller tdx_early_init() isn't performance critical anyway.
Suggested-by: Peter Zijlstra peterz@infradead.org Signed-off-by: Kai Huang kai.huang@intel.com Signed-off-by: Dave Hansen dave.hansen@linux.intel.com Reviewed-by: Kirill A. Shutemov kirill.shutemov@linux.intel.com Acked-by: Peter Zijlstra (Intel) peterz@infradead.org Link: https://lore.kernel.org/all/483616c1762d85eb3a3c3035a7de061cfacf2f14.1692096... Stable-dep-of: f65aa0ad79fc ("x86/tdx: Dynamically disable SEPT violations from causing #VEs") Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/coco/tdx/tdcall.S | 47 ++++++--------- arch/x86/coco/tdx/tdx-shared.c | 6 +- arch/x86/coco/tdx/tdx.c | 44 +++++++------- arch/x86/include/asm/shared/tdx.h | 8 +-- arch/x86/kernel/asm-offsets.c | 12 ++-- arch/x86/virt/vmx/tdx/tdxcall.S | 95 +++++++++++++------------------ 6 files changed, 95 insertions(+), 117 deletions(-)
diff --git a/arch/x86/coco/tdx/tdcall.S b/arch/x86/coco/tdx/tdcall.S index 6aebac08f2bfe..56b9cd32895e4 100644 --- a/arch/x86/coco/tdx/tdcall.S +++ b/arch/x86/coco/tdx/tdcall.S @@ -43,37 +43,10 @@ * __tdcall() - 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: - * - * 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 - * @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. + * @fn (RDI) - TDCALL Leaf ID, moved to RAX + * @args (RSI) - struct tdx_module_args for input * * Return status of TDCALL via RAX. */ @@ -81,6 +54,22 @@ SYM_FUNC_START(__tdcall) TDX_MODULE_CALL host=0 SYM_FUNC_END(__tdcall)
+/* + * __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. + * + * __tdcall_ret() function ABI: + * + * @fn (RDI) - TDCALL Leaf ID, moved to RAX + * @args (RSI) - struct tdx_module_args for input and output + * + * Return status of TDCALL via RAX. + */ +SYM_FUNC_START(__tdcall_ret) + TDX_MODULE_CALL host=0 ret=1 +SYM_FUNC_END(__tdcall_ret) + /* * TDX_HYPERCALL - Make hypercalls to a TDX VMM using TDVMCALL leaf of TDCALL * instruction diff --git a/arch/x86/coco/tdx/tdx-shared.c b/arch/x86/coco/tdx/tdx-shared.c index 90631abdac34d..a7396d0ddef9e 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 (__tdcall(TDG_MEM_PAGE_ACCEPT, tdcall_rcx, 0, 0, 0, NULL)) + args.rcx = start | page_size; + if (__tdcall(TDG_MEM_PAGE_ACCEPT, &args)) return 0;
return accept_size; diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c index e37a2464ac7fc..d0d7a42230b84 100644 --- a/arch/x86/coco/tdx/tdx.c +++ b/arch/x86/coco/tdx/tdx.c @@ -68,10 +68,9 @@ 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 tdcall(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 (__tdcall(fn, rcx, rdx, r8, r9, out)) + if (__tdcall_ret(fn, args)) panic("TDCALL %lld failed (Buggy TDX module!)\n", fn); }
@@ -91,11 +90,14 @@ static inline void tdcall(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 = __tdcall(TDG_MR_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; @@ -143,7 +145,7 @@ 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;
@@ -154,7 +156,7 @@ static void tdx_parse_tdinfo(u64 *cc_mask) * Guest-Host-Communication Interface (GHCI), section 2.4.2 TDCALL * [TDG.VP.INFO]. */ - tdcall(TDG_VP_INFO, 0, 0, 0, 0, &out); + tdcall(TDG_VP_INFO, &args);
/* * The highest bit of a guest physical address is the "sharing" bit. @@ -163,7 +165,7 @@ 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);
/* @@ -171,7 +173,7 @@ 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.";
@@ -583,7 +585,7 @@ __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 @@ -600,15 +602,15 @@ 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. */ - tdcall(TDG_VP_VEINFO_GET, 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); }
/* @@ -765,6 +767,10 @@ 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];
@@ -780,7 +786,7 @@ void __init tdx_early_init(void) cc_set_mask(cc_mask);
/* Kernel does not use NOTIFY_ENABLES and does not need random #VEs */ - tdcall(TDG_VM_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/include/asm/shared/tdx.h b/arch/x86/include/asm/shared/tdx.h index 9e3699b751ef2..3606463ebf6fb 100644 --- a/arch/x86/include/asm/shared/tdx.h +++ b/arch/x86/include/asm/shared/tdx.h @@ -74,11 +74,11 @@ static inline u64 _tdx_hypercall(u64 fn, u64 r12, u64 r13, u64 r14, u64 r15) void __tdx_hypercall_failed(void);
/* - * Used in __tdx_module_call() to gather the output registers' values of the + * 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_module_output { +struct tdx_module_args { u64 rcx; u64 rdx; u64 r8; @@ -88,8 +88,8 @@ struct tdx_module_output { };
/* Used to communicate with the TDX module */ -u64 __tdcall(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r9, - struct tdx_module_output *out); +u64 __tdcall(u64 fn, struct tdx_module_args *args); +u64 __tdcall_ret(u64 fn, struct tdx_module_args *args);
bool tdx_accept_memory(phys_addr_t start, phys_addr_t end);
diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c index dc3576303f1ad..50383bc46dd77 100644 --- a/arch/x86/kernel/asm-offsets.c +++ b/arch/x86/kernel/asm-offsets.c @@ -68,12 +68,12 @@ 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); + 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);
BLANK(); OFFSET(TDX_HYPERCALL_r8, tdx_hypercall_args, r8); diff --git a/arch/x86/virt/vmx/tdx/tdxcall.S b/arch/x86/virt/vmx/tdx/tdxcall.S index 6bdf6e1379534..e9e19e7d77f81 100644 --- a/arch/x86/virt/vmx/tdx/tdxcall.S +++ b/arch/x86/virt/vmx/tdx/tdxcall.S @@ -17,34 +17,35 @@ * 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,R8-R11 - TDCALL/SEAMCALL Leaf specific input registers. + * + * Output Registers: + * + * RAX - TDCALL/SEAMCALL instruction error code. + * RCX,RDX,R8-R11 - TDCALL/SEAMCALL Leaf specific output registers. + * + *------------------------------------------------------------------------- */ -.macro TDX_MODULE_CALL host:req +.macro TDX_MODULE_CALL host:req ret=0 FRAME_BEGIN - /* - * 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. - */ - - /* Callee saved, so preserve it */ - push %r12 - - /* - * Push output pointer to stack. - * After the operation, it will be fetched into R12 register. - */ - push %r9
- /* 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 */ + + /* 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 \host seamcall @@ -59,49 +60,31 @@ * This value will never be used as actual SEAMCALL error code as * it is from the Reserved status code class. */ - jc .Lseamcall_vmfailinvalid + jc .Lseamcall_vmfailinvalid@ .else tdcall .endif
- /* - * Fetch output pointer from stack to R12 (It is used - * as temporary storage) - */ - pop %r12 - - /* - * Since this macro can be invoked with NULL as an output pointer, - * check if caller provided an output struct before storing output - * registers. - * - * Update output registers, even if the call failed (RAX != 0). - * Other registers may contain details of the failure. - */ - test %r12, %r12 - jz .Lout - - /* 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) - -.Lout: - /* Restore the state of R12 register */ - pop %r12 +.if \ret + /* 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
+.if \host +.Lout@: +.endif FRAME_END RET
.if \host -.Lseamcall_vmfailinvalid: +.Lseamcall_vmfailinvalid@: mov $TDX_SEAMCALL_VMFAILINVALID, %rax - /* pop the unused output pointer back to %r9 */ - pop %r9 - jmp .Lout + jmp .Lout@ .endif /* \host */
.endm