From c641cfb5c157b6c3062a824fd8ba190bf06fb952 Mon Sep 17 00:00:00 2001 From: Kai Huang Date: Tue, 15 Aug 2023 23:02:01 +1200 Subject: x86/tdx: Make TDX_HYPERCALL asm similar to TDX_MODULE_CALL Now the 'struct tdx_hypercall_args' and 'struct tdx_module_args' are almost the same, and the TDX_HYPERCALL and TDX_MODULE_CALL asm macro share similar code pattern too. The __tdx_hypercall() and __tdcall() should be unified to use the same assembly code. As a preparation to unify them, simplify the TDX_HYPERCALL to make it more like the TDX_MODULE_CALL. The TDX_HYPERCALL takes the pointer of 'struct tdx_hypercall_args' as function call argument, and does below extra things comparing to the TDX_MODULE_CALL: 1) It sets RAX to 0 (TDG.VP.VMCALL leaf) internally; 2) It sets RCX to the (fixed) bitmap of shared registers internally; 3) It calls __tdx_hypercall_failed() internally (and panics) when the TDCALL instruction itself fails; 4) After TDCALL, it moves R10 to RAX to return the return code of the VMCALL leaf, regardless the '\ret' asm macro argument; Firstly, change the TDX_HYPERCALL to take the same function call arguments as the TDX_MODULE_CALL does: TDCALL leaf ID, and the pointer to 'struct tdx_module_args'. Then 1) and 2) can be moved to the caller: - TDG.VP.VMCALL leaf ID can be passed via the function call argument; - 'struct tdx_module_args' is 'struct tdx_hypercall_args' + RCX, thus the bitmap of shared registers can be passed via RCX in the structure. Secondly, to move 3) and 4) out of assembly, make the TDX_HYPERCALL always save output registers to the structure. The caller then can: - Call __tdx_hypercall_failed() when TDX_HYPERCALL returns error; - Return R10 in the structure as the return code of the VMCALL leaf; With above changes, change the asm function from __tdx_hypercall() to __tdcall_hypercall(), and reimplement __tdx_hypercall() as the C wrapper of it. This avoids having to add another wrapper of __tdx_hypercall() (_tdx_hypercall() is already taken). The __tdcall_hypercall() will be replaced with a __tdcall() variant using TDX_MODULE_CALL in a later commit as the final goal is to have one assembly to handle both TDCALL and TDVMCALL. Currently, the __tdx_hypercall() asm is in '.noinstr.text'. To keep this unchanged, annotate __tdx_hypercall(), which is a C function now, as 'noinstr'. Remove the __tdx_hypercall_ret() as __tdx_hypercall() already does so. Implement __tdx_hypercall() in tdx-shared.c so it can be shared with the compressed code. Opportunistically fix a checkpatch error complaining using space around parenthesis '(' and ')' while moving the bitmap of shared registers to . [ dhansen: quash new calls of __tdx_hypercall_ret() that showed up ] Suggested-by: Peter Zijlstra Signed-off-by: Kai Huang Signed-off-by: Dave Hansen Reviewed-by: Kirill A. Shutemov Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/all/0cbf25e7aee3256288045023a31f65f0cef90af4.1692096753.git.kai.huang%40intel.com --- arch/x86/boot/compressed/tdx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/boot') diff --git a/arch/x86/boot/compressed/tdx.c b/arch/x86/boot/compressed/tdx.c index 8841b945a1e2..bc03eae2c560 100644 --- a/arch/x86/boot/compressed/tdx.c +++ b/arch/x86/boot/compressed/tdx.c @@ -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; -- cgit v1.2.3 From 8a8544bde858e5d62d79df6baaa387e0b6587dc7 Mon Sep 17 00:00:00 2001 From: Kai Huang Date: Tue, 15 Aug 2023 23:02:03 +1200 Subject: x86/tdx: Remove 'struct tdx_hypercall_args' Now 'struct tdx_hypercall_args' is basically 'struct tdx_module_args' minus RCX. Although from __tdx_hypercall()'s perspective RCX isn't used as shared register thus not part of input/output registers, it's not worth to have a separate structure just due to one register. Remove the 'struct tdx_hypercall_args' and use 'struct tdx_module_args' instead in __tdx_hypercall() related code. This also saves the memory copy between the two structures within __tdx_hypercall(). Suggested-by: Peter Zijlstra Signed-off-by: Kai Huang Signed-off-by: Dave Hansen Reviewed-by: Kirill A. Shutemov Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/all/798dad5ce24e9d745cf0e16825b75ccc433ad065.1692096753.git.kai.huang%40intel.com --- arch/x86/boot/compressed/tdx.c | 4 ++-- arch/x86/coco/tdx/tdx-shared.c | 37 +++++++------------------------------ arch/x86/coco/tdx/tdx.c | 18 +++++++++--------- arch/x86/hyperv/ivm.c | 6 +++--- arch/x86/include/asm/shared/tdx.h | 25 ++----------------------- 5 files changed, 23 insertions(+), 67 deletions(-) (limited to 'arch/x86/boot') diff --git a/arch/x86/boot/compressed/tdx.c b/arch/x86/boot/compressed/tdx.c index bc03eae2c560..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, @@ -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/tdx-shared.c b/arch/x86/coco/tdx/tdx-shared.c index 344b3818f4c3..78e413269791 100644 --- a/arch/x86/coco/tdx/tdx-shared.c +++ b/arch/x86/coco/tdx/tdx-shared.c @@ -70,45 +70,22 @@ bool tdx_accept_memory(phys_addr_t start, phys_addr_t end) return true; } -noinstr u64 __tdx_hypercall(struct tdx_hypercall_args *args) +noinstr u64 __tdx_hypercall(struct tdx_module_args *args) { - struct tdx_module_args margs = { - .rcx = TDVMCALL_EXPOSE_REGS_MASK, - .rdx = args->rdx, - .r8 = args->r8, - .r9 = args->r9, - .r10 = args->r10, - .r11 = args->r11, - .r12 = args->r12, - .r13 = args->r13, - .r14 = args->r14, - .r15 = args->r15, - .rbx = args->rbx, - .rdi = args->rdi, - .rsi = args->rsi, - }; + /* + * 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, &margs)) + if (__tdcall_saved_ret(TDG_VP_VMCALL, args)) __tdx_hypercall_failed(); - args->r8 = margs.r8; - args->r9 = margs.r9; - args->r10 = margs.r10; - args->r11 = margs.r11; - args->r12 = margs.r12; - args->r13 = margs.r13; - args->r14 = margs.r14; - args->r15 = margs.r15; - args->rdi = margs.rdi; - args->rsi = margs.rsi; - args->rbx = margs.rbx; - args->rdx = margs.rdx; - /* 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 26b6c3d8f0be..3e6dbd2199cf 100644 --- a/arch/x86/coco/tdx/tdx.c +++ b/arch/x86/coco/tdx/tdx.c @@ -48,7 +48,7 @@ noinstr void __noreturn __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, @@ -108,7 +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 */ @@ -230,7 +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, @@ -274,7 +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, @@ -295,7 +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, @@ -315,7 +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, @@ -357,7 +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, @@ -486,7 +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, @@ -723,7 +723,7 @@ static bool tdx_map_gpa(phys_addr_t start, phys_addr_t end, bool enc) } while (retry_count < max_retries_per_page) { - struct tdx_hypercall_args args = { + struct tdx_module_args args = { .r10 = TDX_HYPERCALL_STANDARD, .r11 = TDVMCALL_MAP_GPA, .r12 = start, diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c index e48983550743..c1088d3661d5 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, @@ -398,7 +398,7 @@ 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, @@ -414,7 +414,7 @@ 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; diff --git a/arch/x86/include/asm/shared/tdx.h b/arch/x86/include/asm/shared/tdx.h index f53a41948946..b69886ee1c63 100644 --- a/arch/x86/include/asm/shared/tdx.h +++ b/arch/x86/include/asm/shared/tdx.h @@ -85,29 +85,8 @@ 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 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. - */ -struct tdx_hypercall_args { - u64 r8; - u64 r9; - u64 r10; - u64 r11; - u64 r12; - u64 r13; - u64 r14; - u64 r15; - u64 rdi; - u64 rsi; - u64 rbx; - u64 rdx; -}; - /* Used to request services from the VMM */ -u64 __tdx_hypercall(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 @@ -115,7 +94,7 @@ u64 __tdx_hypercall(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, -- cgit v1.2.3