diff options
Diffstat (limited to 'arch/x86/coco/tdx/tdcall.S')
-rw-r--r-- | arch/x86/coco/tdx/tdcall.S | 133 |
1 files changed, 8 insertions, 125 deletions
diff --git a/arch/x86/coco/tdx/tdcall.S b/arch/x86/coco/tdx/tdcall.S index 6d76d7d49b72..52d9786da308 100644 --- a/arch/x86/coco/tdx/tdcall.S +++ b/arch/x86/coco/tdx/tdcall.S @@ -1,7 +1,6 @@ /* SPDX-License-Identifier: GPL-2.0 */ #include <asm/asm-offsets.h> #include <asm/asm.h> -#include <asm/frame.h> #include <linux/linkage.h> #include <linux/errno.h> @@ -46,135 +45,19 @@ SYM_FUNC_START(__tdcall_ret) SYM_FUNC_END(__tdcall_ret) /* - * TDX_HYPERCALL - Make hypercalls to a TDX VMM using TDVMCALL leaf of TDCALL - * instruction - * - * Transforms values in function call argument struct tdx_module_args @args - * into the TDCALL register ABI. After TDCALL operation, VMM output is saved - * back in @args, if \ret is 1. - * - * Depends on the caller to pass TDG.VP.VMCALL as the TDCALL leaf, and set - * @args::rcx to TDVMCALL_EXPOSE_REGS_MASK. - * - *------------------------------------------------------------------------- - * TD VMCALL ABI: - *------------------------------------------------------------------------- - * - * Input Registers: - * - * 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. - * - * Output Registers: - * - * RAX - TDCALL instruction status (Not related to hypercall - * output). - * RBX, RDX, RDI, RSI - Hypercall sub function specific output values. - * R8-R15 - Same as above. - * - */ -.macro TDX_HYPERCALL - FRAME_BEGIN - - /* Save callee-saved GPRs as mandated by the x86_64 ABI */ - push %r15 - push %r14 - push %r13 - push %r12 - push %rbx - - /* Move Leaf ID to RAX */ - movq %rdi, %rax - - /* Move bitmap of shared registers to RCX */ - movq TDX_MODULE_rcx(%rsi), %rcx - - /* Copy hypercall registers from arg struct: */ - movq TDX_MODULE_r8(%rsi), %r8 - movq TDX_MODULE_r9(%rsi), %r9 - movq TDX_MODULE_r10(%rsi), %r10 - movq TDX_MODULE_r11(%rsi), %r11 - 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_rdi(%rsi), %rdi - movq TDX_MODULE_rbx(%rsi), %rbx - movq TDX_MODULE_rdx(%rsi), %rdx - - pushq %rsi - movq TDX_MODULE_rsi(%rsi), %rsi - - tdcall - - /* - * Restore the pointer of the structure to save output registers. - * - * RCX is used as bitmap of shared registers and doesn't hold any - * value provided by the VMM, thus it can be used as spare to - * restore the structure pointer. - */ - popq %rcx - movq %rsi, TDX_MODULE_rsi(%rcx) - movq %rcx, %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) - 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 %rdi, TDX_MODULE_rdi(%rsi) - movq %rbx, TDX_MODULE_rbx(%rsi) - movq %rdx, TDX_MODULE_rdx(%rsi) - - /* - * 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 %rsi, %rsi - 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 -.endm - -/* + * __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. * - * __tdcall_hypercall() function ABI: + * __tdcall_saved_ret() function ABI: * * @fn (RDI) - TDCALL leaf ID, moved to RAX * @args (RSI) - struct tdx_module_args for input/output * - * @fn and @args::rcx from the caller must be TDG_VP_VMCALL and - * TDVMCALL_EXPOSE_REGS_MASK respectively. + * All registers in @args are used as input/output registers. * * On successful completion, return the hypercall error code. */ -SYM_FUNC_START(__tdcall_hypercall) - TDX_HYPERCALL -SYM_FUNC_END(__tdcall_hypercall) +SYM_FUNC_START(__tdcall_saved_ret) + TDX_MODULE_CALL host=0 ret=1 saved=1 +SYM_FUNC_END(__tdcall_saved_ret) |