On Fri, Mar 15, 2024 at 09:33:20AM -0700, Sean Christopherson wrote: > So my feedback is to not worry about the exports, and instead focus on figuring > out a way to make the generated code less bloated and easier to read/debug. I think it was mistake trying to centralize TDCALL/SEAMCALL calls into few megawrappers. I think we can get better results by shifting leaf function wrappers into assembly. We are going to have more assembly, but it should produce better result. Adding macros can help to write such wrapper and minimizer boilerplate. Below is an example of how it can look like. It's not complete. I only converted TDCALLs, but TDVMCALLs or SEAMCALLs. TDVMCALLs are going to be more complex. Any opinions? Is it something worth investing more time? .set offset_rcx, TDX_MODULE_rcx .set offset_rdx, TDX_MODULE_rdx .set offset_r8, TDX_MODULE_r8 .set offset_r9, TDX_MODULE_r9 .set offset_r10, TDX_MODULE_r10 .set offset_r11, TDX_MODULE_r11 .macro save_output struct_reg regs:vararg .irp reg,\regs movq %\reg, offset_\reg(%\struct_reg) .endr .endm .macro tdcall leaf movq \leaf, %rax .byte 0x66,0x0f,0x01,0xcc .endm .macro tdcall_or_panic leaf tdcall \leaf testq %rax, %rax jnz .Lpanic .endm SYM_FUNC_START(tdg_vm_rd) FRAME_BEGIN xorl %ecx, %ecx movq %rdi, %rdx tdcall_or_panic $TDG_VM_RD movq %r8, %rax RET FRAME_END SYM_FUNC_END(tdg_vm_rd) SYM_FUNC_START(tdg_vm_wr) FRAME_BEGIN xorl %ecx, %ecx movq %rsi, %r8 movq %rdx, %r9 movq %rdi, %rdx tdcall_or_panic $TDG_VM_WR /* Old value */ movq %r8, %rax RET FRAME_END SYM_FUNC_END(tdg_vm_wr) SYM_FUNC_START(tdcs_ctls_set) FRAME_BEGIN movq $TDCS_TD_CTLS, %rdx xorl %ecx, %ecx movq %rdi, %r8 movq %rdi, %r9 tdcall $TDG_VM_WR testq %rax, %rax setz %al RET FRAME_END SYM_FUNC_END(tdcs_ctls_set) SYM_FUNC_START(tdg_sys_rd) FRAME_BEGIN xorl %ecx, %ecx movq %rdi, %rdx tdcall_or_panic $TDG_SYS_RD movq %r8, %rax RET FRAME_END SYM_FUNC_END(tdg_sys_rd) SYM_FUNC_START(tdg_vp_veinfo_get) FRAME_BEGIN tdcall_or_panic $TDG_VP_VEINFO_GET save_output struct_reg=rdi regs=rcx,rdx,r8,r9,r10 FRAME_END RET SYM_FUNC_END(tdg_vp_veinfo_get) SYM_FUNC_START(tdg_vp_info) FRAME_BEGIN tdcall_or_panic $TDG_VP_INFO save_output struct_reg=rdi regs=rcx,rdx,r8,r9,r10,r11 FRAME_END RET SYM_FUNC_END(tdg_vp_info) SYM_FUNC_START(tdg_mem_page_accept) FRAME_BEGIN movq %rdi, %rcx tdcall $TDG_MEM_PAGE_ACCEPT FRAME_END RET SYM_FUNC_END(tdg_mem_page_accept) SYM_FUNC_START(tdg_mr_report) FRAME_BEGIN movq %rdx, %r8 movq %rdi, %rcx movq %rsi, %rdx tdcall $TDG_MR_REPORT FRAME_END RET SYM_FUNC_END(tdg_mr_report) .Lpanic: ud2 -- Kiryl Shutsemau / Kirill A. Shutemov
