> From: Michael Kelley (LINUX) <mikelley@xxxxxxxxxxxxx> > Sent: Wednesday, November 23, 2022 6:45 AM > To: Dexuan Cui <decui@xxxxxxxxxxxxx>; ak@xxxxxxxxxxxxxxx; arnd@xxxxxxxx; > > Two thoughts: > > 1) The #ifdef CONFIG_INTEL_TDX_GUEST could probably be removed > entirely > with a tweak. hv_isolation_type_tdx() already doesn't need the #ifdef as > there's > already a stub that returns 'false'. Then you just need a way to handle > __tdx_ms_hv_hypercall(), or whatever it becomes based on the other > discussion. > As long as you can provide a stub that does nothing, the #ifdef won't be > needed. > > 2) Assuming that we end up with some kind of Hyper-V specific version of > __tdx_hypercall(), and hopefully as a "C" function, could you move the > handling > of ms_hyperv.shared_gpa_boundary into that function? Then you won't > need > to break out a separate include file for struct ms_hyperv. The Hyper-V TDX > hypercall function must handle both normal and "fast" hypercalls, and the > shared_gpa_boundary adjustment is needed only for normal hypercalls, > but you can check the "fast" bit in the control word to decide. > > I haven't coded these ideas, so maybe there are snags I haven't thought of. > But I'm really hoping we can avoid having to create a separate include > file for struct ms_hyperv. > > Michael Thanks for the great suggestions! Now the code looks like this: (the full list of v2 patches are still WIP: https://github.com/dcui/tdx/commits/decui/hyperv-next/2022-1121/v6.1-rc5/v2) diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c index 13ccb52eecd7..00e5c84e380b 100644 --- a/arch/x86/hyperv/ivm.c +++ b/arch/x86/hyperv/ivm.c @@ -276,6 +276,27 @@ bool hv_isolation_type_tdx(void) { return static_branch_unlikely(&isolation_type_tdx); } + +u64 hv_tdx_hypercall(u64 control, u64 input_addr, u64 output_addr) +{ + struct tdx_hypercall_args args = { }; + + if (!(control & HV_HYPERCALL_FAST_BIT)) { + if (input_addr) + input_addr += ms_hyperv.shared_gpa_boundary; + + if (output_addr) + output_addr += ms_hyperv.shared_gpa_boundary; + } + + args.r10 = control; + args.rdx = input_addr; + args.r8 = output_addr; + + (void)__tdx_hypercall(&args, TDX_HCALL_HAS_OUTPUT); + + return args.r11; +} #endif /* diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h index 8a2cafec4675..1be7bcf0d7d1 100644 --- a/arch/x86/include/asm/mshyperv.h +++ b/arch/x86/include/asm/mshyperv.h @@ -39,6 +39,8 @@ int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages); int hv_call_add_logical_proc(int node, u32 lp_index, u32 acpi_id); int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags); +u64 hv_tdx_hypercall(u64 control, u64 input_addr, u64 output_addr); + static inline u64 hv_do_hypercall(u64 control, void *input, void *output) { u64 input_address = input ? virt_to_phys(input) : 0; @@ -46,6 +48,9 @@ static inline u64 hv_do_hypercall(u64 control, void *input, void *output) u64 hv_status; #ifdef CONFIG_X86_64 + if (hv_isolation_type_tdx()) + return hv_tdx_hypercall(control, input_address, output_address); + if (!hv_hypercall_pg) return U64_MAX; @@ -83,6 +88,9 @@ static inline u64 hv_do_fast_hypercall8(u16 code, u64 input1) u64 hv_status, control = (u64)code | HV_HYPERCALL_FAST_BIT; #ifdef CONFIG_X86_64 + if (hv_isolation_type_tdx()) + return hv_tdx_hypercall(control, input1, 0); + { __asm__ __volatile__(CALL_NOSPEC : "=a" (hv_status), ASM_CALL_CONSTRAINT, @@ -114,6 +122,9 @@ static inline u64 hv_do_fast_hypercall16(u16 code, u64 input1, u64 input2) u64 hv_status, control = (u64)code | HV_HYPERCALL_FAST_BIT; #ifdef CONFIG_X86_64 + if (hv_isolation_type_tdx()) + return hv_tdx_hypercall(control, input1, input2); + { __asm__ __volatile__("mov %4, %%r8\n" CALL_NOSPEC
