Messages in this thread | | | From | "Huang, Kai" <> | Subject | Re: [PATCH v3 06/12] x86/tdx: Extend TDX_MODULE_CALL to support more TDCALL/SEAMCALL leafs | Date | Thu, 27 Jul 2023 22:58:12 +0000 |
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On Thu, 2023-07-27 at 19:50 +0300, kirill.shutemov@linux.intel.com wrote: > On Wed, Jul 26, 2023 at 11:25:08PM +1200, Kai Huang wrote: > > @@ -64,6 +103,37 @@ > > .endif > > > > .if \ret > > +.if \saved > > + /* > > + * Restore the structure from stack to save the output registers > > + * > > + * In case of VP.ENTER returns due to TDVMCALL, all registers are > > + * valid thus no register can be used as spare to restore the > > + * structure from the stack (see "TDH.VP.ENTER Output Operands > > + * Definition on TDCALL(TDG.VP.VMCALL) Following a TD Entry"). > > + * For this case, need to make one register as spare by saving it > > + * to the stack and then manually load the structure pointer to > > + * the spare register. > > + * > > + * Note for other TDCALLs/SEAMCALLs there are spare registers > > + * thus no need for such hack but just use this for all. > > + */ > > + pushq %rax /* save the TDCALL/SEAMCALL return code */ > > + movq 8(%rsp), %rax /* restore the structure pointer */ > > + movq %rsi, TDX_MODULE_rsi(%rax) /* save %rsi */ > > + movq %rax, %rsi /* use %rsi as structure pointer */ > > This looks redundant. You get struct in RSI with popq two lines below.
Yes I guess so. Will remove and have a test.
> > And please use upper case for registers: RSI instead of %rsi.
In the comments? Will do.
> > > + popq %rax /* restore the return code */ > > + popq %rsi /* pop the structure pointer */ > > + > > + /* Copy additional output regs to the structure */ > > + 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 %rbx, TDX_MODULE_rbx(%rsi) > > + movq %rdi, TDX_MODULE_rdi(%rsi) > > +.endif /* \saved */ > > + > > /* Copy output registers to the structure */ > > movq %rcx, TDX_MODULE_rcx(%rsi) > > movq %rdx, TDX_MODULE_rdx(%rsi) > > Otherwise, looks sane: > > Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> >
Thanks.
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