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Date: Fri, 4 Feb 2022 16:20:23 +0300 From: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com> To: Kai Huang <kai.huang@...el.com> Cc: Thomas Gleixner <tglx@...utronix.de>, mingo@...hat.com, bp@...en8.de, dave.hansen@...el.com, luto@...nel.org, peterz@...radead.org, sathyanarayanan.kuppuswamy@...ux.intel.com, aarcange@...hat.com, ak@...ux.intel.com, dan.j.williams@...el.com, david@...hat.com, hpa@...or.com, jgross@...e.com, jmattson@...gle.com, joro@...tes.org, jpoimboe@...hat.com, knsathya@...nel.org, pbonzini@...hat.com, sdeep@...are.com, seanjc@...gle.com, tony.luck@...el.com, vkuznets@...hat.com, wanpengli@...cent.com, x86@...nel.org, linux-kernel@...r.kernel.org Subject: Re: [PATCHv2 03/29] x86/tdx: Add __tdx_module_call() and __tdx_hypercall() helper functions On Fri, Feb 04, 2022 at 10:51:38PM +1300, Kai Huang wrote: > > + .if \host > > + seamcall > > + /* > > + * SEAMCALL instruction is essentially a VMExit from VMX root > > + * mode to SEAM VMX root mode. VMfailInvalid (CF=1) indicates > > + * that the targeted SEAM firmware is not loaded or disabled, > > + * or P-SEAMLDR is busy with another SEAMCALL. %rax is not > > + * changed in this case. > > + * > > + * Set %rax to TDX_SEAMCALL_VMFAILINVALID for VMfailInvalid. > > + * This value will never be used as actual SEAMCALL error code. > > + */ > > + jnc .Lno_vmfailinvalid > > + mov $TDX_SEAMCALL_VMFAILINVALID, %rax > > + jmp .Lno_output_struct > > If I read correctly, in case of VMfailInvalid, another "pop %r12" is needed > before jmp to .Lno_output_struct, otherwise it doesn't match the stack (pushed > twice). Oopsie. Thanks for catching it. > However, since "test %rax, %rax" will also catch TDX_SEAMCALL_VMFAILINVALID, it > seems we can just delete above "jmp .Lno_output_struct"? Good point. Will do it this way. -- Kirill A. Shutemov
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