linux-kernel - Re: [PATCHv5 03/30] x86/tdx: Add __tdx_module_call() and __tdx

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Message-ID: <YjC3HuH7mrupwwwd@zn.tnic>
Date:   Tue, 15 Mar 2022 16:56:14 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Cc:     tglx@...utronix.de, mingo@...hat.com, 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,
        thomas.lendacky@....com, brijesh.singh@....com, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCHv5 03/30] x86/tdx: Add __tdx_module_call() and
 __tdx_hypercall() helper functions

On Fri, Mar 11, 2022 at 12:48:28AM +0300, Kirill A. Shutemov wrote:
> Here how it can look like. Is it what you want?

Yap, that's better.

> diff --git a/arch/x86/boot/compressed/tdx.c b/arch/x86/boot/compressed/tdx.c
> index f00fd3a39b64..b26eab2c3c59 100644
> --- a/arch/x86/boot/compressed/tdx.c
> +++ b/arch/x86/boot/compressed/tdx.c
> @@ -3,6 +3,7 @@
>  #include "../cpuflags.h"
>  #include "../string.h"
>  #include "../io.h"
> +#include "error.h"
> 
>  #include <vdso/limits.h>
>  #include <uapi/asm/vmx.h>
> @@ -16,6 +17,11 @@ bool early_is_tdx_guest(void)
>  	return tdx_guest_detected;
>  }
> 
> +void __tdx_hypercall_failed(void)
> +{
> +	error("TDVMCALL failed. TDX module bug?");
> +}
> +
>  static inline unsigned int tdx_io_in(int size, u16 port)
>  {
>  	struct tdx_hypercall_args args = {


> diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c
> index 8e19694d33e2..29fc5941b80c 100644
> --- a/arch/x86/coco/tdx/tdx.c
> +++ b/arch/x86/coco/tdx/tdx.c
> @@ -53,6 +53,11 @@ static inline u64 _tdx_hypercall(u64 fn, u64 r12, u64 r13, u64 r14, u64 r15)
>  	return __tdx_hypercall(&args, 0);
>  }
> 
> +void __tdx_hypercall_failed(void)
> +{
> +	panic("TDVMCALL failed. TDX module bug?");
> +}

Btw, if there's going to be more code duplication in TDX-land, I'd
suggest doing a shared file like

arch/x86/kernel/sev-shared.c

which you can include in both kernel stages.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette