linux-kernel - Re: [PATCH 06/26] x86/tdx: Add MSR support for TDX guests

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Message-ID: <YcxNqavkZylqoHjw@zn.tnic>
Date:   Wed, 29 Dec 2021 12:59:37 +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,
        x86@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 06/26] x86/tdx: Add MSR support for TDX guests

On Tue, Dec 14, 2021 at 06:02:44PM +0300, Kirill A. Shutemov wrote:
> +static bool tdx_read_msr_safe(unsigned int msr, u64 *val)
> +{
> +	struct tdx_hypercall_output out;
> +
> +	/*
> +	 * Emulate the MSR read via hypercall. More info about ABI
> +	 * can be found in TDX Guest-Host-Communication Interface
> +	 * (GHCI), sec titled "TDG.VP.VMCALL<Instruction.RDMSR>".
> +	 */
> +	if (_tdx_hypercall(EXIT_REASON_MSR_READ, msr, 0, 0, 0, &out))
> +		return false;
> +
> +	*val = out.r11;
> +
> +	return true;
> +}
> +
> +static bool tdx_write_msr_safe(unsigned int msr, unsigned int low,

Why the "_safe" suffix?

-- 
Regards/Gruss,
    Boris.

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