linux-kernel - Re: [PATCH 08/26] x86/tdx: Handle in-kernel MMIO

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Message-ID: <20220106150815.2upux2pelguazfue@box.shutemov.name>
Date:   Thu, 6 Jan 2022 18:08:15 +0300
From:   "Kirill A. Shutemov" <kirill@...temov.name>
To:     Josh Poimboeuf <jpoimboe@...hat.com>
Cc:     "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        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, 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 08/26] x86/tdx: Handle in-kernel MMIO

On Wed, Dec 15, 2021 at 03:31:16PM -0800, Josh Poimboeuf wrote:
> > +static int tdx_handle_mmio(struct pt_regs *regs, struct ve_info *ve)
> 
> Similarly, tdx_handle_mmio() returns (int) 0 for success, while other
> tdx_handle_*() functions return (bool) true for success.  Also
> confusing.

Looked at this again, you read it wrong. tdx_handle_mmio() return size of
instruction it handled so we can advance RIP and <= 0 on error. It is
consistent with other #VE handlers that positive (true) on success.

-- 
 Kirill A. Shutemov