linux-kernel - Re: [PATCHv4 3/3] x86/tdx: Handle load_unaligned

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Message-ID: <20220615224303.el4qtowheu2rgpdn@black.fi.intel.com>
Date:   Thu, 16 Jun 2022 01:43:03 +0300
From:   "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
To:     Dave Hansen <dave.hansen@...el.com>
Cc:     tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
        luto@...nel.org, peterz@...radead.org, ak@...ux.intel.com,
        dan.j.williams@...el.com, david@...hat.com, hpa@...or.com,
        linux-kernel@...r.kernel.org,
        sathyanarayanan.kuppuswamy@...ux.intel.com, seanjc@...gle.com,
        thomas.lendacky@....com, x86@...nel.org
Subject: Re: [PATCHv4 3/3] x86/tdx: Handle load_unaligned_zeropad()
 page-cross to a shared page

On Wed, Jun 15, 2022 at 02:55:13PM -0700, Dave Hansen wrote:
> On 6/15/22 10:10, Kirill A. Shutemov wrote:
> >> I thought this whole exercise was kicked off by hitting this in testing.
> >>  Am I remembering this wrong?
> >>
> >>> https://lore.kernel.org/all/20220517153444.11195-10-kirill.shutemov@linux.intel.com/
> >> Says:
> >>
> >>> This is an actual, real-world problem which was discovered during TDX
> >>> testing.
> >> Or were you considering this a different problem somehow?
> > They are different.
> > 
> > The patch by the link addresses issue of load_unaligned_zeropad() stepping
> > onto unaccepted memory. This was triggered in practice.
> 
> OK, so we've got two problems both triggered by
> load_unaligned_zeropad(), but where the fixes are different.  We
> actually hit the "unaccepted memory one" in testing, but that made us
> think about other problems in the area and that's where this one came up.

I will reword it like this:

	The issue was discovered by analysis after triggering other issue with
	load_unaligned_zeropad().

Works for you?

-- 
 Kirill A. Shutemov