Re: [PATCHv4 3/3] x86/tdx: Handle load_unaligned_zeropad() page-cross to a shared page

From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
	luto@kernel.org, peterz@infradead.org, ak@linux.intel.com,
	dan.j.williams@intel.com, david@redhat.com, hpa@zytor.com,
	linux-kernel@vger.kernel.org,
	sathyanarayanan.kuppuswamy@linux.intel.com, seanjc@google.com,
	thomas.lendacky@amd.com, x86@kernel.org
Subject: Re: [PATCHv4 3/3] x86/tdx: Handle load_unaligned_zeropad() page-cross to a shared page
Date: Thu, 16 Jun 2022 01:43:03 +0300	[thread overview]
Message-ID: <20220615224303.el4qtowheu2rgpdn@black.fi.intel.com> (raw)
In-Reply-To: <1d190555-2bb1-e483-2405-e28ddabead07@intel.com>

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