From: Kiryl Shutsemau <kas@kernel.org>
To: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Cc: Thomas Gleixner <tglx@kernel.org>, Ingo Molnar <mingo@redhat.com>,
Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H . Peter Anvin" <hpa@zytor.com>,
Rick Edgecombe <rick.p.edgecombe@intel.com>,
Borys Tsyrulnikov <tsyrulnikov.borys@gmail.com>,
linux-kernel@vger.kernel.org, linux-coco@lists.linux.dev,
kvm@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH 1/2] x86/tdx: Fix off-by-one in port I/O handling
Date: Wed, 1 Apr 2026 09:34:50 +0100 [thread overview]
Message-ID: <aczYg5hk8yoIi05W@thinkstation> (raw)
In-Reply-To: <ee096f1e-b994-4d56-a78c-cb0e867ea047@linux.intel.com>
On Tue, Mar 31, 2026 at 02:57:32PM -0700, Kuppuswamy Sathyanarayanan wrote:
> Hi Kirill,
>
> On 3/31/2026 4:24 AM, Kiryl Shutsemau (Meta) wrote:
> > handle_in() and handle_out() in arch/x86/coco/tdx/tdx.c use:
> >
> > u64 mask = GENMASK(BITS_PER_BYTE * size, 0);
> >
> > GENMASK(h, l) includes bit h. For size=1 (INB), this produces
> > GENMASK(8, 0) = 0x1FF (9 bits) instead of GENMASK(7, 0) = 0xFF (8
> > bits). The mask is one bit too wide for all I/O sizes.
> >
> > Fix the mask calculation.
> >
> > Fixes: 03149948832a ("x86/tdx: Port I/O: Add runtime hypercalls")
> > Reported-by: Borys Tsyrulnikov <tsyrulnikov.borys@gmail.com>
> > Signed-off-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
> > Cc: stable@vger.kernel.org
> > ---
>
> LGTM. Can you include a link to the bug report or related discussion in
> the commit log? It will help understand the impact of this issue.
Link: https://lore.kernel.org/all/CAKw_Dz96rfSQc6Rn+9QBcUFHhmkK+9zu+P=bxowfZwxrATCBRg@mail.gmail.com/
It is relevant for both.
--
Kiryl Shutsemau / Kirill A. Shutemov
next prev parent reply other threads:[~2026-04-01 8:34 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-31 11:24 [PATCH 0/2] x86/tdx: Port I/O emulation fixes Kiryl Shutsemau (Meta)
2026-03-31 11:24 ` [PATCH 1/2] x86/tdx: Fix off-by-one in port I/O handling Kiryl Shutsemau (Meta)
2026-03-31 21:57 ` Kuppuswamy Sathyanarayanan
2026-04-01 8:34 ` Kiryl Shutsemau [this message]
2026-03-31 22:06 ` Huang, Kai
2026-03-31 11:24 ` [PATCH 2/2] x86/tdx: Fix zero-extension for 32-bit port I/O Kiryl Shutsemau (Meta)
2026-03-31 22:10 ` Kuppuswamy Sathyanarayanan
2026-03-31 22:13 ` Huang, Kai
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