From: Dave Hansen <dave.hansen@intel.com>
To: Sohil Mehta <sohil.mehta@intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, Andy Lutomirski <luto@kernel.org>,
Borislav Petkov <bp@alien8.de>
Cc: Jonathan Corbet <corbet@lwn.net>,
Shuah Khan <skhan@linuxfoundation.org>,
Thomas Gleixner <tglx@kernel.org>, Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Kiryl Shutsemau <kas@kernel.org>,
Brendan Jackman <jackmanb@google.com>,
Sean Christopherson <seanjc@google.com>,
Nam Cao <namcao@linutronix.de>,
Cedric Xing <cedric.xing@intel.com>,
Rick Edgecombe <rick.p.edgecombe@intel.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Tony Luck <tony.luck@intel.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Maciej Wieczor-Retman <m.wieczorretman@pm.me>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/5] x86/vsyscall: Add vsyscall emulation for #GP
Date: Wed, 4 Mar 2026 17:45:48 -0800 [thread overview]
Message-ID: <2e3b1765-ae56-4642-8a94-61805a64497e@intel.com> (raw)
In-Reply-To: <eeec4ac0-be05-4a4e-a9c7-8716de50cfbb@intel.com>
On 3/4/26 16:10, Sohil Mehta wrote:
> Vsyscall emulation has two modes of operation, specified by the
> vsyscall={xonly, emulate} kernel command line option. The vsyscall page
> is marked as execute-only in XONLY mode or read-execute in EMULATE mode.
Is it really "marked as execute only"? We don't have a real execute-only
paging permission on x86, the closest we've got is memory marked with a
pkey that's got the AccessDisable bit set.
I think it's _called_ execute-only because the kernel makes it behave
like execute-only memory when it's handling the page fault. But I dobn't
think it is super accurate to say it is "marked" as execute-only.
The rest of it looks great to me, though.
next prev parent reply other threads:[~2026-03-05 1:45 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-19 23:35 [PATCH 0/5] x86: Enable LASS support with vsyscall emulation Sohil Mehta
2026-02-19 23:35 ` [PATCH 1/5] x86/vsyscall: Reorganize the page fault emulation code Sohil Mehta
2026-02-19 23:35 ` [PATCH 2/5] x86/traps: Consolidate user fixups in the #GP handler Sohil Mehta
2026-02-19 23:35 ` [PATCH 3/5] x86/vsyscall: Add vsyscall emulation for #GP Sohil Mehta
2026-03-03 15:51 ` Dave Hansen
2026-03-03 21:20 ` Sohil Mehta
2026-03-03 22:35 ` H. Peter Anvin
2026-03-05 0:10 ` Sohil Mehta
2026-03-05 1:45 ` Dave Hansen [this message]
2026-03-05 6:31 ` H. Peter Anvin
2026-03-05 7:56 ` Sohil Mehta
2026-03-05 6:32 ` H. Peter Anvin
2026-02-19 23:35 ` [PATCH 4/5] x86/vsyscall: Disable LASS if vsyscall mode is set to EMULATE Sohil Mehta
2026-03-03 16:33 ` Dave Hansen
2026-02-19 23:36 ` [PATCH 5/5] x86/cpu: Remove LASS restriction on vsyscall emulation Sohil Mehta
2026-03-03 16:37 ` Dave Hansen
2026-03-03 16:27 ` [PATCH 0/5] x86: Enable LASS support with " Dave Hansen
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