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From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: Andy Lutomirski <luto@kernel.org>, x86@kernel.org
Cc: linux-kernel@vger.kernel.org,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Juergen Gross <jgross@suse.com>,
	Stefano Stabellini <sstabellini@kernel.org>,
	xen-devel@lists.xenproject.org
Subject: Re: [PATCH 3/6] x86/entry/64/compat: Fix Xen PV SYSENTER frame setup
Date: Sat, 27 Jun 2020 22:47:20 -0400	[thread overview]
Message-ID: <5056e7ad-715c-23cc-c0e5-9a9ae5a3d61c@oracle.com> (raw)
In-Reply-To: <947880c41ade688ff4836f665d0c9fcaa9bd1201.1593191971.git.luto@kernel.org>

On 6/26/20 1:21 PM, Andy Lutomirski wrote:
> The SYSENTER frame setup was nonsense.  It worked by accident
> because the normal code into which the Xen asm jumped
> (entry_SYSENTER_32/compat) threw away SP without touching the stack.
> entry_SYSENTER_compat was recently modified such that it relied on
> having a valid stack pointer, so now the Xen asm needs to invoke it
> with a valid stack.
>
> Fix it up like SYSCALL: use the Xen-provided frame and skip the bare
> metal prologue.
>
> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> Cc: Juergen Gross <jgross@suse.com>
> Cc: Stefano Stabellini <sstabellini@kernel.org>
> Cc: xen-devel@lists.xenproject.org
> Fixes: 1c3e5d3f60e2 ("x86/entry: Make entry_64_compat.S objtool clean")
> Signed-off-by: Andy Lutomirski <luto@kernel.org>


Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>


WARNING: multiple messages have this Message-ID (diff)
From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: Andy Lutomirski <luto@kernel.org>, x86@kernel.org
Cc: Juergen Gross <jgross@suse.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Stefano Stabellini <sstabellini@kernel.org>,
	linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org
Subject: Re: [PATCH 3/6] x86/entry/64/compat: Fix Xen PV SYSENTER frame setup
Date: Sat, 27 Jun 2020 22:47:20 -0400	[thread overview]
Message-ID: <5056e7ad-715c-23cc-c0e5-9a9ae5a3d61c@oracle.com> (raw)
In-Reply-To: <947880c41ade688ff4836f665d0c9fcaa9bd1201.1593191971.git.luto@kernel.org>

On 6/26/20 1:21 PM, Andy Lutomirski wrote:
> The SYSENTER frame setup was nonsense.  It worked by accident
> because the normal code into which the Xen asm jumped
> (entry_SYSENTER_32/compat) threw away SP without touching the stack.
> entry_SYSENTER_compat was recently modified such that it relied on
> having a valid stack pointer, so now the Xen asm needs to invoke it
> with a valid stack.
>
> Fix it up like SYSCALL: use the Xen-provided frame and skip the bare
> metal prologue.
>
> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> Cc: Juergen Gross <jgross@suse.com>
> Cc: Stefano Stabellini <sstabellini@kernel.org>
> Cc: xen-devel@lists.xenproject.org
> Fixes: 1c3e5d3f60e2 ("x86/entry: Make entry_64_compat.S objtool clean")
> Signed-off-by: Andy Lutomirski <luto@kernel.org>


Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>



  reply	other threads:[~2020-06-28  2:48 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-26 17:21 [PATCH 0/6] x86/entry: Fixes Andy Lutomirski
2020-06-26 17:21 ` [PATCH 1/6] x86/entry: Assert that syscalls are on the right stack Andy Lutomirski
2020-07-01  8:04   ` [tip: x86/urgent] " tip-bot2 for Andy Lutomirski
2020-07-06 14:34   ` [PATCH] x86/entry: Mark check_user_regs() noinstr Peter Zijlstra
2020-06-26 17:21 ` [PATCH 2/6] x86/entry: Move SYSENTER's regs->sp and regs->flags fixups into C Andy Lutomirski
2020-07-01  8:04   ` [tip: x86/urgent] " tip-bot2 for Andy Lutomirski
2020-06-26 17:21 ` [PATCH 3/6] x86/entry/64/compat: Fix Xen PV SYSENTER frame setup Andy Lutomirski
2020-06-26 17:21   ` Andy Lutomirski
2020-06-28  2:47   ` Boris Ostrovsky [this message]
2020-06-28  2:47     ` Boris Ostrovsky
2020-07-01  8:04   ` [tip: x86/urgent] " tip-bot2 for Andy Lutomirski
2020-07-01 15:42   ` [PATCH 3/6] " Brian Gerst
2020-07-01 15:42     ` Brian Gerst
2020-07-01 18:39     ` Andy Lutomirski
2020-07-01 18:39       ` Andy Lutomirski
2020-07-02 12:54       ` Thomas Gleixner
2020-07-02 12:54         ` Thomas Gleixner
2020-06-26 17:21 ` [PATCH 4/6] selftests/x86/syscall_nt: Add more flag combinations Andy Lutomirski
2020-07-01  8:04   ` [tip: x86/urgent] " tip-bot2 for Andy Lutomirski
2020-06-26 17:21 ` [PATCH 5/6] selftests/x86/syscall_nt: Clear weird flags after each test Andy Lutomirski
2020-07-01  8:04   ` [tip: x86/urgent] " tip-bot2 for Andy Lutomirski
2020-06-26 17:21 ` [PATCH 6/6] selftests/x86: Consolidate and fix get/set_eflags() helpers Andy Lutomirski
2020-07-01  8:04   ` [tip: x86/urgent] " tip-bot2 for Andy Lutomirski

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