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From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com
Cc: linux-kernel@vger.kernel.org,
	virtualization@lists.linux-foundation.org,
	david.vrabel@citrix.com, luto@kernel.org,
	xen-devel@lists.xenproject.org, bp@suse.de
Subject: Re: [PATCH v2 1/3] x86/xen: Avoid fast syscall path for Xen PV guests
Date: Tue, 15 Dec 2015 10:21:37 -0500	[thread overview]
Message-ID: <56703001.9010205__31324.6514219374$1450196499$gmane$org@oracle.com> (raw)
In-Reply-To: <1447970147-1733-2-git-send-email-boris.ostrovsky@oracle.com>

On 11/19/2015 04:55 PM, Boris Ostrovsky wrote:
> After 32-bit syscall rewrite, and specifically after commit 5f310f739b4c
> ("x86/entry/32: Re-implement SYSENTER using the new C path"), the stack
> frame that is passed to xen_sysexit is no longer a "standard" one (i.e.
> it's not pt_regs).
>
> Since we end up calling xen_iret from xen_sysexit we don't need to fix
> up the stack and instead follow entry_SYSENTER_32's IRET path directly
> to xen_iret.
>
> We can do the same thing for compat mode even though stack does not need
> to be fixed. This will allow us to drop usergs_sysret32 paravirt op (in
> the subsequent patch)
>
> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> Suggested-by: Andy Lutomirski <luto@amacapital.net>


I know this has been in the tip tree --- when do you think this will go 
Linus tree? In the 4.4 timeframe?

Xen 32-bit PV guests are broken without this.


Thanks.
-boris

  parent reply	other threads:[~2015-12-15 16:19 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-19 21:55 [PATCH v2 0/3] Fix and cleanup for 32-bit PV sysexit Boris Ostrovsky
2015-11-19 21:55 ` Boris Ostrovsky
2015-11-19 21:55 ` [PATCH v2 1/3] x86/xen: Avoid fast syscall path for Xen PV guests Boris Ostrovsky
2015-11-19 21:55 ` Boris Ostrovsky
2015-11-19 21:55   ` Boris Ostrovsky
2015-11-23 16:28   ` [tip:x86/asm] " tip-bot for Boris Ostrovsky
2015-12-15 15:21   ` [PATCH v2 1/3] " Boris Ostrovsky
2015-12-15 15:21     ` Boris Ostrovsky
2015-12-15 15:48     ` Borislav Petkov
2015-12-15 15:48     ` Borislav Petkov
2015-12-15 15:48       ` Borislav Petkov
2015-12-15 15:54       ` Boris Ostrovsky
2015-12-15 15:54         ` Boris Ostrovsky
2015-12-15 15:57         ` Andy Lutomirski
2015-12-15 15:57           ` Andy Lutomirski
2015-12-15 15:57         ` Andy Lutomirski
2015-12-15 15:54       ` Boris Ostrovsky
2015-12-15 15:21   ` Boris Ostrovsky [this message]
2015-12-19  9:15   ` [tip:x86/urgent] " tip-bot for Boris Ostrovsky
2015-11-19 21:55 ` [PATCH v2 2/3] x86: irq_enable_sysexit pv op is no longer needed Boris Ostrovsky
2015-11-19 21:55   ` Boris Ostrovsky
2015-11-23 16:28   ` [tip:x86/asm] x86/paravirt: Remove the unused irq_enable_sysexit pv op tip-bot for Boris Ostrovsky
2015-11-19 21:55 ` [PATCH v2 2/3] x86: irq_enable_sysexit pv op is no longer needed Boris Ostrovsky
2015-11-19 21:55 ` [PATCH v2 3/3] x86: usergs_sysret32 " Boris Ostrovsky
2015-11-19 21:55 ` Boris Ostrovsky
2015-11-19 21:55   ` Boris Ostrovsky
2015-11-23 16:29   ` [tip:x86/asm] x86/entry, x86/paravirt: Remove the unused usergs_sysret32 PV op tip-bot for Boris Ostrovsky
2015-11-19 22:07 ` [PATCH v2 0/3] Fix and cleanup for 32-bit PV sysexit Andy Lutomirski
2015-11-19 22:07   ` Andy Lutomirski
2015-12-15 20:40   ` Andrew Cooper
2015-12-15 20:40   ` [Xen-devel] " Andrew Cooper
2015-12-15 21:27     ` Andy Lutomirski
2015-12-15 21:27       ` Andy Lutomirski
2015-12-15 21:27     ` Andy Lutomirski
2015-12-15 20:40   ` [Xen-devel] " Andrew Cooper
2015-11-19 22:07 ` Andy Lutomirski
2015-11-19 23:02 ` Borislav Petkov
2015-11-19 23:02 ` Borislav Petkov
2015-11-19 23:02   ` Borislav Petkov

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