From: David Vrabel <david.vrabel@citrix.com>
To: Boris Ostrovsky <boris.ostrovsky@oracle.com>,
<konrad.wilk@oracle.com>, <david.vrabel@citrix.com>,
<hpa@zytor.com>, <mingo@redhat.com>, <tglx@linutronix.de>
Cc: <xen-devel@lists.xenproject.org>, <luto@amacapital.net>,
<linux-kernel@vger.kernel.org>, <linux@eikelenboom.it>
Subject: Re: [Xen-devel] [PATCH] hypervisor/x86/xen: Unset X86_BUG_SYSRET_SS_ATTRS on Xen PV guests
Date: Fri, 1 May 2015 11:37:54 +0100 [thread overview]
Message-ID: <55435782.3040506@citrix.com> (raw)
In-Reply-To: <1430420925-20474-1-git-send-email-boris.ostrovsky@oracle.com>
On 30/04/15 20:08, Boris Ostrovsky wrote:
> Commit 61f01dd941ba ("x86_64, asm: Work around AMD SYSRET SS descriptor
> attribute issue") makes AMD processors set SS to __KERNEL_DS in
> __switch_to() to deal with cases when SS is NULL.
>
> This breaks Xen PV guests who do not want to load SS with__KERNEL_DS.
>
> Since the problem that the commit is trying to address would have to be
> fixed in the hypervisor (if it in fact exists under Xen) there is no
> reason to set X86_BUG_SYSRET_SS_ATTRS flag for PV VPCUs here.
>
> This can be easily achieved by adding x86_hyper_xen_hvm.set_cpu_features
> op which will clear this flag. (And since this structure is no longer
> HVM-specific we should do some renaming).
Applied to for-linus-4.1b, thanks.
David
next prev parent reply other threads:[~2015-05-01 10:38 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-30 19:08 [PATCH] hypervisor/x86/xen: Unset X86_BUG_SYSRET_SS_ATTRS on Xen PV guests Boris Ostrovsky
2015-04-30 19:17 ` Andy Lutomirski
2015-04-30 19:17 ` Andy Lutomirski
2015-04-30 19:30 ` Boris Ostrovsky
2015-04-30 19:30 ` Boris Ostrovsky
2015-04-30 19:35 ` Andy Lutomirski
2015-04-30 22:23 ` Boris Ostrovsky
2015-04-30 22:23 ` Boris Ostrovsky
2015-04-30 19:35 ` Andy Lutomirski
2015-05-01 10:37 ` David Vrabel
2015-05-01 10:37 ` David Vrabel [this message]
2015-05-02 12:10 ` [Xen-devel] " Sander Eikelenboom
2015-05-02 12:10 ` Sander Eikelenboom
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