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From: "H. Peter Anvin" <hpa@zytor.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: Is espfix64's double-fault thing OK on Xen?
Date: Mon, 14 Jul 2014 15:23:19 -0700	[thread overview]
Message-ID: <53C45857.6050605@zytor.com> (raw)
In-Reply-To: <CALCETrWG-dQL8ipJ8cO3wfbYKA=mAv3CS4-1JFwmBXF3pUbAwg@mail.gmail.com>

On 07/14/2014 02:35 PM, Andy Lutomirski wrote:
> Presumably the problem is here:
> 
> ENTRY(xen_iret)
>     pushq $0
> 1:    jmp hypercall_iret
> ENDPATCH(xen_iret)
> 
> This seems rather unlikely to work on the espfix stack.
> 
> Maybe espfix64 should be disabled when running on Xen and Xen should
> implement its own espfix64 in the hypervisor.

Perhaps the first question is: is espfix even necessary on Xen?  How
does the Xen PV IRET handle returning to a 16-bit stack segment?

	-hpa



  reply	other threads:[~2014-07-14 22:23 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-09 23:17 Is espfix64's double-fault thing OK on Xen? Andy Lutomirski
2014-07-14 16:58 ` Konrad Rzeszutek Wilk
2014-07-14 17:04 ` H. Peter Anvin
2014-07-14 17:11   ` Andy Lutomirski
2014-07-14 17:15     ` Andy Lutomirski
2014-07-14 21:31       ` Andy Lutomirski
2014-07-14 21:35         ` Andy Lutomirski
2014-07-14 22:23           ` H. Peter Anvin [this message]
2014-07-15  2:46             ` Andy Lutomirski
2014-07-15  3:20               ` Andy Lutomirski
2014-07-15  4:14               ` H. Peter Anvin

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