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From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Jan Beulich <JBeulich@suse.com>,
	xen-devel <xen-devel@lists.xenproject.org>
Subject: Re: [PATCH v2 11/16] x86/PV: split out dealing with DRn from privileged instruction handling
Date: Thu, 29 Sep 2016 21:13:53 +0100	[thread overview]
Message-ID: <09cdee32-577c-a4fa-13ca-edbe8ed875ff@citrix.com> (raw)
In-Reply-To: <57EB984A02000078001131FF@prv-mh.provo.novell.com>

On 28/09/16 09:15, Jan Beulich wrote:
> This is in preparation for using the generic emulator here.
>
> Some care is needed temporarily to not unduly alter guest register
> state: The local variable "res" can only go away once this code got
> fully switched over to using x86_emulate().
>
> Also switch to IS_ERR_VALUE() instead of (incorrectly) open coding it.

It isn't actually an ERR_PTR().  That bit of code pre-dates the
introduction of ERR_PTR() by some margin.

The return code of do_get_debugreg() is broken and needs fixing, along
with the ABI of the debugreg hypercalls.

This change does cause an ABI change for PV guests, as they now can't
read a debug register whose value is in the top 4k of linear address
space, (ather than the top 8th of a page previously), but given that the
ABI is already known broken, I am not sure I care too much.

Either way, keeping it like this, or switching back to the previous
opencoding, Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

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  reply	other threads:[~2016-09-29 20:13 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-28  7:59 [PATCH v2 00/16] x86: split insn emulator decode and execution Jan Beulich
2016-09-28  8:06 ` [PATCH v2 01/16] x86emul: split instruction decoding from execution Jan Beulich
2016-09-28 16:24   ` Andrew Cooper
2016-09-28  8:07 ` [PATCH v2 02/16] x86emul: fetch all insn bytes during the decode phase Jan Beulich
2016-09-28 16:37   ` Andrew Cooper
2016-09-28  8:08 ` [PATCH v2 03/16] x86emul: track only rIP in emulator state Jan Beulich
2016-09-28 16:41   ` Andrew Cooper
2016-09-28  8:08 ` [PATCH v2 04/16] x86emul: complete decoding of two-byte instructions Jan Beulich
2016-09-28 17:22   ` Andrew Cooper
2016-09-29  6:37     ` Jan Beulich
2016-09-28  8:09 ` [PATCH v2 05/16] x86emul: add XOP decoding Jan Beulich
2016-09-29  9:07   ` Andrew Cooper
2016-09-28  8:10 ` [PATCH v2 06/16] x86emul: add EVEX decoding Jan Beulich
2016-09-29  9:08   ` Andrew Cooper
2016-09-28  8:12 ` [PATCH v2 07/16] x86emul: generate and make use of a canonical opcode representation Jan Beulich
2016-09-29 10:11   ` Andrew Cooper
2016-09-28  8:13 ` [PATCH v2 08/16] SVM: use generic instruction decoding Jan Beulich
2016-09-29 19:24   ` Andrew Cooper
2016-09-29 19:30     ` Andrew Cooper
2016-09-30  8:32     ` Jan Beulich
2016-09-28  8:13 ` [PATCH v2 09/16] x86/32on64: use generic instruction decoding for call gate emulation Jan Beulich
2016-09-29 19:47   ` Andrew Cooper
2016-09-30  7:30     ` Jan Beulich
2016-09-28  8:14 ` [PATCH v2 10/16] x86/PV: split out dealing with CRn from privileged instruction handling Jan Beulich
2016-09-29 20:01   ` Andrew Cooper
2016-09-30  7:12     ` Jan Beulich
2016-09-28  8:15 ` [PATCH v2 11/16] x86/PV: split out dealing with DRn " Jan Beulich
2016-09-29 20:13   ` Andrew Cooper [this message]
2016-09-30  7:16     ` Jan Beulich
2016-09-28  8:16 ` [PATCH v2 12/16] x86/PV: split out dealing with MSRs " Jan Beulich
2016-09-29 20:44   ` Andrew Cooper
2016-09-28  8:17 ` [PATCH v2 13/16] x86emul: support XSETBV Jan Beulich
2016-09-29 20:45   ` Andrew Cooper
2016-09-30  8:05     ` Jan Beulich
2016-09-28  8:18 ` [PATCH v2 14/16] x86emul: sort opcode 0f01 special case switch() statement Jan Beulich
2016-09-29 20:46   ` Andrew Cooper
2016-09-28  8:18 ` [PATCH v2 15/16] x86/PV: use generic emulator for privileged instruction handling Jan Beulich
2016-09-29 21:06   ` Andrew Cooper
2016-09-30  8:55     ` Jan Beulich
2016-09-28  8:19 ` [PATCH v2 16/16] x86emul: don't assume a memory operand Jan Beulich
2016-09-29 21:12   ` Andrew Cooper
2016-09-30  8:25     ` Jan Beulich
2016-09-28  8:42 ` [PATCH v2 00/16] x86: split insn emulator decode and execution Jan Beulich

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