From: Yu Zhang <yu.c.zhang@linux.intel.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: Paul Durrant <Paul.Durrant@citrix.com>,
"Xen-devel@lists.xen.org" <Xen-devel@lists.xen.org>,
George Dunlap <George.Dunlap@citrix.com>,
"Lv, Zhiyuan" <zhiyuan.lv@intel.com>
Subject: Re: [PATCH v6 2/4] x86/ioreq server: Release the p2m lock after mmio is handled.
Date: Fri, 9 Sep 2016 13:56:37 +0800 [thread overview]
Message-ID: <57D24F15.3010509@linux.intel.com> (raw)
In-Reply-To: <57D24782.6010701@linux.intel.com>
On 9/9/2016 1:24 PM, Yu Zhang wrote:
>
>
> On 9/2/2016 6:47 PM, Yu Zhang wrote:
>> Routine hvmemul_do_io() may need to peek the p2m type of a gfn to
>> select the ioreq server. For example, operations on gfns with
>> p2m_ioreq_server type will be delivered to a corresponding ioreq
>> server, and this requires that the p2m type not be switched back
>> to p2m_ram_rw during the emulation process. To avoid this race
>> condition, we delay the release of p2m lock in
>> hvm_hap_nested_page_fault()
>> until mmio is handled.
>>
>> Note: previously in hvm_hap_nested_page_fault(), put_gfn() was moved
>> before the handling of mmio, due to a deadlock risk between the p2m
>> lock and the event lock(in commit 77b8dfe). Later, a per-event channel
>> lock was introduced in commit de6acb7, to send events. So we do not
>> need to worry about the deadlock issue.
>>
>> Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
>>
>
> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
>
> However, shouldn't this go _before_ what is now patch 1?
>
Yes. This should be the patch 1/4. Thanks! :)
Yu
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next prev parent reply other threads:[~2016-09-09 5:56 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-02 10:47 [PATCH v6 0/4] x86/ioreq server: Introduce HVMMEM_ioreq_server mem type Yu Zhang
2016-09-02 10:47 ` [PATCH v6 1/4] x86/ioreq server: Add HVMOP to map guest ram with p2m_ioreq_server to an ioreq server Yu Zhang
2016-09-05 13:31 ` Jan Beulich
2016-09-05 17:20 ` George Dunlap
2016-09-06 7:58 ` Jan Beulich
2016-09-06 8:03 ` Paul Durrant
2016-09-06 8:13 ` Jan Beulich
2016-09-06 10:00 ` Yu Zhang
2016-09-09 5:55 ` Yu Zhang
2016-09-09 8:09 ` Jan Beulich
2016-09-09 8:59 ` Yu Zhang
2016-09-05 17:23 ` George Dunlap
[not found] ` <57D24730.2050904@linux.intel.com>
2016-09-09 5:51 ` Yu Zhang
2016-09-21 13:04 ` George Dunlap
2016-09-22 9:12 ` Yu Zhang
2016-09-22 11:32 ` George Dunlap
2016-09-22 16:02 ` Yu Zhang
2016-09-23 10:35 ` George Dunlap
2016-09-26 6:57 ` Yu Zhang
2016-09-26 6:58 ` Yu Zhang
2016-09-02 10:47 ` [PATCH v6 2/4] x86/ioreq server: Release the p2m lock after mmio is handled Yu Zhang
2016-09-05 13:49 ` Jan Beulich
[not found] ` <57D24782.6010701@linux.intel.com>
2016-09-09 5:56 ` Yu Zhang [this message]
2016-09-02 10:47 ` [PATCH v6 3/4] x86/ioreq server: Handle read-modify-write cases for p2m_ioreq_server pages Yu Zhang
2016-09-05 14:10 ` Jan Beulich
[not found] ` <57D247F6.9010503@linux.intel.com>
2016-09-09 6:21 ` Yu Zhang
2016-09-09 8:12 ` Jan Beulich
2016-09-02 10:47 ` [PATCH v6 4/4] x86/ioreq server: Reset outstanding p2m_ioreq_server entries when an ioreq server unmaps Yu Zhang
2016-09-05 14:47 ` Jan Beulich
[not found] ` <57D24813.2090903@linux.intel.com>
2016-09-09 7:24 ` Yu Zhang
2016-09-09 8:20 ` Jan Beulich
2016-09-09 9:24 ` Yu Zhang
2016-09-09 9:44 ` Jan Beulich
2016-09-09 9:56 ` Yu Zhang
2016-09-09 10:09 ` Jan Beulich
2016-09-09 10:01 ` Yu Zhang
2016-09-20 2:57 ` Yu Zhang
2016-09-22 18:06 ` George Dunlap
2016-09-23 1:31 ` Yu Zhang
2016-09-06 10:57 ` [PATCH v6 0/4] x86/ioreq server: Introduce HVMMEM_ioreq_server mem type Yu Zhang
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