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From: Simon Martin <furryfuttock@gmail.com>
To: Ian Campbell <Ian.Campbell@citrix.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>, xen-devel@lists.xen.org
Subject: Re: Consuming PCI device in PV kernel
Date: Fri, 25 Jul 2014 15:36:30 +0100	[thread overview]
Message-ID: <263120224.20140725153630@gmail.com> (raw)
In-Reply-To: <1406298816.24842.19.camel@kazak.uk.xensource.com>

Hello Ian,

>> > Once you grant map a page from another domain, your domain no longer
>> > owns the PTE.  You should either avoid that PTE, or grant unmap the
>> > foreign frame first.
>> 
>> I  have  not  grant mapped this. I have just called update_va_mapping.
>> Should I be using grant?

> Andrew is saying that the mapping which is currently at the virtual
> address is *already* a grant mapping, not that you are trying to grant
> map something here. Grant maps need to be unmapped with the grant unmap
> hypercall, not just by rewriting the PTE. (IIRC).

> You should not be using grants to map PCI IO space, no.

Thanks  Ian. I'm off traveling next week so I'll pick up on this again
in August. I wonder what has grant mapped this memory area....

-- 
Best regards,
 Simon                            mailto:furryfuttock@gmail.com

  reply	other threads:[~2014-07-25 14:36 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-03 11:13 Consuming PCI device in PV kernel Simon Martin
2014-07-03 18:09 ` Konrad Rzeszutek Wilk
2014-07-07  8:21   ` Simon Martin
2014-07-07 11:22     ` Simon Martin
2014-07-07 12:21       ` Realtime access to PCI NIC Simon Martin
2014-07-08 14:46         ` Ian Campbell
2014-07-10  7:47           ` Simon Martin
2014-07-08 15:01       ` Consuming PCI device in PV kernel Konrad Rzeszutek Wilk
2014-07-10  7:54         ` Simon Martin
2014-07-11 16:47           ` Dario Faggioli
2014-07-15  8:37             ` Simon Martin
2014-07-15 14:56               ` Konrad Rzeszutek Wilk
2014-07-18 14:37       ` Simon Martin
2014-07-18 19:09         ` Konrad Rzeszutek Wilk
2014-07-21 10:13           ` Simon Martin
2014-07-21 10:53             ` Ian Campbell
2014-07-25 12:56               ` Simon Martin
2014-07-25 13:10                 ` Ian Campbell
2014-07-25 13:21                   ` Simon Martin
2014-07-25 13:37                     ` Ian Campbell
2014-07-25 13:50                       ` Andrew Cooper
2014-07-25 14:20                         ` Simon Martin
2014-07-25 14:25                           ` Andrew Cooper
2014-07-25 14:30                             ` Simon Martin
2014-07-25 14:33                               ` Ian Campbell
2014-07-25 14:36                                 ` Simon Martin [this message]
2014-07-25 14:28                       ` Simon Martin

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