From: Ian Campbell <Ian.Campbell@citrix.com>
To: Mukesh Rathor <mukesh.rathor@oracle.com>
Cc: "Xen-devel@lists.xensource.com" <Xen-devel@lists.xensource.com>,
Stefano Stabellini <Stefano.Stabellini@eu.citrix.com>
Subject: Re: [question]: __gnttab_map_grant_ref() and iommu
Date: Wed, 4 Apr 2012 08:28:59 +0100 [thread overview]
Message-ID: <1333524539.12209.20.camel@dagon.hellion.org.uk> (raw)
In-Reply-To: <20120403191455.6967e409@mantra.us.oracle.com>
On Wed, 2012-04-04 at 03:14 +0100, Mukesh Rathor wrote:
> I'm not able to figure why __gnttab_map_grant_ref() does PV iommu
> mappings for GNTMAP_host_map. Should it not check for GNTMAP_device_map
> and do for those only?
I don't know but perhaps it is because when the backend maps a foreign
page there is a reasonably high chance that it is eventually going to
end up passing that page to a hardware device (e.g. a physical NIC or
disk controller) for DMA and therefore the mapping must be reflected in
the IOMMU.
Ian.
prev parent reply other threads:[~2012-04-04 7:28 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-04 2:14 [question]: __gnttab_map_grant_ref() and iommu Mukesh Rathor
2012-04-04 7:28 ` Ian Campbell [this message]
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