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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Arnd Bergmann <arnd@arndb.de>,
	Shamir Rabinovitch <shamir.rabinovitch@oracle.com>,
	David Woodhouse <dwmw2@infradead.org>,
	Andy Lutomirski <luto@amacapital.net>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	linux-arch <linux-arch@vger.kernel.org>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Martin Schwidefsky <schwidefsky@de.ibm.com>,
	"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
	Sebastian Ott <sebott@linux.vnet.ibm.com>,
	linux-s390 <linux-s390@vger.kernel.org>,
	Cornelia Huck <cornelia.huck@de.ibm.com>,
	Joerg Roedel <jroedel@suse.de>, Jonathan Corbet <corbet@lwn.net>,
	KVM <kvm@vger.kernel.org>
Subject: Re: [PATCH v1 2/2] dma-mapping-common: add DMA attribute - DMA_ATTR_IOMMU_BYPASS
Date: Wed, 04 Nov 2015 06:35:10 +1100	[thread overview]
Message-ID: <1446579310.17404.36.camel@kernel.crashing.org> (raw)
In-Reply-To: <20151103131134.GA6384@lst.de>

On Tue, 2015-11-03 at 14:11 +0100, Christoph Hellwig wrote:
> > xHCI for example, vs. something like 10G ethernet... but yes I agree it
> > sucks. I don't like that sort of policy anywhere in drivers. On the
> > other hand the platform doesn't have much information to make that sort
> > of decision either.
> 
> Mabye because it should simply use what's optimal?  E.g. passthrough
> whenever possible, where arguments against possible are:  dma_mask, vfio
> requirements, kernel command line option. 

Right this is what I do today on powerpc with the exception of
the command line option.

>  This is what a lot of
> architectures already do, I remember the SGI Origin / Altix code has the
> same behavior as well.  Those IOMMUs already had the 64 bit passthrough
> and 32-bit sliding window in addition to the real IOMMU 10 years ago.
> --

  reply	other threads:[~2015-11-03 19:36 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1445789224-28032-1-git-send-email-shamir.rabinovitch@oracle.com>
     [not found] ` <1445789224-28032-2-git-send-email-shamir.rabinovitch@oracle.com>
2015-10-28  6:30   ` [PATCH v1 2/2] dma-mapping-common: add DMA attribute - DMA_ATTR_IOMMU_BYPASS David Woodhouse
2015-10-28 11:10     ` Shamir Rabinovitch
2015-10-28 13:31       ` David Woodhouse
2015-10-28 14:07         ` David Miller
2015-10-28 13:57           ` David Woodhouse
2015-10-29  0:23             ` David Miller
2015-10-29  0:32         ` Benjamin Herrenschmidt
2015-10-29  0:42           ` David Woodhouse
2015-10-29  1:10             ` Benjamin Herrenschmidt
2015-10-29 18:31               ` Andy Lutomirski
2015-10-29 22:35                 ` David Woodhouse
2015-11-01  7:45                   ` Shamir Rabinovitch
2015-11-01 21:10                     ` Benjamin Herrenschmidt
2015-11-02  7:23                       ` Shamir Rabinovitch
2015-11-02 10:00                         ` Benjamin Herrenschmidt
2015-11-02 12:07                           ` Shamir Rabinovitch
2015-11-02 20:13                             ` Benjamin Herrenschmidt
2015-11-02 21:45                               ` Arnd Bergmann
2015-11-02 23:08                                 ` Benjamin Herrenschmidt
2015-11-03 13:11                                   ` Christoph Hellwig
2015-11-03 19:35                                     ` Benjamin Herrenschmidt [this message]
2015-11-02 21:49                               ` Shamir Rabinovitch
2015-11-02 22:48                       ` David Woodhouse
2015-11-02 23:10                         ` Benjamin Herrenschmidt
2015-11-05 21:08                   ` David Miller
2015-10-30  1:51                 ` Benjamin Herrenschmidt
2015-10-30 10:32               ` Arnd Bergmann
2015-10-30 23:17                 ` Benjamin Herrenschmidt
2015-10-30 23:24                   ` Arnd Bergmann
2015-11-02 14:51                 ` Joerg Roedel
2015-10-29  7:32             ` Shamir Rabinovitch
2015-11-02 14:44               ` Joerg Roedel
2015-11-02 17:32                 ` Shamir Rabinovitch
2015-11-05 13:42                   ` Joerg Roedel
2015-11-05 21:11                     ` David Miller
2015-11-07 15:06                       ` Shamir Rabinovitch
     [not found]                         ` <CAN+hb0UvztgwNuAh93XdJEe7vgiZgNMc9mHNziHpEopg8Oi4Mg@mail.gmail.com>
2015-11-16  8:42                           ` David Woodhouse
     [not found]                             ` <CAN+hb0UWpfcS5DvgMxNjY-5JOztw2mO1r2FJAW17fn974mhxPA@mail.gmail.com>
2015-11-16 18:42                               ` Benjamin Serebrin
2015-11-16  6:56 Benjamin Serebrin

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