Re: [dpdk-dev] [EXT] Re: [PATCH] bus/pci: fix IOVA as VA mode selection

From: Jerin Jacob Kollanukkaran <jerinj@marvell.com>
To: Bruce Richardson <bruce.richardson@intel.com>
Cc: David Marchand <david.marchand@redhat.com>, dev <dev@dpdk.org>,
	"Thomas Monjalon" <thomas@monjalon.net>,
	Ben Walker <benjamin.walker@intel.com>,
	"Burakov, Anatoly" <anatoly.burakov@intel.com>
Subject: Re: [dpdk-dev] [EXT] Re: [PATCH] bus/pci: fix IOVA as VA mode selection
Date: Tue, 9 Jul 2019 09:05:07 +0000	[thread overview]
Message-ID: <BYAPR18MB2424CDE4C4520F5E9BDEE8B5C8F10@BYAPR18MB2424.namprd18.prod.outlook.com> (raw)
In-Reply-To: <20190709083950.GA485@bricha3-MOBL.ger.corp.intel.com>

> -----Original Message-----
> From: Bruce Richardson <bruce.richardson@intel.com>
> Sent: Tuesday, July 9, 2019 2:10 PM
> To: Jerin Jacob Kollanukkaran <jerinj@marvell.com>
> Cc: David Marchand <david.marchand@redhat.com>; dev <dev@dpdk.org>;
> Thomas Monjalon <thomas@monjalon.net>; Ben Walker
> <benjamin.walker@intel.com>; Burakov, Anatoly
> <anatoly.burakov@intel.com>
> Subject: Re: [dpdk-dev] [EXT] Re: [PATCH] bus/pci: fix IOVA as VA mode
> selection
> 
> On Mon, Jul 08, 2019 at 07:13:28PM +0000, Jerin Jacob Kollanukkaran wrote:
> > See below,
> >
> > Please send the email as text to avoid formatting issue.(No HTML)
> >
> > From: David Marchand <david.marchand@redhat.com>
> > Sent: Tuesday, July 9, 2019 12:09 AM
> > To: Jerin Jacob Kollanukkaran <jerinj@marvell.com>
> > Cc: dev <dev@dpdk.org>; Thomas Monjalon <thomas@monjalon.net>;
> Ben
> > Walker <benjamin.walker@intel.com>; Burakov, Anatoly
> > <anatoly.burakov@intel.com>
> > Subject: [EXT] Re: [dpdk-dev] [PATCH] bus/pci: fix IOVA as VA mode
> > selection
> >
> > ________________________________________
> >
> > On Mon, Jul 8, 2019 at 4:25 PM <mailto:jerinj@marvell.com> wrote:
> > From: Jerin Jacob <mailto:jerinj@marvell.com>
> >
> > Existing logic fails to select IOVA mode as VA if driver request to
> > enable IOVA as VA.
> >
> > IOVA as VA has more strict requirement than other modes, so enabling
> > positive logic for IOVA as VA selection.
> >
> > This patch also updates the default IOVA mode as PA for PCI devices as
> > it has to deal with DMA engines unlike the virtual devices that may
> > need only IOVA as DC.
> >
> > We have three cases:
> > - driver/hw supports IOVA as PA only
> >
> > [Jerin] It is not driver cap, it is more of system cap(IOMMU vs non
> > IOMMU). We are already addressing that case
> >
> 
> Not necessarily. It's possible to have hardware that does not use the IOMMU
> on a platform. Therefore, you have more than two options to support.

Any example such device?

> 
> /Bruce