From: Christoph Hellwig <hch@infradead.org>
To: Srujana Challa <schalla@marvell.com>
Cc: Christoph Hellwig <hch@infradead.org>,
"Michael S. Tsirkin" <mst@redhat.com>,
"virtualization@lists.linux.dev" <virtualization@lists.linux.dev>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"jasowang@redhat.com" <jasowang@redhat.com>,
"eperezma@redhat.com" <eperezma@redhat.com>,
Nithin Kumar Dabilpuram <ndabilpuram@marvell.com>,
Jerin Jacob <jerinj@marvell.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [EXTERNAL] Re: [PATCH v2 0/2] vhost-vdpa: Add support for NO-IOMMU mode
Date: Wed, 6 Nov 2024 07:45:52 -0800 [thread overview]
Message-ID: <ZyuPMI-VOp8eK-dP@infradead.org> (raw)
In-Reply-To: <DS0PR18MB5368B1BCC3CFAE5D7E4EB627A0532@DS0PR18MB5368.namprd18.prod.outlook.com>
On Wed, Nov 06, 2024 at 12:38:02PM +0000, Srujana Challa wrote:
> It is going in circles, let me give the summary,
> Issue: We need to address the lack of no-IOMMU support in the vhost vDPA driver for better performance.
> Measured Performance: On the machine "13th Gen Intel(R) Core(TM) i9-13900K, 32 Cores", we observed
Looks ike you are going in circles indeed. Lack of performance is never
a reason to disable the basic memoy safety for userspace drivers.
The (also quite bad) reason why vfio-nummu was added was to support
hardware entirely with an iommu.
There is absolutely no reason to add krnel code for new methods of
unsafer userspace I/O without an IOMMU ever.
next prev parent reply other threads:[~2024-11-06 15:45 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-09-20 14:05 [PATCH v2 0/2] vhost-vdpa: Add support for NO-IOMMU mode Srujana Challa
2024-09-20 14:05 ` [PATCH v2 1/2] vhost-vdpa: introduce module parameter for no-IOMMU mode Srujana Challa
2024-09-21 17:28 ` kernel test robot
2024-09-20 14:05 ` [PATCH v2 2/2] vhost-vdpa: introduce NO-IOMMU backend feature bit Srujana Challa
2024-09-24 7:43 ` Jason Wang
2024-09-24 10:01 ` [EXTERNAL] " Srujana Challa
2024-10-01 8:47 ` [PATCH v2 0/2] vhost-vdpa: Add support for NO-IOMMU mode Christoph Hellwig
2024-10-14 13:18 ` [EXTERNAL] " Srujana Challa
2024-10-15 3:48 ` Christoph Hellwig
2024-10-16 17:28 ` Srujana Challa
2024-10-17 6:19 ` Christoph Hellwig
2024-10-17 8:53 ` Srujana Challa
2024-10-18 4:54 ` Jason Wang
2024-10-18 5:24 ` Christoph Hellwig
2024-10-18 13:08 ` Srujana Challa
2024-10-16 17:41 ` Michael S. Tsirkin
2024-10-17 6:16 ` Christoph Hellwig
2024-10-20 0:16 ` Michael S. Tsirkin
2024-10-23 6:58 ` Christoph Hellwig
2024-10-23 8:19 ` Michael S. Tsirkin
2024-10-24 9:05 ` Christoph Hellwig
2024-11-06 12:38 ` Srujana Challa
2024-11-06 15:45 ` Christoph Hellwig [this message]
2024-11-07 6:08 ` Srujana Challa
2024-11-12 7:11 ` Srujana Challa
2024-11-06 18:11 ` Michael S. Tsirkin
2024-11-06 18:14 ` Michael S. Tsirkin
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