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From: Alex Williamson <alex.williamson@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Avi Kivity <avi@redhat.com>, Sheng Yang <sheng@linux.intel.com>,
	Marcelo Tosatti <mtosatti@redhat.com>,
	kvm@vger.kernel.org
Subject: Re: [PATCH 0/8][v2] MSI-X mask emulation support for assigned device
Date: Wed, 20 Oct 2010 08:58:38 -0600	[thread overview]
Message-ID: <1287586718.3007.19.camel@x201> (raw)
In-Reply-To: <20101020134329.GB13311@redhat.com>

On Wed, 2010-10-20 at 15:43 +0200, Michael S. Tsirkin wrote:
> On Wed, Oct 20, 2010 at 12:59:42PM +0200, Avi Kivity wrote:
> > How far away is vfio?  If it's merged soon, we might avoid making
> > changes to the old assigned device infrastructure and instead update
> > vfio.
> 
> Hard to be sure, hopefully 2.6.38 material.
> 
> Some issues off the top of my head are
> - readonly/virtualized table correctness
> 	hopefully will start converging now that
> 	we are switching to standard registers from pci_regs.h
> - work out some capability negotiation mechanism so userspace/kernel
>   can detect bug fixes/missing features and recover or fail gracefully
> - with multiple assigned devices in a guest:
>   I don't think we have figured out how do they share an iommu context

A single UIOMMU fd can be used for multiple devices.  The code I wrote
supports this, but it's really only meant to support a uiommufd passed
via the command line for libvirt usage.  Since libvirt doesn't yet
support vfio, it's never been tested.

> - maybe: reset handling (flr support) - need to look a it

I'd add that for the qemu vfio driver, we need to work out the KVM
interrupt optimizations, otherwise we suffer extra latency vs current
code.

> 
> > On the other hand, changes to the old infrastructure are much
> > more amenable to backporting for long term support distro kernels,
> > so we may need to actively develop both for a while.

Yep, I think we'll need to continue development and probably maintain
them both for a while.

Alex


  reply	other threads:[~2010-10-20 14:58 UTC|newest]

Thread overview: 66+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-20  8:26 [PATCH 0/8][v2] MSI-X mask emulation support for assigned device Sheng Yang
2010-10-20  8:26 ` [PATCH 1/8] PCI: MSI: Move MSI-X entry definition to pci_regs.h Sheng Yang
2010-10-20 11:07   ` Matthew Wilcox
2010-10-20  8:26 ` [PATCH 2/8] irq: Export irq_to_desc() to modules Sheng Yang
2010-10-20  8:26 ` [PATCH 3/8] KVM: x86: Enable ENABLE_CAP capability for x86 Sheng Yang
2010-10-20  8:26 ` [PATCH 4/8] KVM: Move struct kvm_io_device to kvm_host.h Sheng Yang
2010-10-20  8:26 ` [PATCH 5/8] KVM: Add kvm_get_irq_routing_entry() func Sheng Yang
2010-10-20  8:53   ` Avi Kivity
2010-10-20  8:58     ` Sheng Yang
2010-10-20  9:13     ` Sheng Yang
2010-10-20  9:17       ` Sheng Yang
2010-10-20  9:32         ` Avi Kivity
2010-10-20  8:26 ` [PATCH 6/8] KVM: assigned dev: Preparation for mask support in userspace Sheng Yang
2010-10-20  9:30   ` Avi Kivity
2010-10-22 14:53   ` Marcelo Tosatti
2010-10-24 12:19     ` Sheng Yang
2010-10-24 12:23       ` Michael S. Tsirkin
2010-10-28  8:21         ` Sheng Yang
2010-10-20  8:26 ` [PATCH 7/8] KVM: assigned dev: Introduce io_device for MSI-X MMIO accessing Sheng Yang
2010-10-20  9:46   ` Avi Kivity
2010-10-20 10:33     ` Michael S. Tsirkin
2010-10-21  6:46     ` Sheng Yang
2010-10-21  9:27       ` Avi Kivity
2010-10-21  9:24         ` Michael S. Tsirkin
2010-10-21  9:47           ` Avi Kivity
2010-10-21 10:51             ` Michael S. Tsirkin
2010-10-20 22:35   ` Michael S. Tsirkin
2010-10-21  7:44     ` Sheng Yang
2010-10-20  8:26 ` [PATCH 8/8] KVM: Emulation MSI-X mask bits for assigned devices Sheng Yang
2010-10-20  9:49   ` Avi Kivity
2010-10-20 22:24   ` Michael S. Tsirkin
2010-10-21  8:30   ` Sheng Yang
2010-10-21  8:39     ` Michael S. Tsirkin
2010-10-22  4:42       ` Sheng Yang
2010-10-22 10:17         ` Michael S. Tsirkin
2010-10-22 13:30           ` Sheng Yang
2010-10-22 14:32             ` Michael S. Tsirkin
2010-10-20  9:51 ` [PATCH 0/8][v2] MSI-X mask emulation support for assigned device Avi Kivity
2010-10-20 10:44   ` Michael S. Tsirkin
2010-10-20 10:59     ` Avi Kivity
2010-10-20 13:43       ` Michael S. Tsirkin
2010-10-20 14:58         ` Alex Williamson [this message]
2010-10-20 14:58           ` Michael S. Tsirkin
2010-10-20 15:12             ` Alex Williamson
2010-10-20 15:17         ` Avi Kivity
2010-10-20 15:22           ` Alex Williamson
2010-10-20 15:26             ` Avi Kivity
2010-10-20 15:38               ` Alex Williamson
2010-10-20 14:47     ` Alex Williamson
2010-10-20 14:46       ` Michael S. Tsirkin
2010-10-20 15:07         ` Alex Williamson
2010-10-20 15:13           ` Michael S. Tsirkin
2010-10-20 20:13             ` Alex Williamson
2010-10-20 22:06               ` Michael S. Tsirkin
2010-10-20 15:23       ` Avi Kivity
2010-10-20 15:38         ` Alex Williamson
2010-10-20 15:54           ` Avi Kivity
2010-10-20 15:59             ` Michael S. Tsirkin
2010-10-20 16:13               ` Avi Kivity
2010-10-20 17:11                 ` Michael S. Tsirkin
2010-10-20 18:31               ` Alex Williamson
2010-10-21  7:41   ` Sheng Yang
2010-10-20 19:02 ` Marcelo Tosatti
2010-10-21  7:10   ` Sheng Yang
2010-10-21  8:21     ` Michael S. Tsirkin
2010-10-20 22:20 ` Michael S. Tsirkin

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