On Sat, Oct 25, 2014 at 04:24:52PM +0800, john.liuli wrote: > From: Li Liu <john.liuli@xxxxxxxxxx> > > This set of patches try to implemet irqfd support of vhost-net > based on virtio-mmio. > > I had posted a mail to talking about the status of vhost-net > on kvm-arm refer to http://www.spinics.net/lists/kvm-arm/msg10804.html. > Some dependent patches are listed in the mail too. Basically the > vhost-net brings great performance improvements, almost 50%+. > > It's easy to implement irqfd support with PCI MSI-X. But till > now arm32 do not provide equivalent mechanism to let a device > allocate multiple interrupts. And even the aarch64 provid LPI > but also not available in a short time. > > As Gauguey Remy said "Vhost does not emulate a complete virtio > adapter but only manage virtqueue operations". Vhost module > don't update the ISR register, so if with only one irq then it's > no way to get the interrupt reason even we can inject the > irq correctly. Well guests don't read ISR in MSI-X mode so why does it help to set the ISR bit? > To get the interrupt reason to support such VIRTIO_NET_F_STATUS > features I add a new register offset VIRTIO_MMIO_ISRMEM which > will help to establish a shared memory region between qemu and > virtio-mmio device. Then the interrupt reason can be accessed by > guest driver through this region. At the same time, the virtio-mmio > dirver check this region to see irqfd is supported or not during > the irq handler registration, and different handler will be assigned. > > I want to know it's the right direction? Does it comply with the > virtio-mmio spec.? Or anyone have more good ideas to emulate mis-x > based on virtio-mmio? I hope to get feedback and guidance. > Thx for any help. > > Li Liu (2): > Add a new register offset let interrupt reason available > Assign a new irq handler while irqfd enabled > > drivers/virtio/virtio_mmio.c | 55 +++++++++++++++++++++++++++++++++++++++--- > include/linux/virtio_mmio.h | 3 +++ > 2 files changed, 55 insertions(+), 3 deletions(-) > > -- > 1.7.9.5 > _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
