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. 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
