Messages in this thread | ![/](/images/icornerl.gif) | | Date | Wed, 29 Apr 2020 09:05:39 +0530 | From | Srivatsa Vaddagiri <> | Subject | Re: [PATCH 5/5] virtio: Add bounce DMA ops |
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* Michael S. Tsirkin <mst@redhat.com> [2020-04-28 16:41:04]:
> > Won't we still need some changes to virtio to make use of its own pool (to > > bounce buffers)? Something similar to its own DMA ops proposed in this patch? > > If you are doing this for all devices, you need to either find a way > to do this without chaning DMA ops, or by doing some automatic change > to all drivers.
Ok thanks for this input. I will see how we can obfuscate this in DMA APIs itself.
Can you also comment on the virtio transport problem I cited? The hypervisor we are dealing with does not support MMIO transport. It supports message queue send/recv and also doorbell, which I think can be used if we can make some change like this to virtio_mmio.c:
+static inline u32 +virtio_readl(struct virtio_mmio_device *vm_dev, u32 reg_offset) +{ + return vm_dev->mmio_ops->readl(vm_dev, reg_offset); +} + +static inline void +virtio_writel(struct virtio_mmio_device *vm_dev, u32 reg_offset, u32 data) +{ + vm_dev->mmio_ops->writel(vm_dev, reg_offset, data); +}
/* Check magic value */ - magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE); + magic = vrito_readl(vm_dev, VIRTIO_MMIO_MAGIC_VALUE);
mmio_ops->readl on most platforms can default to readl itself, while on a platform like us, it can boil down to message_queue send/recv. Would such a change be acceptable?
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