Re: [Qemu-devel] [virtio-dev] Re: [PATCH v3 7/7] virtio/vhost.c: vhost-pci needs remote gpa

[Wei Wang <wei.w.wang@intel.com>]

On 12/06/2017 12:05 AM, Stefan Hajnoczi wrote:
> On Tue, Dec 05, 2017 at 11:33:16AM +0800, Wei Wang wrote:
>> The vhost-pci driver uses the remote guest physical address to send/receive
>> packets from the remote guest, so when sending the ving info to the vhost-pci
>> device, send the guest physical adress directly.
>>
>> Signed-off-by: Wei Wang <wei.w.wang@intel.com>
>> ---
>>   hw/virtio/vhost.c | 56 +++++++++++++++++++++++++++++++++++--------------------
>>   1 file changed, 36 insertions(+), 20 deletions(-)
> Can you do it inside vhost_memory_map()/vhost_memory_unmap() instead of
> modifying callers?
>
> Looks like vhost_dev_has_iommu() already takes this approach:
>
>    static void *vhost_memory_map(struct vhost_dev *dev, hwaddr addr,
>                                  hwaddr *plen, int is_write)
>    {
>        if (!vhost_dev_has_iommu(dev)) {
>            return cpu_physical_memory_map(addr, plen, is_write);
>        } else {
>            return (void *)(uintptr_t)addr;
>        }
>    }
>
>    static void vhost_memory_unmap(struct vhost_dev *dev, void *buffer,
>                                   hwaddr len, int is_write,
>                                   hwaddr access_len)
>    {
>        if (!vhost_dev_has_iommu(dev)) {
>            cpu_physical_memory_unmap(buffer, len, is_write, access_len);
>        }
>    }

Thanks for the reminder. I think this patch may be not needed with 
adding the F_IOMMU_PLATFORM feature.


Best,
Wei