At 2022-03-24 12:27:46, "Jason Wang" <jasowang@redhat.com> wrote:
>On Thu, Mar 24, 2022 at 12:15 PM leohou <leohou163@163.com> wrote:
>>
>> hi all,
>> When I use DPDK in guestOS and configering the VM with vIOMMU, I found that sending the gVA to the hardware device , the hardware device can't find the real data.
>> But sending the gPA to the hardware device, the hardware device can find the real data.
>>
>> Environment:
>> OS: Linux version 5.4.0-104-generic (buildd@ubuntu) (gcc version 9.3.0 (Ubuntu 9.3.0-17ubuntu1~20.04)) #118-Ubuntu SMP Wed Mar 2 19:02:41 UTC 2022
>> QEMU: QEMU emulator version 4.2.1 (Debian 1:4.2-3ubuntu6.21)
>> Device: virtio-net
>>
>> Question:
>> The vIOMMU doesn't work?
>> I know virtio-net does not have DMA, so when virtio-net and DPDK are combined, IOMMU is not needed?
>
>vIOMMU + virtio-net works for me like a charm.
>
>DPDK supported vIOMMU long ago with virtio-net.
>
>Make sure you vIOMMU is enabled in the guest (intel_iommu=on in guest
>kernel command line, and enable_unsafe_noiommu_mode is *not* 1)
>
>Thanks
>
>>
>>
>>
>
hi, jason
I'm sure my vIOMMU is enabled in the guestOS(intel_iommu=on in guest kernel command line, and enable_unsafe_noiommu_mode is "0"),
but it only work when I config the DPDK in passing physical addresses model.
So, I think qEMU emulation of Virtio-net has no DMA, so virt queue register in PCIe space of Virtio-NET can only configure the physical address of virt queue.
Can I take it this way?
Thanks!