Re: [dpdk-dev] [PATCH v3 01/21] net/virtio: by default disable packed virtqueues

[Jens Freimann <jfreimann@redhat.com>]

On Thu, Apr 05, 2018 at 03:42:47PM +0200, Maxime Coquelin wrote:
>
>
>On 04/05/2018 12:10 PM, Jens Freimann wrote:
>>Disable packed virtqueues for now and make it dependend on a build-time
>>config option. This can be reverted once we have missing features like
>>indirect descriptors implemented.
>>
>>Signed-off-by: Jens Freimann <jfreimann@redhat.com>
>>---
>>  config/common_base                 | 1 +
>>  drivers/net/virtio/virtio_ethdev.c | 4 ++++
>>  2 files changed, 5 insertions(+)
>>
>>diff --git a/config/common_base b/config/common_base
>>index c09c7cf88..cd4b419b4 100644
>>--- a/config/common_base
>>+++ b/config/common_base
>>@@ -346,6 +346,7 @@ CONFIG_RTE_LIBRTE_VIRTIO_PMD=y
>>  CONFIG_RTE_LIBRTE_VIRTIO_DEBUG_RX=n
>>  CONFIG_RTE_LIBRTE_VIRTIO_DEBUG_TX=n
>>  CONFIG_RTE_LIBRTE_VIRTIO_DEBUG_DUMP=n
>>+CONFIG_RTE_LIBRTE_VIRTIO_PQ=n
>>  #
>>  # Compile virtio device emulation inside virtio PMD driver
>>diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
>>index 11f758929..06fbf7311 100644
>>--- a/drivers/net/virtio/virtio_ethdev.c
>>+++ b/drivers/net/virtio/virtio_ethdev.c
>>@@ -1149,6 +1149,10 @@ virtio_negotiate_features(struct virtio_hw *hw, uint64_t req_features)
>>  			req_features &= ~(1ULL << VIRTIO_NET_F_MTU);
>>  	}
>>+#ifndef RTE_LIBRTE_VIRTIO_PQ
>>+	req_features &= ~(1ull << VIRTIO_F_RING_PACKED);
>Is VIRTIO_F_RING_PACKED already declared here?
>I don't think it is, so would break build when bisecting.

yes, you are right it is not. I pushed this patch to far up during git
rebase. 
>
>Maybe the thing to do is to not have VIRTIO_F_RING_PACKED in the 
>feature set by default. And when RTE_LIBRTE_VIRTIO_PQ is set, enable 
>it and
>explicitly disable indirect descs.

Yes, both would work. I'll go with your suggestion.
Thanks!

regards,
Jens 
>
>>+#endif
>>+
>>  	/*
>>  	 * Negotiate features: Subset of device feature bits are written back
>>  	 * guest feature bits.
>>