[dpdk-dev] vhost: initializing iotlb memory only when IOMMU feature is enabled.
Nitin Katiyar
nitin.katiyar at ericsson.com
Thu Aug 23 09:33:50 CEST 2018
Hi Ilya,
Thanks for your comments. I haven't tested with IOMMU enabled. I covered more of memory utilization by testing OVS with DPDK. I will test out by enabling IOMMU and send the updated patch.
Regards,
Nitin
-----Original Message-----
From: Ilya Maximets [mailto:i.maximets at samsung.com]
Sent: Friday, August 17, 2018 7:36 PM
To: Nitin Katiyar <nitin.katiyar at ericsson.com>; dev at dpdk.org
Cc: Maxime Coquelin <maxime.coquelin at redhat.com>; Bie, Tiwei <tiwei.bie at intel.com>; Zhihong Wang <zhihong.wang at intel.com>
Subject: Re: vhost: initializing iotlb memory only when IOMMU feature is enabled.
On 17.08.2018 23:19, Nitin Katiyar wrote:
> DPDK 17.11 introduced the IOMMU feature which caused additional DPDK
> memory requirement per vhostuser device as part of iotlb_init(). Today
> this is done unconditionally (from DPDK
> 17.11 onwards) i.e. irrespective of IOMMU feature being enabled on the
> vhostuser device, iotlb is initialized. This breaks the backward
> compatibility for applications like OVS due to increase in the DPDK
> memory footprint and causes upgrade failures.
>> This patch is to do iotlb_init only if IOMMU feature is
> enabled on device.
I guess, "Fixes" line should be here?
>
> Signed-off-by: Nitin Katiyar <nitin.katiyar at ericsson.com>
> ---
> lib/librte_vhost/iotlb.c | 7 +++++++
> lib/librte_vhost/vhost_user.c | 6 ++++++
> 2 files changed, 13 insertions(+)
>
> diff --git a/lib/librte_vhost/iotlb.c b/lib/librte_vhost/iotlb.c index
> c6354fe..befa2d3 100644
> --- a/lib/librte_vhost/iotlb.c
> +++ b/lib/librte_vhost/iotlb.c
> @@ -317,6 +317,13 @@ struct vhost_iotlb_entry {
> struct vhost_virtqueue *vq = dev->virtqueue[vq_index];
> int socket = 0;
>
> + if (!(dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))) {
vhost_user_iotlb_init() is called on the virtqueue allocation stage, most likely while processing VHOST_USER_SET_VRING_CALL.
QEMU usually sends VHOST_USER_SET_FEATURES after the VHOST_USER_SET_VRING_CALL. This means that 'dev->features' are not yet initialized here.
Have you tested that IOMMU feature works with this patch applied?
> + RTE_LOG(INFO, VHOST_CONFIG,
> + "IOMMU feature is not enabled for this dev(%s)\n",
> + dev->ifname);
> + return 0;
> + }
> +
> if (vq->iotlb_pool) {
> /*
> * The cache has already been initialized, diff --git
> a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c index
> a2d4c9f..7553a03 100644
> --- a/lib/librte_vhost/vhost_user.c
> +++ b/lib/librte_vhost/vhost_user.c
> @@ -1366,6 +1366,12 @@
> uint16_t i;
> uint64_t vva, len;
>
> + if (!(dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))) {
> + RTE_LOG(ERR, VHOST_CONFIG,
> + "IOMMU feature is not enabled for this dev(%s)\n",
> + dev->ifname);
> + return -1;
> + }
> switch (imsg->type) {
> case VHOST_IOTLB_UPDATE:
> len = imsg->size;
>
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