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vhost: add flag to enable IOMMU support

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Qemu versions from v2.7.0 to v2.9.0 have their reply-ack protocol
feature implementation broken with multiqueue. The reply-ack
protocol feature is optional except for IOMMU feature.

This patch introduce a new RTE_VHOST_USER_IOMMU_SUPPORT flag to
enable VIRTIO_F_IOMMU_PLATFORM virtio feature.

By default, the IOMMU support is now disabled.

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Acked-by: Yuanhan Liu <yliu@fridaylinux.org>
Tested-by: Mark Kavanagh <mark.b.kavanagh@intel.com>
Acked-by: Mark Kavanagh <mark.b.kavanagh@intel.com>
This commit is contained in:
Maxime Coquelin 2017-11-06 21:38:11 +01:00 committed by Thomas Monjalon
parent 6ea069651e
commit 002d6a7e55
4 changed files with 23 additions and 1 deletions
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14
doc/guides/prog_guide/vhost_lib.rst
View File

@ -110,6 +110,20 @@ The following is an overview of some key Vhost API functions:
of those segments, thus the fewer the segments, the quicker we will get
the mapping. NOTE: we may speed it by using tree searching in future.
- ``RTE_VHOST_USER_IOMMU_SUPPORT``
IOMMU support will be enabled when this flag is set. It is disabled by
default.
Enabling this flag makes possible to use guest vIOMMU to protect vhost
from accessing memory the virtio device isn't allowed to, when the feature
is negotiated and an IOMMU device is declared.
However, this feature enables vhost-user's reply-ack protocol feature,
which implementation is buggy in Qemu v2.7.0-v2.9.0 when doing multiqueue.
Enabling this flag with these Qemu version results in Qemu being blocked
when multiple queue pairs are declared.
* ``rte_vhost_driver_set_features(path, features)``
This function sets the feature bits the vhost-user driver supports. The

3
doc/guides/rel_notes/release_17_11.rst
View File

@ -173,7 +173,8 @@ New Features
* **Added IOMMU support to libvhost-user**
Implemented device IOTLB in Vhost-user backend, and enabled Virtio's IOMMU
feature.
feature. The feature is disabled by default, and can be enabled by setting
RTE_VHOST_USER_IOMMU_SUPPORT flag at vhost device registration time.
* **Added the Event Ethernet Adapter Library.**

1
lib/librte_vhost/rte_vhost.h
View File

@ -56,6 +56,7 @@ extern "C" {
#define RTE_VHOST_USER_CLIENT (1ULL << 0)
#define RTE_VHOST_USER_NO_RECONNECT (1ULL << 1)
#define RTE_VHOST_USER_DEQUEUE_ZERO_COPY (1ULL << 2)
#define RTE_VHOST_USER_IOMMU_SUPPORT (1ULL << 3)
/**
* Information relating to memory regions including offsets to

6
lib/librte_vhost/socket.c
View File

@ -68,6 +68,7 @@ struct vhost_user_socket {
bool is_server;
bool reconnect;
bool dequeue_zero_copy;
bool iommu_support;
/*
* The "supported_features" indicates the feature bits the
@ -669,6 +670,11 @@ rte_vhost_driver_register(const char *path, uint64_t flags)
vsocket->supported_features = VIRTIO_NET_SUPPORTED_FEATURES;
vsocket->features = VIRTIO_NET_SUPPORTED_FEATURES;
if (!(flags & RTE_VHOST_USER_IOMMU_SUPPORT)) {
vsocket->supported_features &= ~(1ULL << VIRTIO_F_IOMMU_PLATFORM);
vsocket->features &= ~(1ULL << VIRTIO_F_IOMMU_PLATFORM);
}
if ((flags & RTE_VHOST_USER_CLIENT) != 0) {
vsocket->reconnect = !(flags & RTE_VHOST_USER_NO_RECONNECT);
if (vsocket->reconnect && reconn_tid == 0) {