- 02 8月, 2016 2 次提交
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由 Jason Wang 提交于
This patch tries to implement an device IOTLB for vhost. This could be used with userspace(qemu) implementation of DMA remapping to emulate an IOMMU for the guest. The idea is simple, cache the translation in a software device IOTLB (which is implemented as an interval tree) in vhost and use vhost_net file descriptor for reporting IOTLB miss and IOTLB update/invalidation. When vhost meets an IOTLB miss, the fault address, size and access can be read from the file. After userspace finishes the translation, it writes the translated address to the vhost_net file to update the device IOTLB. When device IOTLB is enabled by setting VIRTIO_F_IOMMU_PLATFORM all vq addresses set by ioctl are treated as iova instead of virtual address and the accessing can only be done through IOTLB instead of direct userspace memory access. Before each round or vq processing, all vq metadata is prefetched in device IOTLB to make sure no translation fault happens during vq processing. In most cases, virtqueues are contiguous even in virtual address space. The IOTLB translation for virtqueue itself may make it a little slower. We might add fast path cache on top of this patch. Signed-off-by: NJason Wang <jasowang@redhat.com> [mst: use virtio feature bit: VHOST_F_DEVICE_IOTLB -> VIRTIO_F_IOMMU_PLATFORM ] [mst: fix build warnings ] Signed-off-by: NMichael S. Tsirkin <mst@redhat.com> [ weiyj.lk: missing unlock on error ] Signed-off-by: NWei Yongjun <weiyj.lk@gmail.com>
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由 Asias He 提交于
VM sockets vhost transport implementation. This driver runs on the host. Signed-off-by: NAsias He <asias@redhat.com> Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com> Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
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- 11 3月, 2016 1 次提交
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由 Jason Wang 提交于
This patch tries to poll for new added tx buffer or socket receive queue for a while at the end of tx/rx processing. The maximum time spent on polling were specified through a new kind of vring ioctl. Signed-off-by: NJason Wang <jasowang@redhat.com> Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
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- 01 6月, 2015 1 次提交
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由 Greg Kurz 提交于
This patch brings cross-endian support to vhost when used to implement legacy virtio devices. Since it is a relatively rare situation, the feature availability is controlled by a kernel config option (not set by default). The vq->is_le boolean field is added to cache the endianness to be used for ring accesses. It defaults to native endian, as expected by legacy virtio devices. When the ring gets active, we force little endian if the device is modern. When the ring is deactivated, we revert to the native endian default. If cross-endian was compiled in, a vq->user_be boolean field is added so that userspace may request a specific endianness. This field is used to override the default when activating the ring of a legacy device. It has no effect on modern devices. Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com> Signed-off-by: NMichael S. Tsirkin <mst@redhat.com> Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com> Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
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- 02 5月, 2013 1 次提交
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由 Michael S. Tsirkin 提交于
move uapi parts to vhost.h move .c private parts to .c itself Signed-off-by: NMichael S. Tsirkin <mst@redhat.com> Reviewed-by: NAsias He <asias@redhat.com> Acked-by: NNicholas Bellinger <nab@linux-iscsi.org>
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- 13 10月, 2012 1 次提交
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由 David Howells 提交于
Signed-off-by: NDavid Howells <dhowells@redhat.com> Acked-by: NArnd Bergmann <arnd@arndb.de> Acked-by: NThomas Gleixner <tglx@linutronix.de> Acked-by: NMichael Kerrisk <mtk.manpages@gmail.com> Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: NDave Jones <davej@redhat.com>
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- 15 1月, 2010 1 次提交
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由 Michael S. Tsirkin 提交于
What it is: vhost net is a character device that can be used to reduce the number of system calls involved in virtio networking. Existing virtio net code is used in the guest without modification. There's similarity with vringfd, with some differences and reduced scope - uses eventfd for signalling - structures can be moved around in memory at any time (good for migration, bug work-arounds in userspace) - write logging is supported (good for migration) - support memory table and not just an offset (needed for kvm) common virtio related code has been put in a separate file vhost.c and can be made into a separate module if/when more backends appear. I used Rusty's lguest.c as the source for developing this part : this supplied me with witty comments I wouldn't be able to write myself. What it is not: vhost net is not a bus, and not a generic new system call. No assumptions are made on how guest performs hypercalls. Userspace hypervisors are supported as well as kvm. How it works: Basically, we connect virtio frontend (configured by userspace) to a backend. The backend could be a network device, or a tap device. Backend is also configured by userspace, including vlan/mac etc. Status: This works for me, and I haven't see any crashes. Compared to userspace, people reported improved latency (as I save up to 4 system calls per packet), as well as better bandwidth and CPU utilization. Features that I plan to look at in the future: - mergeable buffers - zero copy - scalability tuning: figure out the best threading model to use Note on RCU usage (this is also documented in vhost.h, near private_pointer which is the value protected by this variant of RCU): what is happening is that the rcu_dereference() is being used in a workqueue item. The role of rcu_read_lock() is taken on by the start of execution of the workqueue item, of rcu_read_unlock() by the end of execution of the workqueue item, and of synchronize_rcu() by flush_workqueue()/flush_work(). In the future we might need to apply some gcc attribute or sparse annotation to the function passed to INIT_WORK(). Paul's ack below is for this RCU usage. (Includes fixes by Alan Cox <alan@linux.intel.com>, David L Stevens <dlstevens@us.ibm.com>, Chris Wright <chrisw@redhat.com>) Acked-by: NRusty Russell <rusty@rustcorp.com.au> Acked-by: NArnd Bergmann <arnd@arndb.de> Acked-by: N"Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Signed-off-by: NMichael S. Tsirkin <mst@redhat.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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