linux/drivers/virtio, branch v3.1

virtio: expose for non-virtualization users too

2011-07-23T06:50:30Z

virtio has been so far used only in the context of virtualization, and the virtio Kconfig was sourced directly by the relevant arch Kconfigs when VIRTUALIZATION was selected. Now that we start using virtio for inter-processor communications, we need to source the virtio Kconfig outside of the virtualization scope too. Moreover, some architectures might use virtio for both virtualization and inter-processor communications, so directly sourcing virtio might yield unexpected results due to conflicting selections. The simple solution offered by this patch is to always source virtio's Kconfig in drivers/Kconfig, and remove it from the appropriate arch Kconfigs. Additionally, a virtio menu entry has been added so virtio drivers don't show up in the general drivers menu. This way anyone can use virtio, though it's arguably less accessible (and neat!) for virtualization users now. Note: some architectures (mips and sh) seem to have a VIRTUALIZATION menu merely for sourcing virtio's Kconfig, so that menu is removed too. Signed-off-by: Ohad Ben-Cohen Signed-off-by: Rusty Russell

virtio: add api for delayed callbacks

2011-05-30T01:44:16Z

Add an API that tells the other side that callbacks should be delayed until a lot of work has been done. Implement using the new event_idx feature. Note: it might seem advantageous to let the drivers ask for a callback after a specific capacity has been reached. However, as a single head can free many entries in the descriptor table, we don't really have a clue about capacity until get_buf is called. The API is the simplest to implement at the moment, we'll see what kind of hints drivers can pass when there's more than one user of the feature. Signed-off-by: Michael S. Tsirkin Signed-off-by: Rusty Russell

virtio_ring: support event idx feature

2011-05-30T01:44:15Z

Support for the new event idx feature: 1. When enabling interrupts, publish the current avail index value to the host to get interrupts on the next update. 2. Use the new avail_event feature to reduce the number of exits from the guest. Simple test with the simulator: [virtio]# time ./virtio_test spurious wakeus: 0x7 real 0m0.169s user 0m0.140s sys 0m0.019s [virtio]# time ./virtio_test --no-event-idx spurious wakeus: 0x11 real 0m0.649s user 0m0.295s sys 0m0.335s Signed-off-by: Michael S. Tsirkin Signed-off-by: Rusty Russell

virtio balloon: kill tell-host-first logic

2011-05-30T01:44:13Z

The virtio balloon driver has a VIRTIO_BALLOON_F_MUST_TELL_HOST feature bit. Whenever the bit is set, the guest kernel must always tell the host before we free pages back to the allocator. Without this feature, we might free a page (and have another user touch it) while the hypervisor is unprepared for it. But, if the bit is _not_ set, we are under no obligation to reverse the order; we're under no obligation to do _anything_. As of now, qemu-kvm defines the bit, but doesn't set it. This patch makes the "tell host first" logic the only case. This should make everybody happy, and reduce the amount of untested or untestable code in the kernel. This _also_ means that we don't have to preserve a pfn list after the pages are freed, which should let us get rid of some temporary storage (vb->pfns) eventually. Signed-off-by: Dave Hansen Signed-off-by: Rusty Russell

virtio_pci: Prevent double-free of pci regions after device hot-unplug

2011-04-21T13:27:00Z

In the case where a virtio-console port is in use (opened by a program) and a virtio-console device is removed, the port is kept around but all the virtio-related state is assumed to be gone. When the port is finally released (close() called), we call device_destroy() on the port's device. This results in the parent device's structures to be freed as well. This includes the PCI regions for the virtio-console PCI device. Once this is done, however, virtio_pci_release_dev() kicks in, as the last ref to the virtio device is now gone, and attempts to do pci_iounmap(pci_dev, vp_dev->ioaddr); pci_release_regions(pci_dev); pci_disable_device(pci_dev); which results in a double-free warning. Move the code that releases regions, etc., to the virtio_pci_remove() function, and all that's now left in release_dev is the final freeing of the vp_dev. Signed-off-by: Amit Shah Signed-off-by: Rusty Russell

virtio: Decrement avail idx on buffer detach

2011-04-21T13:27:00Z

When detaching a buffer from a vq, the avail.idx value should be decremented as well. This was noticed by hot-unplugging a virtio console port and then plugging in a new one on the same number (re-using the vqs which were just 'disowned'). qemu reported 'Guest moved used index from 0 to 256' when any IO was attempted on the new port. CC: stable@kernel.org Reported-by: juzhang Signed-off-by: Amit Shah Signed-off-by: Rusty Russell

virtio: remove virtio-pci root device

2011-01-20T11:07:30Z

We sometimes need to map between the virtio device and the given pci device. One such use is OS installer that gets the boot pci device from BIOS and needs to find the relevant block device. Since it can't, installation fails. Instead of creating a top-level devices/virtio-pci directory, create each device under the corresponding pci device node. Symlinks to all virtio-pci devices can be found under the pci driver link in bus/pci/drivers/virtio-pci/devices, and all virtio devices under drivers/bus/virtio/devices. Signed-off-by: Milton Miller Signed-off-by: Rusty Russell Acked-by: Michael S. Tsirkin Tested-by: Michael S. Tsirkin Acked-by: Gleb Natapov Tested-by: "Daniel P. Berrange" Cc: stable@kernel.org

virtio: fix format of sysfs driver/vendor files

2010-11-24T04:51:12Z

The sysfs files for virtio produce the wrong format and are missing the required newline. The output for virtio bus vendor/device should have the same format as the corresponding entries for PCI devices. Although this technically changes the ABI for sysfs, these files were broken to start with! Signed-off-by: Stephen Hemminger Signed-off-by: Rusty Russell

virtio: return correct capacity to users

2010-11-24T04:51:11Z

We can't rely on indirect buffers for capacity calculations because they need a memory allocation which might fail. In particular, virtio_net can get into this situation under stress, and it drops packets and performs badly. So return the number of buffers we can guarantee users. Signed-off-by: Michael S. Tsirkin Signed-off-by: Rusty Russell Reported-By: Krishna Kumar2

virtio: fix oops on OOM

2010-07-26T15:05:31Z

virtio ring was changed to return an error code on OOM, but one caller was missed and still checks for vq->vring.num. The fix is just to check for <0 error code. Long term it might make sense to change goto add_head to just return an error on oom instead, but let's apply a minimal fix for 2.6.35. Reported-by: Chris Mason Signed-off-by: Michael S. Tsirkin Signed-off-by: Rusty Russell Tested-by: Chris Mason Cc: stable@kernel.org # .34.x Signed-off-by: Linus Torvalds