Include linux/delay.h to fix compiler error: drivers/virtio/virtio_balloon.c: In function 'fill_balloon': drivers/virtio/virtio_balloon.c:98: error: implicit declaration of function 'msleep' Signed-off-by: Johann Felix Soden <johfel@users.sourceforge.net> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After discussions with Anthony Liguori, it seems that the virtio balloon can be made even simpler. Here's my attempt. The device configuration tells the driver how much memory it should take from the guest (ie. balloon size). The guest feeds the page numbers it has taken via one virtqueue. A second virtqueue feeds the page numbers the driver wants back: if the device has the VIRTIO_BALLOON_F_MUST_TELL_HOST bit, then this queue is compulsory, otherwise it's advisory (and the guest can simply fault the pages back in). This driver can be enhanced later to deflate the balloon via a shrinker, oom callback or we could even go for a complete set of in-guest regulators. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
As Avi pointed out, as we continue to massage the virtio PCI ABI, we can make things a little more friendly to users by utilizing the PCI revision field to indicate which version of the ABI we're using. This is a hard ABI version and incrementing it will cause the guest driver to break. This is the necessary changes to virtio_pci to support this. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This is a PCI device that implements a transport for virtio. It allows virtio devices to be used by QEMU based VMMs like KVM or Xen. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This is needed for the virtio PCI device to be compiled as a module. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Simple cleanup. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Anthony Liguori found double interrupt suppression in the virtio_net driver, triggered by two skb_recv_done's in a row. This is because virtio_ring's interrupt suppression is a best-effort optimization: it contains no synchronization so the host can miss it and still send interrupts. But it's certainly nicer for virtio users if calling disable_cb actually disables callbacks, so we check for the race in the interrupt routine. Note: SMP guests might require syncronization here, but since disable_cb is actually called from interrupt context, there has to be some form of synchronization before the next same interrupt handler is called (Linux guarantees that the same device's irq handler will never run simultanously on multiple CPUs). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
A reset function solves three problems: 1) It allows us to renegotiate features, eg. if we want to upgrade a guest driver without rebooting the guest. 2) It gives us a clean way of shutting down virtqueues: after a reset, we know that the buffers won't be used by the host, and 3) It helps the guest recover from messed-up drivers. So we remove the ->shutdown hook, and the only way we now remove feature bits is via reset. We leave it to the driver to do the reset before it deletes queues: the balloon driver, for example, needs to chat to the host in its remove function. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
The other side (host) can set the NO_NOTIFY flag as an optimization, to say "no need to kick me when you add things". Make it clear that this is advisory only; especially that we should always notify when the ring is full. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
It seems that virtio_net wants to disable callbacks (interrupts) before calling netif_rx_schedule(), so we can't use the return value to do so. Rename "restart" to "cb_enable" and introduce "cb_disable" hook: callback now returns void, rather than a boolean. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>