From b3258ff1d6086bd2b9eeb556844a868ad7d49bc8 Mon Sep 17 00:00:00 2001 From: Amit Shah Date: Wed, 16 Mar 2011 19:12:10 +0530 Subject: virtio: Decrement avail idx on buffer detach 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 --- drivers/virtio/virtio_ring.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers') diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index cc2f73e0347..b0043fb26a4 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -371,6 +371,7 @@ void *virtqueue_detach_unused_buf(struct virtqueue *_vq) /* detach_buf clears data, so grab it now. */ buf = vq->data[i]; detach_buf(vq, i); + vq->vring.avail->idx--; END_USE(vq); return buf; } -- cgit v1.2.3-70-g09d2 From 31a3ddda166cda86d2b5111e09ba4bda5239fae6 Mon Sep 17 00:00:00 2001 From: Amit Shah Date: Mon, 14 Mar 2011 17:45:02 +0530 Subject: virtio_pci: Prevent double-free of pci regions after device hot-unplug 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 --- drivers/virtio/virtio_pci.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) (limited to 'drivers') diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c index 4fb5b2bf234..4bcc8b82640 100644 --- a/drivers/virtio/virtio_pci.c +++ b/drivers/virtio/virtio_pci.c @@ -590,15 +590,10 @@ static struct virtio_config_ops virtio_pci_config_ops = { static void virtio_pci_release_dev(struct device *_d) { - struct virtio_device *dev = container_of(_d, struct virtio_device, dev); + struct virtio_device *dev = container_of(_d, struct virtio_device, + dev); struct virtio_pci_device *vp_dev = to_vp_device(dev); - struct pci_dev *pci_dev = vp_dev->pci_dev; - vp_del_vqs(dev); - pci_set_drvdata(pci_dev, NULL); - pci_iounmap(pci_dev, vp_dev->ioaddr); - pci_release_regions(pci_dev); - pci_disable_device(pci_dev); kfree(vp_dev); } @@ -681,6 +676,12 @@ static void __devexit virtio_pci_remove(struct pci_dev *pci_dev) struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev); unregister_virtio_device(&vp_dev->vdev); + + vp_del_vqs(&vp_dev->vdev); + pci_set_drvdata(pci_dev, NULL); + pci_iounmap(pci_dev, vp_dev->ioaddr); + pci_release_regions(pci_dev); + pci_disable_device(pci_dev); } #ifdef CONFIG_PM -- cgit v1.2.3-70-g09d2 From afa2689e19073cd2e762d0f2c1358fab1ab9f18c Mon Sep 17 00:00:00 2001 From: Amit Shah Date: Mon, 14 Mar 2011 17:45:48 +0530 Subject: virtio: console: Enable call to hvc_remove() on console port remove This call was disabled as hot-unplugging one virtconsole port led to another virtconsole port freezing. Upon testing it again, this now works, so enable it. In addition, a bug was found in qemu wherein removing a port of one type caused the guest output from another port to stop working. I doubt it was just this bug that caused it (since disabling the hvc_remove() call did allow other ports to continue working), but since it's all solved now, we're fine with hot-unplugging of virtconsole ports. Signed-off-by: Amit Shah Signed-off-by: Rusty Russell --- drivers/char/virtio_console.c | 11 ----------- 1 file changed, 11 deletions(-) (limited to 'drivers') diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index 84b164d1eb2..838568a7dbf 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -1280,18 +1280,7 @@ static void unplug_port(struct port *port) spin_lock_irq(&pdrvdata_lock); list_del(&port->cons.list); spin_unlock_irq(&pdrvdata_lock); -#if 0 - /* - * hvc_remove() not called as removing one hvc port - * results in other hvc ports getting frozen. - * - * Once this is resolved in hvc, this functionality - * will be enabled. Till that is done, the -EPIPE - * return from get_chars() above will help - * hvc_console.c to clean up on ports we remove here. - */ hvc_remove(port->cons.hvc); -#endif } /* Remove unused data this port might have received. */ -- cgit v1.2.3-70-g09d2