similar to: [PATCH] virtio_console: remove vq buf while unpluging port

On Sun, Apr 28, 2019 at 09:50:04AM +0800, zhenwei pi wrote: > A bug can be easily reproduced: > Host# cat guest-agent.xml > <channel type="unix"> > <source mode="bind" path="/var/lib/libvirt/qemu/stretch.agent"/> > <target type="virtio" name="org.qemu.guest_agent.0" state="connected"/> >

A bug can be easily reproduced: Host# cat guest-agent.xml <channel type="unix"> <source mode="bind" path="/var/lib/libvirt/qemu/stretch.agent"/> <target type="virtio" name="org.qemu.guest_agent.0" state="connected"/> </channel> Host# virsh attach-device instance guest-agent.xml Host# virsh detach-device

The commit a7a69ec0d8e4 ("virtio_console: free buffers after reset") deffered detaching of unused buffer to virtio device unplug time. This causes unplug/replug of single port in virtio device with an error "Error allocating inbufs\n". As we don't free the unused buffers attached with the port. Re-plug the same port tries to allocate new buffers in virtqueue

The commit a7a69ec0d8e4 ("virtio_console: free buffers after reset") deffered detaching of unused buffer to virtio device unplug time. This causes unplug/replug of single port in virtio device with an error "Error allocating inbufs\n". As we don't free the unused buffers attached with the port. Re-plug the same port tries to allocate new buffers in virtqueue

Hello Michael, Thanks for your reply. > > On Mon, Mar 04, 2019 at 06:35:11PM +0530, Pankaj Gupta wrote: > > The commit a7a69ec0d8e4 ("virtio_console: free buffers after reset") > > deffered detaching of unused buffer to virtio device unplug time. > > > > This causes unplug/replug of single port in virtio device with an > > error "Error

Hello Michael, Thanks for your reply. > > On Mon, Mar 04, 2019 at 06:35:11PM +0530, Pankaj Gupta wrote: > > The commit a7a69ec0d8e4 ("virtio_console: free buffers after reset") > > deffered detaching of unused buffer to virtio device unplug time. > > > > This causes unplug/replug of single port in virtio device with an > > error "Error

On Fri, Aug 09, 2019 at 12:18:46PM +0530, Pankaj Gupta wrote: > The commit a7a69ec0d8e4 ("virtio_console: free buffers after reset") > deferred detaching of unused buffer to virtio device unplug time. > This causes unplug/replug of single port in virtio device with an > error "Error allocating inbufs\n". As we don't free the unused buffers > attached with the

On Fri, Aug 09, 2019 at 12:18:46PM +0530, Pankaj Gupta wrote: > The commit a7a69ec0d8e4 ("virtio_console: free buffers after reset") > deferred detaching of unused buffer to virtio device unplug time. > This causes unplug/replug of single port in virtio device with an > error "Error allocating inbufs\n". As we don't free the unused buffers > attached with the

Turns out virtio console tries to take a buffer out of an active vq. Works by sheer luck, and is explicitly forbidden by spec. And while going over it I saw that error handling is also broken - failure is easy to trigger if I force allocations to fail. Lightly tested. Michael S. Tsirkin (6): virtio_console: don't tie bufs to a vq virtio: add ability to iterate over vqs virtio_console:

Turns out virtio console tries to take a buffer out of an active vq. Works by sheer luck, and is explicitly forbidden by spec. And while going over it I saw that error handling is also broken - failure is easy to trigger if I force allocations to fail. Lightly tested. Michael S. Tsirkin (6): virtio_console: don't tie bufs to a vq virtio: add ability to iterate over vqs virtio_console:

Console driver is out of spec. The spec says: A driver MUST NOT decrement the available idx on a live virtqueue (ie. there is no way to ?unexpose? buffers). and it does exactly that by trying to detach unused buffers without doing a device reset first. Defer detaching the buffers until device unplug. Of course this means we might get an interrupt for a vq without an attached port now. Handle

This patch series fixes the issue with unplug/replug of a port in virtio console driver which fails with an error "Error allocating inbufs\n". Patch 1 makes use of 'virtqueue_detach_unused_buf' function to detach the unused buffers during port hotunplug time. Patch 2 updates the next avail index for packed ring code. Tested the packed ring code with the qemu virtio 1.1 device

On Mon, Mar 04, 2019 at 06:35:11PM +0530, Pankaj Gupta wrote: > The commit a7a69ec0d8e4 ("virtio_console: free buffers after reset") > deffered detaching of unused buffer to virtio device unplug time. > > This causes unplug/replug of single port in virtio device with an > error "Error allocating inbufs\n". As we don't free the unused buffers >

> > The commit a7a69ec0d8e4 ("virtio_console: free buffers after reset") > deffered detaching of unused buffer to virtio device unplug time. > > This causes unplug/replug of single port in virtio device with an > error "Error allocating inbufs\n". As we don't free the unused buffers > attached with the port. Re-plug the same port tries to

The commit a7a69ec0d8e4 ("virtio_console: free buffers after reset") deferred detaching of unused buffer to virtio device unplug time. This causes unplug/replug of single port in virtio device with an error "Error allocating inbufs\n". As we don't free the unused buffers attached with the port. Re-plug the same port tries to allocate new buffers in virtqueue and

The commit a7a69ec0d8e4 ("virtio_console: free buffers after reset") deferred detaching of unused buffer to virtio device unplug time. This causes unplug/replug of single port in virtio device with an error "Error allocating inbufs\n". As we don't free the unused buffers attached with the port. Re-plug the same port tries to allocate new buffers in virtqueue and results in

On Tue, Mar 05, 2019 at 02:09:06AM -0500, Pankaj Gupta wrote: > > Hello Michael, > > Thanks for your reply. > > > > > On Mon, Mar 04, 2019 at 06:35:11PM +0530, Pankaj Gupta wrote: > > > The commit a7a69ec0d8e4 ("virtio_console: free buffers after reset") > > > deffered detaching of unused buffer to virtio device unplug time. > >

When we hot unplug a virtserialport and then try to hot plug again, it fails: (qemu) chardev-add socket,id=serial0,path=/tmp/serial0,server,nowait (qemu) device_add virtserialport,bus=virtio-serial0.0,nr=2,\ chardev=serial0,id=serial0,name=serial0 (qemu) device_del serial0 (qemu) device_add virtserialport,bus=virtio-serial0.0,nr=2,\

When we hot unplug a virtserialport and then try to hot plug again, it fails: (qemu) chardev-add socket,id=serial0,path=/tmp/serial0,server,nowait (qemu) device_add virtserialport,bus=virtio-serial0.0,nr=2,\ chardev=serial0,id=serial0,name=serial0 (qemu) device_del serial0 (qemu) device_add virtserialport,bus=virtio-serial0.0,nr=2,\

> > On Fri, Aug 09, 2019 at 12:18:46PM +0530, Pankaj Gupta wrote: > > The commit a7a69ec0d8e4 ("virtio_console: free buffers after reset") > > deferred detaching of unused buffer to virtio device unplug time. > > This causes unplug/replug of single port in virtio device with an > > error "Error allocating inbufs\n". As we don't free the unused