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path: root/drivers/char/virtio_console.c
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2010-06-03virtio: console: Fix crash when port is unplugged and blocked for writeAmit Shah
When a program that has a virtio port opened and blocked for a write operation, a port hot-unplug event will later led to a crash when SIGTERM was sent to the program. Fix that. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-06-03virtio: console: Fix crash when hot-unplugging a port and read is blockedAmit Shah
When removing a port we don't check if a program was blocked for read. This leads to a crash when SIGTERM is sent to the program after hot-unplugging the port. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-05-19drivers/char: Eliminate use after freeJulia Lawall
In each case, the first argument to send_control_msg or __send_control_msg, respectively, has either not been successfully allocated or has been freed at the point of the call. In the first case, the first argument, port, is only used to access the portdev and id fields, in order to call __send_control_msg. Thus it seems possible instead to call __send_control_msg directly. In the second case, the call to __send_control_msg is moved up to a place where it seems like the first argument, portdev, has been initialized sufficiently to make the call to __send_control_msg meaningful. This has only been compile tested. A simplified version of the semantic match that finds this problem is as follows: (http://coccinelle.lip6.fr/) // <smpl> @free@ expression E; position p; @@ kfree@p(E) @@ expression free.E, subE<=free.E, E1; position free.p; @@ kfree@p(E) ... ( subE = E1 | * E ) // </smpl> Signed-off-by: Julia Lawall <julia@diku.dk> Acked-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-05-19virtio: console: Accept console size along with resize control messageAmit Shah
The VIRTIO_CONSOLE_RESIZE control message sent to us by the host now contains the new {rows, cols} values for the console. This ensures each console port gets its own size, and we don't depend on the config-space rows and cols values at all now. Signed-off-by: Amit Shah <amit.shah@redhat.com> CC: Christian Borntraeger <borntraeger@de.ibm.com> CC: linuxppc-dev@ozlabs.org CC: Kusanagi Kouichi <slash@ac.auone-net.jp> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-05-19virtio: console: Store each console's size in the console structureAmit Shah
With support for multiple consoles, just using one {rows,cols} pair in the config space is not going to suffice. Store each console's size as part of the console struct. This changes the behaviour for one case when multiport is not enabled: when notifier_add_vio() is called, the console size is taken from that of the last config-space update instead of fetching it afresh from the config space. Also add a helper to update the size in the console struct as we'll need to use the same code to update the size via control messages when multiport support is enabled. Signed-off-by: Amit Shah <amit.shah@redhat.com> CC: Christian Borntraeger <borntraeger@de.ibm.com> CC: linuxppc-dev@ozlabs.org CC: Kusanagi Kouichi <slash@ac.auone-net.jp> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-05-19virtio: console: Resize console port 0 on config intr only if multiport is offAmit Shah
When using multiport, we'll use control messages. Ensure we don't accidentally update port 0 size on config interrupts. Signed-off-by: Amit Shah <amit.shah@redhat.com> CC: Christian Borntraeger <borntraeger@de.ibm.com> CC: linuxppc-dev@ozlabs.org CC: Kusanagi Kouichi <slash@ac.auone-net.jp> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-05-19virtio: console: Add support for nonblocking write()sAmit Shah
If the host port is not open, a write() should either just return if the file is opened in non-blocking mode, or block till the host port is opened. Also, don't spin till host consumes data for nonblocking ports. For non-blocking ports, we can do away with the spinning and reclaim the buffers consumed by the host on the next write call or on the condition that'll make poll return. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-05-19virtio: console: Rename wait_is_over() to will_read_block()Amit Shah
We'll introduce a function that checks if write will block. Have function names that are similar for the two cases. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-05-19virtio: console: Don't always create a port 0 if using multiportAmit Shah
If we're using multiport, there's no point in always creating a console port. Create the console port only if the host doesn't support multiport. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-05-19virtio: console: Use a control message to add portsAmit Shah
Instead of the host and guest independently enumerating ports, switch to a control message to add ports where the host supplies the port number so there's no ambiguity or a possibility of a race between the host and the guest port numbers. We now no longer need the 'nr_ports' config value. Since no kernel has been released with the MULTIPORT changes yet, we have a chance to fiddle with the config space without adding compatibility features. This is beneficial for management software, which would now be able to instantiate ports at known locations and avoid problems that arise with implicit numbering in the host and the guest. This removes the 'guessing game' part of it, and management software can now actually indicate which id to spawn a particular port on. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-05-19virtio: console: Move code around for future patchesAmit Shah
We're going to use add_port() from handle_control_message() in the next patch. Move the add_port() and fill_queue(), which depends on it, above handle_control_message() to avoid forward declarations. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-05-19virtio: console: Remove config work handlerAmit Shah
We're going to switch to using control messages for port hot-plug and initial port discovery. Remove the config work handler which handled port hot-plug so far. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-05-19virtio: console: Don't call hvc_remove() on unplugging console portsAmit Shah
hvc_remove() has some bug which freezes other active hvc ports when one port is removed. So disable calling of hvc_remove() which deregisters a port with the hvc_console. If the hvc_console code calls into our get_chars() routine as a result of a poll operation, we will return -EPIPE and the hvc_console code will then do the necessary cleanup. This call will be restored when the bug in hvc_remove() is found and fixed. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-05-19virtio: console: Return -EPIPE to hvc_console if we lost the connectionAmit Shah
hvc_console handles -EPIPE properly when the connection to the host is lost. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-05-19virtio: console: Let host know of port or device add failuresAmit Shah
The host may want to know and let management apps notify of port or device add failures. Send a control message saying the device or port is not ready in this case. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-05-19virtio: console: Add a __send_control_msg() that can send messages without a ↵Amit Shah
valid port We will introduce control messages that operate on the device as a whole rather than just ports. Make send_control_msg() a wrapper around __send_control_msg() which does not need a valid port. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-05-19virtio: Revert "virtio: disable multiport console support."Amit Shah
This reverts commit b7a413015d2986edf020fba765c906cc9cbcbfc9. Multiport support was disabled for 2.6.34 because we wanted to introduce a new ABI and since we didn't have any released kernel with the older ABI and were out of the merge window, it didn't make sense keeping the older ABI around. Now we revert the patch disabling multiport and rework the ABI in the following patches. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-05-19virtio_console: use virtqueue_xxx wrappersMichael S. Tsirkin
Switch virtio_console to new virtqueue_xxx wrappers. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-04-08virtio: disable multiport console support.Michael S. Tsirkin
Move MULTIPORT feature and related config changes out of exported headers, and disable the feature at runtime. At this point, it seems less risky to keep code around until we can enable it than rip it out completely. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-04-08virtio: console makes incorrect assumption about virtio APIRusty Russell
The get_buf() API sets the second arg to the number of bytes *written* by the other side; in this case it should be zero as these are output buffers. lguest gets this right (obviously kvm's console doesn't), resulting in continual buildup of console writes. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Amit Shah <amit.shah@redhat.com>
2010-04-08virtio: console: Fix early_put_chars usageFrançois Diakhaté
Currently early_put_chars is not used by virtio_console because it can only be used once a port has been found, at which point it's too late because it is no longer needed. This patch should fix it. Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-03-30include cleanup: Update gfp.h and slab.h includes to prepare for breaking ↵Tejun Heo
implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-22virtio: console: Check if port is valid in resize_consoleAmit Shah
The console port could have been hot-unplugged. Check if it is valid before working on it. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2010-03-22virtio: console: Generate a kobject CHANGE event on adding 'name' attributeAmit Shah
When the host lets us know what 'name' a port is assigned, we create the sysfs 'name' attribute. Generate a 'change' event after this so that udev wakes up and acts on the rules for virtio-ports (currently there's only one rule that creates a symlink from the 'name' to the actual char device). Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2010-03-04virtio: console: Use better variable names for fill_queue operationAmit Shah
We want to keep track of the number of buffers added to a vq. Use nr_added_bufs instead of 'ret'. Also, the users of fill_queue() overloaded a local 'err' variable to check the numbers of buffers allocated. Use nr_added_bufs instead of err. Signed-off-by: Amit Shah <amit.shah@redhat.com> Reported-by: Juan Quintela <quintela@redhat.com>
2010-03-04virtio: console: Fix type of 'len' as unsigned intAmit Shah
We declare 'len' as int type but it should be 'unsigned int', as get_buf() wants it to be. Signed-off-by: Amit Shah <amit.shah@redhat.com> Reported-by: Juan Quintela <quintela@redhat.com>
2010-02-24virtio: console: Fill ports' entire in_vq with buffersAmit Shah
Instead of allocating just one buffer for a port's in_vq, fill the entire in_vq with buffers so the host need not stall while an application consumes the data and makes the buffer available again for the host. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24virtio: console: Error out if we can't allocate buffers for control queueAmit Shah
With MULTIPORT support, the control queue is an integral part of the functioning of the device. If we can't get any buffers allocated, the host won't be able to relay important information and the device may not function as intended. Ensure 'probe' doesn't succeed until the control queue has at least one buffer allocated for its ivq. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24virtio: console: Add ability to remove moduleAmit Shah
Add the ability to remove the virtio_console module. This aids debugging. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24virtio: console: Ensure no memleaks in case of unused buffersAmit Shah
If unused data exists in in_vq, ensure we flush that first and then detach unused buffers, which will ensure all buffers from the in_vq are removed. Also ensure we free the buffers after detaching them. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24virtio: console: show error message if hvc_alloc fails for console portsAmit Shah
Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24virtio: console: Add debugfs files for each port to expose debug infoAmit Shah
This is helpful in examining ports' state. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24virtio: console: Add ability to hot-unplug portsAmit Shah
Remove port data; deregister from the hvc core if it's a console port. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24virtio: console: Handle port hot-plugAmit Shah
If the 'nr_ports' variable in the config space is updated to a higher value, that means new ports have been hotplugged. Introduce a new workqueue to handle such updates and create new ports. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24virtio: console: Remove cached data on port closeAmit Shah
Remove any data that we might have in a port's inbuf when closing a port or when any data is received when a port is closed. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24virtio: console: Register with sysfs and create a 'name' attribute for portsAmit Shah
The host can set a name for ports so that they're easily discoverable instead of going by the /dev/vportNpn naming. This attribute will be placed in /sys/class/virtio-ports/vportNpn/name. udev scripts can then create symlinks to the port using the name. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24virtio: console: Ensure only one process can have a port open at a timeAmit Shah
Add a guest_connected field that ensures only one process can have a port open at a time. This also ensures we don't have a race when we later add support for dropping buffers when closing the char dev and buffer caching is turned off for the particular port. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24virtio: console: Add file operations to ports for open/read/write/pollAmit Shah
Allow guest userspace applications to open, read from, write to, poll the ports via the char dev interface. When a port gets opened, a notification is sent to the host via a control message indicating a connection has been established. Similarly, on closing of the port, a notification is sent indicating disconnection. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24virtio: console: Associate each port with a char deviceAmit Shah
The char device will be used as an interface by applications on the guest to communicate with apps on the host. The devices created are placed in /dev/vportNpn where N is the virtio-console device number and n is the port number for that device. One dynamic major device number is allocated for each device and minor numbers are allocated for the ports contained within that device. The file operation for the char devs will be added in the following commits. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24virtio: console: Prepare for writing to userspace buffersAmit Shah
When ports get advertised as char devices, the buffers will come from userspace. Equip the fill_readbuf function with the ability to write to userspace buffers. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24virtio: console: Add a new MULTIPORT feature, support for generic portsAmit Shah
This commit adds a new feature, MULTIPORT. If the host supports this feature as well, the config space has the number of ports defined for that device. New ports are spawned according to this information. The config space also has the maximum number of ports that can be spawned for a particular device. This is useful in initializing the appropriate number of virtqueues in advance, as ports might be hot-plugged in later. Using this feature, generic ports can be created which are not tied to hvc consoles. We also open up a private channel between the host and the guest via which some "control" messages are exchanged for the ports, like whether the port being spawned is a console port, resizing the console window, etc. Next commits will add support for hotplugging and presenting char devices in /dev/ for bi-directional guest-host communication. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24virtio: console: Introduce a send_buf function for a common path for sending ↵Amit Shah
data to host Adding support for generic ports that will write to userspace will need some code changes. Consolidate the write routine into send_buf() and put_chars() now just calls into the new function. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24virtio: console: Introduce function to hand off data from host to readersAmit Shah
In preparation for serving data to userspace (generic ports) as well as in-kernel users (hvc consoles), separate out the functionality common to both in a 'fill_readbuf()' function. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24virtio: console: Separate out find_vqs operation into a different functionAmit Shah
With support for multiple ports, each port will have its own input and output vqs. Prepare the probe function for this change. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24virtio: console: Separate out console init into a new functionAmit Shah
Console ports could be hot-added. Also, with the new multiport support, a port is identified as a console port only if the host sends a control message. Move the console port init into a separate function so it can be invoked from other places. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24virtio: console: Separate out console-specific data into a separate structAmit Shah
Move out console-specific stuff into a separate struct from 'struct port' as we need to maintain two lists: one for all the ports (which includes consoles) and one only for consoles since the hvc callbacks only give us the vtermno. This makes console handling cleaner. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24virtio: console: ensure console size is updated on hvc openAmit Shah
When multiple console support is added, ensure each port's size gets updated when a new one is opened via hvc. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24virtio: console: struct ports for multiple ports per device.Amit Shah
Rather than assume a single port, add a 'struct ports_device' which stores data related to all the ports for that device. Currently, there's only one port and is hooked up with hvc, but that will change. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24virtio: console: remove global varRusty Russell
Now we can use an allocation function to remove our global console variable. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24virtio: console: don't assume a single console port.Amit Shah
Keep a list of all ports being used as a console, and provide a lock and a lookup function. The hvc callbacks only give us a vterm number, so we need to map this. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>