While we are at it, don't do kmap() under kmap_atomic(), *especially*
for a page we'd allocated with GFP_KERNEL. It's spelled "page_address",
and had that been more than that, we'd have a real trouble - kmap_high()
can block, and doing that while holding kmap_atomic() is a Bad Idea(tm).
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
If virtqueue_get_buf() returns with a NULL pointer it should be verified
if the virtqueue is broken, in order to avoid loop calling cpu_relax().
Signed-off-by: Heinz Graalfs <graalfs@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This lets the transport do endian conversion if necessary, and insulates
the drivers from the difference.
Most drivers can use the simple helpers virtio_cread() and virtio_cwrite().
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
The freeze and restore functions defined in virtio drivers are used
for suspend and hibernate, so CONFIG_PM_SLEEP is more appropriate than
CONFIG_PM. This patch replace all CONFIG_PM with CONFIG_PM_SLEEP for
virtio drivers that implement freeze and restore callbacks.
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Remove the debugfs path before freeing port->name, to prevent a possible
use-after-free.
Reported-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
The next commit gets conflicts because it relies on patches which were
cc:stable and thus had to be merged into Linus' tree before the coming
merge window. So pull in master now.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
The PTR_ERR(NULL) here is not useful.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
send_sigio_to_port() checks the value of guest_connected, which we
always modify under the inbuf_lock; make sure invocations of
send_sigio_to_port() have take the inbuf_lock around the call.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Port unplug can race with close() in port_fops_release().
port_fops_release() already takes the necessary locks, ensure
unplug_port() does that too.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
The removal functions act on the vqs, and the vq operations need to be
locked.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
If a port gets unplugged while a user is blocked on read(), -ENODEV is
returned. However, subsequent read()s returned 0, indicating there's no
host-side connection (but not indicating the device went away).
This also happened when a port was unplugged and the user didn't have
any blocking operation pending. If the user didn't monitor the SIGIO
signal, they won't have a chance to find out if the port went away.
Fix by returning -ENODEV on all read()s after the port gets unplugged.
write() already behaves this way.
CC: <stable@vger.kernel.org>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
SIGIO should be sent when a port gets unplugged. It should only be sent
to prcesses that have the port opened, and have asked for SIGIO to be
delivered. We were clearing out guest_connected before calling
send_sigio_to_port(), resulting in a sigio not getting sent to
processes.
Fix by setting guest_connected to false after invoking the sigio
function.
CC: <stable@vger.kernel.org>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We used to keep the port's char device structs and the /sys entries
around till the last reference to the port was dropped. This is
actually unnecessary, and resulted in buggy behaviour:
1. Open port in guest
2. Hot-unplug port
3. Hot-plug a port with the same 'name' property as the unplugged one
This resulted in hot-plug being unsuccessful, as a port with the same
name already exists (even though it was unplugged).
This behaviour resulted in a warning message like this one:
-------------------8<---------------------------------------
WARNING: at fs/sysfs/dir.c:512 sysfs_add_one+0xc9/0x130() (Not tainted)
Hardware name: KVM
sysfs: cannot create duplicate filename
'/devices/pci0000:00/0000:00:04.0/virtio0/virtio-ports/vport0p1'
Call Trace:
[<ffffffff8106b607>] ? warn_slowpath_common+0x87/0xc0
[<ffffffff8106b6f6>] ? warn_slowpath_fmt+0x46/0x50
[<ffffffff811f2319>] ? sysfs_add_one+0xc9/0x130
[<ffffffff811f23e8>] ? create_dir+0x68/0xb0
[<ffffffff811f2469>] ? sysfs_create_dir+0x39/0x50
[<ffffffff81273129>] ? kobject_add_internal+0xb9/0x260
[<ffffffff812733d8>] ? kobject_add_varg+0x38/0x60
[<ffffffff812734b4>] ? kobject_add+0x44/0x70
[<ffffffff81349de4>] ? get_device_parent+0xf4/0x1d0
[<ffffffff8134b389>] ? device_add+0xc9/0x650
-------------------8<---------------------------------------
Instead of relying on guest applications to release all references to
the ports, we should go ahead and unregister the port from all the core
layers. Any open/read calls on the port will then just return errors,
and an unplug/plug operation on the host will succeed as expected.
This also caused buggy behaviour in case of the device removal (not just
a port): when the device was removed (which means all ports on that
device are removed automatically as well), the ports with active
users would clean up only when the last references were dropped -- and
it would be too late then to be referencing char device pointers,
resulting in oopses:
-------------------8<---------------------------------------
PID: 6162 TASK: ffff8801147ad500 CPU: 0 COMMAND: "cat"
#0 [ffff88011b9d5a90] machine_kexec at ffffffff8103232b
#1 [ffff88011b9d5af0] crash_kexec at ffffffff810b9322
#2 [ffff88011b9d5bc0] oops_end at ffffffff814f4a50
#3 [ffff88011b9d5bf0] die at ffffffff8100f26b
#4 [ffff88011b9d5c20] do_general_protection at ffffffff814f45e2
#5 [ffff88011b9d5c50] general_protection at ffffffff814f3db5
[exception RIP: strlen+2]
RIP: ffffffff81272ae2 RSP: ffff88011b9d5d00 RFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff880118901c18 RCX: 0000000000000000
RDX: ffff88011799982c RSI: 00000000000000d0 RDI: 3a303030302f3030
RBP: ffff88011b9d5d38 R8: 0000000000000006 R9: ffffffffa0134500
R10: 0000000000001000 R11: 0000000000001000 R12: ffff880117a1cc10
R13: 00000000000000d0 R14: 0000000000000017 R15: ffffffff81aff700
ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
#6 [ffff88011b9d5d00] kobject_get_path at ffffffff8126dc5d
#7 [ffff88011b9d5d40] kobject_uevent_env at ffffffff8126e551
#8 [ffff88011b9d5dd0] kobject_uevent at ffffffff8126e9eb
#9 [ffff88011b9d5de0] device_del at ffffffff813440c7
-------------------8<---------------------------------------
So clean up when we have all the context, and all that's left to do when
the references to the port have dropped is to free up the port struct
itself.
CC: <stable@vger.kernel.org>
Reported-by: chayang <chayang@redhat.com>
Reported-by: YOGANANTH SUBRAMANIAN <anantyog@in.ibm.com>
Reported-by: FuXiangChun <xfu@redhat.com>
Reported-by: Qunfang Zhang <qzhang@redhat.com>
Reported-by: Sibiao Luo <sluo@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Between open() being called and processed, the port can be unplugged.
Check if this happened, and bail out.
A simple test script to reproduce this is:
while true; do for i in $(seq 1 100); do echo $i > /dev/vport0p3; done; done;
This opens and closes the port a lot of times; unplugging the port while
this is happening triggers the bug.
CC: <stable@vger.kernel.org>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
There's a window between find_port_by_devt() returning a port and us
taking a kref on the port, where the port could get unplugged. Fix it
by taking the reference in find_port_by_devt() itself.
Problem reported and analyzed by Mateusz Guzik.
CC: <stable@vger.kernel.org>
Reported-by: Mateusz Guzik <mguzik@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Quit from splice_write if pipe->nrbufs is 0 for avoiding oops in virtio-serial.
When an application was doing splice from a kernel buffer to virtio-serial on
a guest, the application received signal(SIGINT). This situation will normally
happen, but the kernel executed a kernel panic by oops as follows:
BUG: unable to handle kernel paging request at ffff882071c8ef28
IP: [<ffffffff812de48f>] sg_init_table+0x2f/0x50
PGD 1fac067 PUD 0
Oops: 0000 [#1] SMP
Modules linked in: lockd sunrpc bnep bluetooth rfkill ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter ip6_tables snd_hda_intel snd_hda_codec snd_hwdep snd_pcm snd_page_alloc snd_timer snd microcode virtio_balloon virtio_net pcspkr soundcore i2c_piix4 i2c_core uinput floppy
CPU: 1 PID: 908 Comm: trace-cmd Not tainted 3.10.0+ #49
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007
task: ffff880071c64650 ti: ffff88007bf24000 task.ti: ffff88007bf24000
RIP: 0010:[<ffffffff812de48f>] [<ffffffff812de48f>] sg_init_table+0x2f/0x50
RSP: 0018:ffff88007bf25dd8 EFLAGS: 00010286
RAX: 0000001fffffffe0 RBX: ffff882071c8ef28 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff880071c8ef48
RBP: ffff88007bf25de8 R08: ffff88007fd15d40 R09: ffff880071c8ef48
R10: ffffea0001c71040 R11: ffffffff8139c555 R12: 0000000000000000
R13: ffff88007506a3c0 R14: ffff88007c862500 R15: ffff880071c8ef00
FS: 00007f0a3646c740(0000) GS:ffff88007fd00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff882071c8ef28 CR3: 000000007acbb000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Stack:
ffff880071c8ef48 ffff88007bf25e20 ffff88007bf25e88 ffffffff8139d6fa
ffff88007bf25e28 ffffffff8127a3f4 0000000000000000 0000000000000000
ffff880071c8ef48 0000100000000000 0000000000000003 ffff88007bf25e08
Call Trace:
[<ffffffff8139d6fa>] port_fops_splice_write+0xaa/0x130
[<ffffffff8127a3f4>] ? selinux_file_permission+0xc4/0x120
[<ffffffff8139d650>] ? wait_port_writable+0x1b0/0x1b0
[<ffffffff811a6fe0>] do_splice_from+0xa0/0x110
[<ffffffff811a951f>] SyS_splice+0x5ff/0x6b0
[<ffffffff8161f8c2>] system_call_fastpath+0x16/0x1b
Code: c1 e2 05 48 89 e5 48 83 ec 10 4c 89 65 f8 41 89 f4 31 f6 48 89 5d f0 48 89 fb e8 8d ce ff ff 41 8d 44 24 ff 48 c1 e0 05 48 01 c3 <48> 8b 03 48 83 e0 fe 48 83 c8 02 48 89 03 48 8b 5d f0 4c 8b 65
RIP [<ffffffff812de48f>] sg_init_table+0x2f/0x50
RSP <ffff88007bf25dd8>
CR2: ffff882071c8ef28
---[ end trace 86323505eb42ea8f ]---
It seems to induce pagefault in sg_init_tabel() when pipe->nrbufs is equal to
zero. This may happen in a following situation:
(1) The application normally does splice(read) from a kernel buffer, then does
splice(write) to virtio-serial.
(2) The application receives SIGINT when is doing splice(read), so splice(read)
is failed by EINTR. However, the application does not finish the operation.
(3) The application tries to do splice(write) without pipe->nrbufs.
(4) The virtio-console driver tries to touch scatterlist structure sgl in
sg_init_table(), but the region is out of bound.
To avoid the case, a kernel should check whether pipe->nrbufs is empty or not
when splice_write is executed in the virtio-console driver.
V3: Add Reviewed-by lines and stable@ line in sign-off area.
Signed-off-by: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Amit Shah <amit.shah@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable@vger.kernel.org
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
I dived into lguest again, reworking the pagetable code so we can move
the switcher page: our fixmaps sometimes take more than 2MB now...
Cheers,
Rusty.
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Merge tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux
Pull virtio & lguest updates from Rusty Russell:
"Lots of virtio work which wasn't quite ready for last merge window.
Plus I dived into lguest again, reworking the pagetable code so we can
move the switcher page: our fixmaps sometimes take more than 2MB now..."
Ugh. Annoying conflicts with the tcm_vhost -> vhost_scsi rename.
Hopefully correctly resolved.
* tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (57 commits)
caif_virtio: Remove bouncing email addresses
lguest: improve code readability in lg_cpu_start.
virtio-net: fill only rx queues which are being used
lguest: map Switcher below fixmap.
lguest: cache last cpu we ran on.
lguest: map Switcher text whenever we allocate a new pagetable.
lguest: don't share Switcher PTE pages between guests.
lguest: expost switcher_pages array (as lg_switcher_pages).
lguest: extract shadow PTE walking / allocating.
lguest: make check_gpte et. al return bool.
lguest: assume Switcher text is a single page.
lguest: rename switcher_page to switcher_pages.
lguest: remove RESERVE_MEM constant.
lguest: check vaddr not pgd for Switcher protection.
lguest: prepare to make SWITCHER_ADDR a variable.
virtio: console: replace EMFILE with EBUSY for already-open port
virtio-scsi: reset virtqueue affinity when doing cpu hotplug
virtio-scsi: introduce multiqueue support
virtio-scsi: push vq lock/unlock into virtscsi_vq_done
virtio-scsi: pass struct virtio_scsi to virtqueue completion function
...
Returning EMFILE (process has too many open files) is incorrect to
indicate a port is already open by another process. Use EBUSY for that.
This does change what we report to userspace, but I believe userspace
can look at it this way: it gets EBUSY, a new error code, instead of
EMFILE. It's still an error, and that's not changing.
Reported-by: Mateusz Guzik <mguzik@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Those symbols only used within this file, and should be static.
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
When multiple ovq operations are being performed (lots of open/close
operations on virtio_console fds), the __send_control_msg() function can
get confused without locking.
A simple recipe to cause badness is:
* create a QEMU VM with two virtio-serial ports
* in the guest, do
while true;do echo abc >/dev/vport0p1;done
while true;do echo edf >/dev/vport0p2;done
In one run, this caused a panic in __send_control_msg(). In another, I
got
virtio_console virtio0: control-o:id 0 is not a head!
This also results repeated messages similar to these on the host:
qemu-kvm: virtio-serial-bus: Unexpected port id 478762112 for device virtio-serial-bus.0
qemu-kvm: virtio-serial-bus: Unexpected port id 478762368 for device virtio-serial-bus.0
Reported-by: FuXiangChun <xfu@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Reviewed-by: Asias He <asias@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org
The cvq_lock was taken for the c_ivq. Rename the lock to make that
obvious.
We'll also add a lock around the c_ovq in the next commit, so there's no
ambiguity.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Asias He <asias@redhat.com>
Reviewed-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org
We never add buffers with input and output parts, so use the new accessors.
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This reverts commit 8078db789a, and
adds a lengthy comment explaining the problem area.
The reverted patch caused opening of ports to fail for rproc_serial.
In probe guest_connected was set to true, but port_fops_open()
fails with -EMFILE if guest_connected already is true.
Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cheers,
Rusty.
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Merge tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux
Pull virtio updates from Rusty Russell:
"All trivial, thanks to the stuff which didn't quite make it time"
* tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
virtio_console: Initialize guest_connected=true for rproc_serial
virtio: use module_virtio_driver.
virtio: Add module driver macro for virtio drivers.
virtio_console: Use virtio device index to generate port name
virtio: make pci_device_id const
virtio: make config_ops const
virtio-mmio: fix wrong comment about register offset
virtio_console: Let unconnected rproc device receive data.
When rproc_serial is initialized, guest_connected should be set
to true. We can then revert the extra checks introduced in
commit: "virtio_console: Let unconnected rproc device receive data."
Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Use virtio device index for creating unique device port names.
Current index allocation in virtio is based on a monotonically
increasing variable "index". A better handling of this is to
use device index which is allocated by ida.
Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Allow rproc serial ports to receive data before the port
is connected.
Rproc serial ports usually talk to very simple remote devices
with no control queue managing open/close events. So we must
let remote devices write to the virtio ring even if the device
is not yet fully initialized.
Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
CONFIG_HOTPLUG is going away as an option. As a result, the __dev*
markings need to be removed.
This change removes the use of __devinit, __devexit_p, __devinitdata,
__devinitconst, and __devexit from these drivers.
Based on patches originally written by Bill Pemberton, but redone by me
in order to handle some of the coding style issues better, by hand.
Cc: Bill Pemberton <wfp5p@virginia.edu>
Cc: David Airlie <airlied@linux.ie>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Latinoware 2012.
There's a slightly non-trivial merge in virtio-net, as we cleaned up the
virtio add_buf interface while DaveM accepted the mq virtio-net patches.
You can see my solution in my pending-rebases branch, if that helps, but I
know you love merging:
https://git.kernel.org/?p=linux/kernel/git/rusty/linux.git;a=commit;h=12e4e64fa66a4c812e4855de32abdb4d819526fe
Cheers,
Rusty.
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Merge tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux
Pull virtio update from Rusty Russell:
"Some nice cleanups, and even a patch my wife did as a "live" demo for
Latinoware 2012.
There's a slightly non-trivial merge in virtio-net, as we cleaned up
the virtio add_buf interface while DaveM accepted the mq virtio-net
patches."
* tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (27 commits)
virtio_console: Add support for remoteproc serial
virtio_console: Merge struct buffer_token into struct port_buffer
virtio: add drv_to_virtio to make code clearly
virtio: use dev_to_virtio wrapper in virtio
virtio-mmio: Fix irq parsing in command line parameter
virtio_console: Free buffers from out-queue upon close
virtio: Convert dev_printk(KERN_<LEVEL> to dev_<level>(
virtio_console: Use kmalloc instead of kzalloc
virtio_console: Free buffer if splice fails
virtio: tools: make it clear that virtqueue_add_buf() no longer returns > 0
virtio: scsi: make it clear that virtqueue_add_buf() no longer returns > 0
virtio: rpmsg: make it clear that virtqueue_add_buf() no longer returns > 0
virtio: net: make it clear that virtqueue_add_buf() no longer returns > 0
virtio: console: make it clear that virtqueue_add_buf() no longer returns > 0
virtio: make virtqueue_add_buf() returning 0 on success, not capacity.
virtio: console: don't rely on virtqueue_add_buf() returning capacity.
virtio_net: don't rely on virtqueue_add_buf() returning capacity.
virtio-net: remove unused skb_vnet_hdr->num_sg field
virtio-net: correct capacity math on ring full
virtio: move queue_index and num_free fields into core struct virtqueue.
...
Add a simple serial connection driver called
VIRTIO_ID_RPROC_SERIAL (11) for communicating with a
remote processor in an asymmetric multi-processing
configuration.
This implementation reuses the existing virtio_console
implementation, and adds support for DMA allocation
of data buffers and disables use of tty console and
the virtio control queue.
Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Refactoring the splice functionality by unifying the approach for
sending scatter-lists and regular buffers. This simplifies
buffer handling and reduces code size. Splice will now allocate
a port_buffer and send_buf() and free_buf() can always be used
for any buffer.
Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Free pending output buffers from the virtio out-queue when
host has acknowledged port_close.
Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (rebased & cut down)
Avoid the more cpu expensive kzalloc when allocating buffers.
Originally kzalloc was intended for isolating the guest from
the host by not sending random guest data to the host. But device
isolation is not yet in place so kzalloc is not really needed.
Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Free the allocated scatter list if send_pages fails in function
port_splice_write.
Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
If register_virtio_driver() fails, virtio-ports class is not destroyed.
The patch adds error handling of register_virtio_driver().
Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Allocate scatterlist according to the current pipe size.
This allows splicing bigger buffer if the pipe size has
been changed by fcntl.
Changes in v2:
- Just a minor fix for avoiding a confliction with previous patch.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Wait if the port is not connected or full on splice
like as write is doing.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Add a failback memcpy path for unstealable pipe buffer.
If buf->ops->steal() fails, virtio-serial tries to
copy the page contents to an allocated page, instead
of just failing splice().
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Enable to use splice_write from pipe to virtio-console port.
This steals pages from pipe and directly send it to host.
Note that this may accelerate only the guest to host path.
Changes in v2:
- Use GFP_KERNEL instead of GFP_ATOMIC in syscall context function.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
If a port was open before going into one of the sleep states, the port
can continue normal operation after restore. However, the host has to
be told that the guest side of the connection is open to restore
pre-suspend state.
This wasn't noticed so far due to a bug in qemu that was fixed recently
(which marked the guest-side connection as always open).
CC: stable@vger.kernel.org # Only for 3.3
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Many users of debugfs copy the implementation of default_open() when
they want to support a custom read/write function op. This leads to a
proliferation of the default_open() implementation across the entire
tree.
Now that the common implementation has been consolidated into libfs we
can replace all the users of this function with simple_open().
This replacement was done with the following semantic patch:
<smpl>
@ open @
identifier open_f != simple_open;
identifier i, f;
@@
-int open_f(struct inode *i, struct file *f)
-{
(
-if (i->i_private)
-f->private_data = i->i_private;
|
-f->private_data = i->i_private;
)
-return 0;
-}
@ has_open depends on open @
identifier fops;
identifier open.open_f;
@@
struct file_operations fops = {
...
-.open = open_f,
+.open = simple_open,
...
};
</smpl>
[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Julia Lawall <Julia.Lawall@lip6.fr>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
To ensure we don't receive any more interrupts from the host after we
enter the freeze function, disable all vq interrupts.
There wasn't any problem seen due to this in tests, but applying this
patch makes the freeze case more robust.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Remove all vqs and associated buffers in the freeze callback which
prepares us to go into hibernation state. On restore, re-create all the
vqs and populate the input vqs with buffers to get to the pre-hibernate
state.
Note: Any outstanding unconsumed buffers are discarded; which means
there's a possibility of data loss in case the host or the guest didn't
consume any data already present in the vqs. This can be addressed in a
later patch series, perhaps in virtio common code.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This common code will be shared with the PM freeze function.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Remove wrapper functions. This makes the allocation type explicit in
all callers; I used GPF_KERNEL where it seemed obvious, left it at
GFP_ATOMIC otherwise.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Reviewed-by: Christoph Hellwig <hch@lst.de>
* 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: (230 commits)
Revert "tracing: Include module.h in define_trace.h"
irq: don't put module.h into irq.h for tracking irqgen modules.
bluetooth: macroize two small inlines to avoid module.h
ip_vs.h: fix implicit use of module_get/module_put from module.h
nf_conntrack.h: fix up fallout from implicit moduleparam.h presence
include: replace linux/module.h with "struct module" wherever possible
include: convert various register fcns to macros to avoid include chaining
crypto.h: remove unused crypto_tfm_alg_modname() inline
uwb.h: fix implicit use of asm/page.h for PAGE_SIZE
pm_runtime.h: explicitly requires notifier.h
linux/dmaengine.h: fix implicit use of bitmap.h and asm/page.h
miscdevice.h: fix up implicit use of lists and types
stop_machine.h: fix implicit use of smp.h for smp_processor_id
of: fix implicit use of errno.h in include/linux/of.h
of_platform.h: delete needless include <linux/module.h>
acpi: remove module.h include from platform/aclinux.h
miscdevice.h: delete unnecessary inclusion of module.h
device_cgroup.h: delete needless include <linux/module.h>
net: sch_generic remove redundant use of <linux/module.h>
net: inet_timewait_sock doesnt need <linux/module.h>
...
Fix up trivial conflicts (other header files, and removal of the ab3550 mfd driver) in
- drivers/media/dvb/frontends/dibx000_common.c
- drivers/media/video/{mt9m111.c,ov6650.c}
- drivers/mfd/ab3550-core.c
- include/linux/dmaengine.h
On s390 I have seen some random
"Warning: unable to open an initial console"
boot failure. Turns out that tty_open fails, because the
hvc_alloc was not yet done. In former times this could not happen,
since the probe function automatically called hvc_alloc. With newer
versions (multiport) some host<->guest interaction is required
before hvc_alloc is called. This might be too late, especially if
an initramfs is involved. Lets use a completion if we have
multiport and an early console.
[Amit:
* Use NULL instead of 0 for pointer comparison
* Rename 'port_added' to 'early_console_added'
* Re-format, re-word commit message
* Rebase patch on top of current queue]
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Acked-by: Chrstian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit adds port-specific stats for the number of bytes received,
sent and discarded. They're exposed via the debugfs interface. This
data can be used to check for data loss bugs (or disprove such claims).
It can also be used for accounting, if there's such a need.
The stats remain valid throughout the lifetime of the port. Unplugging
a port will reset the stats. The numbers are not reset across port
opens/closes.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
discard_port_data() used virtqueue_get_buf() directly instead of using
get_inbuf(). Fix this, so that we get accounting for all received
bytes. This also simplifies the code a lot.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Instead of pulling in a buffer from the vq each time it's called,
get_inbuf() now checks if the current active buffer, in port->inbuf is
valid. If it is, just returns a pointer to it. This ends up
simplifying a lot of code calling get_inbuf() since the check for
port->inbuf being valid was done by all the callers.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
get_inbuf() returns void *. There's no reason to return void pointers
instead of the correct struct port_buffer *.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Get ready to support suspend/resume by using the freezable calls so that
blocking read/write syscalls are handled properly across suspend/resume.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We don't allow port name changes dynamically for a port. So any
requests by the host to change the name are ignored.
Before this patch, if the hypervisor sent a port name while we had one
set already, we would leak memory equivalent to the size of the old
name.
This scenario wasn't expected so far, but with the suspend-resume
support, we'll send the VIRTIO_CONSOLE_PORT_READY message after restore,
which can get us into this situation.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Convert spaces to tabs and fix indentation for an if statement split
into multiple lines.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This patch modifies virtio-console to use virtio_config_val() instead
of a 'if(virtio_has_feature()) vdev->config->get()' construct to retrieve
optional values from the config space.
Cc: Amit Shah <amit.shah@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
A pending cleanup will mean that module.h won't be implicitly
everywhere anymore. Make sure the modular drivers in char are
actually calling out for <module.h> explicitly in advance.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
That's already been done by the virtio infrastructure before the probe
function is called.
Reported-by: alexey.kardashevskiy@au1.ibm.com
Acked-by: Amit Shah <amit.shah@redhat.com>
Tested-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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 <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
If a virtio-console device gets unplugged while a port is open, a
subsequent close() call on the port accesses vqs to free up buffers.
This can lead to a crash.
The buffers are already freed up as a result of the call to
unplug_ports() from virtcons_remove(). The fix is to simply not access
vq information if port->portdev is NULL.
Reported-by: juzhang <juzhang@redhat.com>
CC: stable@kernel.org
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'tty-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6:
serial: bfin_5xx: split uart RX lock from uart port lock to avoid deadlock
68360serial: Plumb in rs_360_get_icount()
n_gsm: copy mtu over when configuring via ioctl interface
virtio: console: Move file back to drivers/char/
Commit 728674a7e4 moved virtio_console.c
to drivers/tty/hvc/ under the perception of this being an hvc driver.
It was such once, but these days it has generic communication
capabilities as well, so move it to drivers/char/.
In the future, the hvc part from this file can be split off and moved
under drivers/tty/hvc/.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
CC: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
As requested by Arnd Bergmann, the hvc drivers are now
moved to the drivers/tty/hvc/ directory. The virtio_console.c driver
was also moved, as it required the hvc_console.h file to be able to be
built, and it really is a hvc driver.
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Stanse found that in init_vqs, memory is leaked under certain
circumstanses (the fail path order is incorrect). Fix that by checking
allocations in one turn and free all of them at once if some fails
(some may be NULL, but this is OK).
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Amit Shah <amit.shah@redhat.com>
Cc: virtualization@lists.linux-foundation.org
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
The ports are char devices; do not have seeking capabilities. Calling
nonseekable_open() from the fops_open() call and setting the llseek fops
pointer to no_llseek ensures an lseek() call from userspace returns
-ESPIPE.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
CC: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
If a port has registered for SIGIO signals, let the application
know that the port is getting unplugged.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Send a SIGIO signal when new data arrives on a port. This is sent only
when the process has requested for the signal to be sent using fcntl().
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
A process can request for SIGIO on host connect / disconnect events
using the O_ASYNC file flag using fcntl().
If that's requested, and if the guest-side connection for the port is
open, any host-side open/close events for that port will raise a SIGIO.
The process can then use poll() within the signal handler to find out
which port triggered the signal.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Explain in a comment why there's no need to reference-count the portdev
struct: when a device is yanked out, we can't do anything more with it
anyway so just give up doing anything more with the data or the vqs and
exit cleanly.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
When a port got hot-unplugged, when a port was open, any file operation
after the unplugging resulted in a crash. This is fixed by ref-counting
the port structure, and releasing it only when the file is closed.
This splits the unplug operation in two parts: first marks the port
as unavailable, removes all the buffers in the vqs and removes the port
from the per-device list of ports. The second stage, invoked when all
references drop to zero, releases the chardev and frees all other memory.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This moves to using cdev on the heap instead of it being embedded in the
ports struct. This helps individual refcounting and will allow us to
properly remove cdev structs after hot-unplugs and close operations.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
To convert to using cdev as a pointer to avoid kref troubles, we have to
use a different method to get to a port from an inode than the current
container_of method.
Add find_port_by_devt() that looks up all portdevs and ports with those
portdevs to find the right port.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
The virtio_console.c driver is capable of handling multiple devices at a
time. Maintain a list of devices for future traversal.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
When a port is removed, we have to assume the port is gone. So a
success/failure return value doesn't make sense.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
When a port is hot-unplugged while an app was blocked on a write() call,
the call was unblocked but would not get an error returned.
Return -ENODEV to ensure the app knows the port has gone away.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
When a port is hot-unplugged while an app was blocked on a read() call,
the call was unblocked but would not get an error returned.
Return -ENODEV to ensure the app knows the port has gone away.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
When a port is hot-unplugged while an app is blocked on poll(), unblock
the poll() and return.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
If a chardev is closed, any blocked read / poll calls should just return
and not attempt to use other state.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
A portdev may have been hot-unplugged while a port was open()ed. Skip
sending control messages when the portdev isn't valid.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
If a portdev isn't using multiport support, it won't have any control vq
data to remove.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
The virtqueues should be disabled before attempting to remove the
device.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
If the host is slow in reading data or doesn't read data at all,
blocking write calls not only blocked the program that called write()
but the entire guest itself.
To overcome this, let's not block till the host signals it has given
back the virtio ring element we passed it. Instead, send the buffer to
the host and return to userspace. This operation then becomes similar
to how non-blocking writes work, so let's use the existing code for this
path as well.
This code change also ensures blocking write calls do get blocked if
there's not enough room in the virtio ring as well as they don't return
-EAGAIN to userspace.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
CC: stable@kernel.org
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A userspace could submit a buffer with 0 length to be written to the
host. Prevent such a situation.
This was not needed previously, but recent changes in the way write()
works exposed this condition to trigger a virtqueue event to the host,
causing a NULL buffer to be sent across.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
CC: stable@kernel.org
I found this while working on a Linux agent for spice, the symptom I was
seeing was select blocking on the spice vdagent virtio serial port even
though there were messages queued up there.
virtio_console's port_fops_poll checks port->inbuf != NULL to determine
if read won't block. However if an application reads enough bytes from
inbuf through port_fops_read, to empty the current port->inbuf,
port->inbuf will be NULL even though there may be buffers left in the
virtqueue.
This causes poll() to block even though there is data to be read,
this patch fixes this by using will_read_block(port) instead of the
port->inbuf != NULL check.
Signed-off-By: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
