On Tue, Mar 24, 2015 at 11:36:31AM +0100, Michael S. Tsirkin wrote:> On Tue, Mar 24, 2015 at 08:32:01AM +0100, Gerd Hoffmann wrote: > > virtio-input is basically evdev-events-over-virtio, so this driver isn't > > much more than reading configuration from config space and forwarding > > incoming events to the linux input layer. > > > > Signed-off-by: Gerd Hoffmann <kraxel at redhat.com> > > Looks pretty neat overall. I think I still see some > small issues, but it's getting there. > > > --- > > MAINTAINERS | 6 + > > drivers/virtio/Kconfig | 10 ++ > > drivers/virtio/Makefile | 1 + > > drivers/virtio/virtio_input.c | 313 ++++++++++++++++++++++++++++++++++++++ > > include/uapi/linux/Kbuild | 1 + > > include/uapi/linux/virtio_ids.h | 1 + > > include/uapi/linux/virtio_input.h | 76 +++++++++ > > 7 files changed, 408 insertions(+) > > create mode 100644 drivers/virtio/virtio_input.c > > create mode 100644 include/uapi/linux/virtio_input.h > > > > diff --git a/MAINTAINERS b/MAINTAINERS > > index 358eb01..6f233dd 100644 > > --- a/MAINTAINERS > > +++ b/MAINTAINERS > > @@ -10442,6 +10442,12 @@ S: Maintained > > F: drivers/vhost/ > > F: include/uapi/linux/vhost.h > > > > +VIRTIO INPUT DRIVER > > +M: Gerd Hoffmann <kraxel at redhat.com> > > +S: Maintained > > +F: drivers/virtio/virtio_input.c > > +F: include/uapi/linux/virtio_input.h > > + > > VIA RHINE NETWORK DRIVER > > M: Roger Luethi <rl at hellgate.ch> > > S: Maintained > > diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig > > index b546da5..cab9f3f 100644 > > --- a/drivers/virtio/Kconfig > > +++ b/drivers/virtio/Kconfig > > @@ -48,6 +48,16 @@ config VIRTIO_BALLOON > > > > If unsure, say M. > > > > +config VIRTIO_INPUT > > + tristate "Virtio input driver" > > + depends on VIRTIO > > + depends on INPUT > > + ---help--- > > + This driver supports virtio input devices such as > > + keyboards, mice and tablets. > > + > > + If unsure, say M. > > + > > config VIRTIO_MMIO > > tristate "Platform bus driver for memory mapped virtio devices" > > depends on HAS_IOMEM > > diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile > > index d85565b..41e30e3 100644 > > --- a/drivers/virtio/Makefile > > +++ b/drivers/virtio/Makefile > > @@ -4,3 +4,4 @@ obj-$(CONFIG_VIRTIO_PCI) += virtio_pci.o > > virtio_pci-y := virtio_pci_modern.o virtio_pci_common.o > > virtio_pci-$(CONFIG_VIRTIO_PCI_LEGACY) += virtio_pci_legacy.o > > obj-$(CONFIG_VIRTIO_BALLOON) += virtio_balloon.o > > +obj-$(CONFIG_VIRTIO_INPUT) += virtio_input.o > > diff --git a/drivers/virtio/virtio_input.c b/drivers/virtio/virtio_input.c > > new file mode 100644 > > index 0000000..cf112b2 > > --- /dev/null > > +++ b/drivers/virtio/virtio_input.c > > @@ -0,0 +1,313 @@ > > +#include <linux/module.h> > > +#include <linux/virtio.h> > > +#include <linux/input.h> > > + > > +#include <uapi/linux/virtio_ids.h> > > +#include <uapi/linux/virtio_input.h> > > + > > +struct virtio_input { > > + struct virtio_device *vdev; > > + struct input_dev *idev; > > + char name[64]; > > + char serial[64]; > > + char phys[64]; > > + struct virtqueue *evt, *sts; > > + struct virtio_input_event evts[64]; > > + spinlock_t lock; > > +}; > > + > > +static void virtinput_queue_evtbuf(struct virtio_input *vi, > > + struct virtio_input_event *evtbuf) > > +{ > > + struct scatterlist sg[1]; > > + > > + sg_init_one(sg, evtbuf, sizeof(*evtbuf)); > > + virtqueue_add_inbuf(vi->evt, sg, 1, evtbuf, GFP_ATOMIC); > > +} > > + > > +static void virtinput_recv_events(struct virtqueue *vq) > > +{ > > + struct virtio_input *vi = vq->vdev->priv; > > + struct virtio_input_event *event; > > + unsigned long flags; > > + unsigned int len; > > + > > + spin_lock_irqsave(&vi->lock, flags); > > + while ((event = virtqueue_get_buf(vi->evt, &len)) != NULL) { > > + input_event(vi->idev, > > + le16_to_cpu(event->type), > > + le16_to_cpu(event->code), > > + le32_to_cpu(event->value)); > > What happens if input layer gets an > unexpected event code or value? > Or does something prevent it? > > > > > + virtinput_queue_evtbuf(vi, event); > > + } > > + virtqueue_kick(vq); > > + spin_unlock_irqrestore(&vi->lock, flags); > > +} > > + > > +static int virtinput_send_status(struct virtio_input *vi, > > + u16 type, u16 code, s32 value) > > +{ > > + struct virtio_input_event *stsbuf; > > + struct scatterlist sg[1]; > > + unsigned long flags; > > + int rc; > > + > > + stsbuf = kzalloc(sizeof(*stsbuf), GFP_ATOMIC); > > + if (!stsbuf) > > + return -ENOMEM; > > + > > + stsbuf->type = cpu_to_le16(type); > > + stsbuf->code = cpu_to_le16(code); > > + stsbuf->value = cpu_to_le32(value); > > + sg_init_one(sg, stsbuf, sizeof(*stsbuf)); > > + > > + spin_lock_irqsave(&vi->lock, flags); > > + rc = virtqueue_add_outbuf(vi->sts, sg, 1, stsbuf, GFP_ATOMIC); > > + virtqueue_kick(vi->sts); > > + spin_unlock_irqrestore(&vi->lock, flags);I think locking is wrong here. This is basically input_dev->event() which is called with input_dev->event_lock spinlock held, and it is taking vi->lock. OTOH virtinput_recv_events() takes vi->lock and then calls input_event(), which will try taking input_dev->event_lock. It is bound to deadlock at some point. I guess the easiest way would be to drop vi->lock() after fetching virtio event and before calling input_event().> > + > > + if (rc != 0) > > + kfree(stsbuf); > > + return rc; > > This means that caller will get errors if it happens to call > send_status at a rate that's faster than host's consumption of them. > To me this looks wrong. > Poking at input layer, it seems to simply discard errors. > Is it always safe to discard status updates? > If yes, some kind of comment to clarify the logic would > make sense IMHO. > > > > > +} > > + > > +static void virtinput_recv_status(struct virtqueue *vq) > > +{ > > + struct virtio_input *vi = vq->vdev->priv; > > + struct virtio_input_event *stsbuf; > > + unsigned long flags; > > + unsigned int len; > > + > > + spin_lock_irqsave(&vi->lock, flags); > > + while ((stsbuf = virtqueue_get_buf(vi->sts, &len)) != NULL) > > + kfree(stsbuf); > > + spin_unlock_irqrestore(&vi->lock, flags); > > +} > > + > > +static int virtinput_status(struct input_dev *idev, unsigned int type, > > + unsigned int code, int value) > > +{ > > + struct virtio_input *vi = input_get_drvdata(idev); > > + > > + return virtinput_send_status(vi, type, code, value); > > +} > > + > > +static size_t virtinput_cfg_select(struct virtio_input *vi, > > + u8 select, u8 subsel) > > +{ > > + u8 size; > > + > > + virtio_cwrite(vi->vdev, struct virtio_input_config, select, &select); > > + virtio_cwrite(vi->vdev, struct virtio_input_config, subsel, &subsel); > > + virtio_cread(vi->vdev, struct virtio_input_config, size, &size); > > + return size; > > +} > > + > > +static void virtinput_cfg_bits(struct virtio_input *vi, int select, int subsel, > > + unsigned long *bits, unsigned int bitcount) > > +{ > > + unsigned int bit; > > + size_t bytes; > > + u8 *virtio_bits; > > + > > + bytes = virtinput_cfg_select(vi, select, subsel); > > + if (!bytes) > > + return; > > How about limiting bytes to sizeof struct virtio_input_config->u? > > > + if (bitcount > bytes*8) > > + bitcount = bytes*8; > > Space around * pls. > > > + > > + /* > > + * Bitmap in virtio config space is a simple stream of bytes, > > + * with the first byte carrying bits 0-7, second bits 8-15 and > > + * so on. > > + */ > > + virtio_bits = kzalloc(bytes, GFP_KERNEL); > > + if (!virtio_bits) > > + return; > > + virtio_cread_bytes(vi->vdev, offsetof(struct virtio_input_config, u), > > + virtio_bits, bytes); > > + for (bit = 0; bit < bitcount; bit++) { > > + if (virtio_bits[bit / 8] & (1 << (bit % 8))) > > + __set_bit(bit, bits); > > + } > > + kfree(virtio_bits); > > + > > + if (select == VIRTIO_INPUT_CFG_EV_BITS) > > + __set_bit(subsel, vi->idev->evbit); > > +} > > + > > +static void virtinput_cfg_abs(struct virtio_input *vi, int abs) > > +{ > > + u32 mi, ma, re, fu, fl; > > + > > + virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_ABS_INFO, abs); > > + virtio_cread(vi->vdev, struct virtio_input_config, u.abs.min, &mi); > > + virtio_cread(vi->vdev, struct virtio_input_config, u.abs.max, &ma); > > + virtio_cread(vi->vdev, struct virtio_input_config, u.abs.res, &re); > > + virtio_cread(vi->vdev, struct virtio_input_config, u.abs.fuzz, &fu); > > + virtio_cread(vi->vdev, struct virtio_input_config, u.abs.flat, &fl); > > + input_set_abs_params(vi->idev, abs, mi, ma, fu, fl); > > + input_abs_set_res(vi->idev, abs, re); > > +} > > + > > +static int virtinput_init_vqs(struct virtio_input *vi) > > +{ > > + struct virtqueue *vqs[2]; > > + vq_callback_t *cbs[] = { virtinput_recv_events, > > + virtinput_recv_status }; > > + static const char * names[] = { "events", "status" }; > > No space between * and names expected > > > + int i, err, size; > > + > > + err = vi->vdev->config->find_vqs(vi->vdev, 2, vqs, cbs, names); > > + if (err) > > + return err; > > + vi->evt = vqs[0]; > > + vi->sts = vqs[1]; > > + > > + size = virtqueue_get_vring_size(vi->evt); > > + if (size > ARRAY_SIZE(vi->evts)) > > + size = ARRAY_SIZE(vi->evts); > > + for (i = 0; i < size; i++) > > + virtinput_queue_evtbuf(vi, &vi->evts[i]); > > + virtqueue_kick(vi->evt); > > + > > + return 0; > > +} > > + > > +static int virtinput_probe(struct virtio_device *vdev) > > +{ > > + struct virtio_input *vi; > > + size_t size; > > + int abs, err; > > + > > + if (!virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) > > + return -ENODEV; > > + > > + vi = kzalloc(sizeof(*vi), GFP_KERNEL); > > + if (!vi) > > + return -ENOMEM; > > + > > + vdev->priv = vi; > > + vi->vdev = vdev; > > + spin_lock_init(&vi->lock); > > + > > + err = virtinput_init_vqs(vi); > > + if (err) > > + goto err_init_vq; > > + > > + vi->idev = input_allocate_device(); > > + if (!vi->idev) { > > + err = -ENOMEM; > > + goto err_input_alloc; > > + } > > + input_set_drvdata(vi->idev, vi); > > + > > + size = virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_ID_NAME, 0); > > + virtio_cread_bytes(vi->vdev, offsetof(struct virtio_input_config, u), > > + vi->name, min(size, sizeof(vi->name))); > > + size = virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_ID_SERIAL, 0); > > + virtio_cread_bytes(vi->vdev, offsetof(struct virtio_input_config, u), > > + vi->serial, min(size, sizeof(vi->serial))); > > + snprintf(vi->phys, sizeof(vi->phys), > > + "virtio%d/input0", vdev->index); > > + vi->idev->name = vi->name; > > + vi->idev->phys = vi->phys; > > + vi->idev->uniq = vi->serial; > > + > > + size = virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_ID_DEVIDS, 0); > > + if (size >= 8) { > > What does 8 mean here? Should be sizeof virtio_input_devids? > > > + virtio_cread(vi->vdev, struct virtio_input_config, > > + u.ids.bustype, &vi->idev->id.bustype); > > + virtio_cread(vi->vdev, struct virtio_input_config, > > + u.ids.vendor, &vi->idev->id.vendor); > > + virtio_cread(vi->vdev, struct virtio_input_config, > > + u.ids.product, &vi->idev->id.product); > > + virtio_cread(vi->vdev, struct virtio_input_config, > > + u.ids.version, &vi->idev->id.version); > > + } else { > > + vi->idev->id.bustype = BUS_VIRTUAL; > > + } > > + > > + virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_PROP_BITS, 0, > > + vi->idev->propbit, INPUT_PROP_CNT); > > + size = virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_REP); > > + if (size) > > + __set_bit(EV_REP, vi->idev->evbit); > > + > > + vi->idev->dev.parent = &vdev->dev; > > + vi->idev->event = virtinput_status; > > + > > + /* device -> kernel */ > > + virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_KEY, > > + vi->idev->keybit, KEY_CNT); > > + virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_REL, > > + vi->idev->relbit, REL_CNT); > > + virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_ABS, > > + vi->idev->absbit, ABS_CNT); > > + virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_MSC, > > + vi->idev->mscbit, MSC_CNT); > > + virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_SW, > > + vi->idev->swbit, SW_CNT); > > + > > + /* kernel -> device */ > > + virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_LED, > > + vi->idev->ledbit, LED_CNT); > > + virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_SND, > > + vi->idev->sndbit, SND_CNT); > > + > > + if (test_bit(EV_ABS, vi->idev->evbit)) { > > + for (abs = 0; abs < ABS_CNT; abs++) { > > + if (!test_bit(abs, vi->idev->absbit)) > > + continue; > > + virtinput_cfg_abs(vi, abs); > > + } > > + } > > + virtio_device_ready(vdev); > > + > At this point you can already get interrupts. > This will cause events to be forwarded. > I'm guessing this is ok since you called > input_allocate_device, but worth checking, > and maybe adding a comment.Yes, it is OK to send events though yet unregistered input device, as long as it was allocated with input_allocate_device().> > > + err = input_register_device(vi->idev); > > + if (err) > > + goto err_input_register; > > + > > + return 0; > > + > > +err_input_register: > > > + input_free_device(vi->idev); > > At this point you can already get interrupts > since you called virtio_device_ready, and > getting events from a freed device likely won't > DTRT.Right. I guess you want to mark the virtio device ready only after registering input device.> > > +err_input_alloc: > > + vdev->config->del_vqs(vdev); > > +err_init_vq: > > + kfree(vi); > > + return err; > > +} > > + > > +static void virtinput_remove(struct virtio_device *vdev) > > +{ > > + struct virtio_input *vi = vdev->priv; > > + > > + input_unregister_device(vi->idev); > > same thing here, you might get an event at this point. > You need to somehow block new events > being sent to device while keeping > device around. > > Since you already do everything under a spinlock, > it's probably easiest to add a flag discarding > recv events. You can then check it in virtinput_recv_events > before calling input_event.Instead of checking the flag is it possible to pause virio device? Maybe virtio_break_device()?> > > > > + vdev->config->del_vqs(vdev); > > + kfree(vi); > > +} > > + > > +static unsigned int features[] = { > > +}; > > +static struct virtio_device_id id_table[] = { > > + { VIRTIO_ID_INPUT, VIRTIO_DEV_ANY_ID }, > > + { 0 }, > > +}; > > + > > +static struct virtio_driver virtio_input_driver = { > > + .driver.name = KBUILD_MODNAME, > > + .driver.owner = THIS_MODULE, > > + .feature_table = features, > > + .feature_table_size = ARRAY_SIZE(features), > > + .id_table = id_table, > > + .probe = virtinput_probe, > > + .remove = virtinput_remove, > > I note this driver doesn't seem to handle hybernation, > that's probably a bug? > > > > +}; > > + > > +module_virtio_driver(virtio_input_driver); > > +MODULE_DEVICE_TABLE(virtio, id_table); > > + > > +MODULE_LICENSE("GPL"); > > +MODULE_DESCRIPTION("Virtio input device driver"); > > +MODULE_AUTHOR("Gerd Hoffmann <kraxel at redhat.com>"); > > diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild > > index 68ceb97..04b829e 100644 > > --- a/include/uapi/linux/Kbuild > > +++ b/include/uapi/linux/Kbuild > > @@ -430,6 +430,7 @@ header-y += virtio_blk.h > > header-y += virtio_config.h > > header-y += virtio_console.h > > header-y += virtio_ids.h > > +header-y += virtio_input.h > > header-y += virtio_net.h > > header-y += virtio_pci.h > > header-y += virtio_ring.h > > diff --git a/include/uapi/linux/virtio_ids.h b/include/uapi/linux/virtio_ids.h > > index 284fc3a..5f60aa4 100644 > > --- a/include/uapi/linux/virtio_ids.h > > +++ b/include/uapi/linux/virtio_ids.h > > @@ -39,5 +39,6 @@ > > #define VIRTIO_ID_9P 9 /* 9p virtio console */ > > #define VIRTIO_ID_RPROC_SERIAL 11 /* virtio remoteproc serial link */ > > #define VIRTIO_ID_CAIF 12 /* Virtio caif */ > > +#define VIRTIO_ID_INPUT 18 /* virtio input */ > > > > #endif /* _LINUX_VIRTIO_IDS_H */ > > diff --git a/include/uapi/linux/virtio_input.h b/include/uapi/linux/virtio_input.h > > new file mode 100644 > > index 0000000..7fceabd > > --- /dev/null > > +++ b/include/uapi/linux/virtio_input.h > > @@ -0,0 +1,76 @@ > > +#ifndef _LINUX_VIRTIO_INPUT_H > > +#define _LINUX_VIRTIO_INPUT_H > > +/* This header is BSD licensed so anyone can use the definitions to implement > > + * compatible drivers/servers. > > + * > > + * Redistribution and use in source and binary forms, with or without > > + * modification, are permitted provided that the following conditions > > + * are met: > > + * 1. Redistributions of source code must retain the above copyright > > + * notice, this list of conditions and the following disclaimer. > > + * 2. Redistributions in binary form must reproduce the above copyright > > + * notice, this list of conditions and the following disclaimer in the > > + * documentation and/or other materials provided with the distribution. > > + * 3. Neither the name of IBM nor the names of its contributors > > + * may be used to endorse or promote products derived from this software > > + * without specific prior written permission. > > + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS > > + * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT > > + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS > > + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL IBM OR > > + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, > > + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT > > + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF > > + * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND > > + * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, > > + * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT > > + * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF > > + * SUCH DAMAGE. */ > > +#include <linux/virtio_ids.h> > > +#include <linux/virtio_config.h> > > + > > +enum virtio_input_config_select { > > + VIRTIO_INPUT_CFG_UNSET = 0x00, > > + VIRTIO_INPUT_CFG_ID_NAME = 0x01, > > + VIRTIO_INPUT_CFG_ID_SERIAL = 0x02, > > + VIRTIO_INPUT_CFG_ID_DEVIDS = 0x03, > > + VIRTIO_INPUT_CFG_PROP_BITS = 0x10, > > + VIRTIO_INPUT_CFG_EV_BITS = 0x11, > > + VIRTIO_INPUT_CFG_ABS_INFO = 0x12, > > +}; > > + > > +struct virtio_input_absinfo { > > + __virtio32 min; > > + __virtio32 max; > > + __virtio32 fuzz; > > + __virtio32 flat; > > + __virtio32 res; > > +}; > > + > > +struct virtio_input_devids { > > + __virtio16 bustype; > > + __virtio16 vendor; > > + __virtio16 product; > > + __virtio16 version; > > +}; > > + > > this padding bt two spaces looks weird. > > > +struct virtio_input_config { > > + __u8 select; > > + __u8 subsel; > > + __u8 size; > > + __u8 reserved; > > + union { > > + char string[128]; > > + __u8 bitmap[128]; > > I note that neither string nor bitmap are used by > driver. What are they in aid of?Also, what happens if we need more than 1024 bits to pass bitmap data? We might get there with keyboards.> > > + struct virtio_input_absinfo abs; > > + struct virtio_input_devids ids; > > + } u; > > +}; > > + > > +struct virtio_input_event { > > + __le16 type; > > + __le16 code; > > + __le32 value; > > +}; > > + > > +#endif /* _LINUX_VIRTIO_INPUT_H */ > > -- > > 1.8.3.1Thanks. -- Dmitry
On Tue, Mar 24, 2015 at 09:23:37AM -0700, Dmitry Torokhov wrote:> On Tue, Mar 24, 2015 at 11:36:31AM +0100, Michael S. Tsirkin wrote: > > On Tue, Mar 24, 2015 at 08:32:01AM +0100, Gerd Hoffmann wrote: > > > virtio-input is basically evdev-events-over-virtio, so this driver isn't > > > much more than reading configuration from config space and forwarding > > > incoming events to the linux input layer. > > > > > > Signed-off-by: Gerd Hoffmann <kraxel at redhat.com> > > > > Looks pretty neat overall. I think I still see some > > small issues, but it's getting there. > > > > > --- > > > MAINTAINERS | 6 + > > > drivers/virtio/Kconfig | 10 ++ > > > drivers/virtio/Makefile | 1 + > > > drivers/virtio/virtio_input.c | 313 ++++++++++++++++++++++++++++++++++++++ > > > include/uapi/linux/Kbuild | 1 + > > > include/uapi/linux/virtio_ids.h | 1 + > > > include/uapi/linux/virtio_input.h | 76 +++++++++ > > > 7 files changed, 408 insertions(+) > > > create mode 100644 drivers/virtio/virtio_input.c > > > create mode 100644 include/uapi/linux/virtio_input.h > > > > > > diff --git a/MAINTAINERS b/MAINTAINERS > > > index 358eb01..6f233dd 100644 > > > --- a/MAINTAINERS > > > +++ b/MAINTAINERS > > > @@ -10442,6 +10442,12 @@ S: Maintained > > > F: drivers/vhost/ > > > F: include/uapi/linux/vhost.h > > > > > > +VIRTIO INPUT DRIVER > > > +M: Gerd Hoffmann <kraxel at redhat.com> > > > +S: Maintained > > > +F: drivers/virtio/virtio_input.c > > > +F: include/uapi/linux/virtio_input.h > > > + > > > VIA RHINE NETWORK DRIVER > > > M: Roger Luethi <rl at hellgate.ch> > > > S: Maintained > > > diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig > > > index b546da5..cab9f3f 100644 > > > --- a/drivers/virtio/Kconfig > > > +++ b/drivers/virtio/Kconfig > > > @@ -48,6 +48,16 @@ config VIRTIO_BALLOON > > > > > > If unsure, say M. > > > > > > +config VIRTIO_INPUT > > > + tristate "Virtio input driver" > > > + depends on VIRTIO > > > + depends on INPUT > > > + ---help--- > > > + This driver supports virtio input devices such as > > > + keyboards, mice and tablets. > > > + > > > + If unsure, say M. > > > + > > > config VIRTIO_MMIO > > > tristate "Platform bus driver for memory mapped virtio devices" > > > depends on HAS_IOMEM > > > diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile > > > index d85565b..41e30e3 100644 > > > --- a/drivers/virtio/Makefile > > > +++ b/drivers/virtio/Makefile > > > @@ -4,3 +4,4 @@ obj-$(CONFIG_VIRTIO_PCI) += virtio_pci.o > > > virtio_pci-y := virtio_pci_modern.o virtio_pci_common.o > > > virtio_pci-$(CONFIG_VIRTIO_PCI_LEGACY) += virtio_pci_legacy.o > > > obj-$(CONFIG_VIRTIO_BALLOON) += virtio_balloon.o > > > +obj-$(CONFIG_VIRTIO_INPUT) += virtio_input.o > > > diff --git a/drivers/virtio/virtio_input.c b/drivers/virtio/virtio_input.c > > > new file mode 100644 > > > index 0000000..cf112b2 > > > --- /dev/null > > > +++ b/drivers/virtio/virtio_input.c > > > @@ -0,0 +1,313 @@ > > > +#include <linux/module.h> > > > +#include <linux/virtio.h> > > > +#include <linux/input.h> > > > + > > > +#include <uapi/linux/virtio_ids.h> > > > +#include <uapi/linux/virtio_input.h> > > > + > > > +struct virtio_input { > > > + struct virtio_device *vdev; > > > + struct input_dev *idev; > > > + char name[64]; > > > + char serial[64]; > > > + char phys[64]; > > > + struct virtqueue *evt, *sts; > > > + struct virtio_input_event evts[64]; > > > + spinlock_t lock; > > > +}; > > > + > > > +static void virtinput_queue_evtbuf(struct virtio_input *vi, > > > + struct virtio_input_event *evtbuf) > > > +{ > > > + struct scatterlist sg[1]; > > > + > > > + sg_init_one(sg, evtbuf, sizeof(*evtbuf)); > > > + virtqueue_add_inbuf(vi->evt, sg, 1, evtbuf, GFP_ATOMIC); > > > +} > > > + > > > +static void virtinput_recv_events(struct virtqueue *vq) > > > +{ > > > + struct virtio_input *vi = vq->vdev->priv; > > > + struct virtio_input_event *event; > > > + unsigned long flags; > > > + unsigned int len; > > > + > > > + spin_lock_irqsave(&vi->lock, flags); > > > + while ((event = virtqueue_get_buf(vi->evt, &len)) != NULL) { > > > + input_event(vi->idev, > > > + le16_to_cpu(event->type), > > > + le16_to_cpu(event->code), > > > + le32_to_cpu(event->value)); > > > > What happens if input layer gets an > > unexpected event code or value? > > Or does something prevent it? > > > > > > > > > + virtinput_queue_evtbuf(vi, event); > > > + } > > > + virtqueue_kick(vq); > > > + spin_unlock_irqrestore(&vi->lock, flags); > > > +} > > > + > > > +static int virtinput_send_status(struct virtio_input *vi, > > > + u16 type, u16 code, s32 value) > > > +{ > > > + struct virtio_input_event *stsbuf; > > > + struct scatterlist sg[1]; > > > + unsigned long flags; > > > + int rc; > > > + > > > + stsbuf = kzalloc(sizeof(*stsbuf), GFP_ATOMIC); > > > + if (!stsbuf) > > > + return -ENOMEM; > > > + > > > + stsbuf->type = cpu_to_le16(type); > > > + stsbuf->code = cpu_to_le16(code); > > > + stsbuf->value = cpu_to_le32(value); > > > + sg_init_one(sg, stsbuf, sizeof(*stsbuf)); > > > + > > > + spin_lock_irqsave(&vi->lock, flags); > > > + rc = virtqueue_add_outbuf(vi->sts, sg, 1, stsbuf, GFP_ATOMIC); > > > + virtqueue_kick(vi->sts); > > > + spin_unlock_irqrestore(&vi->lock, flags); > > I think locking is wrong here. This is basically input_dev->event() > which is called with input_dev->event_lock spinlock held, and it is > taking vi->lock. OTOH virtinput_recv_events() takes vi->lock and then > calls input_event(), which will try taking input_dev->event_lock. It is > bound to deadlock at some point. > > I guess the easiest way would be to drop vi->lock() after fetching > virtio event and before calling input_event().Or just always use event_lock for event vq, leave vq->lock for status vq only.> > > + > > > + if (rc != 0) > > > + kfree(stsbuf); > > > + return rc; > > > > This means that caller will get errors if it happens to call > > send_status at a rate that's faster than host's consumption of them. > > To me this looks wrong. > > Poking at input layer, it seems to simply discard errors. > > Is it always safe to discard status updates? > > If yes, some kind of comment to clarify the logic would > > make sense IMHO. > > > > > > > > > +} > > > + > > > +static void virtinput_recv_status(struct virtqueue *vq) > > > +{ > > > + struct virtio_input *vi = vq->vdev->priv; > > > + struct virtio_input_event *stsbuf; > > > + unsigned long flags; > > > + unsigned int len; > > > + > > > + spin_lock_irqsave(&vi->lock, flags); > > > + while ((stsbuf = virtqueue_get_buf(vi->sts, &len)) != NULL) > > > + kfree(stsbuf); > > > + spin_unlock_irqrestore(&vi->lock, flags); > > > +} > > > + > > > +static int virtinput_status(struct input_dev *idev, unsigned int type, > > > + unsigned int code, int value) > > > +{ > > > + struct virtio_input *vi = input_get_drvdata(idev); > > > + > > > + return virtinput_send_status(vi, type, code, value); > > > +} > > > + > > > +static size_t virtinput_cfg_select(struct virtio_input *vi, > > > + u8 select, u8 subsel) > > > +{ > > > + u8 size; > > > + > > > + virtio_cwrite(vi->vdev, struct virtio_input_config, select, &select); > > > + virtio_cwrite(vi->vdev, struct virtio_input_config, subsel, &subsel); > > > + virtio_cread(vi->vdev, struct virtio_input_config, size, &size); > > > + return size; > > > +} > > > + > > > +static void virtinput_cfg_bits(struct virtio_input *vi, int select, int subsel, > > > + unsigned long *bits, unsigned int bitcount) > > > +{ > > > + unsigned int bit; > > > + size_t bytes; > > > + u8 *virtio_bits; > > > + > > > + bytes = virtinput_cfg_select(vi, select, subsel); > > > + if (!bytes) > > > + return; > > > > How about limiting bytes to sizeof struct virtio_input_config->u? > > > > > + if (bitcount > bytes*8) > > > + bitcount = bytes*8; > > > > Space around * pls. > > > > > + > > > + /* > > > + * Bitmap in virtio config space is a simple stream of bytes, > > > + * with the first byte carrying bits 0-7, second bits 8-15 and > > > + * so on. > > > + */ > > > + virtio_bits = kzalloc(bytes, GFP_KERNEL); > > > + if (!virtio_bits) > > > + return; > > > + virtio_cread_bytes(vi->vdev, offsetof(struct virtio_input_config, u), > > > + virtio_bits, bytes); > > > + for (bit = 0; bit < bitcount; bit++) { > > > + if (virtio_bits[bit / 8] & (1 << (bit % 8))) > > > + __set_bit(bit, bits); > > > + } > > > + kfree(virtio_bits); > > > + > > > + if (select == VIRTIO_INPUT_CFG_EV_BITS) > > > + __set_bit(subsel, vi->idev->evbit); > > > +} > > > + > > > +static void virtinput_cfg_abs(struct virtio_input *vi, int abs) > > > +{ > > > + u32 mi, ma, re, fu, fl; > > > + > > > + virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_ABS_INFO, abs); > > > + virtio_cread(vi->vdev, struct virtio_input_config, u.abs.min, &mi); > > > + virtio_cread(vi->vdev, struct virtio_input_config, u.abs.max, &ma); > > > + virtio_cread(vi->vdev, struct virtio_input_config, u.abs.res, &re); > > > + virtio_cread(vi->vdev, struct virtio_input_config, u.abs.fuzz, &fu); > > > + virtio_cread(vi->vdev, struct virtio_input_config, u.abs.flat, &fl); > > > + input_set_abs_params(vi->idev, abs, mi, ma, fu, fl); > > > + input_abs_set_res(vi->idev, abs, re); > > > +} > > > + > > > +static int virtinput_init_vqs(struct virtio_input *vi) > > > +{ > > > + struct virtqueue *vqs[2]; > > > + vq_callback_t *cbs[] = { virtinput_recv_events, > > > + virtinput_recv_status }; > > > + static const char * names[] = { "events", "status" }; > > > > No space between * and names expected > > > > > + int i, err, size; > > > + > > > + err = vi->vdev->config->find_vqs(vi->vdev, 2, vqs, cbs, names); > > > + if (err) > > > + return err; > > > + vi->evt = vqs[0]; > > > + vi->sts = vqs[1]; > > > + > > > + size = virtqueue_get_vring_size(vi->evt); > > > + if (size > ARRAY_SIZE(vi->evts)) > > > + size = ARRAY_SIZE(vi->evts); > > > + for (i = 0; i < size; i++) > > > + virtinput_queue_evtbuf(vi, &vi->evts[i]); > > > + virtqueue_kick(vi->evt); > > > + > > > + return 0; > > > +} > > > + > > > +static int virtinput_probe(struct virtio_device *vdev) > > > +{ > > > + struct virtio_input *vi; > > > + size_t size; > > > + int abs, err; > > > + > > > + if (!virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) > > > + return -ENODEV; > > > + > > > + vi = kzalloc(sizeof(*vi), GFP_KERNEL); > > > + if (!vi) > > > + return -ENOMEM; > > > + > > > + vdev->priv = vi; > > > + vi->vdev = vdev; > > > + spin_lock_init(&vi->lock); > > > + > > > + err = virtinput_init_vqs(vi); > > > + if (err) > > > + goto err_init_vq; > > > + > > > + vi->idev = input_allocate_device(); > > > + if (!vi->idev) { > > > + err = -ENOMEM; > > > + goto err_input_alloc; > > > + } > > > + input_set_drvdata(vi->idev, vi); > > > + > > > + size = virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_ID_NAME, 0); > > > + virtio_cread_bytes(vi->vdev, offsetof(struct virtio_input_config, u), > > > + vi->name, min(size, sizeof(vi->name))); > > > + size = virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_ID_SERIAL, 0); > > > + virtio_cread_bytes(vi->vdev, offsetof(struct virtio_input_config, u), > > > + vi->serial, min(size, sizeof(vi->serial))); > > > + snprintf(vi->phys, sizeof(vi->phys), > > > + "virtio%d/input0", vdev->index); > > > + vi->idev->name = vi->name; > > > + vi->idev->phys = vi->phys; > > > + vi->idev->uniq = vi->serial; > > > + > > > + size = virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_ID_DEVIDS, 0); > > > + if (size >= 8) { > > > > What does 8 mean here? Should be sizeof virtio_input_devids? > > > > > + virtio_cread(vi->vdev, struct virtio_input_config, > > > + u.ids.bustype, &vi->idev->id.bustype); > > > + virtio_cread(vi->vdev, struct virtio_input_config, > > > + u.ids.vendor, &vi->idev->id.vendor); > > > + virtio_cread(vi->vdev, struct virtio_input_config, > > > + u.ids.product, &vi->idev->id.product); > > > + virtio_cread(vi->vdev, struct virtio_input_config, > > > + u.ids.version, &vi->idev->id.version); > > > + } else { > > > + vi->idev->id.bustype = BUS_VIRTUAL; > > > + } > > > + > > > + virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_PROP_BITS, 0, > > > + vi->idev->propbit, INPUT_PROP_CNT); > > > + size = virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_REP); > > > + if (size) > > > + __set_bit(EV_REP, vi->idev->evbit); > > > + > > > + vi->idev->dev.parent = &vdev->dev; > > > + vi->idev->event = virtinput_status; > > > + > > > + /* device -> kernel */ > > > + virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_KEY, > > > + vi->idev->keybit, KEY_CNT); > > > + virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_REL, > > > + vi->idev->relbit, REL_CNT); > > > + virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_ABS, > > > + vi->idev->absbit, ABS_CNT); > > > + virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_MSC, > > > + vi->idev->mscbit, MSC_CNT); > > > + virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_SW, > > > + vi->idev->swbit, SW_CNT); > > > + > > > + /* kernel -> device */ > > > + virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_LED, > > > + vi->idev->ledbit, LED_CNT); > > > + virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_SND, > > > + vi->idev->sndbit, SND_CNT); > > > + > > > + if (test_bit(EV_ABS, vi->idev->evbit)) { > > > + for (abs = 0; abs < ABS_CNT; abs++) { > > > + if (!test_bit(abs, vi->idev->absbit)) > > > + continue; > > > + virtinput_cfg_abs(vi, abs); > > > + } > > > + } > > > + virtio_device_ready(vdev); > > > + > > At this point you can already get interrupts. > > This will cause events to be forwarded. > > I'm guessing this is ok since you called > > input_allocate_device, but worth checking, > > and maybe adding a comment. > > Yes, it is OK to send events though yet unregistered input device, as > long as it was allocated with input_allocate_device(). > > > > > > + err = input_register_device(vi->idev); > > > + if (err) > > > + goto err_input_register; > > > + > > > + return 0; > > > + > > > +err_input_register: > > > > > + input_free_device(vi->idev); > > > > At this point you can already get interrupts > > since you called virtio_device_ready, and > > getting events from a freed device likely won't > > DTRT. > > Right. I guess you want to mark the virtio device ready only after > registering input device.No that's broken since you can get events after this point, and you won't be able to forward them.> > > > > +err_input_alloc: > > > + vdev->config->del_vqs(vdev); > > > +err_init_vq: > > > + kfree(vi); > > > + return err; > > > +} > > > + > > > +static void virtinput_remove(struct virtio_device *vdev) > > > +{ > > > + struct virtio_input *vi = vdev->priv; > > > + > > > + input_unregister_device(vi->idev); > > > > same thing here, you might get an event at this point. > > You need to somehow block new events > > being sent to device while keeping > > device around. > > > > Since you already do everything under a spinlock, > > it's probably easiest to add a flag discarding > > recv events. You can then check it in virtinput_recv_events > > before calling input_event. > > Instead of checking the flag is it possible to pause virio device? Maybe > virtio_break_device()? > > > > > > > > > > + vdev->config->del_vqs(vdev); > > > + kfree(vi); > > > +} > > > + > > > +static unsigned int features[] = { > > > +}; > > > +static struct virtio_device_id id_table[] = { > > > + { VIRTIO_ID_INPUT, VIRTIO_DEV_ANY_ID }, > > > + { 0 }, > > > +}; > > > + > > > +static struct virtio_driver virtio_input_driver = { > > > + .driver.name = KBUILD_MODNAME, > > > + .driver.owner = THIS_MODULE, > > > + .feature_table = features, > > > + .feature_table_size = ARRAY_SIZE(features), > > > + .id_table = id_table, > > > + .probe = virtinput_probe, > > > + .remove = virtinput_remove, > > > > I note this driver doesn't seem to handle hybernation, > > that's probably a bug? > > > > > > > +}; > > > + > > > +module_virtio_driver(virtio_input_driver); > > > +MODULE_DEVICE_TABLE(virtio, id_table); > > > + > > > +MODULE_LICENSE("GPL"); > > > +MODULE_DESCRIPTION("Virtio input device driver"); > > > +MODULE_AUTHOR("Gerd Hoffmann <kraxel at redhat.com>"); > > > diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild > > > index 68ceb97..04b829e 100644 > > > --- a/include/uapi/linux/Kbuild > > > +++ b/include/uapi/linux/Kbuild > > > @@ -430,6 +430,7 @@ header-y += virtio_blk.h > > > header-y += virtio_config.h > > > header-y += virtio_console.h > > > header-y += virtio_ids.h > > > +header-y += virtio_input.h > > > header-y += virtio_net.h > > > header-y += virtio_pci.h > > > header-y += virtio_ring.h > > > diff --git a/include/uapi/linux/virtio_ids.h b/include/uapi/linux/virtio_ids.h > > > index 284fc3a..5f60aa4 100644 > > > --- a/include/uapi/linux/virtio_ids.h > > > +++ b/include/uapi/linux/virtio_ids.h > > > @@ -39,5 +39,6 @@ > > > #define VIRTIO_ID_9P 9 /* 9p virtio console */ > > > #define VIRTIO_ID_RPROC_SERIAL 11 /* virtio remoteproc serial link */ > > > #define VIRTIO_ID_CAIF 12 /* Virtio caif */ > > > +#define VIRTIO_ID_INPUT 18 /* virtio input */ > > > > > > #endif /* _LINUX_VIRTIO_IDS_H */ > > > diff --git a/include/uapi/linux/virtio_input.h b/include/uapi/linux/virtio_input.h > > > new file mode 100644 > > > index 0000000..7fceabd > > > --- /dev/null > > > +++ b/include/uapi/linux/virtio_input.h > > > @@ -0,0 +1,76 @@ > > > +#ifndef _LINUX_VIRTIO_INPUT_H > > > +#define _LINUX_VIRTIO_INPUT_H > > > +/* This header is BSD licensed so anyone can use the definitions to implement > > > + * compatible drivers/servers. > > > + * > > > + * Redistribution and use in source and binary forms, with or without > > > + * modification, are permitted provided that the following conditions > > > + * are met: > > > + * 1. Redistributions of source code must retain the above copyright > > > + * notice, this list of conditions and the following disclaimer. > > > + * 2. Redistributions in binary form must reproduce the above copyright > > > + * notice, this list of conditions and the following disclaimer in the > > > + * documentation and/or other materials provided with the distribution. > > > + * 3. Neither the name of IBM nor the names of its contributors > > > + * may be used to endorse or promote products derived from this software > > > + * without specific prior written permission. > > > + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS > > > + * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT > > > + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS > > > + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL IBM OR > > > + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, > > > + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT > > > + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF > > > + * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND > > > + * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, > > > + * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT > > > + * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF > > > + * SUCH DAMAGE. */ > > > +#include <linux/virtio_ids.h> > > > +#include <linux/virtio_config.h> > > > + > > > +enum virtio_input_config_select { > > > + VIRTIO_INPUT_CFG_UNSET = 0x00, > > > + VIRTIO_INPUT_CFG_ID_NAME = 0x01, > > > + VIRTIO_INPUT_CFG_ID_SERIAL = 0x02, > > > + VIRTIO_INPUT_CFG_ID_DEVIDS = 0x03, > > > + VIRTIO_INPUT_CFG_PROP_BITS = 0x10, > > > + VIRTIO_INPUT_CFG_EV_BITS = 0x11, > > > + VIRTIO_INPUT_CFG_ABS_INFO = 0x12, > > > +}; > > > + > > > +struct virtio_input_absinfo { > > > + __virtio32 min; > > > + __virtio32 max; > > > + __virtio32 fuzz; > > > + __virtio32 flat; > > > + __virtio32 res; > > > +}; > > > + > > > +struct virtio_input_devids { > > > + __virtio16 bustype; > > > + __virtio16 vendor; > > > + __virtio16 product; > > > + __virtio16 version; > > > +}; > > > + > > > > this padding bt two spaces looks weird. > > > > > +struct virtio_input_config { > > > + __u8 select; > > > + __u8 subsel; > > > + __u8 size; > > > + __u8 reserved; > > > + union { > > > + char string[128]; > > > + __u8 bitmap[128]; > > > > I note that neither string nor bitmap are used by > > driver. What are they in aid of? > > Also, what happens if we need more than 1024 bits to pass bitmap data? > We might get there with keyboards. > > > > > > + struct virtio_input_absinfo abs; > > > + struct virtio_input_devids ids; > > > + } u; > > > +}; > > > + > > > +struct virtio_input_event { > > > + __le16 type; > > > + __le16 code; > > > + __le32 value; > > > +}; > > > + > > > +#endif /* _LINUX_VIRTIO_INPUT_H */ > > > -- > > > 1.8.3.1 > > Thanks. > > -- > Dmitry
On Tue, Mar 24, 2015 at 06:22:36PM +0100, Michael S. Tsirkin wrote:> On Tue, Mar 24, 2015 at 09:23:37AM -0700, Dmitry Torokhov wrote: > > On Tue, Mar 24, 2015 at 11:36:31AM +0100, Michael S. Tsirkin wrote: > > > On Tue, Mar 24, 2015 at 08:32:01AM +0100, Gerd Hoffmann wrote: > > > > virtio-input is basically evdev-events-over-virtio, so this driver isn't > > > > much more than reading configuration from config space and forwarding > > > > incoming events to the linux input layer. > > > > > > > > Signed-off-by: Gerd Hoffmann <kraxel at redhat.com> > > > > > > Looks pretty neat overall. I think I still see some > > > small issues, but it's getting there. > > > > > > > --- > > > > MAINTAINERS | 6 + > > > > drivers/virtio/Kconfig | 10 ++ > > > > drivers/virtio/Makefile | 1 + > > > > drivers/virtio/virtio_input.c | 313 ++++++++++++++++++++++++++++++++++++++ > > > > include/uapi/linux/Kbuild | 1 + > > > > include/uapi/linux/virtio_ids.h | 1 + > > > > include/uapi/linux/virtio_input.h | 76 +++++++++ > > > > 7 files changed, 408 insertions(+) > > > > create mode 100644 drivers/virtio/virtio_input.c > > > > create mode 100644 include/uapi/linux/virtio_input.h > > > > > > > > diff --git a/MAINTAINERS b/MAINTAINERS > > > > index 358eb01..6f233dd 100644 > > > > --- a/MAINTAINERS > > > > +++ b/MAINTAINERS > > > > @@ -10442,6 +10442,12 @@ S: Maintained > > > > F: drivers/vhost/ > > > > F: include/uapi/linux/vhost.h > > > > > > > > +VIRTIO INPUT DRIVER > > > > +M: Gerd Hoffmann <kraxel at redhat.com> > > > > +S: Maintained > > > > +F: drivers/virtio/virtio_input.c > > > > +F: include/uapi/linux/virtio_input.h > > > > + > > > > VIA RHINE NETWORK DRIVER > > > > M: Roger Luethi <rl at hellgate.ch> > > > > S: Maintained > > > > diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig > > > > index b546da5..cab9f3f 100644 > > > > --- a/drivers/virtio/Kconfig > > > > +++ b/drivers/virtio/Kconfig > > > > @@ -48,6 +48,16 @@ config VIRTIO_BALLOON > > > > > > > > If unsure, say M. > > > > > > > > +config VIRTIO_INPUT > > > > + tristate "Virtio input driver" > > > > + depends on VIRTIO > > > > + depends on INPUT > > > > + ---help--- > > > > + This driver supports virtio input devices such as > > > > + keyboards, mice and tablets. > > > > + > > > > + If unsure, say M. > > > > + > > > > config VIRTIO_MMIO > > > > tristate "Platform bus driver for memory mapped virtio devices" > > > > depends on HAS_IOMEM > > > > diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile > > > > index d85565b..41e30e3 100644 > > > > --- a/drivers/virtio/Makefile > > > > +++ b/drivers/virtio/Makefile > > > > @@ -4,3 +4,4 @@ obj-$(CONFIG_VIRTIO_PCI) += virtio_pci.o > > > > virtio_pci-y := virtio_pci_modern.o virtio_pci_common.o > > > > virtio_pci-$(CONFIG_VIRTIO_PCI_LEGACY) += virtio_pci_legacy.o > > > > obj-$(CONFIG_VIRTIO_BALLOON) += virtio_balloon.o > > > > +obj-$(CONFIG_VIRTIO_INPUT) += virtio_input.o > > > > diff --git a/drivers/virtio/virtio_input.c b/drivers/virtio/virtio_input.c > > > > new file mode 100644 > > > > index 0000000..cf112b2 > > > > --- /dev/null > > > > +++ b/drivers/virtio/virtio_input.c > > > > @@ -0,0 +1,313 @@ > > > > +#include <linux/module.h> > > > > +#include <linux/virtio.h> > > > > +#include <linux/input.h> > > > > + > > > > +#include <uapi/linux/virtio_ids.h> > > > > +#include <uapi/linux/virtio_input.h> > > > > + > > > > +struct virtio_input { > > > > + struct virtio_device *vdev; > > > > + struct input_dev *idev; > > > > + char name[64]; > > > > + char serial[64]; > > > > + char phys[64]; > > > > + struct virtqueue *evt, *sts; > > > > + struct virtio_input_event evts[64]; > > > > + spinlock_t lock; > > > > +}; > > > > + > > > > +static void virtinput_queue_evtbuf(struct virtio_input *vi, > > > > + struct virtio_input_event *evtbuf) > > > > +{ > > > > + struct scatterlist sg[1]; > > > > + > > > > + sg_init_one(sg, evtbuf, sizeof(*evtbuf)); > > > > + virtqueue_add_inbuf(vi->evt, sg, 1, evtbuf, GFP_ATOMIC); > > > > +} > > > > + > > > > +static void virtinput_recv_events(struct virtqueue *vq) > > > > +{ > > > > + struct virtio_input *vi = vq->vdev->priv; > > > > + struct virtio_input_event *event; > > > > + unsigned long flags; > > > > + unsigned int len; > > > > + > > > > + spin_lock_irqsave(&vi->lock, flags); > > > > + while ((event = virtqueue_get_buf(vi->evt, &len)) != NULL) { > > > > + input_event(vi->idev, > > > > + le16_to_cpu(event->type), > > > > + le16_to_cpu(event->code), > > > > + le32_to_cpu(event->value)); > > > > > > What happens if input layer gets an > > > unexpected event code or value? > > > Or does something prevent it? > > > > > > > > > > > > > + virtinput_queue_evtbuf(vi, event); > > > > + } > > > > + virtqueue_kick(vq); > > > > + spin_unlock_irqrestore(&vi->lock, flags); > > > > +} > > > > + > > > > +static int virtinput_send_status(struct virtio_input *vi, > > > > + u16 type, u16 code, s32 value) > > > > +{ > > > > + struct virtio_input_event *stsbuf; > > > > + struct scatterlist sg[1]; > > > > + unsigned long flags; > > > > + int rc; > > > > + > > > > + stsbuf = kzalloc(sizeof(*stsbuf), GFP_ATOMIC); > > > > + if (!stsbuf) > > > > + return -ENOMEM; > > > > + > > > > + stsbuf->type = cpu_to_le16(type); > > > > + stsbuf->code = cpu_to_le16(code); > > > > + stsbuf->value = cpu_to_le32(value); > > > > + sg_init_one(sg, stsbuf, sizeof(*stsbuf)); > > > > + > > > > + spin_lock_irqsave(&vi->lock, flags); > > > > + rc = virtqueue_add_outbuf(vi->sts, sg, 1, stsbuf, GFP_ATOMIC); > > > > + virtqueue_kick(vi->sts); > > > > + spin_unlock_irqrestore(&vi->lock, flags); > > > > I think locking is wrong here. This is basically input_dev->event() > > which is called with input_dev->event_lock spinlock held, and it is > > taking vi->lock. OTOH virtinput_recv_events() takes vi->lock and then > > calls input_event(), which will try taking input_dev->event_lock. It is > > bound to deadlock at some point. > > > > I guess the easiest way would be to drop vi->lock() after fetching > > virtio event and before calling input_event(). > > Or just always use event_lock for event vq, leave vq->lock for > status vq only. > > > > > + > > > > + if (rc != 0) > > > > + kfree(stsbuf); > > > > + return rc; > > > > > > This means that caller will get errors if it happens to call > > > send_status at a rate that's faster than host's consumption of them. > > > To me this looks wrong. > > > Poking at input layer, it seems to simply discard errors. > > > Is it always safe to discard status updates? > > > If yes, some kind of comment to clarify the logic would > > > make sense IMHO. > > > > > > > > > > > > > +} > > > > + > > > > +static void virtinput_recv_status(struct virtqueue *vq) > > > > +{ > > > > + struct virtio_input *vi = vq->vdev->priv; > > > > + struct virtio_input_event *stsbuf; > > > > + unsigned long flags; > > > > + unsigned int len; > > > > + > > > > + spin_lock_irqsave(&vi->lock, flags); > > > > + while ((stsbuf = virtqueue_get_buf(vi->sts, &len)) != NULL) > > > > + kfree(stsbuf); > > > > + spin_unlock_irqrestore(&vi->lock, flags); > > > > +} > > > > + > > > > +static int virtinput_status(struct input_dev *idev, unsigned int type, > > > > + unsigned int code, int value) > > > > +{ > > > > + struct virtio_input *vi = input_get_drvdata(idev); > > > > + > > > > + return virtinput_send_status(vi, type, code, value); > > > > +} > > > > + > > > > +static size_t virtinput_cfg_select(struct virtio_input *vi, > > > > + u8 select, u8 subsel) > > > > +{ > > > > + u8 size; > > > > + > > > > + virtio_cwrite(vi->vdev, struct virtio_input_config, select, &select); > > > > + virtio_cwrite(vi->vdev, struct virtio_input_config, subsel, &subsel); > > > > + virtio_cread(vi->vdev, struct virtio_input_config, size, &size); > > > > + return size; > > > > +} > > > > + > > > > +static void virtinput_cfg_bits(struct virtio_input *vi, int select, int subsel, > > > > + unsigned long *bits, unsigned int bitcount) > > > > +{ > > > > + unsigned int bit; > > > > + size_t bytes; > > > > + u8 *virtio_bits; > > > > + > > > > + bytes = virtinput_cfg_select(vi, select, subsel); > > > > + if (!bytes) > > > > + return; > > > > > > How about limiting bytes to sizeof struct virtio_input_config->u? > > > > > > > + if (bitcount > bytes*8) > > > > + bitcount = bytes*8; > > > > > > Space around * pls. > > > > > > > + > > > > + /* > > > > + * Bitmap in virtio config space is a simple stream of bytes, > > > > + * with the first byte carrying bits 0-7, second bits 8-15 and > > > > + * so on. > > > > + */ > > > > + virtio_bits = kzalloc(bytes, GFP_KERNEL); > > > > + if (!virtio_bits) > > > > + return; > > > > + virtio_cread_bytes(vi->vdev, offsetof(struct virtio_input_config, u), > > > > + virtio_bits, bytes); > > > > + for (bit = 0; bit < bitcount; bit++) { > > > > + if (virtio_bits[bit / 8] & (1 << (bit % 8))) > > > > + __set_bit(bit, bits); > > > > + } > > > > + kfree(virtio_bits); > > > > + > > > > + if (select == VIRTIO_INPUT_CFG_EV_BITS) > > > > + __set_bit(subsel, vi->idev->evbit); > > > > +} > > > > + > > > > +static void virtinput_cfg_abs(struct virtio_input *vi, int abs) > > > > +{ > > > > + u32 mi, ma, re, fu, fl; > > > > + > > > > + virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_ABS_INFO, abs); > > > > + virtio_cread(vi->vdev, struct virtio_input_config, u.abs.min, &mi); > > > > + virtio_cread(vi->vdev, struct virtio_input_config, u.abs.max, &ma); > > > > + virtio_cread(vi->vdev, struct virtio_input_config, u.abs.res, &re); > > > > + virtio_cread(vi->vdev, struct virtio_input_config, u.abs.fuzz, &fu); > > > > + virtio_cread(vi->vdev, struct virtio_input_config, u.abs.flat, &fl); > > > > + input_set_abs_params(vi->idev, abs, mi, ma, fu, fl); > > > > + input_abs_set_res(vi->idev, abs, re); > > > > +} > > > > + > > > > +static int virtinput_init_vqs(struct virtio_input *vi) > > > > +{ > > > > + struct virtqueue *vqs[2]; > > > > + vq_callback_t *cbs[] = { virtinput_recv_events, > > > > + virtinput_recv_status }; > > > > + static const char * names[] = { "events", "status" }; > > > > > > No space between * and names expected > > > > > > > + int i, err, size; > > > > + > > > > + err = vi->vdev->config->find_vqs(vi->vdev, 2, vqs, cbs, names); > > > > + if (err) > > > > + return err; > > > > + vi->evt = vqs[0]; > > > > + vi->sts = vqs[1]; > > > > + > > > > + size = virtqueue_get_vring_size(vi->evt); > > > > + if (size > ARRAY_SIZE(vi->evts)) > > > > + size = ARRAY_SIZE(vi->evts); > > > > + for (i = 0; i < size; i++) > > > > + virtinput_queue_evtbuf(vi, &vi->evts[i]); > > > > + virtqueue_kick(vi->evt); > > > > + > > > > + return 0; > > > > +} > > > > + > > > > +static int virtinput_probe(struct virtio_device *vdev) > > > > +{ > > > > + struct virtio_input *vi; > > > > + size_t size; > > > > + int abs, err; > > > > + > > > > + if (!virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) > > > > + return -ENODEV; > > > > + > > > > + vi = kzalloc(sizeof(*vi), GFP_KERNEL); > > > > + if (!vi) > > > > + return -ENOMEM; > > > > + > > > > + vdev->priv = vi; > > > > + vi->vdev = vdev; > > > > + spin_lock_init(&vi->lock); > > > > + > > > > + err = virtinput_init_vqs(vi); > > > > + if (err) > > > > + goto err_init_vq; > > > > + > > > > + vi->idev = input_allocate_device(); > > > > + if (!vi->idev) { > > > > + err = -ENOMEM; > > > > + goto err_input_alloc; > > > > + } > > > > + input_set_drvdata(vi->idev, vi); > > > > + > > > > + size = virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_ID_NAME, 0); > > > > + virtio_cread_bytes(vi->vdev, offsetof(struct virtio_input_config, u), > > > > + vi->name, min(size, sizeof(vi->name))); > > > > + size = virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_ID_SERIAL, 0); > > > > + virtio_cread_bytes(vi->vdev, offsetof(struct virtio_input_config, u), > > > > + vi->serial, min(size, sizeof(vi->serial))); > > > > + snprintf(vi->phys, sizeof(vi->phys), > > > > + "virtio%d/input0", vdev->index); > > > > + vi->idev->name = vi->name; > > > > + vi->idev->phys = vi->phys; > > > > + vi->idev->uniq = vi->serial; > > > > + > > > > + size = virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_ID_DEVIDS, 0); > > > > + if (size >= 8) { > > > > > > What does 8 mean here? Should be sizeof virtio_input_devids? > > > > > > > + virtio_cread(vi->vdev, struct virtio_input_config, > > > > + u.ids.bustype, &vi->idev->id.bustype); > > > > + virtio_cread(vi->vdev, struct virtio_input_config, > > > > + u.ids.vendor, &vi->idev->id.vendor); > > > > + virtio_cread(vi->vdev, struct virtio_input_config, > > > > + u.ids.product, &vi->idev->id.product); > > > > + virtio_cread(vi->vdev, struct virtio_input_config, > > > > + u.ids.version, &vi->idev->id.version); > > > > + } else { > > > > + vi->idev->id.bustype = BUS_VIRTUAL; > > > > + } > > > > + > > > > + virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_PROP_BITS, 0, > > > > + vi->idev->propbit, INPUT_PROP_CNT); > > > > + size = virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_REP); > > > > + if (size) > > > > + __set_bit(EV_REP, vi->idev->evbit); > > > > + > > > > + vi->idev->dev.parent = &vdev->dev; > > > > + vi->idev->event = virtinput_status; > > > > + > > > > + /* device -> kernel */ > > > > + virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_KEY, > > > > + vi->idev->keybit, KEY_CNT); > > > > + virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_REL, > > > > + vi->idev->relbit, REL_CNT); > > > > + virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_ABS, > > > > + vi->idev->absbit, ABS_CNT); > > > > + virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_MSC, > > > > + vi->idev->mscbit, MSC_CNT); > > > > + virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_SW, > > > > + vi->idev->swbit, SW_CNT); > > > > + > > > > + /* kernel -> device */ > > > > + virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_LED, > > > > + vi->idev->ledbit, LED_CNT); > > > > + virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_SND, > > > > + vi->idev->sndbit, SND_CNT); > > > > + > > > > + if (test_bit(EV_ABS, vi->idev->evbit)) { > > > > + for (abs = 0; abs < ABS_CNT; abs++) { > > > > + if (!test_bit(abs, vi->idev->absbit)) > > > > + continue; > > > > + virtinput_cfg_abs(vi, abs); > > > > + } > > > > + } > > > > + virtio_device_ready(vdev); > > > > + > > > At this point you can already get interrupts. > > > This will cause events to be forwarded. > > > I'm guessing this is ok since you called > > > input_allocate_device, but worth checking, > > > and maybe adding a comment. > > > > Yes, it is OK to send events though yet unregistered input device, as > > long as it was allocated with input_allocate_device(). > > > > > > > > > + err = input_register_device(vi->idev); > > > > + if (err) > > > > + goto err_input_register; > > > > + > > > > + return 0; > > > > + > > > > +err_input_register: > > > > > > > + input_free_device(vi->idev); > > > > > > At this point you can already get interrupts > > > since you called virtio_device_ready, and > > > getting events from a freed device likely won't > > > DTRT. > > > > Right. I guess you want to mark the virtio device ready only after > > registering input device. > > No that's broken since you can get events after this > point, and you won't be able to forward them.Who cares? What makes these events needed compared to ones sent 1 ms earlier before we had input device registered? But I guess if you can call virtio_device_ready/virtio_device_broken several times then the best option is putting them into input_dev->open and input_dev->close callbacks. Thanks. -- Dmitry