From 9564e138b1f6eb137f7149772438d3f3fb3277dd Mon Sep 17 00:00:00 2001 From: Adam Litke Date: Mon, 30 Nov 2009 10:14:15 -0600 Subject: virtio: Add memory statistics reporting to the balloon driver (V4) Changes since V3: - Do not do endian conversions as they will be done in the host - Report stats that reference a quantity of memory in bytes - Minor coding style updates Changes since V2: - Increase stat field size to 64 bits - Report all sizes in kb (not pages) - Drop anon_pages stat and fix endianness conversion Changes since V1: - Use a virtqueue instead of the device config space When using ballooning to manage overcommitted memory on a host, a system for guests to communicate their memory usage to the host can provide information that will minimize the impact of ballooning on the guests. The current method employs a daemon running in each guest that communicates memory statistics to a host daemon at a specified time interval. The host daemon aggregates this information and inflates and/or deflates balloons according to the level of host memory pressure. This approach is effective but overly complex since a daemon must be installed inside each guest and coordinated to communicate with the host. A simpler approach is to collect memory statistics in the virtio balloon driver and communicate them directly to the hypervisor. This patch enables the guest-side support by adding stats collection and reporting to the virtio balloon driver. Signed-off-by: Adam Litke Cc: Anthony Liguori Cc: virtualization@lists.linux-foundation.org Signed-off-by: Rusty Russell (minor fixes) --- include/linux/virtio_balloon.h | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'include') diff --git a/include/linux/virtio_balloon.h b/include/linux/virtio_balloon.h index 1418f048cb34..a50ecd1b81a2 100644 --- a/include/linux/virtio_balloon.h +++ b/include/linux/virtio_balloon.h @@ -7,6 +7,7 @@ /* The feature bitmap for virtio balloon */ #define VIRTIO_BALLOON_F_MUST_TELL_HOST 0 /* Tell before reclaiming pages */ +#define VIRTIO_BALLOON_F_STATS_VQ 1 /* Memory Stats virtqueue */ /* Size of a PFN in the balloon interface. */ #define VIRTIO_BALLOON_PFN_SHIFT 12 @@ -18,4 +19,18 @@ struct virtio_balloon_config /* Number of pages we've actually got in balloon. */ __le32 actual; }; + +#define VIRTIO_BALLOON_S_SWAP_IN 0 /* Amount of memory swapped in */ +#define VIRTIO_BALLOON_S_SWAP_OUT 1 /* Amount of memory swapped out */ +#define VIRTIO_BALLOON_S_MAJFLT 2 /* Number of major faults */ +#define VIRTIO_BALLOON_S_MINFLT 3 /* Number of minor faults */ +#define VIRTIO_BALLOON_S_MEMFREE 4 /* Total amount of free memory */ +#define VIRTIO_BALLOON_S_MEMTOT 5 /* Total amount of memory */ +#define VIRTIO_BALLOON_S_NR 6 + +struct virtio_balloon_stat { + u16 tag; + u64 val; +} __attribute__((packed)); + #endif /* _LINUX_VIRTIO_BALLOON_H */ -- cgit v1.2.3 From 69740c8ba878f58bc3c71f74618fc2cd1da990da Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 24 Feb 2010 14:22:25 -0600 Subject: virtio_blk: add block topology support Allow reading various alignment values from the config page. This allows the guest to much better align I/O requests depending on the storage topology. Note that the formats for the config values appear a bit messed up, but we follow the formats used by ATA and SCSI so they are expected in the storage world. Signed-off-by: Christoph Hellwig Signed-off-by: Rusty Russell --- drivers/block/virtio_blk.c | 61 ++++++++++++++++++++++++++++++++++------------ include/linux/virtio_blk.h | 13 ++++++++++ 2 files changed, 59 insertions(+), 15 deletions(-) (limited to 'include') diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index 51042f0ba7e1..7eff828b2117 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -243,10 +243,12 @@ static int index_to_minor(int index) static int __devinit virtblk_probe(struct virtio_device *vdev) { struct virtio_blk *vblk; + struct request_queue *q; int err; u64 cap; - u32 v; - u32 blk_size, sg_elems; + u32 v, blk_size, sg_elems, opt_io_size; + u16 min_io_size; + u8 physical_block_exp, alignment_offset; if (index_to_minor(index) >= 1 << MINORBITS) return -ENOSPC; @@ -293,13 +295,13 @@ static int __devinit virtblk_probe(struct virtio_device *vdev) goto out_mempool; } - vblk->disk->queue = blk_init_queue(do_virtblk_request, &vblk->lock); - if (!vblk->disk->queue) { + q = vblk->disk->queue = blk_init_queue(do_virtblk_request, &vblk->lock); + if (!q) { err = -ENOMEM; goto out_put_disk; } - vblk->disk->queue->queuedata = vblk; + q->queuedata = vblk; if (index < 26) { sprintf(vblk->disk->disk_name, "vd%c", 'a' + index % 26); @@ -323,10 +325,10 @@ static int __devinit virtblk_probe(struct virtio_device *vdev) /* If barriers are supported, tell block layer that queue is ordered */ if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH)) - blk_queue_ordered(vblk->disk->queue, QUEUE_ORDERED_DRAIN_FLUSH, + blk_queue_ordered(q, QUEUE_ORDERED_DRAIN_FLUSH, virtblk_prepare_flush); else if (virtio_has_feature(vdev, VIRTIO_BLK_F_BARRIER)) - blk_queue_ordered(vblk->disk->queue, QUEUE_ORDERED_TAG, NULL); + blk_queue_ordered(q, QUEUE_ORDERED_TAG, NULL); /* If disk is read-only in the host, the guest should obey */ if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO)) @@ -345,14 +347,14 @@ static int __devinit virtblk_probe(struct virtio_device *vdev) set_capacity(vblk->disk, cap); /* We can handle whatever the host told us to handle. */ - blk_queue_max_phys_segments(vblk->disk->queue, vblk->sg_elems-2); - blk_queue_max_hw_segments(vblk->disk->queue, vblk->sg_elems-2); + blk_queue_max_phys_segments(q, vblk->sg_elems-2); + blk_queue_max_hw_segments(q, vblk->sg_elems-2); /* No need to bounce any requests */ - blk_queue_bounce_limit(vblk->disk->queue, BLK_BOUNCE_ANY); + blk_queue_bounce_limit(q, BLK_BOUNCE_ANY); /* No real sector limit. */ - blk_queue_max_sectors(vblk->disk->queue, -1U); + blk_queue_max_sectors(q, -1U); /* Host can optionally specify maximum segment size and number of * segments. */ @@ -360,16 +362,45 @@ static int __devinit virtblk_probe(struct virtio_device *vdev) offsetof(struct virtio_blk_config, size_max), &v); if (!err) - blk_queue_max_segment_size(vblk->disk->queue, v); + blk_queue_max_segment_size(q, v); else - blk_queue_max_segment_size(vblk->disk->queue, -1U); + blk_queue_max_segment_size(q, -1U); /* Host can optionally specify the block size of the device */ err = virtio_config_val(vdev, VIRTIO_BLK_F_BLK_SIZE, offsetof(struct virtio_blk_config, blk_size), &blk_size); if (!err) - blk_queue_logical_block_size(vblk->disk->queue, blk_size); + blk_queue_logical_block_size(q, blk_size); + else + blk_size = queue_logical_block_size(q); + + /* Use topology information if available */ + err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY, + offsetof(struct virtio_blk_config, physical_block_exp), + &physical_block_exp); + if (!err && physical_block_exp) + blk_queue_physical_block_size(q, + blk_size * (1 << physical_block_exp)); + + err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY, + offsetof(struct virtio_blk_config, alignment_offset), + &alignment_offset); + if (!err && alignment_offset) + blk_queue_alignment_offset(q, blk_size * alignment_offset); + + err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY, + offsetof(struct virtio_blk_config, min_io_size), + &min_io_size); + if (!err && min_io_size) + blk_queue_io_min(q, blk_size * min_io_size); + + err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY, + offsetof(struct virtio_blk_config, opt_io_size), + &opt_io_size); + if (!err && opt_io_size) + blk_queue_io_opt(q, blk_size * opt_io_size); + add_disk(vblk->disk); return 0; @@ -412,7 +443,7 @@ static struct virtio_device_id id_table[] = { static unsigned int features[] = { VIRTIO_BLK_F_BARRIER, VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY, VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, - VIRTIO_BLK_F_SCSI, VIRTIO_BLK_F_FLUSH + VIRTIO_BLK_F_SCSI, VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY }; /* diff --git a/include/linux/virtio_blk.h b/include/linux/virtio_blk.h index fd294c56d571..e52029e98919 100644 --- a/include/linux/virtio_blk.h +++ b/include/linux/virtio_blk.h @@ -15,6 +15,7 @@ #define VIRTIO_BLK_F_BLK_SIZE 6 /* Block size of disk is available*/ #define VIRTIO_BLK_F_SCSI 7 /* Supports scsi command passthru */ #define VIRTIO_BLK_F_FLUSH 9 /* Cache flush command support */ +#define VIRTIO_BLK_F_TOPOLOGY 10 /* Topology information is available */ struct virtio_blk_config { /* The capacity (in 512-byte sectors). */ @@ -29,8 +30,20 @@ struct virtio_blk_config { __u8 heads; __u8 sectors; } geometry; + /* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */ __u32 blk_size; + + /* the next 4 entries are guarded by VIRTIO_BLK_F_TOPOLOGY */ + /* exponent for physical block per logical block. */ + __u8 physical_block_exp; + /* alignment offset in logical blocks. */ + __u8 alignment_offset; + /* minimum I/O size without performance penalty in logical blocks. */ + __u16 min_io_size; + /* optimal sustained I/O size in logical blocks. */ + __u32 opt_io_size; + } __attribute__((packed)); /* -- cgit v1.2.3 From c021eac4148c16bf53baa0dd14e8ebee6f39dab5 Mon Sep 17 00:00:00 2001 From: Shirley Ma Date: Mon, 18 Jan 2010 19:15:23 +0530 Subject: virtio: Add ability to detach unused buffers from vrings There's currently no way for a virtio driver to ask for unused buffers, so it has to keep a list itself to reclaim them at shutdown. This is redundant, since virtio_ring stores that information. So add a new hook to do this. Signed-off-by: Shirley Ma Signed-off-by: Amit Shah Signed-off-by: Rusty Russell --- drivers/virtio/virtio_ring.c | 25 +++++++++++++++++++++++++ include/linux/virtio.h | 4 ++++ 2 files changed, 29 insertions(+) (limited to 'include') diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 827f7e042610..782b7292a3d8 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -351,6 +351,30 @@ static bool vring_enable_cb(struct virtqueue *_vq) return true; } +static void *vring_detach_unused_buf(struct virtqueue *_vq) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + unsigned int i; + void *buf; + + START_USE(vq); + + for (i = 0; i < vq->vring.num; i++) { + if (!vq->data[i]) + continue; + /* detach_buf clears data, so grab it now. */ + buf = vq->data[i]; + detach_buf(vq, i); + END_USE(vq); + return buf; + } + /* That should have freed everything. */ + BUG_ON(vq->num_free != vq->vring.num); + + END_USE(vq); + return NULL; +} + irqreturn_t vring_interrupt(int irq, void *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); @@ -377,6 +401,7 @@ static struct virtqueue_ops vring_vq_ops = { .kick = vring_kick, .disable_cb = vring_disable_cb, .enable_cb = vring_enable_cb, + .detach_unused_buf = vring_detach_unused_buf, }; struct virtqueue *vring_new_virtqueue(unsigned int num, diff --git a/include/linux/virtio.h b/include/linux/virtio.h index 057a2e010758..f508c651e53d 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -51,6 +51,9 @@ struct virtqueue { * This re-enables callbacks; it returns "false" if there are pending * buffers in the queue, to detect a possible race between the driver * checking for more work, and enabling callbacks. + * @detach_unused_buf: detach first unused buffer + * vq: the struct virtqueue we're talking about. + * Returns NULL or the "data" token handed to add_buf * * Locking rules are straightforward: the driver is responsible for * locking. No two operations may be invoked simultaneously, with the exception @@ -71,6 +74,7 @@ struct virtqueue_ops { void (*disable_cb)(struct virtqueue *vq); bool (*enable_cb)(struct virtqueue *vq); + void *(*detach_unused_buf)(struct virtqueue *vq); }; /** -- cgit v1.2.3 From a23ea92474e558b071d3e43d961ec767c31faebd Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Mon, 18 Jan 2010 19:14:55 +0530 Subject: virtio: console: comment cleanup Remove old lguest-style comments. [Amit: - wingify comments acc. to kernel style - indent comments ] Signed-off-by: Rusty Russell Signed-off-by: Amit Shah Signed-off-by: Rusty Russell --- drivers/char/virtio_console.c | 108 ++++++++++++++++++++--------------------- include/linux/virtio_console.h | 6 ++- 2 files changed, 58 insertions(+), 56 deletions(-) (limited to 'include') diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index a035ae39a359..26e238cd7d2f 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -1,18 +1,5 @@ -/*D:300 - * The Guest console driver - * - * Writing console drivers is one of the few remaining Dark Arts in Linux. - * Fortunately for us, the path of virtual consoles has been well-trodden by - * the PowerPC folks, who wrote "hvc_console.c" to generically support any - * virtual console. We use that infrastructure which only requires us to write - * the basic put_chars and get_chars functions and call the right register - * functions. - :*/ - -/*M:002 The console can be flooded: while the Guest is processing input the - * Host can send more. Buffering in the Host could alleviate this, but it is a - * difficult problem in general. :*/ -/* Copyright (C) 2006, 2007 Rusty Russell, IBM Corporation +/* + * Copyright (C) 2006, 2007, 2009 Rusty Russell, IBM Corporation * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -34,8 +21,6 @@ #include #include "hvc_console.h" -/*D:340 These represent our input and output console queues, and the virtio - * operations for them. */ static struct virtqueue *in_vq, *out_vq; static struct virtio_device *vdev; @@ -49,12 +34,14 @@ static struct hv_ops virtio_cons; /* The hvc device */ static struct hvc_struct *hvc; -/*D:310 The put_chars() callback is pretty straightforward. +/* + * The put_chars() callback is pretty straightforward. * - * We turn the characters into a scatter-gather list, add it to the output - * queue and then kick the Host. Then we sit here waiting for it to finish: - * inefficient in theory, but in practice implementations will do it - * immediately (lguest's Launcher does). */ + * We turn the characters into a scatter-gather list, add it to the + * output queue and then kick the Host. Then we sit here waiting for + * it to finish: inefficient in theory, but in practice + * implementations will do it immediately (lguest's Launcher does). + */ static int put_chars(u32 vtermno, const char *buf, int count) { struct scatterlist sg[1]; @@ -63,8 +50,10 @@ static int put_chars(u32 vtermno, const char *buf, int count) /* This is a convenient routine to initialize a single-elem sg list */ sg_init_one(sg, buf, count); - /* add_buf wants a token to identify this buffer: we hand it any - * non-NULL pointer, since there's only ever one buffer. */ + /* + * add_buf wants a token to identify this buffer: we hand it + * any non-NULL pointer, since there's only ever one buffer. + */ if (out_vq->vq_ops->add_buf(out_vq, sg, 1, 0, (void *)1) >= 0) { /* Tell Host to go! */ out_vq->vq_ops->kick(out_vq); @@ -77,8 +66,10 @@ static int put_chars(u32 vtermno, const char *buf, int count) return count; } -/* Create a scatter-gather list representing our input buffer and put it in the - * queue. */ +/* + * Create a scatter-gather list representing our input buffer and put + * it in the queue. + */ static void add_inbuf(void) { struct scatterlist sg[1]; @@ -90,12 +81,14 @@ static void add_inbuf(void) in_vq->vq_ops->kick(in_vq); } -/*D:350 get_chars() is the callback from the hvc_console infrastructure when - * an interrupt is received. +/* + * get_chars() is the callback from the hvc_console infrastructure + * when an interrupt is received. * - * Most of the code deals with the fact that the hvc_console() infrastructure - * only asks us for 16 bytes at a time. We keep in_offset and in_used fields - * for partially-filled buffers. */ + * Most of the code deals with the fact that the hvc_console() + * infrastructure only asks us for 16 bytes at a time. We keep + * in_offset and in_used fields for partially-filled buffers. + */ static int get_chars(u32 vtermno, char *buf, int count) { /* If we don't have an input queue yet, we can't get input. */ @@ -123,14 +116,16 @@ static int get_chars(u32 vtermno, char *buf, int count) return count; } -/*:*/ -/*D:320 Console drivers are initialized very early so boot messages can go out, - * so we do things slightly differently from the generic virtio initialization - * of the net and block drivers. +/* + * Console drivers are initialized very early so boot messages can go + * out, so we do things slightly differently from the generic virtio + * initialization of the net and block drivers. * - * At this stage, the console is output-only. It's too early to set up a - * virtqueue, so we let the drivers do some boutique early-output thing. */ + * At this stage, the console is output-only. It's too early to set + * up a virtqueue, so we let the drivers do some boutique early-output + * thing. + */ int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int)) { virtio_cons.put_chars = put_chars; @@ -157,8 +152,8 @@ static void virtcons_apply_config(struct virtio_device *dev) } /* - * we support only one console, the hvc struct is a global var - * We set the configuration at this point, since we now have a tty + * we support only one console, the hvc struct is a global var We set + * the configuration at this point, since we now have a tty */ static int notifier_add_vio(struct hvc_struct *hp, int data) { @@ -179,13 +174,17 @@ static void hvc_handle_input(struct virtqueue *vq) hvc_kick(); } -/*D:370 Once we're further in boot, we get probed like any other virtio device. - * At this stage we set up the output virtqueue. +/* + * Once we're further in boot, we get probed like any other virtio + * device. At this stage we set up the output virtqueue. * - * To set up and manage our virtual console, we call hvc_alloc(). Since we - * never remove the console device we never need this pointer again. + * To set up and manage our virtual console, we call hvc_alloc(). + * Since we never remove the console device we never need this pointer + * again. * - * Finally we put our input buffer in the input queue, ready to receive. */ + * Finally we put our input buffer in the input queue, ready to + * receive. + */ static int __devinit virtcons_probe(struct virtio_device *dev) { vq_callback_t *callbacks[] = { hvc_handle_input, NULL}; @@ -203,8 +202,6 @@ static int __devinit virtcons_probe(struct virtio_device *dev) } /* Find the queues. */ - /* FIXME: This is why we want to wean off hvc: we do nothing - * when input comes in. */ err = vdev->config->find_vqs(vdev, 2, vqs, callbacks, names); if (err) goto free; @@ -219,15 +216,18 @@ static int __devinit virtcons_probe(struct virtio_device *dev) virtio_cons.notifier_del = notifier_del_vio; virtio_cons.notifier_hangup = notifier_del_vio; - /* The first argument of hvc_alloc() is the virtual console number, so - * we use zero. The second argument is the parameter for the - * notification mechanism (like irq number). We currently leave this - * as zero, virtqueues have implicit notifications. + /* + * The first argument of hvc_alloc() is the virtual console + * number, so we use zero. The second argument is the + * parameter for the notification mechanism (like irq + * number). We currently leave this as zero, virtqueues have + * implicit notifications. * - * The third argument is a "struct hv_ops" containing the put_chars() - * get_chars(), notifier_add() and notifier_del() pointers. - * The final argument is the output buffer size: we can do any size, - * so we put PAGE_SIZE here. */ + * The third argument is a "struct hv_ops" containing the + * put_chars(), get_chars(), notifier_add() and notifier_del() + * pointers. The final argument is the output buffer size: we + * can do any size, so we put PAGE_SIZE here. + */ hvc = hvc_alloc(0, 0, &virtio_cons, PAGE_SIZE); if (IS_ERR(hvc)) { err = PTR_ERR(hvc); diff --git a/include/linux/virtio_console.h b/include/linux/virtio_console.h index fe885174cc1f..9e0da40beae0 100644 --- a/include/linux/virtio_console.h +++ b/include/linux/virtio_console.h @@ -3,8 +3,10 @@ #include #include #include -/* This header, excluding the #ifdef __KERNEL__ part, is BSD licensed so - * anyone can use the definitions to implement compatible drivers/servers. */ +/* + * This header, excluding the #ifdef __KERNEL__ part, is BSD licensed so + * anyone can use the definitions to implement compatible drivers/servers. + */ /* Feature bits */ #define VIRTIO_CONSOLE_F_SIZE 0 /* Does host provide console size? */ -- cgit v1.2.3 From 17634ba25544d60af1968982929150efad755032 Mon Sep 17 00:00:00 2001 From: Amit Shah Date: Mon, 21 Dec 2009 21:03:25 +0530 Subject: virtio: console: Add a new MULTIPORT feature, support for generic ports This commit adds a new feature, MULTIPORT. If the host supports this feature as well, the config space has the number of ports defined for that device. New ports are spawned according to this information. The config space also has the maximum number of ports that can be spawned for a particular device. This is useful in initializing the appropriate number of virtqueues in advance, as ports might be hot-plugged in later. Using this feature, generic ports can be created which are not tied to hvc consoles. We also open up a private channel between the host and the guest via which some "control" messages are exchanged for the ports, like whether the port being spawned is a console port, resizing the console window, etc. Next commits will add support for hotplugging and presenting char devices in /dev/ for bi-directional guest-host communication. Signed-off-by: Amit Shah Signed-off-by: Rusty Russell --- drivers/char/virtio_console.c | 392 +++++++++++++++++++++++++++++++++++------ include/linux/virtio_console.h | 21 +++ 2 files changed, 357 insertions(+), 56 deletions(-) (limited to 'include') diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index d01051060be3..a70f2b3a9e64 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -1,5 +1,6 @@ /* * Copyright (C) 2006, 2007, 2009 Rusty Russell, IBM Corporation + * Copyright (C) 2009, 2010 Red Hat, Inc. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -21,6 +22,7 @@ #include #include #include +#include #include "hvc_console.h" /* @@ -69,17 +71,6 @@ struct console { u32 vtermno; }; -/* - * This is a per-device struct that stores data common to all the - * ports for that device (vdev->priv). - */ -struct ports_device { - /* Array of per-port IO virtqueues */ - struct virtqueue **in_vqs, **out_vqs; - - struct virtio_device *vdev; -}; - struct port_buffer { char *buf; @@ -92,8 +83,46 @@ struct port_buffer { size_t offset; }; +/* + * This is a per-device struct that stores data common to all the + * ports for that device (vdev->priv). + */ +struct ports_device { + /* + * Workqueue handlers where we process deferred work after + * notification + */ + struct work_struct control_work; + + struct list_head ports; + + /* To protect the list of ports */ + spinlock_t ports_lock; + + /* To protect the vq operations for the control channel */ + spinlock_t cvq_lock; + + /* The current config space is stored here */ + struct virtio_console_config config; + + /* The virtio device we're associated with */ + struct virtio_device *vdev; + + /* + * A couple of virtqueues for the control channel: one for + * guest->host transfers, one for host->guest transfers + */ + struct virtqueue *c_ivq, *c_ovq; + + /* Array of per-port IO virtqueues */ + struct virtqueue **in_vqs, **out_vqs; +}; + /* This struct holds the per-port data */ struct port { + /* Next port in the list, head is in the ports_device */ + struct list_head list; + /* Pointer to the parent virtio_console device */ struct ports_device *portdev; @@ -115,6 +144,9 @@ struct port { * hooked up to an hvc console */ struct console cons; + + /* The 'id' to identify the port with the Host */ + u32 id; }; /* This is the very early arch-specified put chars function. */ @@ -139,25 +171,56 @@ out: return port; } +static struct port *find_port_by_id(struct ports_device *portdev, u32 id) +{ + struct port *port; + unsigned long flags; + + spin_lock_irqsave(&portdev->ports_lock, flags); + list_for_each_entry(port, &portdev->ports, list) + if (port->id == id) + goto out; + port = NULL; +out: + spin_unlock_irqrestore(&portdev->ports_lock, flags); + + return port; +} + static struct port *find_port_by_vq(struct ports_device *portdev, struct virtqueue *vq) { struct port *port; - struct console *cons; unsigned long flags; - spin_lock_irqsave(&pdrvdata_lock, flags); - list_for_each_entry(cons, &pdrvdata.consoles, list) { - port = container_of(cons, struct port, cons); + spin_lock_irqsave(&portdev->ports_lock, flags); + list_for_each_entry(port, &portdev->ports, list) if (port->in_vq == vq || port->out_vq == vq) goto out; - } port = NULL; out: - spin_unlock_irqrestore(&pdrvdata_lock, flags); + spin_unlock_irqrestore(&portdev->ports_lock, flags); return port; } +static bool is_console_port(struct port *port) +{ + if (port->cons.hvc) + return true; + return false; +} + +static inline bool use_multiport(struct ports_device *portdev) +{ + /* + * This condition can be true when put_chars is called from + * early_init + */ + if (!portdev->vdev) + return 0; + return portdev->vdev->features[0] & (1 << VIRTIO_CONSOLE_F_MULTIPORT); +} + static void free_buf(struct port_buffer *buf) { kfree(buf->buf); @@ -233,6 +296,32 @@ static bool port_has_data(struct port *port) return ret; } +static ssize_t send_control_msg(struct port *port, unsigned int event, + unsigned int value) +{ + struct scatterlist sg[1]; + struct virtio_console_control cpkt; + struct virtqueue *vq; + int len; + + if (!use_multiport(port->portdev)) + return 0; + + cpkt.id = port->id; + cpkt.event = event; + cpkt.value = value; + + vq = port->portdev->c_ovq; + + sg_init_one(sg, &cpkt, sizeof(cpkt)); + if (vq->vq_ops->add_buf(vq, sg, 1, 0, &cpkt) >= 0) { + vq->vq_ops->kick(vq); + while (!vq->vq_ops->get_buf(vq, &len)) + cpu_relax(); + } + return 0; +} + static ssize_t send_buf(struct port *port, void *in_buf, size_t in_count) { struct scatterlist sg[1]; @@ -387,24 +476,7 @@ static void notifier_del_vio(struct hvc_struct *hp, int data) hp->irq_requested = 0; } -static void hvc_handle_input(struct virtqueue *vq) -{ - struct port *port; - unsigned long flags; - - port = find_port_by_vq(vq->vdev->priv, vq); - if (!port) - return; - - spin_lock_irqsave(&port->inbuf_lock, flags); - port->inbuf = get_inbuf(port); - spin_unlock_irqrestore(&port->inbuf_lock, flags); - - if (hvc_poll(port->cons.hvc)) - hvc_kick(); -} - -/* The operations for the console. */ +/* The operations for console ports. */ static const struct hv_ops hv_ops = { .get_chars = get_chars, .put_chars = put_chars, @@ -428,7 +500,7 @@ int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int)) return hvc_instantiate(0, 0, &hv_ops); } -int __devinit init_port_console(struct port *port) +int init_port_console(struct port *port) { int ret; @@ -465,7 +537,122 @@ int __devinit init_port_console(struct port *port) return 0; } -static int __devinit add_port(struct ports_device *portdev) +/* Any private messages that the Host and Guest want to share */ +static void handle_control_message(struct ports_device *portdev, + struct port_buffer *buf) +{ + struct virtio_console_control *cpkt; + struct port *port; + + cpkt = (struct virtio_console_control *)(buf->buf + buf->offset); + + port = find_port_by_id(portdev, cpkt->id); + if (!port) { + /* No valid header at start of buffer. Drop it. */ + dev_dbg(&portdev->vdev->dev, + "Invalid index %u in control packet\n", cpkt->id); + return; + } + + switch (cpkt->event) { + case VIRTIO_CONSOLE_CONSOLE_PORT: + if (!cpkt->value) + break; + if (is_console_port(port)) + break; + + init_port_console(port); + /* + * Could remove the port here in case init fails - but + * have to notify the host first. + */ + break; + case VIRTIO_CONSOLE_RESIZE: + if (!is_console_port(port)) + break; + port->cons.hvc->irq_requested = 1; + resize_console(port); + break; + } +} + +static void control_work_handler(struct work_struct *work) +{ + struct ports_device *portdev; + struct virtqueue *vq; + struct port_buffer *buf; + unsigned int len; + + portdev = container_of(work, struct ports_device, control_work); + vq = portdev->c_ivq; + + spin_lock(&portdev->cvq_lock); + while ((buf = vq->vq_ops->get_buf(vq, &len))) { + spin_unlock(&portdev->cvq_lock); + + buf->len = len; + buf->offset = 0; + + handle_control_message(portdev, buf); + + spin_lock(&portdev->cvq_lock); + if (add_inbuf(portdev->c_ivq, buf) < 0) { + dev_warn(&portdev->vdev->dev, + "Error adding buffer to queue\n"); + free_buf(buf); + } + } + spin_unlock(&portdev->cvq_lock); +} + +static void in_intr(struct virtqueue *vq) +{ + struct port *port; + unsigned long flags; + + port = find_port_by_vq(vq->vdev->priv, vq); + if (!port) + return; + + spin_lock_irqsave(&port->inbuf_lock, flags); + port->inbuf = get_inbuf(port); + + spin_unlock_irqrestore(&port->inbuf_lock, flags); + + if (is_console_port(port) && hvc_poll(port->cons.hvc)) + hvc_kick(); +} + +static void control_intr(struct virtqueue *vq) +{ + struct ports_device *portdev; + + portdev = vq->vdev->priv; + schedule_work(&portdev->control_work); +} + +static void fill_queue(struct virtqueue *vq, spinlock_t *lock) +{ + struct port_buffer *buf; + int ret; + + do { + buf = alloc_buf(PAGE_SIZE); + if (!buf) + break; + + spin_lock_irq(lock); + ret = add_inbuf(vq, buf); + if (ret < 0) { + spin_unlock_irq(lock); + free_buf(buf); + break; + } + spin_unlock_irq(lock); + } while (ret > 0); +} + +static int add_port(struct ports_device *portdev, u32 id) { struct port *port; struct port_buffer *inbuf; @@ -478,11 +665,13 @@ static int __devinit add_port(struct ports_device *portdev) } port->portdev = portdev; + port->id = id; port->inbuf = NULL; + port->cons.hvc = NULL; - port->in_vq = portdev->in_vqs[0]; - port->out_vq = portdev->out_vqs[0]; + port->in_vq = portdev->in_vqs[port->id]; + port->out_vq = portdev->out_vqs[port->id]; spin_lock_init(&port->inbuf_lock); @@ -495,9 +684,25 @@ static int __devinit add_port(struct ports_device *portdev) /* Register the input buffer the first time. */ add_inbuf(port->in_vq, inbuf); - err = init_port_console(port); - if (err) - goto free_inbuf; + /* + * If we're not using multiport support, this has to be a console port + */ + if (!use_multiport(port->portdev)) { + err = init_port_console(port); + if (err) + goto free_inbuf; + } + + spin_lock_irq(&portdev->ports_lock); + list_add_tail(&port->list, &port->portdev->ports); + spin_unlock_irq(&portdev->ports_lock); + + /* + * Tell the Host we're set so that it can send us various + * configuration parameters for this port (eg, port name, + * caching, whether this is a console port, etc.) + */ + send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1); return 0; @@ -514,12 +719,11 @@ static int init_vqs(struct ports_device *portdev) vq_callback_t **io_callbacks; char **io_names; struct virtqueue **vqs; - u32 nr_ports, nr_queues; + u32 i, j, nr_ports, nr_queues; int err; - /* We currently only have one port and two queues for that port */ - nr_ports = 1; - nr_queues = 2; + nr_ports = portdev->config.max_nr_ports; + nr_queues = use_multiport(portdev) ? (nr_ports + 1) * 2 : 2; vqs = kmalloc(nr_queues * sizeof(struct virtqueue *), GFP_KERNEL); if (!vqs) { @@ -549,11 +753,32 @@ static int init_vqs(struct ports_device *portdev) goto free_invqs; } - io_callbacks[0] = hvc_handle_input; - io_callbacks[1] = NULL; - io_names[0] = "input"; - io_names[1] = "output"; - + /* + * For backward compat (newer host but older guest), the host + * spawns a console port first and also inits the vqs for port + * 0 before others. + */ + j = 0; + io_callbacks[j] = in_intr; + io_callbacks[j + 1] = NULL; + io_names[j] = "input"; + io_names[j + 1] = "output"; + j += 2; + + if (use_multiport(portdev)) { + io_callbacks[j] = control_intr; + io_callbacks[j + 1] = NULL; + io_names[j] = "control-i"; + io_names[j + 1] = "control-o"; + + for (i = 1; i < nr_ports; i++) { + j += 2; + io_callbacks[j] = in_intr; + io_callbacks[j + 1] = NULL; + io_names[j] = "input"; + io_names[j + 1] = "output"; + } + } /* Find the queues. */ err = portdev->vdev->config->find_vqs(portdev->vdev, nr_queues, vqs, io_callbacks, @@ -561,9 +786,20 @@ static int init_vqs(struct ports_device *portdev) if (err) goto free_outvqs; + j = 0; portdev->in_vqs[0] = vqs[0]; portdev->out_vqs[0] = vqs[1]; - + j += 2; + if (use_multiport(portdev)) { + portdev->c_ivq = vqs[j]; + portdev->c_ovq = vqs[j + 1]; + + for (i = 1; i < nr_ports; i++) { + j += 2; + portdev->in_vqs[i] = vqs[j]; + portdev->out_vqs[i] = vqs[j + 1]; + } + } kfree(io_callbacks); kfree(io_names); kfree(vqs); @@ -587,11 +823,17 @@ fail: /* * Once we're further in boot, we get probed like any other virtio * device. + * + * If the host also supports multiple console ports, we check the + * config space to see how many ports the host has spawned. We + * initialize each port found. */ static int __devinit virtcons_probe(struct virtio_device *vdev) { struct ports_device *portdev; + u32 i; int err; + bool multiport; portdev = kmalloc(sizeof(*portdev), GFP_KERNEL); if (!portdev) { @@ -603,16 +845,53 @@ static int __devinit virtcons_probe(struct virtio_device *vdev) portdev->vdev = vdev; vdev->priv = portdev; + multiport = false; + portdev->config.nr_ports = 1; + portdev->config.max_nr_ports = 1; + if (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT)) { + multiport = true; + vdev->features[0] |= 1 << VIRTIO_CONSOLE_F_MULTIPORT; + + vdev->config->get(vdev, offsetof(struct virtio_console_config, + nr_ports), + &portdev->config.nr_ports, + sizeof(portdev->config.nr_ports)); + vdev->config->get(vdev, offsetof(struct virtio_console_config, + max_nr_ports), + &portdev->config.max_nr_ports, + sizeof(portdev->config.max_nr_ports)); + if (portdev->config.nr_ports > portdev->config.max_nr_ports) { + dev_warn(&vdev->dev, + "More ports (%u) specified than allowed (%u). Will init %u ports.", + portdev->config.nr_ports, + portdev->config.max_nr_ports, + portdev->config.max_nr_ports); + + portdev->config.nr_ports = portdev->config.max_nr_ports; + } + } + + /* Let the Host know we support multiple ports.*/ + vdev->config->finalize_features(vdev); + err = init_vqs(portdev); if (err < 0) { dev_err(&vdev->dev, "Error %d initializing vqs\n", err); goto free; } - /* We only have one port. */ - err = add_port(portdev); - if (err) - goto free_vqs; + spin_lock_init(&portdev->ports_lock); + INIT_LIST_HEAD(&portdev->ports); + + if (multiport) { + spin_lock_init(&portdev->cvq_lock); + INIT_WORK(&portdev->control_work, &control_work_handler); + + fill_queue(portdev->c_ivq, &portdev->cvq_lock); + } + + for (i = 0; i < portdev->config.nr_ports; i++) + add_port(portdev, i); /* Start using the new console output. */ early_put_chars = NULL; @@ -635,6 +914,7 @@ static struct virtio_device_id id_table[] = { static unsigned int features[] = { VIRTIO_CONSOLE_F_SIZE, + VIRTIO_CONSOLE_F_MULTIPORT, }; static struct virtio_driver virtio_console = { diff --git a/include/linux/virtio_console.h b/include/linux/virtio_console.h index 9e0da40beae0..f4d183b5b493 100644 --- a/include/linux/virtio_console.h +++ b/include/linux/virtio_console.h @@ -6,18 +6,39 @@ /* * This header, excluding the #ifdef __KERNEL__ part, is BSD licensed so * anyone can use the definitions to implement compatible drivers/servers. + * + * Copyright (C) Red Hat, Inc., 2009, 2010 */ /* Feature bits */ #define VIRTIO_CONSOLE_F_SIZE 0 /* Does host provide console size? */ +#define VIRTIO_CONSOLE_F_MULTIPORT 1 /* Does host provide multiple ports? */ struct virtio_console_config { /* colums of the screens */ __u16 cols; /* rows of the screens */ __u16 rows; + /* max. number of ports this device can hold */ + __u32 max_nr_ports; + /* number of ports added so far */ + __u32 nr_ports; } __attribute__((packed)); +/* + * A message that's passed between the Host and the Guest for a + * particular port. + */ +struct virtio_console_control { + __u32 id; /* Port number */ + __u16 event; /* The kind of control event (see below) */ + __u16 value; /* Extra information for the key */ +}; + +/* Some events for control messages */ +#define VIRTIO_CONSOLE_PORT_READY 0 +#define VIRTIO_CONSOLE_CONSOLE_PORT 1 +#define VIRTIO_CONSOLE_RESIZE 2 #ifdef __KERNEL__ int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int)); -- cgit v1.2.3 From 2030fa496d74b49220308eaccf656e2338019cfd Mon Sep 17 00:00:00 2001 From: Amit Shah Date: Mon, 21 Dec 2009 21:49:30 +0530 Subject: virtio: console: Add file operations to ports for open/read/write/poll Allow guest userspace applications to open, read from, write to, poll the ports via the char dev interface. When a port gets opened, a notification is sent to the host via a control message indicating a connection has been established. Similarly, on closing of the port, a notification is sent indicating disconnection. Signed-off-by: Amit Shah Signed-off-by: Rusty Russell --- drivers/char/virtio_console.c | 164 ++++++++++++++++++++++++++++++++++++++++- include/linux/virtio_console.h | 1 + 2 files changed, 164 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index 64ef476d6557..ece1546fbb20 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -19,11 +19,15 @@ #include #include #include +#include #include #include +#include +#include #include #include #include +#include #include #include "hvc_console.h" @@ -163,8 +167,14 @@ struct port { struct cdev cdev; struct device *dev; + /* A waitqueue for poll() or blocking read operations */ + wait_queue_head_t waitqueue; + /* The 'id' to identify the port with the Host */ u32 id; + + /* Is the host device open */ + bool host_connected; }; /* This is the very early arch-specified put chars function. */ @@ -417,6 +427,146 @@ static ssize_t fill_readbuf(struct port *port, char *out_buf, size_t out_count, return out_count; } +/* The condition that must be true for polling to end */ +static bool wait_is_over(struct port *port) +{ + return port_has_data(port) || !port->host_connected; +} + +static ssize_t port_fops_read(struct file *filp, char __user *ubuf, + size_t count, loff_t *offp) +{ + struct port *port; + ssize_t ret; + + port = filp->private_data; + + if (!port_has_data(port)) { + /* + * If nothing's connected on the host just return 0 in + * case of list_empty; this tells the userspace app + * that there's no connection + */ + if (!port->host_connected) + return 0; + if (filp->f_flags & O_NONBLOCK) + return -EAGAIN; + + ret = wait_event_interruptible(port->waitqueue, + wait_is_over(port)); + if (ret < 0) + return ret; + } + /* + * We could've received a disconnection message while we were + * waiting for more data. + * + * This check is not clubbed in the if() statement above as we + * might receive some data as well as the host could get + * disconnected after we got woken up from our wait. So we + * really want to give off whatever data we have and only then + * check for host_connected. + */ + if (!port_has_data(port) && !port->host_connected) + return 0; + + return fill_readbuf(port, ubuf, count, true); +} + +static ssize_t port_fops_write(struct file *filp, const char __user *ubuf, + size_t count, loff_t *offp) +{ + struct port *port; + char *buf; + ssize_t ret; + + port = filp->private_data; + + count = min((size_t)(32 * 1024), count); + + buf = kmalloc(count, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + ret = copy_from_user(buf, ubuf, count); + if (ret) { + ret = -EFAULT; + goto free_buf; + } + + ret = send_buf(port, buf, count); +free_buf: + kfree(buf); + return ret; +} + +static unsigned int port_fops_poll(struct file *filp, poll_table *wait) +{ + struct port *port; + unsigned int ret; + + port = filp->private_data; + poll_wait(filp, &port->waitqueue, wait); + + ret = 0; + if (port->inbuf) + ret |= POLLIN | POLLRDNORM; + if (port->host_connected) + ret |= POLLOUT; + if (!port->host_connected) + ret |= POLLHUP; + + return ret; +} + +static int port_fops_release(struct inode *inode, struct file *filp) +{ + struct port *port; + + port = filp->private_data; + + /* Notify host of port being closed */ + send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 0); + + return 0; +} + +static int port_fops_open(struct inode *inode, struct file *filp) +{ + struct cdev *cdev = inode->i_cdev; + struct port *port; + + port = container_of(cdev, struct port, cdev); + filp->private_data = port; + + /* + * Don't allow opening of console port devices -- that's done + * via /dev/hvc + */ + if (is_console_port(port)) + return -ENXIO; + + /* Notify host of port being opened */ + send_control_msg(filp->private_data, VIRTIO_CONSOLE_PORT_OPEN, 1); + + return 0; +} + +/* + * The file operations that we support: programs in the guest can open + * a console device, read from it, write to it, poll for data and + * close it. The devices are at + * /dev/vportp + */ +static const struct file_operations port_fops = { + .owner = THIS_MODULE, + .open = port_fops_open, + .read = port_fops_read, + .write = port_fops_write, + .poll = port_fops_poll, + .release = port_fops_release, +}; + /* * The put_chars() callback is pretty straightforward. * @@ -560,6 +710,9 @@ int init_port_console(struct port *port) list_add_tail(&port->cons.list, &pdrvdata.consoles); spin_unlock_irq(&pdrvdata_lock); + /* Notify host of port being opened */ + send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1); + return 0; } @@ -599,6 +752,10 @@ static void handle_control_message(struct ports_device *portdev, port->cons.hvc->irq_requested = 1; resize_console(port); break; + case VIRTIO_CONSOLE_PORT_OPEN: + port->host_connected = cpkt->value; + wake_up_interruptible(&port->waitqueue); + break; } } @@ -645,6 +802,8 @@ static void in_intr(struct virtqueue *vq) spin_unlock_irqrestore(&port->inbuf_lock, flags); + wake_up_interruptible(&port->waitqueue); + if (is_console_port(port) && hvc_poll(port->cons.hvc)) hvc_kick(); } @@ -697,10 +856,12 @@ static int add_port(struct ports_device *portdev, u32 id) port->inbuf = NULL; port->cons.hvc = NULL; + port->host_connected = false; + port->in_vq = portdev->in_vqs[port->id]; port->out_vq = portdev->out_vqs[port->id]; - cdev_init(&port->cdev, NULL); + cdev_init(&port->cdev, &port_fops); devt = MKDEV(portdev->chr_major, id); err = cdev_add(&port->cdev, devt, 1); @@ -721,6 +882,7 @@ static int add_port(struct ports_device *portdev, u32 id) } spin_lock_init(&port->inbuf_lock); + init_waitqueue_head(&port->waitqueue); inbuf = alloc_buf(PAGE_SIZE); if (!inbuf) { diff --git a/include/linux/virtio_console.h b/include/linux/virtio_console.h index f4d183b5b493..bd0e2a596f93 100644 --- a/include/linux/virtio_console.h +++ b/include/linux/virtio_console.h @@ -39,6 +39,7 @@ struct virtio_console_control { #define VIRTIO_CONSOLE_PORT_READY 0 #define VIRTIO_CONSOLE_CONSOLE_PORT 1 #define VIRTIO_CONSOLE_RESIZE 2 +#define VIRTIO_CONSOLE_PORT_OPEN 3 #ifdef __KERNEL__ int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int)); -- cgit v1.2.3 From 431edb8a8bca71008fefceadf53b9315ef7196ec Mon Sep 17 00:00:00 2001 From: Amit Shah Date: Mon, 21 Dec 2009 21:57:40 +0530 Subject: virtio: console: Register with sysfs and create a 'name' attribute for ports The host can set a name for ports so that they're easily discoverable instead of going by the /dev/vportNpn naming. This attribute will be placed in /sys/class/virtio-ports/vportNpn/name. udev scripts can then create symlinks to the port using the name. Signed-off-by: Amit Shah Signed-off-by: Rusty Russell --- drivers/char/virtio_console.c | 57 ++++++++++++++++++++++++++++++++++++++++++ include/linux/virtio_console.h | 1 + 2 files changed, 58 insertions(+) (limited to 'include') diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index 5e3503a31312..99d182b132c4 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -170,6 +170,9 @@ struct port { /* A waitqueue for poll() or blocking read operations */ wait_queue_head_t waitqueue; + /* The 'name' of the port that we expose via sysfs properties */ + char *name; + /* The 'id' to identify the port with the Host */ u32 id; @@ -732,12 +735,36 @@ int init_port_console(struct port *port) return 0; } +static ssize_t show_port_name(struct device *dev, + struct device_attribute *attr, char *buffer) +{ + struct port *port; + + port = dev_get_drvdata(dev); + + return sprintf(buffer, "%s\n", port->name); +} + +static DEVICE_ATTR(name, S_IRUGO, show_port_name, NULL); + +static struct attribute *port_sysfs_entries[] = { + &dev_attr_name.attr, + NULL +}; + +static struct attribute_group port_attribute_group = { + .name = NULL, /* put in device directory */ + .attrs = port_sysfs_entries, +}; + /* Any private messages that the Host and Guest want to share */ static void handle_control_message(struct ports_device *portdev, struct port_buffer *buf) { struct virtio_console_control *cpkt; struct port *port; + size_t name_size; + int err; cpkt = (struct virtio_console_control *)(buf->buf + buf->offset); @@ -772,6 +799,35 @@ static void handle_control_message(struct ports_device *portdev, port->host_connected = cpkt->value; wake_up_interruptible(&port->waitqueue); break; + case VIRTIO_CONSOLE_PORT_NAME: + /* + * Skip the size of the header and the cpkt to get the size + * of the name that was sent + */ + name_size = buf->len - buf->offset - sizeof(*cpkt) + 1; + + port->name = kmalloc(name_size, GFP_KERNEL); + if (!port->name) { + dev_err(port->dev, + "Not enough space to store port name\n"); + break; + } + strncpy(port->name, buf->buf + buf->offset + sizeof(*cpkt), + name_size - 1); + port->name[name_size - 1] = 0; + + /* + * Since we only have one sysfs attribute, 'name', + * create it only if we have a name for the port. + */ + err = sysfs_create_group(&port->dev->kobj, + &port_attribute_group); + if (err) + dev_err(port->dev, + "Error %d creating sysfs device attributes\n", + err); + + break; } } @@ -869,6 +925,7 @@ static int add_port(struct ports_device *portdev, u32 id) port->portdev = portdev; port->id = id; + port->name = NULL; port->inbuf = NULL; port->cons.hvc = NULL; diff --git a/include/linux/virtio_console.h b/include/linux/virtio_console.h index bd0e2a596f93..1ebf007812a8 100644 --- a/include/linux/virtio_console.h +++ b/include/linux/virtio_console.h @@ -40,6 +40,7 @@ struct virtio_console_control { #define VIRTIO_CONSOLE_CONSOLE_PORT 1 #define VIRTIO_CONSOLE_RESIZE 2 #define VIRTIO_CONSOLE_PORT_OPEN 3 +#define VIRTIO_CONSOLE_PORT_NAME 4 #ifdef __KERNEL__ int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int)); -- cgit v1.2.3 From 1f7aa42d166cd104b0700d61efe2064178a3f6da Mon Sep 17 00:00:00 2001 From: Amit Shah Date: Mon, 21 Dec 2009 22:27:31 +0530 Subject: virtio: console: Add ability to hot-unplug ports Remove port data; deregister from the hvc core if it's a console port. Signed-off-by: Amit Shah Signed-off-by: Rusty Russell --- drivers/char/virtio_console.c | 65 ++++++++++++++++++++++++++++++++++++++++-- include/linux/virtio_console.h | 1 + 2 files changed, 64 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index 7c53f58c87ba..9f20fda9c56f 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -783,6 +783,36 @@ static struct attribute_group port_attribute_group = { .attrs = port_sysfs_entries, }; +/* Remove all port-specific data. */ +static int remove_port(struct port *port) +{ + spin_lock_irq(&port->portdev->ports_lock); + list_del(&port->list); + spin_unlock_irq(&port->portdev->ports_lock); + + if (is_console_port(port)) { + spin_lock_irq(&pdrvdata_lock); + list_del(&port->cons.list); + spin_unlock_irq(&pdrvdata_lock); + hvc_remove(port->cons.hvc); + } + if (port->guest_connected) + send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 0); + + while (port->in_vq->vq_ops->detach_unused_buf(port->in_vq)) + ; + + sysfs_remove_group(&port->dev->kobj, &port_attribute_group); + device_destroy(pdrvdata.class, port->dev->devt); + cdev_del(&port->cdev); + + discard_port_data(port); + kfree(port->name); + + kfree(port); + return 0; +} + /* Any private messages that the Host and Guest want to share */ static void handle_control_message(struct ports_device *portdev, struct port_buffer *buf) @@ -854,6 +884,32 @@ static void handle_control_message(struct ports_device *portdev, err); break; + case VIRTIO_CONSOLE_PORT_REMOVE: + /* + * Hot unplug the port. We don't decrement nr_ports + * since we don't want to deal with extra complexities + * of using the lowest-available port id: We can just + * pick up the nr_ports number as the id and not have + * userspace send it to us. This helps us in two + * ways: + * + * - We don't need to have a 'port_id' field in the + * config space when a port is hot-added. This is a + * good thing as we might queue up multiple hotplug + * requests issued in our workqueue. + * + * - Another way to deal with this would have been to + * use a bitmap of the active ports and select the + * lowest non-active port from that map. That + * bloats the already tight config space and we + * would end up artificially limiting the + * max. number of ports to sizeof(bitmap). Right + * now we can support 2^32 ports (as the port id is + * stored in a u32 type). + * + */ + remove_port(port); + break; } } @@ -1078,12 +1134,17 @@ static void config_work_handler(struct work_struct *work) /* * Port 0 got hot-added. Since we already did all the * other initialisation for it, just tell the Host - * that the port is ready. + * that the port is ready if we find the port. In + * case the port was hot-removed earlier, we call + * add_port to add the port. */ struct port *port; port = find_port_by_id(portdev, 0); - send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1); + if (!port) + add_port(portdev, 0); + else + send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1); return; } if (virtconconf.nr_ports > portdev->config.max_nr_ports) { diff --git a/include/linux/virtio_console.h b/include/linux/virtio_console.h index 1ebf007812a8..ae4f039515b4 100644 --- a/include/linux/virtio_console.h +++ b/include/linux/virtio_console.h @@ -41,6 +41,7 @@ struct virtio_console_control { #define VIRTIO_CONSOLE_RESIZE 2 #define VIRTIO_CONSOLE_PORT_OPEN 3 #define VIRTIO_CONSOLE_PORT_NAME 4 +#define VIRTIO_CONSOLE_PORT_REMOVE 5 #ifdef __KERNEL__ int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int)); -- cgit v1.2.3