diff options
Diffstat (limited to 'drivers/lguest/lguest_device.c')
| -rw-r--r-- | drivers/lguest/lguest_device.c | 335 |
1 files changed, 231 insertions, 104 deletions
diff --git a/drivers/lguest/lguest_device.c b/drivers/lguest/lguest_device.c index 2bc9bf7e88e..d0a1d8a45c8 100644 --- a/drivers/lguest/lguest_device.c +++ b/drivers/lguest/lguest_device.c @@ -1,10 +1,12 @@ -/*P:050 Lguest guests use a very simple method to describe devices. It's a +/*P:050 + * Lguest guests use a very simple method to describe devices. It's a * series of device descriptors contained just above the top of normal Guest * memory. * * We use the standard "virtio" device infrastructure, which provides us with a * console, a network and a block driver. Each one expects some configuration - * information and a "virtqueue" or two to send and receive data. :*/ + * information and a "virtqueue" or two to send and receive data. +:*/ #include <linux/init.h> #include <linux/bootmem.h> #include <linux/lguest_launcher.h> @@ -13,6 +15,8 @@ #include <linux/interrupt.h> #include <linux/virtio_ring.h> #include <linux/err.h> +#include <linux/export.h> +#include <linux/slab.h> #include <asm/io.h> #include <asm/paravirt.h> #include <asm/lguest_hcall.h> @@ -20,14 +24,13 @@ /* The pointer to our (page) of device descriptions. */ static void *lguest_devices; -/* Unique numbering for lguest devices. */ -static unsigned int dev_index; - -/* For Guests, device memory can be used as normal memory, so we cast away the - * __iomem to quieten sparse. */ +/* + * For Guests, device memory can be used as normal memory, so we cast away the + * __iomem to quieten sparse. + */ static inline void *lguest_map(unsigned long phys_addr, unsigned long pages) { - return (__force void *)ioremap(phys_addr, PAGE_SIZE*pages); + return (__force void *)ioremap_cache(phys_addr, PAGE_SIZE*pages); } static inline void lguest_unmap(void *addr) @@ -35,8 +38,10 @@ static inline void lguest_unmap(void *addr) iounmap((__force void __iomem *)addr); } -/*D:100 Each lguest device is just a virtio device plus a pointer to its entry - * in the lguest_devices page. */ +/*D:100 + * Each lguest device is just a virtio device plus a pointer to its entry + * in the lguest_devices page. + */ struct lguest_device { struct virtio_device vdev; @@ -44,9 +49,11 @@ struct lguest_device { struct lguest_device_desc *desc; }; -/* Since the virtio infrastructure hands us a pointer to the virtio_device all +/* + * Since the virtio infrastructure hands us a pointer to the virtio_device all * the time, it helps to have a curt macro to get a pointer to the struct - * lguest_device it's enclosed in. */ + * lguest_device it's enclosed in. + */ #define to_lgdev(vd) container_of(vd, struct lguest_device, vdev) /*D:130 @@ -58,7 +65,8 @@ struct lguest_device { * the driver will look at them during setup. * * A convenient routine to return the device's virtqueue config array: - * immediately after the descriptor. */ + * immediately after the descriptor. + */ static struct lguest_vqconfig *lg_vq(const struct lguest_device_desc *desc) { return (void *)(desc + 1); @@ -85,27 +93,63 @@ static unsigned desc_size(const struct lguest_device_desc *desc) + desc->config_len; } -/* This tests (and acknowleges) a feature bit. */ -static bool lg_feature(struct virtio_device *vdev, unsigned fbit) +/* This gets the device's feature bits. */ +static u32 lg_get_features(struct virtio_device *vdev) { + unsigned int i; + u32 features = 0; struct lguest_device_desc *desc = to_lgdev(vdev)->desc; - u8 *features; - - /* Obviously if they ask for a feature off the end of our feature - * bitmap, it's not set. */ - if (fbit / 8 > desc->feature_len) - return false; - - /* The feature bitmap comes after the virtqueues. */ - features = lg_features(desc); - if (!(features[fbit / 8] & (1 << (fbit % 8)))) - return false; - - /* We set the matching bit in the other half of the bitmap to tell the - * Host we want to use this feature. We don't use this yet, but we - * could in future. */ - features[desc->feature_len + fbit / 8] |= (1 << (fbit % 8)); - return true; + u8 *in_features = lg_features(desc); + + /* We do this the slow but generic way. */ + for (i = 0; i < min(desc->feature_len * 8, 32); i++) + if (in_features[i / 8] & (1 << (i % 8))) + features |= (1 << i); + + return features; +} + +/* + * To notify on reset or feature finalization, we (ab)use the NOTIFY + * hypercall, with the descriptor address of the device. + */ +static void status_notify(struct virtio_device *vdev) +{ + unsigned long offset = (void *)to_lgdev(vdev)->desc - lguest_devices; + + hcall(LHCALL_NOTIFY, (max_pfn << PAGE_SHIFT) + offset, 0, 0, 0); +} + +/* + * The virtio core takes the features the Host offers, and copies the ones + * supported by the driver into the vdev->features array. Once that's all + * sorted out, this routine is called so we can tell the Host which features we + * understand and accept. + */ +static void lg_finalize_features(struct virtio_device *vdev) +{ + unsigned int i, bits; + struct lguest_device_desc *desc = to_lgdev(vdev)->desc; + /* Second half of bitmap is features we accept. */ + u8 *out_features = lg_features(desc) + desc->feature_len; + + /* Give virtio_ring a chance to accept features. */ + vring_transport_features(vdev); + + /* + * The vdev->feature array is a Linux bitmask: this isn't the same as a + * the simple array of bits used by lguest devices for features. So we + * do this slow, manual conversion which is completely general. + */ + memset(out_features, 0, desc->feature_len); + bits = min_t(unsigned, desc->feature_len, sizeof(vdev->features)) * 8; + for (i = 0; i < bits; i++) { + if (test_bit(i, vdev->features)) + out_features[i / 8] |= (1 << (i % 8)); + } + + /* Tell Host we've finished with this device's feature negotiation */ + status_notify(vdev); } /* Once they've found a field, getting a copy of it is easy. */ @@ -130,8 +174,10 @@ static void lg_set(struct virtio_device *vdev, unsigned int offset, memcpy(lg_config(desc) + offset, buf, len); } -/* The operations to get and set the status word just access the status field - * of the device descriptor. */ +/* + * The operations to get and set the status word just access the status field + * of the device descriptor. + */ static u8 lg_get_status(struct virtio_device *vdev) { return to_lgdev(vdev)->desc->status; @@ -141,16 +187,17 @@ static void lg_set_status(struct virtio_device *vdev, u8 status) { BUG_ON(!status); to_lgdev(vdev)->desc->status = status; + + /* Tell Host immediately if we failed. */ + if (status & VIRTIO_CONFIG_S_FAILED) + status_notify(vdev); } -/* To reset the device, we (ab)use the NOTIFY hypercall, with the descriptor - * address of the device. The Host will zero the status and all the - * features. */ static void lg_reset(struct virtio_device *vdev) { - unsigned long offset = (void *)to_lgdev(vdev)->desc - lguest_devices; - - hcall(LHCALL_NOTIFY, (max_pfn<<PAGE_SHIFT) + offset, 0, 0); + /* 0 status means "reset" */ + to_lgdev(vdev)->desc->status = 0; + status_notify(vdev); } /* @@ -169,8 +216,7 @@ static void lg_reset(struct virtio_device *vdev) */ /*D:140 This is the information we remember about each virtqueue. */ -struct lguest_vq_info -{ +struct lguest_vq_info { /* A copy of the information contained in the device config. */ struct lguest_vqconfig config; @@ -178,19 +224,28 @@ struct lguest_vq_info void *pages; }; -/* When the virtio_ring code wants to prod the Host, it calls us here and we +/* + * When the virtio_ring code wants to prod the Host, it calls us here and we * make a hypercall. We hand the physical address of the virtqueue so the Host - * knows which virtqueue we're talking about. */ -static void lg_notify(struct virtqueue *vq) + * knows which virtqueue we're talking about. + */ +static bool lg_notify(struct virtqueue *vq) { - /* We store our virtqueue information in the "priv" pointer of the - * virtqueue structure. */ + /* + * We store our virtqueue information in the "priv" pointer of the + * virtqueue structure. + */ struct lguest_vq_info *lvq = vq->priv; - hcall(LHCALL_NOTIFY, lvq->config.pfn << PAGE_SHIFT, 0, 0); + hcall(LHCALL_NOTIFY, lvq->config.pfn << PAGE_SHIFT, 0, 0, 0); + return true; } -/* This routine finds the first virtqueue described in the configuration of +/* An extern declaration inside a C file is bad form. Don't do it. */ +extern int lguest_setup_irq(unsigned int irq); + +/* + * This routine finds the Nth virtqueue described in the configuration of * this device and sets it up. * * This is kind of an ugly duckling. It'd be nicer to have a standard @@ -198,18 +253,20 @@ static void lg_notify(struct virtqueue *vq) * everyone wants to do it differently. The KVM coders want the Guest to * allocate its own pages and tell the Host where they are, but for lguest it's * simpler for the Host to simply tell us where the pages are. - * - * So we provide drivers with a "find the Nth virtqueue and set it up" - * function. */ + */ static struct virtqueue *lg_find_vq(struct virtio_device *vdev, unsigned index, - void (*callback)(struct virtqueue *vq)) + void (*callback)(struct virtqueue *vq), + const char *name) { struct lguest_device *ldev = to_lgdev(vdev); struct lguest_vq_info *lvq; struct virtqueue *vq; int err; + if (!name) + return NULL; + /* We must have this many virtqueues. */ if (index >= ldev->desc->num_vq) return ERR_PTR(-ENOENT); @@ -218,9 +275,11 @@ static struct virtqueue *lg_find_vq(struct virtio_device *vdev, if (!lvq) return ERR_PTR(-ENOMEM); - /* Make a copy of the "struct lguest_vqconfig" entry, which sits after + /* + * Make a copy of the "struct lguest_vqconfig" entry, which sits after * the descriptor. We need a copy because the config space might not - * be aligned correctly. */ + * be aligned correctly. + */ memcpy(&lvq->config, lg_vq(ldev->desc)+index, sizeof(lvq->config)); printk("Mapping virtqueue %i addr %lx\n", index, @@ -228,37 +287,53 @@ static struct virtqueue *lg_find_vq(struct virtio_device *vdev, /* Figure out how many pages the ring will take, and map that memory */ lvq->pages = lguest_map((unsigned long)lvq->config.pfn << PAGE_SHIFT, DIV_ROUND_UP(vring_size(lvq->config.num, - PAGE_SIZE), + LGUEST_VRING_ALIGN), PAGE_SIZE)); if (!lvq->pages) { err = -ENOMEM; goto free_lvq; } - /* OK, tell virtio_ring.c to set up a virtqueue now we know its size - * and we've got a pointer to its pages. */ - vq = vring_new_virtqueue(lvq->config.num, vdev, lvq->pages, - lg_notify, callback); + /* + * OK, tell virtio_ring.c to set up a virtqueue now we know its size + * and we've got a pointer to its pages. Note that we set weak_barriers + * to 'true': the host just a(nother) SMP CPU, so we only need inter-cpu + * barriers. + */ + vq = vring_new_virtqueue(index, lvq->config.num, LGUEST_VRING_ALIGN, vdev, + true, lvq->pages, lg_notify, callback, name); if (!vq) { err = -ENOMEM; goto unmap; } - /* Tell the interrupt for this virtqueue to go to the virtio_ring - * interrupt handler. */ - /* FIXME: We used to have a flag for the Host to tell us we could use + /* Make sure the interrupt is allocated. */ + err = lguest_setup_irq(lvq->config.irq); + if (err) + goto destroy_vring; + + /* + * Tell the interrupt for this virtqueue to go to the virtio_ring + * interrupt handler. + * + * FIXME: We used to have a flag for the Host to tell us we could use * the interrupt as a source of randomness: it'd be nice to have that - * back.. */ + * back. + */ err = request_irq(lvq->config.irq, vring_interrupt, IRQF_SHARED, - vdev->dev.bus_id, vq); + dev_name(&vdev->dev), vq); if (err) - goto destroy_vring; + goto free_desc; - /* Last of all we hook up our 'struct lguest_vq_info" to the - * virtqueue's priv pointer. */ + /* + * Last of all we hook up our 'struct lguest_vq_info" to the + * virtqueue's priv pointer. + */ vq->priv = lvq; return vq; +free_desc: + irq_free_desc(lvq->config.irq); destroy_vring: vring_del_virtqueue(vq); unmap: @@ -284,26 +359,65 @@ static void lg_del_vq(struct virtqueue *vq) kfree(lvq); } +static void lg_del_vqs(struct virtio_device *vdev) +{ + struct virtqueue *vq, *n; + + list_for_each_entry_safe(vq, n, &vdev->vqs, list) + lg_del_vq(vq); +} + +static int lg_find_vqs(struct virtio_device *vdev, unsigned nvqs, + struct virtqueue *vqs[], + vq_callback_t *callbacks[], + const char *names[]) +{ + struct lguest_device *ldev = to_lgdev(vdev); + int i; + + /* We must have this many virtqueues. */ + if (nvqs > ldev->desc->num_vq) + return -ENOENT; + + for (i = 0; i < nvqs; ++i) { + vqs[i] = lg_find_vq(vdev, i, callbacks[i], names[i]); + if (IS_ERR(vqs[i])) + goto error; + } + return 0; + +error: + lg_del_vqs(vdev); + return PTR_ERR(vqs[i]); +} + +static const char *lg_bus_name(struct virtio_device *vdev) +{ + return ""; +} + /* The ops structure which hooks everything together. */ -static struct virtio_config_ops lguest_config_ops = { - .feature = lg_feature, +static const struct virtio_config_ops lguest_config_ops = { + .get_features = lg_get_features, + .finalize_features = lg_finalize_features, .get = lg_get, .set = lg_set, .get_status = lg_get_status, .set_status = lg_set_status, .reset = lg_reset, - .find_vq = lg_find_vq, - .del_vq = lg_del_vq, + .find_vqs = lg_find_vqs, + .del_vqs = lg_del_vqs, + .bus_name = lg_bus_name, }; -/* The root device for the lguest virtio devices. This makes them appear as - * /sys/devices/lguest/0,1,2 not /sys/devices/0,1,2. */ -static struct device lguest_root = { - .parent = NULL, - .bus_id = "lguest", -}; +/* + * The root device for the lguest virtio devices. This makes them appear as + * /sys/devices/lguest/0,1,2 not /sys/devices/0,1,2. + */ +static struct device *lguest_root; -/*D:120 This is the core of the lguest bus: actually adding a new device. +/*D:120 + * This is the core of the lguest bus: actually adding a new device. * It's a separate function because it's neater that way, and because an * earlier version of the code supported hotplug and unplug. They were removed * early on because they were never used. @@ -311,46 +425,54 @@ static struct device lguest_root = { * As Andrew Tridgell says, "Untested code is buggy code". * * It's worth reading this carefully: we start with a pointer to the new device - * descriptor in the "lguest_devices" page. */ -static void add_lguest_device(struct lguest_device_desc *d) + * descriptor in the "lguest_devices" page, and the offset into the device + * descriptor page so we can uniquely identify it if things go badly wrong. + */ +static void add_lguest_device(struct lguest_device_desc *d, + unsigned int offset) { struct lguest_device *ldev; - /* Start with zeroed memory; Linux's device layer seems to count on - * it. */ + /* Start with zeroed memory; Linux's device layer counts on it. */ ldev = kzalloc(sizeof(*ldev), GFP_KERNEL); if (!ldev) { - printk(KERN_EMERG "Cannot allocate lguest dev %u\n", - dev_index++); + printk(KERN_EMERG "Cannot allocate lguest dev %u type %u\n", + offset, d->type); return; } /* This devices' parent is the lguest/ dir. */ - ldev->vdev.dev.parent = &lguest_root; - /* We have a unique device index thanks to the dev_index counter. */ - ldev->vdev.index = dev_index++; - /* The device type comes straight from the descriptor. There's also a + ldev->vdev.dev.parent = lguest_root; + /* + * The device type comes straight from the descriptor. There's also a * device vendor field in the virtio_device struct, which we leave as - * 0. */ + * 0. + */ ldev->vdev.id.device = d->type; - /* We have a simple set of routines for querying the device's - * configuration information and setting its status. */ + /* + * We have a simple set of routines for querying the device's + * configuration information and setting its status. + */ ldev->vdev.config = &lguest_config_ops; /* And we remember the device's descriptor for lguest_config_ops. */ ldev->desc = d; - /* register_virtio_device() sets up the generic fields for the struct + /* + * register_virtio_device() sets up the generic fields for the struct * virtio_device and calls device_register(). This makes the bus - * infrastructure look for a matching driver. */ + * infrastructure look for a matching driver. + */ if (register_virtio_device(&ldev->vdev) != 0) { - printk(KERN_ERR "Failed to register lguest device %u\n", - ldev->vdev.index); + printk(KERN_ERR "Failed to register lguest dev %u type %u\n", + offset, d->type); kfree(ldev); } } -/*D:110 scan_devices() simply iterates through the device page. The type 0 is - * reserved to mean "end of devices". */ +/*D:110 + * scan_devices() simply iterates through the device page. The type 0 is + * reserved to mean "end of devices". + */ static void scan_devices(void) { unsigned int i; @@ -365,11 +487,12 @@ static void scan_devices(void) break; printk("Device at %i has size %u\n", i, desc_size(d)); - add_lguest_device(d); + add_lguest_device(d, i); } } -/*D:105 Fairly early in boot, lguest_devices_init() is called to set up the +/*D:105 + * Fairly early in boot, lguest_devices_init() is called to set up the * lguest device infrastructure. We check that we are a Guest by checking * pv_info.name: there are other ways of checking, but this seems most * obvious to me. @@ -380,13 +503,15 @@ static void scan_devices(void) * correct sysfs incantation). * * Finally we call scan_devices() which adds all the devices found in the - * lguest_devices page. */ + * lguest_devices page. + */ static int __init lguest_devices_init(void) { if (strcmp(pv_info.name, "lguest") != 0) return 0; - if (device_register(&lguest_root) != 0) + lguest_root = root_device_register("lguest"); + if (IS_ERR(lguest_root)) panic("Could not register lguest root"); /* Devices are in a single page above top of "normal" mem */ @@ -398,11 +523,13 @@ static int __init lguest_devices_init(void) /* We do this after core stuff, but before the drivers. */ postcore_initcall(lguest_devices_init); -/*D:150 At this point in the journey we used to now wade through the lguest +/*D:150 + * At this point in the journey we used to now wade through the lguest * devices themselves: net, block and console. Since they're all now virtio * devices rather than lguest-specific, I've decided to ignore them. Mostly, * they're kind of boring. But this does mean you'll never experience the * thrill of reading the forbidden love scene buried deep in the block driver. * * "make Launcher" beckons, where we answer questions like "Where do Guests - * come from?", and "What do you do when someone asks for optimization?". */ + * come from?", and "What do you do when someone asks for optimization?". + */ |