diff options
Diffstat (limited to 'drivers/lguest/lguest_device.c')
| -rw-r--r-- | drivers/lguest/lguest_device.c | 93 |
1 files changed, 51 insertions, 42 deletions
diff --git a/drivers/lguest/lguest_device.c b/drivers/lguest/lguest_device.c index 2bc9bf7e88e5..1a8de57289eb 100644 --- a/drivers/lguest/lguest_device.c +++ b/drivers/lguest/lguest_device.c @@ -20,14 +20,11 @@ /* 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. */ 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) @@ -85,27 +82,34 @@ 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; +} + +static void lg_set_features(struct virtio_device *vdev, u32 features) +{ + unsigned int i; + 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; + + memset(out_features, 0, desc->feature_len); + for (i = 0; i < min(desc->feature_len * 8, 32); i++) { + if (features & (1 << i)) + out_features[i / 8] |= (1 << (i % 8)); + } } /* Once they've found a field, getting a copy of it is easy. */ @@ -137,20 +141,26 @@ static u8 lg_get_status(struct virtio_device *vdev) return to_lgdev(vdev)->desc->status; } +/* To notify on status updates, we (ab)use the NOTIFY hypercall, with the + * descriptor address of the device. A zero status means "reset". */ +static void set_status(struct virtio_device *vdev, u8 status) +{ + unsigned long offset = (void *)to_lgdev(vdev)->desc - lguest_devices; + + /* We set the status. */ + to_lgdev(vdev)->desc->status = status; + hcall(LHCALL_NOTIFY, (max_pfn<<PAGE_SHIFT) + offset, 0, 0); +} + static void lg_set_status(struct virtio_device *vdev, u8 status) { BUG_ON(!status); - to_lgdev(vdev)->desc->status = status; + set_status(vdev, status); } -/* 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); + set_status(vdev, 0); } /* @@ -286,7 +296,8 @@ static void lg_del_vq(struct virtqueue *vq) /* The ops structure which hooks everything together. */ static struct virtio_config_ops lguest_config_ops = { - .feature = lg_feature, + .get_features = lg_get_features, + .set_features = lg_set_features, .get = lg_get, .set = lg_set, .get_status = lg_get_status, @@ -311,8 +322,10 @@ 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; @@ -320,18 +333,14 @@ static void add_lguest_device(struct lguest_device_desc *d) * 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 - * device vendor field in the virtio_device struct, which we leave as - * 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. */ @@ -343,8 +352,8 @@ static void add_lguest_device(struct lguest_device_desc *d) * virtio_device and calls device_register(). This makes the bus * 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); } } @@ -365,7 +374,7 @@ 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); } } |