diff options
author | Cornelia Huck <cornelia.huck@de.ibm.com> | 2015-07-07 09:41:01 (GMT) |
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committer | Michael S. Tsirkin <mst@redhat.com> | 2015-07-07 11:27:06 (GMT) |
commit | 1b568d934eec1c5c99565c41f6c8ca66e9743e96 (patch) | |
tree | ad8b38dbbc858d8b2e620765f5b8c7de9e5b2e15 /drivers/s390/virtio/kvm_virtio.c | |
parent | f2dbda3b4fc2833f0a6240ac28b0e3a17f09893b (diff) | |
download | linux-1b568d934eec1c5c99565c41f6c8ca66e9743e96.tar.xz |
virtio/s390: rename drivers/s390/kvm -> drivers/s390/virtio
This more accurately reflects what these drivers actually do.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'drivers/s390/virtio/kvm_virtio.c')
-rw-r--r-- | drivers/s390/virtio/kvm_virtio.c | 510 |
1 files changed, 510 insertions, 0 deletions
diff --git a/drivers/s390/virtio/kvm_virtio.c b/drivers/s390/virtio/kvm_virtio.c new file mode 100644 index 0000000..dd65c8b --- /dev/null +++ b/drivers/s390/virtio/kvm_virtio.c @@ -0,0 +1,510 @@ +/* + * virtio for kvm on s390 + * + * Copyright IBM Corp. 2008 + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License (version 2 only) + * as published by the Free Software Foundation. + * + * Author(s): Christian Borntraeger <borntraeger@de.ibm.com> + */ + +#include <linux/kernel_stat.h> +#include <linux/init.h> +#include <linux/bootmem.h> +#include <linux/err.h> +#include <linux/virtio.h> +#include <linux/virtio_config.h> +#include <linux/slab.h> +#include <linux/virtio_console.h> +#include <linux/interrupt.h> +#include <linux/virtio_ring.h> +#include <linux/export.h> +#include <linux/pfn.h> +#include <asm/io.h> +#include <asm/kvm_para.h> +#include <asm/kvm_virtio.h> +#include <asm/sclp.h> +#include <asm/setup.h> +#include <asm/irq.h> + +#define VIRTIO_SUBCODE_64 0x0D00 + +/* + * The pointer to our (page) of device descriptions. + */ +static void *kvm_devices; +static struct work_struct hotplug_work; + +struct kvm_device { + struct virtio_device vdev; + struct kvm_device_desc *desc; +}; + +#define to_kvmdev(vd) container_of(vd, struct kvm_device, vdev) + +/* + * memory layout: + * - kvm_device_descriptor + * struct kvm_device_desc + * - configuration + * struct kvm_vqconfig + * - feature bits + * - config space + */ +static struct kvm_vqconfig *kvm_vq_config(const struct kvm_device_desc *desc) +{ + return (struct kvm_vqconfig *)(desc + 1); +} + +static u8 *kvm_vq_features(const struct kvm_device_desc *desc) +{ + return (u8 *)(kvm_vq_config(desc) + desc->num_vq); +} + +static u8 *kvm_vq_configspace(const struct kvm_device_desc *desc) +{ + return kvm_vq_features(desc) + desc->feature_len * 2; +} + +/* + * The total size of the config page used by this device (incl. desc) + */ +static unsigned desc_size(const struct kvm_device_desc *desc) +{ + return sizeof(*desc) + + desc->num_vq * sizeof(struct kvm_vqconfig) + + desc->feature_len * 2 + + desc->config_len; +} + +/* This gets the device's feature bits. */ +static u64 kvm_get_features(struct virtio_device *vdev) +{ + unsigned int i; + u32 features = 0; + struct kvm_device_desc *desc = to_kvmdev(vdev)->desc; + u8 *in_features = kvm_vq_features(desc); + + 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 int kvm_finalize_features(struct virtio_device *vdev) +{ + unsigned int i, bits; + struct kvm_device_desc *desc = to_kvmdev(vdev)->desc; + /* Second half of bitmap is features we accept. */ + u8 *out_features = kvm_vq_features(desc) + desc->feature_len; + + /* Give virtio_ring a chance to accept features. */ + vring_transport_features(vdev); + + /* Make sure we don't have any features > 32 bits! */ + BUG_ON((u32)vdev->features != vdev->features); + + 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 (__virtio_test_bit(vdev, i)) + out_features[i / 8] |= (1 << (i % 8)); + } + + return 0; +} + +/* + * Reading and writing elements in config space + */ +static void kvm_get(struct virtio_device *vdev, unsigned int offset, + void *buf, unsigned len) +{ + struct kvm_device_desc *desc = to_kvmdev(vdev)->desc; + + BUG_ON(offset + len > desc->config_len); + memcpy(buf, kvm_vq_configspace(desc) + offset, len); +} + +static void kvm_set(struct virtio_device *vdev, unsigned int offset, + const void *buf, unsigned len) +{ + struct kvm_device_desc *desc = to_kvmdev(vdev)->desc; + + BUG_ON(offset + len > desc->config_len); + memcpy(kvm_vq_configspace(desc) + offset, buf, len); +} + +/* + * The operations to get and set the status word just access + * the status field of the device descriptor. set_status will also + * make a hypercall to the host, to tell about status changes + */ +static u8 kvm_get_status(struct virtio_device *vdev) +{ + return to_kvmdev(vdev)->desc->status; +} + +static void kvm_set_status(struct virtio_device *vdev, u8 status) +{ + BUG_ON(!status); + to_kvmdev(vdev)->desc->status = status; + kvm_hypercall1(KVM_S390_VIRTIO_SET_STATUS, + (unsigned long) to_kvmdev(vdev)->desc); +} + +/* + * To reset the device, we use the KVM_VIRTIO_RESET hypercall, using the + * descriptor address. The Host will zero the status and all the + * features. + */ +static void kvm_reset(struct virtio_device *vdev) +{ + kvm_hypercall1(KVM_S390_VIRTIO_RESET, + (unsigned long) to_kvmdev(vdev)->desc); +} + +/* + * When the virtio_ring code wants to notify the Host, it calls us here and we + * make a hypercall. We hand the address of the virtqueue so the Host + * knows which virtqueue we're talking about. + */ +static bool kvm_notify(struct virtqueue *vq) +{ + long rc; + struct kvm_vqconfig *config = vq->priv; + + rc = kvm_hypercall1(KVM_S390_VIRTIO_NOTIFY, config->address); + if (rc < 0) + return false; + return true; +} + +/* + * This routine finds the first virtqueue described in the configuration of + * this device and sets it up. + */ +static struct virtqueue *kvm_find_vq(struct virtio_device *vdev, + unsigned index, + void (*callback)(struct virtqueue *vq), + const char *name) +{ + struct kvm_device *kdev = to_kvmdev(vdev); + struct kvm_vqconfig *config; + struct virtqueue *vq; + int err; + + if (index >= kdev->desc->num_vq) + return ERR_PTR(-ENOENT); + + if (!name) + return NULL; + + config = kvm_vq_config(kdev->desc)+index; + + err = vmem_add_mapping(config->address, + vring_size(config->num, + KVM_S390_VIRTIO_RING_ALIGN)); + if (err) + goto out; + + vq = vring_new_virtqueue(index, config->num, KVM_S390_VIRTIO_RING_ALIGN, + vdev, true, (void *) config->address, + kvm_notify, callback, name); + if (!vq) { + err = -ENOMEM; + goto unmap; + } + + /* + * register a callback token + * The host will sent this via the external interrupt parameter + */ + config->token = (u64) vq; + + vq->priv = config; + return vq; +unmap: + vmem_remove_mapping(config->address, + vring_size(config->num, + KVM_S390_VIRTIO_RING_ALIGN)); +out: + return ERR_PTR(err); +} + +static void kvm_del_vq(struct virtqueue *vq) +{ + struct kvm_vqconfig *config = vq->priv; + + vring_del_virtqueue(vq); + vmem_remove_mapping(config->address, + vring_size(config->num, + KVM_S390_VIRTIO_RING_ALIGN)); +} + +static void kvm_del_vqs(struct virtio_device *vdev) +{ + struct virtqueue *vq, *n; + + list_for_each_entry_safe(vq, n, &vdev->vqs, list) + kvm_del_vq(vq); +} + +static int kvm_find_vqs(struct virtio_device *vdev, unsigned nvqs, + struct virtqueue *vqs[], + vq_callback_t *callbacks[], + const char *names[]) +{ + struct kvm_device *kdev = to_kvmdev(vdev); + int i; + + /* We must have this many virtqueues. */ + if (nvqs > kdev->desc->num_vq) + return -ENOENT; + + for (i = 0; i < nvqs; ++i) { + vqs[i] = kvm_find_vq(vdev, i, callbacks[i], names[i]); + if (IS_ERR(vqs[i])) + goto error; + } + return 0; + +error: + kvm_del_vqs(vdev); + return PTR_ERR(vqs[i]); +} + +static const char *kvm_bus_name(struct virtio_device *vdev) +{ + return ""; +} + +/* + * The config ops structure as defined by virtio config + */ +static const struct virtio_config_ops kvm_vq_configspace_ops = { + .get_features = kvm_get_features, + .finalize_features = kvm_finalize_features, + .get = kvm_get, + .set = kvm_set, + .get_status = kvm_get_status, + .set_status = kvm_set_status, + .reset = kvm_reset, + .find_vqs = kvm_find_vqs, + .del_vqs = kvm_del_vqs, + .bus_name = kvm_bus_name, +}; + +/* + * The root device for the kvm virtio devices. + * This makes them appear as /sys/devices/kvm_s390/0,1,2 not /sys/devices/0,1,2. + */ +static struct device *kvm_root; + +/* + * adds a new device and register it with virtio + * appropriate drivers are loaded by the device model + */ +static void add_kvm_device(struct kvm_device_desc *d, unsigned int offset) +{ + struct kvm_device *kdev; + + kdev = kzalloc(sizeof(*kdev), GFP_KERNEL); + if (!kdev) { + printk(KERN_EMERG "Cannot allocate kvm dev %u type %u\n", + offset, d->type); + return; + } + + kdev->vdev.dev.parent = kvm_root; + kdev->vdev.id.device = d->type; + kdev->vdev.config = &kvm_vq_configspace_ops; + kdev->desc = d; + + if (register_virtio_device(&kdev->vdev) != 0) { + printk(KERN_ERR "Failed to register kvm device %u type %u\n", + offset, d->type); + kfree(kdev); + } +} + +/* + * 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; + struct kvm_device_desc *d; + + for (i = 0; i < PAGE_SIZE; i += desc_size(d)) { + d = kvm_devices + i; + + if (d->type == 0) + break; + + add_kvm_device(d, i); + } +} + +/* + * match for a kvm device with a specific desc pointer + */ +static int match_desc(struct device *dev, void *data) +{ + struct virtio_device *vdev = dev_to_virtio(dev); + struct kvm_device *kdev = to_kvmdev(vdev); + + return kdev->desc == data; +} + +/* + * hotplug_device tries to find changes in the device page. + */ +static void hotplug_devices(struct work_struct *dummy) +{ + unsigned int i; + struct kvm_device_desc *d; + struct device *dev; + + for (i = 0; i < PAGE_SIZE; i += desc_size(d)) { + d = kvm_devices + i; + + /* end of list */ + if (d->type == 0) + break; + + /* device already exists */ + dev = device_find_child(kvm_root, d, match_desc); + if (dev) { + /* XXX check for hotplug remove */ + put_device(dev); + continue; + } + + /* new device */ + printk(KERN_INFO "Adding new virtio device %p\n", d); + add_kvm_device(d, i); + } +} + +/* + * we emulate the request_irq behaviour on top of s390 extints + */ +static void kvm_extint_handler(struct ext_code ext_code, + unsigned int param32, unsigned long param64) +{ + struct virtqueue *vq; + u32 param; + + if ((ext_code.subcode & 0xff00) != VIRTIO_SUBCODE_64) + return; + inc_irq_stat(IRQEXT_VRT); + + /* The LSB might be overloaded, we have to mask it */ + vq = (struct virtqueue *)(param64 & ~1UL); + + /* We use ext_params to decide what this interrupt means */ + param = param32 & VIRTIO_PARAM_MASK; + + switch (param) { + case VIRTIO_PARAM_CONFIG_CHANGED: + virtio_config_changed(vq->vdev); + break; + case VIRTIO_PARAM_DEV_ADD: + schedule_work(&hotplug_work); + break; + case VIRTIO_PARAM_VRING_INTERRUPT: + default: + vring_interrupt(0, vq); + break; + } +} + +/* + * For s390-virtio, we expect a page above main storage containing + * the virtio configuration. Try to actually load from this area + * in order to figure out if the host provides this page. + */ +static int __init test_devices_support(unsigned long addr) +{ + int ret = -EIO; + + asm volatile( + "0: lura 0,%1\n" + "1: xgr %0,%0\n" + "2:\n" + EX_TABLE(0b,2b) + EX_TABLE(1b,2b) + : "+d" (ret) + : "a" (addr) + : "0", "cc"); + return ret; +} +/* + * Init function for virtio + * devices are in a single page above top of "normal" + standby mem + */ +static int __init kvm_devices_init(void) +{ + int rc; + unsigned long total_memory_size = sclp_get_rzm() * sclp_get_rnmax(); + + if (!MACHINE_IS_KVM) + return -ENODEV; + + if (test_devices_support(total_memory_size) < 0) + return -ENODEV; + + rc = vmem_add_mapping(total_memory_size, PAGE_SIZE); + if (rc) + return rc; + + kvm_devices = (void *) total_memory_size; + + kvm_root = root_device_register("kvm_s390"); + if (IS_ERR(kvm_root)) { + rc = PTR_ERR(kvm_root); + printk(KERN_ERR "Could not register kvm_s390 root device"); + vmem_remove_mapping(total_memory_size, PAGE_SIZE); + return rc; + } + + INIT_WORK(&hotplug_work, hotplug_devices); + + irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL); + register_external_irq(EXT_IRQ_CP_SERVICE, kvm_extint_handler); + + scan_devices(); + return 0; +} + +/* code for early console output with virtio_console */ +static __init int early_put_chars(u32 vtermno, const char *buf, int count) +{ + char scratch[17]; + unsigned int len = count; + + if (len > sizeof(scratch) - 1) + len = sizeof(scratch) - 1; + scratch[len] = '\0'; + memcpy(scratch, buf, len); + kvm_hypercall1(KVM_S390_VIRTIO_NOTIFY, __pa(scratch)); + return len; +} + +static int __init s390_virtio_console_init(void) +{ + if (sclp_has_vt220() || sclp_has_linemode()) + return -ENODEV; + return virtio_cons_early_init(early_put_chars); +} +console_initcall(s390_virtio_console_init); + + +/* + * We do this after core stuff, but before the drivers. + */ +postcore_initcall(kvm_devices_init); |