[PATCH] drivers/s390/virtio: Remove the old KVM virtio transport

Thomas Huth
2017-09-27T11:42:05Z

There is no recent user space application available anymore which still
supports this old virtio transport. Additionally, commit 3b2fbb3f06ef
("virtio/s390: deprecate old transport") introduced a deprecation message
in the driver, and apparently nobody complained so far that it is still
required. So let's simply remove it.

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
arch/s390/Kconfig | 13 -
drivers/s390/virtio/Makefile | 3 -
drivers/s390/virtio/kvm_virtio.c | 515 ---------------------------------------
3 files changed, 531 deletions(-)
delete mode 100644 drivers/s390/virtio/kvm_virtio.c

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 48af970..a0a40dd 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -929,17 +929,4 @@ config S390_GUEST
Select this option if you want to run the kernel as a guest under
the KVM hypervisor.

-config S390_GUEST_OLD_TRANSPORT
- def_bool y
- prompt "Guest support for old s390 virtio transport (DEPRECATED)"
- depends on S390_GUEST
- help
- Enable this option to add support for the old s390-virtio
- transport (i.e. virtio devices NOT based on virtio-ccw). This
- type of virtio devices is only available on the experimental
- kuli userspace or with old (< 2.6) qemu. If you are running
- with a modern version of qemu (which supports virtio-ccw since
- 1.4 and uses it by default since version 2.4), you probably won't
- need this.
-
endmenu
diff --git a/drivers/s390/virtio/Makefile b/drivers/s390/virtio/Makefile
index df40692..d9942e0 100644
--- a/drivers/s390/virtio/Makefile
+++ b/drivers/s390/virtio/Makefile
@@ -7,7 +7,4 @@
# as published by the Free Software Foundation.

s390-virtio-objs := virtio_ccw.o
-ifdef CONFIG_S390_GUEST_OLD_TRANSPORT
-s390-virtio-objs += kvm_virtio.o
-endif
obj-$(CONFIG_S390_GUEST) += $(s390-virtio-objs)
diff --git a/drivers/s390/virtio/kvm_virtio.c b/drivers/s390/virtio/kvm_virtio.c
deleted file mode 100644
index a99d09a..0000000
--- a/drivers/s390/virtio/kvm_virtio.c
+++ /dev/null
@@ -1,515 +0,0 @@
-/*
- * 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, bool ctx)
-{
- 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, ctx, (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 * const names[],
- const bool *ctx,
- struct irq_affinity *desc)
-{
- 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],
- ctx ? ctx[i] : false);
- 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.rzm * sclp.rnmax;
-
- if (!MACHINE_IS_KVM)
- return -ENODEV;
-
- if (test_devices_support(total_memory_size) < 0)
- return -ENODEV;
-
- pr_warn("The s390-virtio transport is deprecated. Please switch to a modern host providing virtio-ccw.\n");
-
- 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 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);
--
1.8.3.1