linux/drivers/virtio/virtio_pci_legacy.c
Jason Wang eb4cecb453 Revert "virtio_pci: harden MSI-X interrupts"
This reverts commit 9e35276a53. Issue
were reported for the drivers that are using affinity managed IRQ
where manually toggling IRQ status is not expected. And we forget to
enable the interrupts in the restore path as well.

In the future, we will rework on the interrupt hardening.

Fixes: 9e35276a53 ("virtio_pci: harden MSI-X interrupts")
Reported-by: Marc Zyngier <maz@kernel.org>
Reported-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20220323031524.6555-2-jasowang@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2022-03-28 16:52:59 -04:00

233 lines
6.1 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Virtio PCI driver - legacy device support
*
* This module allows virtio devices to be used over a virtual PCI device.
* This can be used with QEMU based VMMs like KVM or Xen.
*
* Copyright IBM Corp. 2007
* Copyright Red Hat, Inc. 2014
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
* Rusty Russell <rusty@rustcorp.com.au>
* Michael S. Tsirkin <mst@redhat.com>
*/
#include "linux/virtio_pci_legacy.h"
#include "virtio_pci_common.h"
/* virtio config->get_features() implementation */
static u64 vp_get_features(struct virtio_device *vdev)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
/* When someone needs more than 32 feature bits, we'll need to
* steal a bit to indicate that the rest are somewhere else. */
return vp_legacy_get_features(&vp_dev->ldev);
}
/* virtio config->finalize_features() implementation */
static int vp_finalize_features(struct virtio_device *vdev)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
/* 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);
/* We only support 32 feature bits. */
vp_legacy_set_features(&vp_dev->ldev, vdev->features);
return 0;
}
/* virtio config->get() implementation */
static void vp_get(struct virtio_device *vdev, unsigned offset,
void *buf, unsigned len)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
void __iomem *ioaddr = vp_dev->ldev.ioaddr +
VIRTIO_PCI_CONFIG_OFF(vp_dev->msix_enabled) +
offset;
u8 *ptr = buf;
int i;
for (i = 0; i < len; i++)
ptr[i] = ioread8(ioaddr + i);
}
/* the config->set() implementation. it's symmetric to the config->get()
* implementation */
static void vp_set(struct virtio_device *vdev, unsigned offset,
const void *buf, unsigned len)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
void __iomem *ioaddr = vp_dev->ldev.ioaddr +
VIRTIO_PCI_CONFIG_OFF(vp_dev->msix_enabled) +
offset;
const u8 *ptr = buf;
int i;
for (i = 0; i < len; i++)
iowrite8(ptr[i], ioaddr + i);
}
/* config->{get,set}_status() implementations */
static u8 vp_get_status(struct virtio_device *vdev)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
return vp_legacy_get_status(&vp_dev->ldev);
}
static void vp_set_status(struct virtio_device *vdev, u8 status)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
/* We should never be setting status to 0. */
BUG_ON(status == 0);
vp_legacy_set_status(&vp_dev->ldev, status);
}
static void vp_reset(struct virtio_device *vdev)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
/* 0 status means a reset. */
vp_legacy_set_status(&vp_dev->ldev, 0);
/* Flush out the status write, and flush in device writes,
* including MSi-X interrupts, if any. */
vp_legacy_get_status(&vp_dev->ldev);
/* Flush pending VQ/configuration callbacks. */
vp_synchronize_vectors(vdev);
}
static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
{
return vp_legacy_config_vector(&vp_dev->ldev, vector);
}
static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
struct virtio_pci_vq_info *info,
unsigned index,
void (*callback)(struct virtqueue *vq),
const char *name,
bool ctx,
u16 msix_vec)
{
struct virtqueue *vq;
u16 num;
int err;
u64 q_pfn;
/* Check if queue is either not available or already active. */
num = vp_legacy_get_queue_size(&vp_dev->ldev, index);
if (!num || vp_legacy_get_queue_enable(&vp_dev->ldev, index))
return ERR_PTR(-ENOENT);
info->msix_vector = msix_vec;
/* create the vring */
vq = vring_create_virtqueue(index, num,
VIRTIO_PCI_VRING_ALIGN, &vp_dev->vdev,
true, false, ctx,
vp_notify, callback, name);
if (!vq)
return ERR_PTR(-ENOMEM);
q_pfn = virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT;
if (q_pfn >> 32) {
dev_err(&vp_dev->pci_dev->dev,
"platform bug: legacy virtio-pci must not be used with RAM above 0x%llxGB\n",
0x1ULL << (32 + PAGE_SHIFT - 30));
err = -E2BIG;
goto out_del_vq;
}
/* activate the queue */
vp_legacy_set_queue_address(&vp_dev->ldev, index, q_pfn);
vq->priv = (void __force *)vp_dev->ldev.ioaddr + VIRTIO_PCI_QUEUE_NOTIFY;
if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
msix_vec = vp_legacy_queue_vector(&vp_dev->ldev, index, msix_vec);
if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
err = -EBUSY;
goto out_deactivate;
}
}
return vq;
out_deactivate:
vp_legacy_set_queue_address(&vp_dev->ldev, index, 0);
out_del_vq:
vring_del_virtqueue(vq);
return ERR_PTR(err);
}
static void del_vq(struct virtio_pci_vq_info *info)
{
struct virtqueue *vq = info->vq;
struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
if (vp_dev->msix_enabled) {
vp_legacy_queue_vector(&vp_dev->ldev, vq->index,
VIRTIO_MSI_NO_VECTOR);
/* Flush the write out to device */
ioread8(vp_dev->ldev.ioaddr + VIRTIO_PCI_ISR);
}
/* Select and deactivate the queue */
vp_legacy_set_queue_address(&vp_dev->ldev, vq->index, 0);
vring_del_virtqueue(vq);
}
static const struct virtio_config_ops virtio_pci_config_ops = {
.get = vp_get,
.set = vp_set,
.get_status = vp_get_status,
.set_status = vp_set_status,
.reset = vp_reset,
.find_vqs = vp_find_vqs,
.del_vqs = vp_del_vqs,
.get_features = vp_get_features,
.finalize_features = vp_finalize_features,
.bus_name = vp_bus_name,
.set_vq_affinity = vp_set_vq_affinity,
.get_vq_affinity = vp_get_vq_affinity,
};
/* the PCI probing function */
int virtio_pci_legacy_probe(struct virtio_pci_device *vp_dev)
{
struct virtio_pci_legacy_device *ldev = &vp_dev->ldev;
struct pci_dev *pci_dev = vp_dev->pci_dev;
int rc;
ldev->pci_dev = pci_dev;
rc = vp_legacy_probe(ldev);
if (rc)
return rc;
vp_dev->isr = ldev->isr;
vp_dev->vdev.id = ldev->id;
vp_dev->vdev.config = &virtio_pci_config_ops;
vp_dev->config_vector = vp_config_vector;
vp_dev->setup_vq = setup_vq;
vp_dev->del_vq = del_vq;
return 0;
}
void virtio_pci_legacy_remove(struct virtio_pci_device *vp_dev)
{
struct virtio_pci_legacy_device *ldev = &vp_dev->ldev;
vp_legacy_remove(ldev);
}