mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-05 16:26:39 +07:00
0d5415b489
This reverts commitc7070619f3
. This has been shown to regress on some ARM systems: by forcing on DMA API usage for ARM systems, we have inadvertently kicked open a hornets' nest in terms of cache-coherency. Namely that unless the virtio device is explicitly described as capable of coherent DMA by firmware, the DMA APIs on ARM and other DT-based platforms will assume it is non-coherent. This turns out to cause a big problem for the likes of QEMU and kvmtool, which generate virtio-mmio devices in their guest DTs but neglect to add the often-overlooked "dma-coherent" property; as a result, we end up with the guest making non-cacheable accesses to the vring, the host doing so cacheably, both talking past each other and things going horribly wrong. We are working on a safer work-around. Fixes:c7070619f3
("vring: Force use of DMA API for ARM-based systems with legacy devices") Reported-by: Robin Murphy <robin.murphy@arm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com>
1208 lines
33 KiB
C
1208 lines
33 KiB
C
/* Virtio ring implementation.
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*
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* Copyright 2007 Rusty Russell IBM Corporation
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <linux/virtio.h>
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#include <linux/virtio_ring.h>
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#include <linux/virtio_config.h>
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#include <linux/device.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/hrtimer.h>
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#include <linux/kmemleak.h>
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#include <linux/dma-mapping.h>
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#include <xen/xen.h>
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#ifdef DEBUG
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/* For development, we want to crash whenever the ring is screwed. */
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#define BAD_RING(_vq, fmt, args...) \
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do { \
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dev_err(&(_vq)->vq.vdev->dev, \
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"%s:"fmt, (_vq)->vq.name, ##args); \
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BUG(); \
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} while (0)
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/* Caller is supposed to guarantee no reentry. */
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#define START_USE(_vq) \
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do { \
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if ((_vq)->in_use) \
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panic("%s:in_use = %i\n", \
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(_vq)->vq.name, (_vq)->in_use); \
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(_vq)->in_use = __LINE__; \
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} while (0)
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#define END_USE(_vq) \
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do { BUG_ON(!(_vq)->in_use); (_vq)->in_use = 0; } while(0)
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#else
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#define BAD_RING(_vq, fmt, args...) \
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do { \
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dev_err(&_vq->vq.vdev->dev, \
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"%s:"fmt, (_vq)->vq.name, ##args); \
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(_vq)->broken = true; \
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} while (0)
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#define START_USE(vq)
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#define END_USE(vq)
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#endif
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struct vring_desc_state {
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void *data; /* Data for callback. */
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struct vring_desc *indir_desc; /* Indirect descriptor, if any. */
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};
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struct vring_virtqueue {
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struct virtqueue vq;
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/* Actual memory layout for this queue */
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struct vring vring;
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/* Can we use weak barriers? */
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bool weak_barriers;
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/* Other side has made a mess, don't try any more. */
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bool broken;
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/* Host supports indirect buffers */
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bool indirect;
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/* Host publishes avail event idx */
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bool event;
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/* Head of free buffer list. */
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unsigned int free_head;
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/* Number we've added since last sync. */
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unsigned int num_added;
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/* Last used index we've seen. */
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u16 last_used_idx;
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/* Last written value to avail->flags */
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u16 avail_flags_shadow;
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/* Last written value to avail->idx in guest byte order */
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u16 avail_idx_shadow;
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/* How to notify other side. FIXME: commonalize hcalls! */
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bool (*notify)(struct virtqueue *vq);
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/* DMA, allocation, and size information */
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bool we_own_ring;
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size_t queue_size_in_bytes;
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dma_addr_t queue_dma_addr;
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#ifdef DEBUG
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/* They're supposed to lock for us. */
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unsigned int in_use;
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/* Figure out if their kicks are too delayed. */
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bool last_add_time_valid;
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ktime_t last_add_time;
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#endif
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/* Per-descriptor state. */
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struct vring_desc_state desc_state[];
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};
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#define to_vvq(_vq) container_of(_vq, struct vring_virtqueue, vq)
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/*
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* Modern virtio devices have feature bits to specify whether they need a
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* quirk and bypass the IOMMU. If not there, just use the DMA API.
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*
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* If there, the interaction between virtio and DMA API is messy.
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*
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* On most systems with virtio, physical addresses match bus addresses,
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* and it doesn't particularly matter whether we use the DMA API.
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*
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* On some systems, including Xen and any system with a physical device
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* that speaks virtio behind a physical IOMMU, we must use the DMA API
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* for virtio DMA to work at all.
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*
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* On other systems, including SPARC and PPC64, virtio-pci devices are
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* enumerated as though they are behind an IOMMU, but the virtio host
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* ignores the IOMMU, so we must either pretend that the IOMMU isn't
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* there or somehow map everything as the identity.
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*
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* For the time being, we preserve historic behavior and bypass the DMA
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* API.
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*
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* TODO: install a per-device DMA ops structure that does the right thing
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* taking into account all the above quirks, and use the DMA API
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* unconditionally on data path.
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*/
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static bool vring_use_dma_api(struct virtio_device *vdev)
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{
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if (!virtio_has_iommu_quirk(vdev))
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return true;
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/* Otherwise, we are left to guess. */
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/*
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* In theory, it's possible to have a buggy QEMU-supposed
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* emulated Q35 IOMMU and Xen enabled at the same time. On
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* such a configuration, virtio has never worked and will
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* not work without an even larger kludge. Instead, enable
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* the DMA API if we're a Xen guest, which at least allows
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* all of the sensible Xen configurations to work correctly.
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*/
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if (xen_domain())
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return true;
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return false;
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}
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/*
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* The DMA ops on various arches are rather gnarly right now, and
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* making all of the arch DMA ops work on the vring device itself
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* is a mess. For now, we use the parent device for DMA ops.
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*/
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static inline struct device *vring_dma_dev(const struct vring_virtqueue *vq)
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{
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return vq->vq.vdev->dev.parent;
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}
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/* Map one sg entry. */
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static dma_addr_t vring_map_one_sg(const struct vring_virtqueue *vq,
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struct scatterlist *sg,
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enum dma_data_direction direction)
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{
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if (!vring_use_dma_api(vq->vq.vdev))
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return (dma_addr_t)sg_phys(sg);
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/*
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* We can't use dma_map_sg, because we don't use scatterlists in
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* the way it expects (we don't guarantee that the scatterlist
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* will exist for the lifetime of the mapping).
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*/
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return dma_map_page(vring_dma_dev(vq),
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sg_page(sg), sg->offset, sg->length,
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direction);
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}
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static dma_addr_t vring_map_single(const struct vring_virtqueue *vq,
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void *cpu_addr, size_t size,
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enum dma_data_direction direction)
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{
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if (!vring_use_dma_api(vq->vq.vdev))
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return (dma_addr_t)virt_to_phys(cpu_addr);
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return dma_map_single(vring_dma_dev(vq),
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cpu_addr, size, direction);
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}
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static void vring_unmap_one(const struct vring_virtqueue *vq,
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struct vring_desc *desc)
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{
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u16 flags;
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if (!vring_use_dma_api(vq->vq.vdev))
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return;
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flags = virtio16_to_cpu(vq->vq.vdev, desc->flags);
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if (flags & VRING_DESC_F_INDIRECT) {
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dma_unmap_single(vring_dma_dev(vq),
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virtio64_to_cpu(vq->vq.vdev, desc->addr),
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virtio32_to_cpu(vq->vq.vdev, desc->len),
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(flags & VRING_DESC_F_WRITE) ?
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DMA_FROM_DEVICE : DMA_TO_DEVICE);
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} else {
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dma_unmap_page(vring_dma_dev(vq),
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virtio64_to_cpu(vq->vq.vdev, desc->addr),
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virtio32_to_cpu(vq->vq.vdev, desc->len),
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(flags & VRING_DESC_F_WRITE) ?
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DMA_FROM_DEVICE : DMA_TO_DEVICE);
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}
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}
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static int vring_mapping_error(const struct vring_virtqueue *vq,
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dma_addr_t addr)
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{
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if (!vring_use_dma_api(vq->vq.vdev))
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return 0;
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return dma_mapping_error(vring_dma_dev(vq), addr);
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}
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static struct vring_desc *alloc_indirect(struct virtqueue *_vq,
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unsigned int total_sg, gfp_t gfp)
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{
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struct vring_desc *desc;
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unsigned int i;
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/*
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* We require lowmem mappings for the descriptors because
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* otherwise virt_to_phys will give us bogus addresses in the
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* virtqueue.
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*/
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gfp &= ~__GFP_HIGHMEM;
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desc = kmalloc(total_sg * sizeof(struct vring_desc), gfp);
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if (!desc)
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return NULL;
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for (i = 0; i < total_sg; i++)
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desc[i].next = cpu_to_virtio16(_vq->vdev, i + 1);
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return desc;
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}
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static inline int virtqueue_add(struct virtqueue *_vq,
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struct scatterlist *sgs[],
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unsigned int total_sg,
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unsigned int out_sgs,
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unsigned int in_sgs,
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void *data,
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gfp_t gfp)
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{
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struct vring_virtqueue *vq = to_vvq(_vq);
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struct scatterlist *sg;
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struct vring_desc *desc;
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unsigned int i, n, avail, descs_used, uninitialized_var(prev), err_idx;
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int head;
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bool indirect;
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START_USE(vq);
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BUG_ON(data == NULL);
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if (unlikely(vq->broken)) {
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END_USE(vq);
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return -EIO;
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}
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#ifdef DEBUG
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{
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ktime_t now = ktime_get();
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/* No kick or get, with .1 second between? Warn. */
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if (vq->last_add_time_valid)
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WARN_ON(ktime_to_ms(ktime_sub(now, vq->last_add_time))
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> 100);
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vq->last_add_time = now;
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vq->last_add_time_valid = true;
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}
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#endif
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BUG_ON(total_sg > vq->vring.num);
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BUG_ON(total_sg == 0);
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head = vq->free_head;
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/* If the host supports indirect descriptor tables, and we have multiple
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* buffers, then go indirect. FIXME: tune this threshold */
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if (vq->indirect && total_sg > 1 && vq->vq.num_free)
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desc = alloc_indirect(_vq, total_sg, gfp);
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else
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desc = NULL;
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if (desc) {
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/* Use a single buffer which doesn't continue */
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indirect = true;
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/* Set up rest to use this indirect table. */
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i = 0;
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descs_used = 1;
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} else {
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indirect = false;
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desc = vq->vring.desc;
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i = head;
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descs_used = total_sg;
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}
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if (vq->vq.num_free < descs_used) {
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pr_debug("Can't add buf len %i - avail = %i\n",
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descs_used, vq->vq.num_free);
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/* FIXME: for historical reasons, we force a notify here if
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* there are outgoing parts to the buffer. Presumably the
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* host should service the ring ASAP. */
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if (out_sgs)
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vq->notify(&vq->vq);
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if (indirect)
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kfree(desc);
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END_USE(vq);
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return -ENOSPC;
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}
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for (n = 0; n < out_sgs; n++) {
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for (sg = sgs[n]; sg; sg = sg_next(sg)) {
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dma_addr_t addr = vring_map_one_sg(vq, sg, DMA_TO_DEVICE);
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if (vring_mapping_error(vq, addr))
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goto unmap_release;
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desc[i].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_NEXT);
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desc[i].addr = cpu_to_virtio64(_vq->vdev, addr);
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desc[i].len = cpu_to_virtio32(_vq->vdev, sg->length);
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prev = i;
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i = virtio16_to_cpu(_vq->vdev, desc[i].next);
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}
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}
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for (; n < (out_sgs + in_sgs); n++) {
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for (sg = sgs[n]; sg; sg = sg_next(sg)) {
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dma_addr_t addr = vring_map_one_sg(vq, sg, DMA_FROM_DEVICE);
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if (vring_mapping_error(vq, addr))
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goto unmap_release;
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desc[i].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_NEXT | VRING_DESC_F_WRITE);
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desc[i].addr = cpu_to_virtio64(_vq->vdev, addr);
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desc[i].len = cpu_to_virtio32(_vq->vdev, sg->length);
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prev = i;
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i = virtio16_to_cpu(_vq->vdev, desc[i].next);
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}
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}
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/* Last one doesn't continue. */
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desc[prev].flags &= cpu_to_virtio16(_vq->vdev, ~VRING_DESC_F_NEXT);
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if (indirect) {
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/* Now that the indirect table is filled in, map it. */
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dma_addr_t addr = vring_map_single(
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vq, desc, total_sg * sizeof(struct vring_desc),
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DMA_TO_DEVICE);
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if (vring_mapping_error(vq, addr))
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goto unmap_release;
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vq->vring.desc[head].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_INDIRECT);
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vq->vring.desc[head].addr = cpu_to_virtio64(_vq->vdev, addr);
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vq->vring.desc[head].len = cpu_to_virtio32(_vq->vdev, total_sg * sizeof(struct vring_desc));
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}
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/* We're using some buffers from the free list. */
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vq->vq.num_free -= descs_used;
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/* Update free pointer */
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if (indirect)
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vq->free_head = virtio16_to_cpu(_vq->vdev, vq->vring.desc[head].next);
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else
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vq->free_head = i;
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/* Store token and indirect buffer state. */
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vq->desc_state[head].data = data;
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if (indirect)
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vq->desc_state[head].indir_desc = desc;
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/* Put entry in available array (but don't update avail->idx until they
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* do sync). */
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avail = vq->avail_idx_shadow & (vq->vring.num - 1);
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vq->vring.avail->ring[avail] = cpu_to_virtio16(_vq->vdev, head);
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/* Descriptors and available array need to be set before we expose the
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* new available array entries. */
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virtio_wmb(vq->weak_barriers);
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vq->avail_idx_shadow++;
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vq->vring.avail->idx = cpu_to_virtio16(_vq->vdev, vq->avail_idx_shadow);
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vq->num_added++;
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pr_debug("Added buffer head %i to %p\n", head, vq);
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END_USE(vq);
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/* This is very unlikely, but theoretically possible. Kick
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* just in case. */
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if (unlikely(vq->num_added == (1 << 16) - 1))
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virtqueue_kick(_vq);
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return 0;
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unmap_release:
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err_idx = i;
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i = head;
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for (n = 0; n < total_sg; n++) {
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if (i == err_idx)
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break;
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vring_unmap_one(vq, &desc[i]);
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i = virtio16_to_cpu(_vq->vdev, vq->vring.desc[i].next);
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}
|
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|
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vq->vq.num_free += total_sg;
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|
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if (indirect)
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kfree(desc);
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|
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END_USE(vq);
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return -EIO;
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}
|
|
|
|
/**
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* virtqueue_add_sgs - expose buffers to other end
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* @vq: the struct virtqueue we're talking about.
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* @sgs: array of terminated scatterlists.
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* @out_num: the number of scatterlists readable by other side
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* @in_num: the number of scatterlists which are writable (after readable ones)
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* @data: the token identifying the buffer.
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* @gfp: how to do memory allocations (if necessary).
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*
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* Caller must ensure we don't call this with other virtqueue operations
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* at the same time (except where noted).
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*
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* Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
|
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*/
|
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int virtqueue_add_sgs(struct virtqueue *_vq,
|
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struct scatterlist *sgs[],
|
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unsigned int out_sgs,
|
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unsigned int in_sgs,
|
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void *data,
|
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gfp_t gfp)
|
|
{
|
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unsigned int i, total_sg = 0;
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|
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/* Count them first. */
|
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for (i = 0; i < out_sgs + in_sgs; i++) {
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struct scatterlist *sg;
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for (sg = sgs[i]; sg; sg = sg_next(sg))
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total_sg++;
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}
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return virtqueue_add(_vq, sgs, total_sg, out_sgs, in_sgs, data, gfp);
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}
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EXPORT_SYMBOL_GPL(virtqueue_add_sgs);
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|
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/**
|
|
* virtqueue_add_outbuf - expose output buffers to other end
|
|
* @vq: the struct virtqueue we're talking about.
|
|
* @sg: scatterlist (must be well-formed and terminated!)
|
|
* @num: the number of entries in @sg readable by other side
|
|
* @data: the token identifying the buffer.
|
|
* @gfp: how to do memory allocations (if necessary).
|
|
*
|
|
* Caller must ensure we don't call this with other virtqueue operations
|
|
* at the same time (except where noted).
|
|
*
|
|
* Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
|
|
*/
|
|
int virtqueue_add_outbuf(struct virtqueue *vq,
|
|
struct scatterlist *sg, unsigned int num,
|
|
void *data,
|
|
gfp_t gfp)
|
|
{
|
|
return virtqueue_add(vq, &sg, num, 1, 0, data, gfp);
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_add_outbuf);
|
|
|
|
/**
|
|
* virtqueue_add_inbuf - expose input buffers to other end
|
|
* @vq: the struct virtqueue we're talking about.
|
|
* @sg: scatterlist (must be well-formed and terminated!)
|
|
* @num: the number of entries in @sg writable by other side
|
|
* @data: the token identifying the buffer.
|
|
* @gfp: how to do memory allocations (if necessary).
|
|
*
|
|
* Caller must ensure we don't call this with other virtqueue operations
|
|
* at the same time (except where noted).
|
|
*
|
|
* Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
|
|
*/
|
|
int virtqueue_add_inbuf(struct virtqueue *vq,
|
|
struct scatterlist *sg, unsigned int num,
|
|
void *data,
|
|
gfp_t gfp)
|
|
{
|
|
return virtqueue_add(vq, &sg, num, 0, 1, data, gfp);
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_add_inbuf);
|
|
|
|
/**
|
|
* virtqueue_kick_prepare - first half of split virtqueue_kick call.
|
|
* @vq: the struct virtqueue
|
|
*
|
|
* Instead of virtqueue_kick(), you can do:
|
|
* if (virtqueue_kick_prepare(vq))
|
|
* virtqueue_notify(vq);
|
|
*
|
|
* This is sometimes useful because the virtqueue_kick_prepare() needs
|
|
* to be serialized, but the actual virtqueue_notify() call does not.
|
|
*/
|
|
bool virtqueue_kick_prepare(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
u16 new, old;
|
|
bool needs_kick;
|
|
|
|
START_USE(vq);
|
|
/* We need to expose available array entries before checking avail
|
|
* event. */
|
|
virtio_mb(vq->weak_barriers);
|
|
|
|
old = vq->avail_idx_shadow - vq->num_added;
|
|
new = vq->avail_idx_shadow;
|
|
vq->num_added = 0;
|
|
|
|
#ifdef DEBUG
|
|
if (vq->last_add_time_valid) {
|
|
WARN_ON(ktime_to_ms(ktime_sub(ktime_get(),
|
|
vq->last_add_time)) > 100);
|
|
}
|
|
vq->last_add_time_valid = false;
|
|
#endif
|
|
|
|
if (vq->event) {
|
|
needs_kick = vring_need_event(virtio16_to_cpu(_vq->vdev, vring_avail_event(&vq->vring)),
|
|
new, old);
|
|
} else {
|
|
needs_kick = !(vq->vring.used->flags & cpu_to_virtio16(_vq->vdev, VRING_USED_F_NO_NOTIFY));
|
|
}
|
|
END_USE(vq);
|
|
return needs_kick;
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_kick_prepare);
|
|
|
|
/**
|
|
* virtqueue_notify - second half of split virtqueue_kick call.
|
|
* @vq: the struct virtqueue
|
|
*
|
|
* This does not need to be serialized.
|
|
*
|
|
* Returns false if host notify failed or queue is broken, otherwise true.
|
|
*/
|
|
bool virtqueue_notify(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
if (unlikely(vq->broken))
|
|
return false;
|
|
|
|
/* Prod other side to tell it about changes. */
|
|
if (!vq->notify(_vq)) {
|
|
vq->broken = true;
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_notify);
|
|
|
|
/**
|
|
* virtqueue_kick - update after add_buf
|
|
* @vq: the struct virtqueue
|
|
*
|
|
* After one or more virtqueue_add_* calls, invoke this to kick
|
|
* the other side.
|
|
*
|
|
* Caller must ensure we don't call this with other virtqueue
|
|
* operations at the same time (except where noted).
|
|
*
|
|
* Returns false if kick failed, otherwise true.
|
|
*/
|
|
bool virtqueue_kick(struct virtqueue *vq)
|
|
{
|
|
if (virtqueue_kick_prepare(vq))
|
|
return virtqueue_notify(vq);
|
|
return true;
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_kick);
|
|
|
|
static void detach_buf(struct vring_virtqueue *vq, unsigned int head)
|
|
{
|
|
unsigned int i, j;
|
|
__virtio16 nextflag = cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_NEXT);
|
|
|
|
/* Clear data ptr. */
|
|
vq->desc_state[head].data = NULL;
|
|
|
|
/* Put back on free list: unmap first-level descriptors and find end */
|
|
i = head;
|
|
|
|
while (vq->vring.desc[i].flags & nextflag) {
|
|
vring_unmap_one(vq, &vq->vring.desc[i]);
|
|
i = virtio16_to_cpu(vq->vq.vdev, vq->vring.desc[i].next);
|
|
vq->vq.num_free++;
|
|
}
|
|
|
|
vring_unmap_one(vq, &vq->vring.desc[i]);
|
|
vq->vring.desc[i].next = cpu_to_virtio16(vq->vq.vdev, vq->free_head);
|
|
vq->free_head = head;
|
|
|
|
/* Plus final descriptor */
|
|
vq->vq.num_free++;
|
|
|
|
/* Free the indirect table, if any, now that it's unmapped. */
|
|
if (vq->desc_state[head].indir_desc) {
|
|
struct vring_desc *indir_desc = vq->desc_state[head].indir_desc;
|
|
u32 len = virtio32_to_cpu(vq->vq.vdev, vq->vring.desc[head].len);
|
|
|
|
BUG_ON(!(vq->vring.desc[head].flags &
|
|
cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_INDIRECT)));
|
|
BUG_ON(len == 0 || len % sizeof(struct vring_desc));
|
|
|
|
for (j = 0; j < len / sizeof(struct vring_desc); j++)
|
|
vring_unmap_one(vq, &indir_desc[j]);
|
|
|
|
kfree(vq->desc_state[head].indir_desc);
|
|
vq->desc_state[head].indir_desc = NULL;
|
|
}
|
|
}
|
|
|
|
static inline bool more_used(const struct vring_virtqueue *vq)
|
|
{
|
|
return vq->last_used_idx != virtio16_to_cpu(vq->vq.vdev, vq->vring.used->idx);
|
|
}
|
|
|
|
/**
|
|
* virtqueue_get_buf - get the next used buffer
|
|
* @vq: the struct virtqueue we're talking about.
|
|
* @len: the length written into the buffer
|
|
*
|
|
* If the device wrote data into the buffer, @len will be set to the
|
|
* amount written. This means you don't need to clear the buffer
|
|
* beforehand to ensure there's no data leakage in the case of short
|
|
* writes.
|
|
*
|
|
* Caller must ensure we don't call this with other virtqueue
|
|
* operations at the same time (except where noted).
|
|
*
|
|
* Returns NULL if there are no used buffers, or the "data" token
|
|
* handed to virtqueue_add_*().
|
|
*/
|
|
void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
void *ret;
|
|
unsigned int i;
|
|
u16 last_used;
|
|
|
|
START_USE(vq);
|
|
|
|
if (unlikely(vq->broken)) {
|
|
END_USE(vq);
|
|
return NULL;
|
|
}
|
|
|
|
if (!more_used(vq)) {
|
|
pr_debug("No more buffers in queue\n");
|
|
END_USE(vq);
|
|
return NULL;
|
|
}
|
|
|
|
/* Only get used array entries after they have been exposed by host. */
|
|
virtio_rmb(vq->weak_barriers);
|
|
|
|
last_used = (vq->last_used_idx & (vq->vring.num - 1));
|
|
i = virtio32_to_cpu(_vq->vdev, vq->vring.used->ring[last_used].id);
|
|
*len = virtio32_to_cpu(_vq->vdev, vq->vring.used->ring[last_used].len);
|
|
|
|
if (unlikely(i >= vq->vring.num)) {
|
|
BAD_RING(vq, "id %u out of range\n", i);
|
|
return NULL;
|
|
}
|
|
if (unlikely(!vq->desc_state[i].data)) {
|
|
BAD_RING(vq, "id %u is not a head!\n", i);
|
|
return NULL;
|
|
}
|
|
|
|
/* detach_buf clears data, so grab it now. */
|
|
ret = vq->desc_state[i].data;
|
|
detach_buf(vq, i);
|
|
vq->last_used_idx++;
|
|
/* If we expect an interrupt for the next entry, tell host
|
|
* by writing event index and flush out the write before
|
|
* the read in the next get_buf call. */
|
|
if (!(vq->avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT))
|
|
virtio_store_mb(vq->weak_barriers,
|
|
&vring_used_event(&vq->vring),
|
|
cpu_to_virtio16(_vq->vdev, vq->last_used_idx));
|
|
|
|
#ifdef DEBUG
|
|
vq->last_add_time_valid = false;
|
|
#endif
|
|
|
|
END_USE(vq);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_get_buf);
|
|
|
|
/**
|
|
* virtqueue_disable_cb - disable callbacks
|
|
* @vq: the struct virtqueue we're talking about.
|
|
*
|
|
* Note that this is not necessarily synchronous, hence unreliable and only
|
|
* useful as an optimization.
|
|
*
|
|
* Unlike other operations, this need not be serialized.
|
|
*/
|
|
void virtqueue_disable_cb(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
if (!(vq->avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT)) {
|
|
vq->avail_flags_shadow |= VRING_AVAIL_F_NO_INTERRUPT;
|
|
if (!vq->event)
|
|
vq->vring.avail->flags = cpu_to_virtio16(_vq->vdev, vq->avail_flags_shadow);
|
|
}
|
|
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_disable_cb);
|
|
|
|
/**
|
|
* virtqueue_enable_cb_prepare - restart callbacks after disable_cb
|
|
* @vq: the struct virtqueue we're talking about.
|
|
*
|
|
* This re-enables callbacks; it returns current queue state
|
|
* in an opaque unsigned value. This value should be later tested by
|
|
* virtqueue_poll, to detect a possible race between the driver checking for
|
|
* more work, and enabling callbacks.
|
|
*
|
|
* Caller must ensure we don't call this with other virtqueue
|
|
* operations at the same time (except where noted).
|
|
*/
|
|
unsigned virtqueue_enable_cb_prepare(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
u16 last_used_idx;
|
|
|
|
START_USE(vq);
|
|
|
|
/* We optimistically turn back on interrupts, then check if there was
|
|
* more to do. */
|
|
/* Depending on the VIRTIO_RING_F_EVENT_IDX feature, we need to
|
|
* either clear the flags bit or point the event index at the next
|
|
* entry. Always do both to keep code simple. */
|
|
if (vq->avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT) {
|
|
vq->avail_flags_shadow &= ~VRING_AVAIL_F_NO_INTERRUPT;
|
|
if (!vq->event)
|
|
vq->vring.avail->flags = cpu_to_virtio16(_vq->vdev, vq->avail_flags_shadow);
|
|
}
|
|
vring_used_event(&vq->vring) = cpu_to_virtio16(_vq->vdev, last_used_idx = vq->last_used_idx);
|
|
END_USE(vq);
|
|
return last_used_idx;
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_enable_cb_prepare);
|
|
|
|
/**
|
|
* virtqueue_poll - query pending used buffers
|
|
* @vq: the struct virtqueue we're talking about.
|
|
* @last_used_idx: virtqueue state (from call to virtqueue_enable_cb_prepare).
|
|
*
|
|
* Returns "true" if there are pending used buffers in the queue.
|
|
*
|
|
* This does not need to be serialized.
|
|
*/
|
|
bool virtqueue_poll(struct virtqueue *_vq, unsigned last_used_idx)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
virtio_mb(vq->weak_barriers);
|
|
return (u16)last_used_idx != virtio16_to_cpu(_vq->vdev, vq->vring.used->idx);
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_poll);
|
|
|
|
/**
|
|
* virtqueue_enable_cb - restart callbacks after disable_cb.
|
|
* @vq: the struct virtqueue we're talking about.
|
|
*
|
|
* This re-enables callbacks; it returns "false" if there are pending
|
|
* buffers in the queue, to detect a possible race between the driver
|
|
* checking for more work, and enabling callbacks.
|
|
*
|
|
* Caller must ensure we don't call this with other virtqueue
|
|
* operations at the same time (except where noted).
|
|
*/
|
|
bool virtqueue_enable_cb(struct virtqueue *_vq)
|
|
{
|
|
unsigned last_used_idx = virtqueue_enable_cb_prepare(_vq);
|
|
return !virtqueue_poll(_vq, last_used_idx);
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_enable_cb);
|
|
|
|
/**
|
|
* virtqueue_enable_cb_delayed - restart callbacks after disable_cb.
|
|
* @vq: the struct virtqueue we're talking about.
|
|
*
|
|
* This re-enables callbacks but hints to the other side to delay
|
|
* interrupts until most of the available buffers have been processed;
|
|
* it returns "false" if there are many pending buffers in the queue,
|
|
* to detect a possible race between the driver checking for more work,
|
|
* and enabling callbacks.
|
|
*
|
|
* Caller must ensure we don't call this with other virtqueue
|
|
* operations at the same time (except where noted).
|
|
*/
|
|
bool virtqueue_enable_cb_delayed(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
u16 bufs;
|
|
|
|
START_USE(vq);
|
|
|
|
/* We optimistically turn back on interrupts, then check if there was
|
|
* more to do. */
|
|
/* Depending on the VIRTIO_RING_F_USED_EVENT_IDX feature, we need to
|
|
* either clear the flags bit or point the event index at the next
|
|
* entry. Always update the event index to keep code simple. */
|
|
if (vq->avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT) {
|
|
vq->avail_flags_shadow &= ~VRING_AVAIL_F_NO_INTERRUPT;
|
|
if (!vq->event)
|
|
vq->vring.avail->flags = cpu_to_virtio16(_vq->vdev, vq->avail_flags_shadow);
|
|
}
|
|
/* TODO: tune this threshold */
|
|
bufs = (u16)(vq->avail_idx_shadow - vq->last_used_idx) * 3 / 4;
|
|
|
|
virtio_store_mb(vq->weak_barriers,
|
|
&vring_used_event(&vq->vring),
|
|
cpu_to_virtio16(_vq->vdev, vq->last_used_idx + bufs));
|
|
|
|
if (unlikely((u16)(virtio16_to_cpu(_vq->vdev, vq->vring.used->idx) - vq->last_used_idx) > bufs)) {
|
|
END_USE(vq);
|
|
return false;
|
|
}
|
|
|
|
END_USE(vq);
|
|
return true;
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_enable_cb_delayed);
|
|
|
|
/**
|
|
* virtqueue_detach_unused_buf - detach first unused buffer
|
|
* @vq: the struct virtqueue we're talking about.
|
|
*
|
|
* Returns NULL or the "data" token handed to virtqueue_add_*().
|
|
* This is not valid on an active queue; it is useful only for device
|
|
* shutdown.
|
|
*/
|
|
void *virtqueue_detach_unused_buf(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
unsigned int i;
|
|
void *buf;
|
|
|
|
START_USE(vq);
|
|
|
|
for (i = 0; i < vq->vring.num; i++) {
|
|
if (!vq->desc_state[i].data)
|
|
continue;
|
|
/* detach_buf clears data, so grab it now. */
|
|
buf = vq->desc_state[i].data;
|
|
detach_buf(vq, i);
|
|
vq->avail_idx_shadow--;
|
|
vq->vring.avail->idx = cpu_to_virtio16(_vq->vdev, vq->avail_idx_shadow);
|
|
END_USE(vq);
|
|
return buf;
|
|
}
|
|
/* That should have freed everything. */
|
|
BUG_ON(vq->vq.num_free != vq->vring.num);
|
|
|
|
END_USE(vq);
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_detach_unused_buf);
|
|
|
|
irqreturn_t vring_interrupt(int irq, void *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
if (!more_used(vq)) {
|
|
pr_debug("virtqueue interrupt with no work for %p\n", vq);
|
|
return IRQ_NONE;
|
|
}
|
|
|
|
if (unlikely(vq->broken))
|
|
return IRQ_HANDLED;
|
|
|
|
pr_debug("virtqueue callback for %p (%p)\n", vq, vq->vq.callback);
|
|
if (vq->vq.callback)
|
|
vq->vq.callback(&vq->vq);
|
|
|
|
return IRQ_HANDLED;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vring_interrupt);
|
|
|
|
struct virtqueue *__vring_new_virtqueue(unsigned int index,
|
|
struct vring vring,
|
|
struct virtio_device *vdev,
|
|
bool weak_barriers,
|
|
bool (*notify)(struct virtqueue *),
|
|
void (*callback)(struct virtqueue *),
|
|
const char *name)
|
|
{
|
|
unsigned int i;
|
|
struct vring_virtqueue *vq;
|
|
|
|
vq = kmalloc(sizeof(*vq) + vring.num * sizeof(struct vring_desc_state),
|
|
GFP_KERNEL);
|
|
if (!vq)
|
|
return NULL;
|
|
|
|
vq->vring = vring;
|
|
vq->vq.callback = callback;
|
|
vq->vq.vdev = vdev;
|
|
vq->vq.name = name;
|
|
vq->vq.num_free = vring.num;
|
|
vq->vq.index = index;
|
|
vq->we_own_ring = false;
|
|
vq->queue_dma_addr = 0;
|
|
vq->queue_size_in_bytes = 0;
|
|
vq->notify = notify;
|
|
vq->weak_barriers = weak_barriers;
|
|
vq->broken = false;
|
|
vq->last_used_idx = 0;
|
|
vq->avail_flags_shadow = 0;
|
|
vq->avail_idx_shadow = 0;
|
|
vq->num_added = 0;
|
|
list_add_tail(&vq->vq.list, &vdev->vqs);
|
|
#ifdef DEBUG
|
|
vq->in_use = false;
|
|
vq->last_add_time_valid = false;
|
|
#endif
|
|
|
|
vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC);
|
|
vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX);
|
|
|
|
/* No callback? Tell other side not to bother us. */
|
|
if (!callback) {
|
|
vq->avail_flags_shadow |= VRING_AVAIL_F_NO_INTERRUPT;
|
|
if (!vq->event)
|
|
vq->vring.avail->flags = cpu_to_virtio16(vdev, vq->avail_flags_shadow);
|
|
}
|
|
|
|
/* Put everything in free lists. */
|
|
vq->free_head = 0;
|
|
for (i = 0; i < vring.num-1; i++)
|
|
vq->vring.desc[i].next = cpu_to_virtio16(vdev, i + 1);
|
|
memset(vq->desc_state, 0, vring.num * sizeof(struct vring_desc_state));
|
|
|
|
return &vq->vq;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__vring_new_virtqueue);
|
|
|
|
static void *vring_alloc_queue(struct virtio_device *vdev, size_t size,
|
|
dma_addr_t *dma_handle, gfp_t flag)
|
|
{
|
|
if (vring_use_dma_api(vdev)) {
|
|
return dma_alloc_coherent(vdev->dev.parent, size,
|
|
dma_handle, flag);
|
|
} else {
|
|
void *queue = alloc_pages_exact(PAGE_ALIGN(size), flag);
|
|
if (queue) {
|
|
phys_addr_t phys_addr = virt_to_phys(queue);
|
|
*dma_handle = (dma_addr_t)phys_addr;
|
|
|
|
/*
|
|
* Sanity check: make sure we dind't truncate
|
|
* the address. The only arches I can find that
|
|
* have 64-bit phys_addr_t but 32-bit dma_addr_t
|
|
* are certain non-highmem MIPS and x86
|
|
* configurations, but these configurations
|
|
* should never allocate physical pages above 32
|
|
* bits, so this is fine. Just in case, throw a
|
|
* warning and abort if we end up with an
|
|
* unrepresentable address.
|
|
*/
|
|
if (WARN_ON_ONCE(*dma_handle != phys_addr)) {
|
|
free_pages_exact(queue, PAGE_ALIGN(size));
|
|
return NULL;
|
|
}
|
|
}
|
|
return queue;
|
|
}
|
|
}
|
|
|
|
static void vring_free_queue(struct virtio_device *vdev, size_t size,
|
|
void *queue, dma_addr_t dma_handle)
|
|
{
|
|
if (vring_use_dma_api(vdev)) {
|
|
dma_free_coherent(vdev->dev.parent, size, queue, dma_handle);
|
|
} else {
|
|
free_pages_exact(queue, PAGE_ALIGN(size));
|
|
}
|
|
}
|
|
|
|
struct virtqueue *vring_create_virtqueue(
|
|
unsigned int index,
|
|
unsigned int num,
|
|
unsigned int vring_align,
|
|
struct virtio_device *vdev,
|
|
bool weak_barriers,
|
|
bool may_reduce_num,
|
|
bool (*notify)(struct virtqueue *),
|
|
void (*callback)(struct virtqueue *),
|
|
const char *name)
|
|
{
|
|
struct virtqueue *vq;
|
|
void *queue = NULL;
|
|
dma_addr_t dma_addr;
|
|
size_t queue_size_in_bytes;
|
|
struct vring vring;
|
|
|
|
/* We assume num is a power of 2. */
|
|
if (num & (num - 1)) {
|
|
dev_warn(&vdev->dev, "Bad virtqueue length %u\n", num);
|
|
return NULL;
|
|
}
|
|
|
|
/* TODO: allocate each queue chunk individually */
|
|
for (; num && vring_size(num, vring_align) > PAGE_SIZE; num /= 2) {
|
|
queue = vring_alloc_queue(vdev, vring_size(num, vring_align),
|
|
&dma_addr,
|
|
GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO);
|
|
if (queue)
|
|
break;
|
|
}
|
|
|
|
if (!num)
|
|
return NULL;
|
|
|
|
if (!queue) {
|
|
/* Try to get a single page. You are my only hope! */
|
|
queue = vring_alloc_queue(vdev, vring_size(num, vring_align),
|
|
&dma_addr, GFP_KERNEL|__GFP_ZERO);
|
|
}
|
|
if (!queue)
|
|
return NULL;
|
|
|
|
queue_size_in_bytes = vring_size(num, vring_align);
|
|
vring_init(&vring, num, queue, vring_align);
|
|
|
|
vq = __vring_new_virtqueue(index, vring, vdev, weak_barriers,
|
|
notify, callback, name);
|
|
if (!vq) {
|
|
vring_free_queue(vdev, queue_size_in_bytes, queue,
|
|
dma_addr);
|
|
return NULL;
|
|
}
|
|
|
|
to_vvq(vq)->queue_dma_addr = dma_addr;
|
|
to_vvq(vq)->queue_size_in_bytes = queue_size_in_bytes;
|
|
to_vvq(vq)->we_own_ring = true;
|
|
|
|
return vq;
|
|
}
|
|
EXPORT_SYMBOL_GPL(vring_create_virtqueue);
|
|
|
|
struct virtqueue *vring_new_virtqueue(unsigned int index,
|
|
unsigned int num,
|
|
unsigned int vring_align,
|
|
struct virtio_device *vdev,
|
|
bool weak_barriers,
|
|
void *pages,
|
|
bool (*notify)(struct virtqueue *vq),
|
|
void (*callback)(struct virtqueue *vq),
|
|
const char *name)
|
|
{
|
|
struct vring vring;
|
|
vring_init(&vring, num, pages, vring_align);
|
|
return __vring_new_virtqueue(index, vring, vdev, weak_barriers,
|
|
notify, callback, name);
|
|
}
|
|
EXPORT_SYMBOL_GPL(vring_new_virtqueue);
|
|
|
|
void vring_del_virtqueue(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
if (vq->we_own_ring) {
|
|
vring_free_queue(vq->vq.vdev, vq->queue_size_in_bytes,
|
|
vq->vring.desc, vq->queue_dma_addr);
|
|
}
|
|
list_del(&_vq->list);
|
|
kfree(vq);
|
|
}
|
|
EXPORT_SYMBOL_GPL(vring_del_virtqueue);
|
|
|
|
/* Manipulates transport-specific feature bits. */
|
|
void vring_transport_features(struct virtio_device *vdev)
|
|
{
|
|
unsigned int i;
|
|
|
|
for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++) {
|
|
switch (i) {
|
|
case VIRTIO_RING_F_INDIRECT_DESC:
|
|
break;
|
|
case VIRTIO_RING_F_EVENT_IDX:
|
|
break;
|
|
case VIRTIO_F_VERSION_1:
|
|
break;
|
|
case VIRTIO_F_IOMMU_PLATFORM:
|
|
break;
|
|
default:
|
|
/* We don't understand this bit. */
|
|
__virtio_clear_bit(vdev, i);
|
|
}
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(vring_transport_features);
|
|
|
|
/**
|
|
* virtqueue_get_vring_size - return the size of the virtqueue's vring
|
|
* @vq: the struct virtqueue containing the vring of interest.
|
|
*
|
|
* Returns the size of the vring. This is mainly used for boasting to
|
|
* userspace. Unlike other operations, this need not be serialized.
|
|
*/
|
|
unsigned int virtqueue_get_vring_size(struct virtqueue *_vq)
|
|
{
|
|
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
return vq->vring.num;
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_get_vring_size);
|
|
|
|
bool virtqueue_is_broken(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
return vq->broken;
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_is_broken);
|
|
|
|
/*
|
|
* This should prevent the device from being used, allowing drivers to
|
|
* recover. You may need to grab appropriate locks to flush.
|
|
*/
|
|
void virtio_break_device(struct virtio_device *dev)
|
|
{
|
|
struct virtqueue *_vq;
|
|
|
|
list_for_each_entry(_vq, &dev->vqs, list) {
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
vq->broken = true;
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtio_break_device);
|
|
|
|
dma_addr_t virtqueue_get_desc_addr(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
BUG_ON(!vq->we_own_ring);
|
|
|
|
return vq->queue_dma_addr;
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_get_desc_addr);
|
|
|
|
dma_addr_t virtqueue_get_avail_addr(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
BUG_ON(!vq->we_own_ring);
|
|
|
|
return vq->queue_dma_addr +
|
|
((char *)vq->vring.avail - (char *)vq->vring.desc);
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_get_avail_addr);
|
|
|
|
dma_addr_t virtqueue_get_used_addr(struct virtqueue *_vq)
|
|
{
|
|
struct vring_virtqueue *vq = to_vvq(_vq);
|
|
|
|
BUG_ON(!vq->we_own_ring);
|
|
|
|
return vq->queue_dma_addr +
|
|
((char *)vq->vring.used - (char *)vq->vring.desc);
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_get_used_addr);
|
|
|
|
const struct vring *virtqueue_get_vring(struct virtqueue *vq)
|
|
{
|
|
return &to_vvq(vq)->vring;
|
|
}
|
|
EXPORT_SYMBOL_GPL(virtqueue_get_vring);
|
|
|
|
MODULE_LICENSE("GPL");
|