virtio, vhost: fixes, features, performance

new iommu device
 vhost guest memory access using vmap (just meta-data for now)
 minor fixes
 
 Signed-off-by: Michael S. Tsirkin <[email protected]>
 
 Note: due to code driver changes the driver-core tree, the following
 patch is needed when merging tree with commit 92ce7e83b4
 ("driver_find_device: Unify the match function with
 class_find_device()") in the driver-core tree:
 
 From: Nathan Chancellor <[email protected]>
 Subject: [PATCH] iommu/virtio: Constify data parameter in viommu_match_node
 
 After commit 92ce7e83b4 ("driver_find_device: Unify the match
 function with class_find_device()") in the driver-core tree.
 
 Signed-off-by: Nathan Chancellor <[email protected]>
 Signed-off-by: Michael S. Tsirkin <[email protected]>
 
 ---
  drivers/iommu/virtio-iommu.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)
 
 diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
 index 4620dd221ffd..433f4d2ee956 100644
 --- a/drivers/iommu/virtio-iommu.c
 +++ b/drivers/iommu/virtio-iommu.c
 @@ -839,7 +839,7 @@ static void viommu_put_resv_regions(struct device *dev, struct list_head *head)
  static struct iommu_ops viommu_ops;
  static struct virtio_driver virtio_iommu_drv;
 
 -static int viommu_match_node(struct device *dev, void *data)
 +static int viommu_match_node(struct device *dev, const void *data)
  {
  	return dev->parent->fwnode == data;
  }
 -----BEGIN PGP SIGNATURE-----
 
 iQEcBAABAgAGBQJdJ5qUAAoJECgfDbjSjVRpQs0H/2qWcIG1zjGKyh9KWrfgOusG
 /QIqeP50d7SC6oqdyd00tzmExqO1xdGLPFzYixdOsU817te1gHBP4Rfmzo01jZRd
 CUzZNnZQ2JRsDshiA6G2ui+wn1/a/cB3RPN4rT1mquDYS53QmsRGDQDnpp84TXMV
 aocB8TS6halbRzKMq3VmaWHIvzNXnt4dwQR542+PyeLLn9bUx2QwWj2ON3QwxixK
 dVRZow3GwLGBhKTA/Z1Z/Bta4fEfOKjUGP2XWgvL6zOr+nZR4eQ8w5WXVJYzR+d6
 1JCfqTxleweT2k6Tu5VwtTNlQkxn/XvQAeisppOiEE6NnPjubyI9wMQIvL7bkpo=
 =uJbC
 -----END PGP SIGNATURE-----

Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

Pull virtio, vhost updates from Michael Tsirkin:
 "Fixes, features, performance:

   - new iommu device

   - vhost guest memory access using vmap (just meta-data for now)

   - minor fixes"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  virtio-mmio: add error check for platform_get_irq
  scsi: virtio_scsi: Use struct_size() helper
  iommu/virtio: Add event queue
  iommu/virtio: Add probe request
  iommu: Add virtio-iommu driver
  PCI: OF: Initialize dev->fwnode appropriately
  of: Allow the iommu-map property to omit untranslated devices
  dt-bindings: virtio: Add virtio-pci-iommu node
  dt-bindings: virtio-mmio: Add IOMMU description
  vhost: fix clang build warning
  vhost: access vq metadata through kernel virtual address
  vhost: factor out setting vring addr and num
  vhost: introduce helpers to get the size of metadata area
  vhost: rename vq_iotlb_prefetch() to vq_meta_prefetch()
  vhost: fine grain userspace memory accessors
  vhost: generalize adding used elem

drivers/vhost/net.c

@@ -956,7 +956,7 @@ static void handle_tx(struct vhost_net *net)
 	if (!sock)
 		goto out;
 
-	if (!vq_iotlb_prefetch(vq))
+	if (!vq_meta_prefetch(vq))
 		goto out;
 
 	vhost_disable_notify(&net->dev, vq);
@@ -1125,7 +1125,7 @@ static void handle_rx(struct vhost_net *net)
 	if (!sock)
 		goto out;
 
-	if (!vq_iotlb_prefetch(vq))
+	if (!vq_meta_prefetch(vq))
 		goto out;
 
 	vhost_disable_notify(&net->dev, vq);

drivers/vhost/vhost.h

@@ -12,6 +12,9 @@
 #include <linux/virtio_config.h>
 #include <linux/virtio_ring.h>
 #include <linux/atomic.h>
+#include <linux/pagemap.h>
+#include <linux/mmu_notifier.h>
+#include <asm/cacheflush.h>
 
 struct vhost_work;
 typedef void (*vhost_work_fn_t)(struct vhost_work *work);
@@ -80,6 +83,24 @@ enum vhost_uaddr_type {
 	VHOST_NUM_ADDRS = 3,
 };
 
+struct vhost_map {
+	int npages;
+	void *addr;
+	struct page **pages;
+};
+
+struct vhost_uaddr {
+	unsigned long uaddr;
+	size_t size;
+	bool write;
+};
+
+#if defined(CONFIG_MMU_NOTIFIER) && ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 0
+#define VHOST_ARCH_CAN_ACCEL_UACCESS 1
+#else
+#define VHOST_ARCH_CAN_ACCEL_UACCESS 0
+#endif
+
 /* The virtqueue structure describes a queue attached to a device. */
 struct vhost_virtqueue {
 	struct vhost_dev *dev;
@@ -90,7 +111,22 @@ struct vhost_virtqueue {
 	struct vring_desc __user *desc;
 	struct vring_avail __user *avail;
 	struct vring_used __user *used;
+
+#if VHOST_ARCH_CAN_ACCEL_UACCESS
+	/* Read by memory accessors, modified by meta data
+	 * prefetching, MMU notifier and vring ioctl().
+	 * Synchonrized through mmu_lock (writers) and RCU (writers
+	 * and readers).
+	 */
+	struct vhost_map __rcu *maps[VHOST_NUM_ADDRS];
+	/* Read by MMU notifier, modified by vring ioctl(),
+	 * synchronized through MMU notifier
+	 * registering/unregistering.
+	 */
+	struct vhost_uaddr uaddrs[VHOST_NUM_ADDRS];
+#endif
 	const struct vhost_umem_node *meta_iotlb[VHOST_NUM_ADDRS];
+
 	struct file *kick;
 	struct eventfd_ctx *call_ctx;
 	struct eventfd_ctx *error_ctx;
@@ -145,6 +181,8 @@ struct vhost_virtqueue {
 	bool user_be;
 #endif
 	u32 busyloop_timeout;
+	spinlock_t mmu_lock;
+	int invalidate_count;
 };
 
 struct vhost_msg_node {
@@ -158,6 +196,9 @@ struct vhost_msg_node {
 
 struct vhost_dev {
 	struct mm_struct *mm;
+#ifdef CONFIG_MMU_NOTIFIER
+	struct mmu_notifier mmu_notifier;
+#endif
 	struct mutex mutex;
 	struct vhost_virtqueue **vqs;
 	int nvqs;
@@ -212,7 +253,7 @@ bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);
 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
 		    unsigned int log_num, u64 len,
 		    struct iovec *iov, int count);
-int vq_iotlb_prefetch(struct vhost_virtqueue *vq);
+int vq_meta_prefetch(struct vhost_virtqueue *vq);
 
 struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type);
 void vhost_enqueue_msg(struct vhost_dev *dev,