[RFC 19/27] vhost: add VDUSE callback for IOTLB miss

[Maxime Coquelin]

This patch implements the VDUSE callback for IOTLB misses,
where it unmaps the pages from the invalidated IOTLB entry.

Signed-off-by: Maxime Coquelin <maxime.coque...@redhat.com>
---
 lib/vhost/vduse.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)

diff --git a/lib/vhost/vduse.c b/lib/vhost/vduse.c
index 336761c97a..f46823f589 100644
--- a/lib/vhost/vduse.c
+++ b/lib/vhost/vduse.c
@@ -13,9 +13,11 @@
 
 #include <sys/ioctl.h>
 #include <sys/mman.h>
+#include <sys/stat.h>
 
 #include <rte_common.h>
 
+#include "iotlb.h"
 #include "vduse.h"
 #include "vhost.h"
 
@@ -30,7 +32,63 @@
                                (1ULL << VIRTIO_F_IN_ORDER) | \
                                (1ULL << VIRTIO_F_IOMMU_PLATFORM))
 
+static int
+vduse_iotlb_miss(struct virtio_net *dev, uint64_t iova, uint8_t perm 
__rte_unused)
+{
+       struct vduse_iotlb_entry entry;
+       uint64_t size, page_size;
+       struct stat stat;
+       void *mmap_addr;
+       int fd, ret;
+
+       entry.start = iova;
+       entry.last = iova + 1;
+
+       ret = ioctl(dev->vduse_dev_fd, VDUSE_IOTLB_GET_FD, &entry);
+       if (ret < 0) {
+               VHOST_LOG_CONFIG(dev->ifname, ERR, "Failed to get IOTLB entry 
for 0x%" PRIx64 "\n",
+                               iova);
+               return -1;
+       }
+
+       fd = ret;
+
+       VHOST_LOG_CONFIG(dev->ifname, DEBUG, "New IOTLB entry:\n");
+       VHOST_LOG_CONFIG(dev->ifname, DEBUG, "\tIOVA: %" PRIx64 " - %" PRIx64 
"\n",
+                       (uint64_t)entry.start, (uint64_t)entry.last);
+       VHOST_LOG_CONFIG(dev->ifname, DEBUG, "\toffset: %" PRIx64 "\n", 
(uint64_t)entry.offset);
+       VHOST_LOG_CONFIG(dev->ifname, DEBUG, "\tfd: %d\n", fd);
+       VHOST_LOG_CONFIG(dev->ifname, DEBUG, "\tperm: %x\n", entry.perm);
+
+       size = entry.last - entry.start + 1;
+       mmap_addr = mmap(0, size + entry.offset, entry.perm, MAP_SHARED, fd, 0);
+       if (!mmap_addr) {
+               VHOST_LOG_CONFIG(dev->ifname, ERR,
+                               "Failed to mmap IOTLB entry for 0x%" PRIx64 
"\n", iova);
+               ret = -1;
+               goto close_fd;
+       }
+
+       ret = fstat(fd, &stat);
+       if (ret < 0) {
+               VHOST_LOG_CONFIG(dev->ifname, ERR, "Failed to get page 
size.\n");
+               munmap(mmap_addr, entry.offset + size);
+               goto close_fd;
+       }
+       page_size = (uint64_t)stat.st_blksize;
+
+       vhost_user_iotlb_cache_insert(dev, entry.start, 
(uint64_t)(uintptr_t)mmap_addr,
+               entry.offset, size, page_size, entry.perm);
+
+       ret = 0;
+close_fd:
+       close(fd);
+
+       return ret;
+}
+
 static struct vhost_backend_ops vduse_backend_ops = {
+       .iotlb_miss = vduse_iotlb_miss,
 };
 
 int
-- 
2.39.2