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

[Xia, Chenbo]

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin at redhat.com>
> Sent: Friday, March 31, 2023 11:43 PM
> To: dev at dpdk.org; david.marchand at redhat.com; Xia, Chenbo
> <chenbo.xia at intel.com>; mkp at redhat.com; fbl at redhat.com;
> jasowang at redhat.com; Liang, Cunming <cunming.liang at intel.com>; Xie, Yongji
> <xieyongji at bytedance.com>; echaudro at redhat.com; eperezma at redhat.com;
> amorenoz at redhat.com
> Cc: Maxime Coquelin <maxime.coquelin at redhat.com>
> Subject: [RFC 19/27] vhost: add VDUSE callback for IOTLB miss
> 
> 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.coquelin at 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

Reviewed-by: Chenbo Xia <chenbo.xia at intel.com>