Specify the length of the mapping requested from 'paddr_guest2host()'.

This seems prudent to do in its own right but it also opens up the possibility
of not having to mmap the entire guest address space in the 'bhyve' process
context.

Discussed with:	grehan
Obtained from:	NetApp

1 files changed, 7 insertions, 12 deletions

diff --git a/usr.sbin/bhyve/pci_virtio_block.c b/usr.sbin/bhyve/pci_virtio_block.c
index 62bf801..31ff2e6 100644
--- a/usr.sbin/bhyve/pci_virtio_block.c
+++ b/usr.sbin/bhyve/pci_virtio_block.c
@@ -222,13 +222,13 @@ pci_vtblk_proc(struct pci_vtblk_softc *sc, struct vring_hqueue *hq)
 	assert(nsegs >= 3);
 	assert(nsegs < VTBLK_MAXSEGS + 2);
 
-	vid = paddr_guest2host(vd->vd_addr);
+	vid = paddr_guest2host(vd->vd_addr, vd->vd_len);
 	assert((vid->vd_flags & VRING_DESC_F_INDIRECT) == 0);
 
 	/*
 	 * The first descriptor will be the read-only fixed header
 	 */
-	vbh = paddr_guest2host(vid[0].vd_addr);
+	vbh = paddr_guest2host(vid[0].vd_addr, sizeof(struct virtio_blk_hdr));
 	assert(vid[0].vd_len == sizeof(struct virtio_blk_hdr));
 	assert(vid[0].vd_flags & VRING_DESC_F_NEXT);
 	assert((vid[0].vd_flags & VRING_DESC_F_WRITE) == 0);
@@ -247,7 +247,8 @@ pci_vtblk_proc(struct pci_vtblk_softc *sc, struct vring_hqueue *hq)
 	 * Build up the iovec based on the guest's data descriptors
 	 */
 	for (i = 1, iolen = 0; i < nsegs - 1; i++) {
-		iov[i-1].iov_base = paddr_guest2host(vid[i].vd_addr);
+		iov[i-1].iov_base = paddr_guest2host(vid[i].vd_addr,
+						     vid[i].vd_len);
 		iov[i-1].iov_len = vid[i].vd_len;
 		iolen += vid[i].vd_len;
 
@@ -265,7 +266,7 @@ pci_vtblk_proc(struct pci_vtblk_softc *sc, struct vring_hqueue *hq)
 	}
 
 	/* Lastly, get the address of the status byte */
-	status = paddr_guest2host(vid[nsegs - 1].vd_addr);
+	status = paddr_guest2host(vid[nsegs - 1].vd_addr, 1);
 	assert(vid[nsegs - 1].vd_len == 1);
 	assert((vid[nsegs - 1].vd_flags & VRING_DESC_F_NEXT) == 0);
 	assert(vid[nsegs - 1].vd_flags & VRING_DESC_F_WRITE);
@@ -341,7 +342,8 @@ pci_vtblk_ring_init(struct pci_vtblk_softc *sc, uint64_t pfn)
 	hq = &sc->vbsc_q;
 	hq->hq_size = VTBLK_RINGSZ;
 
-	hq->hq_dtable = paddr_guest2host(pfn << VRING_PFN);
+	hq->hq_dtable = paddr_guest2host(pfn << VRING_PFN,
+					 vring_size(VTBLK_RINGSZ));
 	hq->hq_avail_flags =  (uint16_t *)(hq->hq_dtable + hq->hq_size);
 	hq->hq_avail_idx = hq->hq_avail_flags + 1;
 	hq->hq_avail_ring = hq->hq_avail_flags + 2;
@@ -372,13 +374,6 @@ pci_vtblk_init(struct vmctx *ctx, struct pci_devinst *pi, char *opts)
 	}
 
 	/*
-	 * Access to guest memory is required. Fail if
-	 * memory not mapped
-	 */
-	if (paddr_guest2host(0) == NULL)
-		return (1);
-
-	/*
 	 * The supplied backing file has to exist
 	 */
 	fd = open(opts, O_RDWR);