MFC r256926, r257005

r256926
  Fix AHCI ATAPI emulation when backed with /dev/cd0

  - remove assumption that the backing file/device had
    512-byte sectors
  - fix incorrect iovec size variable that would result
    in a buffer overrun when an o/s issued an i/o request
    with more s/g elements than the blockif api

r257005
  Export the block size capability to guests.
  - Use #defines for capability bits
  - Export the VTBLK_F_BLK_SIZE capability
  - Fix bug in calculating capacity: it is in
    512-byte units, not the underlying sector size

  This allows virtio-blk to have backing devices
  with non 512-byte sector sizes e.g. /dev/cd0, and
  4K-block harddrives.

Approved by:  re (glebius)

2 files changed, 10 insertions, 6 deletions

diff --git a/usr.sbin/bhyve/pci_ahci.c b/usr.sbin/bhyve/pci_ahci.c
index 76f263b..68d9bc1 100644
--- a/usr.sbin/bhyve/pci_ahci.c
+++ b/usr.sbin/bhyve/pci_ahci.c
@@ -663,8 +663,7 @@ atapi_read_capacity(struct ahci_port *p, int slot, uint8_t *cfis)
 	uint8_t buf[8];
 	uint64_t sectors;
 
-	sectors = blockif_size(p->bctx) / blockif_sectsz(p->bctx);
-	sectors >>= 2;
+	sectors = blockif_size(p->bctx) / 2048;
 	be32enc(buf, sectors - 1);
 	be32enc(buf + 4, 2048);
 	cfis[4] = (cfis[4] & ~7) | ATA_I_CMD | ATA_I_IN;
@@ -908,9 +907,9 @@ atapi_read(struct ahci_port *p, int slot, uint8_t *cfis,
 	/*
 	 * Build up the iovec based on the prdt
 	 */
-	for (i = 0; i < hdr->prdtl; i++) {
+	for (i = 0; i < iovcnt; i++) {
 		breq->br_iov[i].iov_base = paddr_guest2host(ahci_ctx(sc),
-				prdt->dba, prdt->dbc + 1);
+		    prdt->dba, prdt->dbc + 1);
 		breq->br_iov[i].iov_len = prdt->dbc + 1;
 		aior->done += (prdt->dbc + 1);
 		prdt++;
diff --git a/usr.sbin/bhyve/pci_virtio_block.c b/usr.sbin/bhyve/pci_virtio_block.c
index a7556d7..a642b11 100644
--- a/usr.sbin/bhyve/pci_virtio_block.c
+++ b/usr.sbin/bhyve/pci_virtio_block.c
@@ -66,11 +66,16 @@ __FBSDID("$FreeBSD$");
 
 #define	VTBLK_BLK_ID_BYTES	20
 
+/* Capability bits */
+#define	VTBLK_F_SEG_MAX		(1 << 2)	/* Maximum request segments */
+#define	VTBLK_F_BLK_SIZE       	(1 << 6)	/* cfg block size valid */
+
 /*
  * Host capabilities
  */
 #define VTBLK_S_HOSTCAPS      \
-  ( 0x00000004 |	/* host maximum request segments */ \
+  ( VTBLK_F_SEG_MAX  |						    \
+    VTBLK_F_BLK_SIZE |						    \
     VIRTIO_RING_F_INDIRECT_DESC )	/* indirect descriptors */
 
 /*
@@ -315,7 +320,7 @@ pci_vtblk_init(struct vmctx *ctx, struct pci_devinst *pi, char *opts)
 	    digest[0], digest[1], digest[2], digest[3], digest[4], digest[5]);
 
 	/* setup virtio block config space */
-	sc->vbsc_cfg.vbc_capacity = size / sectsz;
+	sc->vbsc_cfg.vbc_capacity = size / DEV_BSIZE; /* 512-byte units */
 	sc->vbsc_cfg.vbc_seg_max = VTBLK_MAXSEGS;
 	sc->vbsc_cfg.vbc_blk_size = sectsz;
 	sc->vbsc_cfg.vbc_size_max = 0;	/* not negotiated */