Author: grehan
Date: Tue Jul 15 00:25:54 2014
New Revision: 268638
URL: http://svnweb.freebsd.org/changeset/base/268638
Log:
Add a call to synthesize a C/H/S value for block emulations
that require it (ahci). The algorithm used is from the VHD
specification.
Modified:
head/usr.sbin/bhyve/block_if.c
head/usr.sbin/bhyve/block_if.h
Modified: head/usr.sbin/bhyve/block_if.c
==============================================================================
--- head/usr.sbin/bhyve/block_if.c Mon Jul 14 23:25:29 2014
(r268637)
+++ head/usr.sbin/bhyve/block_if.c Tue Jul 15 00:25:54 2014
(r268638)
@@ -390,6 +390,55 @@ blockif_close(struct blockif_ctxt *bc)
}
/*
+ * Return virtual C/H/S values for a given block. Use the algorithm
+ * outlined in the VHD specification to calculate values.
+ */
+void
+blockif_chs(struct blockif_ctxt *bc, uint16_t *c, uint8_t *h, uint8_t *s)
+{
+ off_t sectors; /* total sectors of the block dev */
+ off_t hcyl; /* cylinders times heads */
+ uint16_t secpt; /* sectors per track */
+ uint8_t heads;
+
+ assert(bc->bc_magic == BLOCKIF_SIG);
+
+ sectors = bc->bc_size / bc->bc_sectsz;
+
+ /* Clamp the size to the largest possible with CHS */
+ if (sectors > 65535UL*16*255)
+ sectors = 65535UL*16*255;
+
+ if (sectors >= 65536UL*16*63) {
+ secpt = 255;
+ heads = 16;
+ hcyl = sectors / secpt;
+ } else {
+ secpt = 17;
+ hcyl = sectors / secpt;
+ heads = (hcyl + 1023) / 1024;
+
+ if (heads < 4)
+ heads = 4;
+
+ if (hcyl >= (heads * 1024) || heads > 16) {
+ secpt = 31;
+ heads = 16;
+ hcyl = sectors / secpt;
+ }
+ if (hcyl >= (heads * 1024)) {
+ secpt = 63;
+ heads = 16;
+ hcyl = sectors / secpt;
+ }
+ }
+
+ *c = hcyl / heads;
+ *h = heads;
+ *s = secpt;
+}
+
+/*
* Accessors
*/
off_t
Modified: head/usr.sbin/bhyve/block_if.h
==============================================================================
--- head/usr.sbin/bhyve/block_if.h Mon Jul 14 23:25:29 2014
(r268637)
+++ head/usr.sbin/bhyve/block_if.h Tue Jul 15 00:25:54 2014
(r268638)
@@ -52,6 +52,8 @@ struct blockif_req {
struct blockif_ctxt;
struct blockif_ctxt *blockif_open(const char *optstr, const char *ident);
off_t blockif_size(struct blockif_ctxt *bc);
+void blockif_chs(struct blockif_ctxt *bc, uint16_t *c, uint8_t *h,
+ uint8_t *s);
int blockif_sectsz(struct blockif_ctxt *bc);
int blockif_queuesz(struct blockif_ctxt *bc);
int blockif_is_ro(struct blockif_ctxt *bc);
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