K 10
svn:author
V 5
chuck
K 8
svn:date
V 27
2019-04-05T16:54:20.812145Z
K 7
svn:log
V 1099
bhyve: Fix NVMe data structure copy to guest

bhyve's NVMe emulation was transferring Identify data back to the guest
incorrectly causing memory corruptions. These corruptions resulted in
core dumps and other system level errors in the guest.

In their simplest form, NVMe Physical Region Page (PRP) values in
commands indicate which physical pages to use for data transfer. The
first PRP value is not required to be page aligned but does not cross a
page boundary. The second PRP value must be page aligned, does not cross
a page boundary, and need not be contiguous with PRP1.

The code was copying Identify data past the end of PRP1. This happens to
work if PRP1 and PRP2 are physically contiguous but will corrupt guest
memory in unpredictable ways if they are not.

Fix is to copy the Identify data back to the guest piecewise (i.e. for
each PRP entry). Also fix a similarly wrong problem when copying back
Log page data.

Reviewed by:	imp (mentor), araujo, jhb, rgrimes, bhyve
Approved by:	imp (mentor), bhyve (jhb)
MFC after:	2 weeks
Differential Revision: https://reviews.freebsd.org/D19695

END