CCing freebsd-virtualization@, because they might know more about this.
Am 25.12.2018 um 02:24 schrieb Chuck Tuffli:
Using the latest bhyve, I'm seeing core dumps in the guest when running:
nvmecontrol identify nvme0
against the emulated NVMe drive. The location of the core dump changes
from run to run, but I suspect the root cause is a memory corruption
caused by the transfer of the Identify data (4KB) back to the guest.
This transfer of data is actually a memcpy to an address returned from
vm_map_gpa() based on the physical address provided by the guest.
Based on the signature of one of the core dumps, I modified
nvmecontrol to always pass a 4KB aligned buffer to the driver instead
of the (typically) unaligned address of the structure on the stack.
With this change, nvmecontrol in the guest no longer core dumps. What
I don't understand is why this changes the behavior. Do the addresses
passed to vm_map_gpa() need to be page aligned?
AFAIK vm_map_gpa maps a page, so yes, it needs to be 4k-aligned.
Or did moving the
memory location from the stack to the heap merely mitigate what is
corrupted?
Thoughts?
--chuck
_______________________________________________
freebsd-hack...@freebsd.org mailing list
https://lists.freebsd.org/mailman/listinfo/freebsd-hackers
To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"
_______________________________________________
freebsd-virtualization@freebsd.org mailing list
https://lists.freebsd.org/mailman/listinfo/freebsd-virtualization
To unsubscribe, send any mail to
"freebsd-virtualization-unsubscr...@freebsd.org"
