If we got fewer bytes from the backend than requested, don't poke the
backend for more bytes; the guest will ask for more (or if the guest has
already asked for more, the backend knows about it via handle_input()).
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Popping an elem from the vq just to find out its length causes problems
with save/load later on. Use the new virtqueue_get_avail_bytes()
function instead, saves us the complexity in the migration code, as well
as makes the migration endian-safe.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This adds parameters to virtio-rng-pci to allow rate limiting the entropy a
guest receives. An example command line:
$ qemu -device virtio-rng-pci,max-bytes=1024,period=1000
Would limit entropy collection to 1Kb/s.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
The Linux kernel already has a virtio-rng driver, this is the device
implementation.
When the guest asks for entropy from the virtio hwrng, it puts a buffer
in the vq. We then put entropy into that buffer, and push it back to
the guest.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
---
aliguori: converted to new RngBackend interface
aliguori: remove entropy needed event
aliguori: fix migration
