qemu-timer: Avoid overflows when converting timeout to struct timespec

In qemu_poll_ns(), when we convert an int64_t nanosecond timeout into
a struct timespec, we may accidentally run into overflow problems if
the timeout is very long. This happens because the tv_sec field is a
time_t, which is signed, so we might end up setting it to a negative
value by mistake. This will result in what was intended to be a
near-infinite timeout turning into an instantaneous timeout, and we'll
busy loop. Cap the maximum timeout at INT32_MAX seconds (about 68 years)
to avoid this problem.

This specifically manifested on ARM hosts as an extreme slowdown on
guest shutdown (when the guest reprogrammed the PL031 RTC to not
generate alarms using a very long timeout) but could happen on other
hosts and guests too.

Reported-by: Christoffer Dall <christoffer.dall@linaro.org>
Cc: qemu-stable@nongnu.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 1416939705-1272-1-git-send-email-peter.maydell@linaro.org
hmp: fix regression of HMP device_del auto-completion

The commits:
 - 6a1fa9f5 (monitor: add del completion for peripheral device)
 - 66e56b13 (qdev: add qdev_build_hotpluggable_device_list helper)

cause a QEMU crash when trying to use HMP device_del auto-completion.
It can be easily reproduced by:
    <qemu-bin> -enable-kvm  ~/images/fedora.qcow2 -monitor stdio -device virtio-net-pci,id=vnet

    (qemu) device_del
    /home/mapfelba/git/upstream/qemu/hw/core/qdev.c:941:qdev_build_hotpluggable_device_list: Object 0x7f6ce04e4fe0 is not an instance of type device
    Aborted (core dumped)

The root cause is qdev_build_hotpluggable_device_list going recursively over
all peripherals and their children assuming all are devices. It doesn't work
since PCI devices have at least on child which is a memory region (bus master).

Solved by observing that all devices appear as direct children of
/machine/peripheral container. No need of going recursively
over all the children.

Signed-off-by: Marcel Apfelbaum <marcel.a@redhat.com>
Reported-by: Gal Hammer <ghammer@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Message-id: 1417002601-20799-1-git-send-email-marcel.a@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
virtio-net: fix unmap leak

virtio_net_handle_ctrl() and other functions that process control vq
request call iov_discard_front() which will shorten the iov. This will
lead unmapping in virtqueue_push() leaks mapping.

Fixes this by keeping the original iov untouched and using a temp variable
in those functions.

Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-id: 1417082643-23907-1-git-send-email-jasowang@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Fix for crash after migration in virtio-rng on bi-endian targets

VirtIO devices now remember which endianness they're operating in in order
to support targets which may have guests of either endianness, such as
powerpc.  This endianness state is transferred in a subsection of the
virtio device's information.

With virtio-rng this can lead to an abort after a loadvm hitting the
assert() in virtio_is_big_endian().  This can be reproduced by doing a
migrate and load from file on a bi-endian target with a virtio-rng device.
The actual guest state isn't particularly important to triggering this.

The cause is that virtio_rng_load_device() calls virtio_rng_process() which
accesses the ring and thus needs the endianness.  However,
virtio_rng_process() is called via virtio_load() before it loads the
subsections.  Essentially the ->load callback in VirtioDeviceClass should
only be used for actually reading the device state from the stream, not for
post-load re-initialization.

This patch fixes the bug by moving the virtio_rng_process() after the call
to virtio_load().  Better yet would be to convert virtio to use vmsd and
have the virtio_rng_process() as a post_load callback, but that's a bigger
project for another day.

This is bugfix, and should be considered for the 2.2 branch.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Message-id: 1417067290-20715-1-git-send-email-david@gibson.dropbear.id.au
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>