virtio 1.0 defines config space as LE,
as opposed to pre-1.0 which was native endian.

Add API for transports to execute word/dword accesses in
little endian format - will be useful for mmio
and pci (byte access is also wrapped, for completeness).

For simplicity, we still keep config in host native
endian format, byteswap to LE on guest access.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>

Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>

virtio-1 allow setting of the FEATURES_OK status bit to fail if
the negotiated feature bits are inconsistent: let's fail
virtio_set_status() in that case and update virtio-ccw to post an
error to the guest.
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>

For virtio-1 devices, the driver must not attempt to set feature bits
after it set FEATURES_OK in the device status. Simply reject it in
that case.
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>

For virtio-1 devices, we allow a more complex queue layout that doesn't
require descriptor table and rings on a physically-contigous memory area:
add virtio_queue_set_rings() to allow transports to set this up.
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>

Add code that checks for the VERSION_1 feature bit in order to make
decisions about the device's endianness. This allows us to support
transitional devices.
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>

Commit "019a3edb virtio: make features 64bit wide" missed a few changes,
as I've noticed while trying to rebase the virtio-1 branch to latest
master.  This patch adds them.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Make features 64bit wide everywhere.

On migration a full 64bit guest_features field is sent if one of the
high bits is set, in addition to the lower 32bit guest_features field
which must stay for compatibility reasons.  That way we send the lower
32 feature bits twice, but the code is simpler because we don't have
to split and compose the 64bit features into two 32bit fields.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

VIRTIO_PCI_QUEUE_MAX is not only used for pci, so rename it be generic.

Cc: Amit Shah <amit.shah@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJason Wang <jasowang@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

This patch introduces virtio_get_num_queues() which iterates the vqs
array and return the number of virtqueues used by device.
Signed-off-by: NJason Wang <jasowang@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

This patch passes error pointer to transport specific device_plugged()
callback. Through this way, device_plugged() can do some transport
specific check and fail. This will be uesd by following patches that
check the number of virtqueues against the transport limitation.

Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Alexander Graf <agraf@suse.de>
Signed-off-by: NJason Wang <jasowang@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Move host_features from the individual transport proxies into
the virtio device. Transports may continue to add feature bits
during device plugging.

This should it make easier to offer different sets of host features
for virtio-1/transitional support.
Tested-by: NShannon Zhao <shannon.zhao@linaro.org>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Currently we will try to traverse all virtqueues to find a subset that
using a specific vector. This is sub optimal when we will support
hundreds or even thousands of virtqueues. So this patch introduces a
method which could be used by transport to get all virtqueues that
using a same vector. This is done through QLISTs and the number of
QLISTs was queried through a transport specific method. When guest
setting vectors, the virtqueue will be linked and helpers for traverse
the list was also introduced.

The first user will be virtio pci which will use this to speed up
MSI-X masking and unmasking handling.

Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: NJason Wang <jasowang@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

We don't validate the existence of handle_output which may let a buggy
guest to trigger a SIGSEV easily. E.g:

1) write 10 to queue_sel to a virtio net device with only 1 queue
2) setup an arbitrary pfn
3) then notify queue 10

Fixing this by validating the existence of handle_output before.

Cc: qemu-stable@nongnu.org
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: NJason Wang <jasowang@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NDon Koch <dkoch@verizon.com>
Reviewed-by: NFam Zheng <famz@redhat.com>

Add a helper function for checking whether a bit is set in the guest
features for a vdev as well as one that works on a feature bit set.

Convert code that open-coded this: It cleans up the code and makes it
easier to extend the guest feature bits.
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Drop a bunch of code duplicated from virtio_config.h and virtio_ring.h.
This makes us rename event index accessors which conflict,
as reusing the ones from virtio_ring.h isn't trivial.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NThomas Huth <thuth@linux.vnet.ibm.com>

One of the annoyances of the current migration format is the fact that
it's not self-describing. In fact, it's not properly describing at all.
Some code randomly scattered throughout QEMU elaborates roughly how to
read and write a stream of bytes.

We discussed an idea during KVM Forum 2013 to add a JSON description of
the migration protocol itself to the migration stream. This patch
adds a section after the VM_END migration end marker that contains
description data on what the device sections of the stream are composed of.

This approach is backwards compatible with any QEMU version reading the
stream, because QEMU just stops reading after the VM_END marker and ignores
any data following it.

With an additional external program this allows us to decipher the
contents of any migration stream and hopefully make migration bugs easier
to track down.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

The event idx in virtio is an effective way to reduce the number of
interrupts and exits of the guest. When the guest puts an request
into the virtio ring, it doesn't exit immediately to inform the
backend. Instead, the guest checks the "avail" event idx to determine
the notification.

In virtqueue_pop, when a request is poped, the current avail event
idx should be set to the number of vq->last_avail_idx.
Signed-off-by: NBin Wu <wu.wubin@huawei.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>

For better code sharing, add a helper function that handles
reference counting of the virtio backend for virtio proxy devices.

Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: NGonglei <arei.gonglei@huawei.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This reverts commit a1bc7b827e422e1ff065640d8ec5347c4aadfcd8.
    virtio: don't call device on !vm_running
It turns out that virtio net assumes that vm_running
is updated before device status callback in many places,
so this change leads to asserts.
Previous commit fixes the root issue that motivated
a1bc7b827e422e1ff065640d8ec5347c4aadfcd8 differently,
so there's no longer a need for this change.

In the future, we might be able to drop checking vm_running
completely, and check vm state directly.
Reported-by: NDietmar Maurer <dietmar@proxmox.com>
Cc: qemu-stable@nongnu.org
Acked-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

On vm stop, virtio changes vm_running state
too soon, so callbacks can get envoked with
vm_running = false;

Cc: qemu-stable@nongnu.org
Cc: Jason Wang <jasowang@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Quoting original text from Rusty: "This is based on a simpler patch by Anthony
Liguouri".
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
[ add VirtIODevice * argument to most helpers,
  Greg Kurz <gkurz@linux.vnet.ibm.com> ]
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Reviewed-by: NThomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: NAlexander Graf <agraf@suse.de>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Some CPU families can dynamically change their endianness. This means we
can have little endian ppc or big endian arm guests for example. This has
an impact on legacy virtio data structures since they are target endian.
We hence introduce a new property to track the endianness of each virtio
device. It is reasonnably assumed that endianness won't change while the
device is in use : we hence capture the device endianness when it gets
reset.

We migrate this property in a subsection, after the device descriptor. This
means the load code must not rely on it until it is restored. As a consequence,
the vring sanity checks had to be moved after the call to vmstate_load_state().
We enforce paranoia by poisoning the property at the begining of virtio_load().
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

There is a need to add some more fields to VirtIODevice that should be
migrated (broken status, endianness). The problem is that we do not
want to break compatibility while adding a new feature... This issue has
been addressed in the generic VMState code with the use of optional
subsections. As a *temporary* alternative to port the whole virtio
migration code to VMState, this patch mimics a similar subsectionning
ability for virtio, using the VMState code.

Since each virtio device is streamed in its own section, the idea is to
stream subsections between the end of the device section and the start
of the next sections. This allows an older QEMU to complain and exit
when fed with subsections:

Unknown savevm section type 5
load of migration failed
Suggested-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Reviewed-by: NAlexander Graf <agraf@suse.de>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

In order to migrate virtio subsections, they should be streamed after
the device itself. We need the device specific code to be called from
the common migration code to achieve this. This patch introduces load
and save methods for this purpose.
Suggested-by: NAndreas Färber <afaerber@suse.de>
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Reviewed-by: NAlexander Graf <agraf@suse.de>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Commit 'virtio: validate config_len on load' restricted config_len
loaded from the wire to match the config_len that the device had.

Unfortunately, there are cases where this isn't true, the one
we found it on was the wce addition in virtio-blk.

Allow mismatched config-lengths:
   *) If the version on the wire is shorter then fine
   *) If the version on the wire is longer, load what we have space
      for and skip the rest.

(This is mst@redhat.com's rework of what I originally posted)
Signed-off-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Suggested-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

It's a loop from i < num_sg  and the array is VIRTQUEUE_MAX_SIZE - so
it's OK if the value read is VIRTQUEUE_MAX_SIZE.

Not a big problem in practice as people don't use
such big queues, but it's inelegant.
Reported-by: N"Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Malformed input can have config_len in migration stream
exceed the array size allocated on destination, the
result will be heap overflow.

To fix, that config_len matches on both sides.

CVE-2014-0182
Reported-by: N"Dr. David Alan Gilbert" <dgilbert@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

--

v2: use %ix and %zx to print config_len values
Signed-off-by: NJuan Quintela <quintela@redhat.com>

CVE-2013-4535
CVE-2013-4536

Both virtio-block and virtio-serial read,
VirtQueueElements are read in as buffers, and passed to
virtqueue_map_sg(), where num_sg is taken from the wire and can force
writes to indicies beyond VIRTQUEUE_MAX_SIZE.

To fix, validate num_sg.
Reported-by: NMichael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Cc: Amit Shah <amit.shah@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

CVE-2013-6399

vdev->queue_sel is read from the wire, and later used in the
emulation code as an index into vdev->vq[]. If the value of
vdev->queue_sel exceeds the length of vdev->vq[], currently
allocated to be VIRTIO_PCI_QUEUE_MAX elements, subsequent PIO
operations such as VIRTIO_PCI_QUEUE_PFN can be used to overrun
the buffer with arbitrary data originating from the source.

Fix this by failing migration if the value from the wire exceeds
VIRTIO_PCI_QUEUE_MAX.
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

CVE-2013-4151 QEMU 1.0 out-of-bounds buffer write in
virtio_load@hw/virtio/virtio.c

So we have this code since way back when:

    num = qemu_get_be32(f);

    for (i = 0; i < num; i++) {
        vdev->vq[i].vring.num = qemu_get_be32(f);

array of vqs has size VIRTIO_PCI_QUEUE_MAX, so
on invalid input this will write beyond end of buffer.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NMichael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NEdgar E. Iglesias <edgar.iglesias@xilinx.com>

Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NEdgar E. Iglesias <edgar.iglesias@xilinx.com>

Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NEdgar E. Iglesias <edgar.iglesias@xilinx.com>

Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NEdgar E. Iglesias <edgar.iglesias@xilinx.com>

Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NEdgar E. Iglesias <edgar.iglesias@xilinx.com>

This got lost in a rebase.
Reported-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>