Useful for testing device virtio 1 compatibility.
Based on patch by Rusty - couldn't resist putting
that flying car joke in there!
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

The ABI *is* stable, and has been for a while now.
Drop Kconfig warning saying that it's not guaranteed
to work.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

This drivers -> this driver.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Most of our code has
struct foo {
}

Fix one instances where ring is inconsistent.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Most of our code has
struct foo {
}

Fix two instances where balloon is inconsistent.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Virtio 1.0 spec lists device config as optional.
Set get/set callbacks to NULL. Drivers can check that
and fail gracefully.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

We don't know the # of VQs that drivers are going to use so it's hard to
predict how much memory we'll need to map. However, the relevant
capability does give us an upper limit.
If that's below a page, we can reduce the number of required
mappings by mapping it all once ahead of the time.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

QEMU wants it, so why not?  Trust, but verify.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Lightly tested against qemu.

One thing *not* implemented here is separate mappings
for descriptor/avail/used rings. That's nice to have,
will be done later after we have core support.

This also exposes the PCI layout to userspace, and
adds macros for PCI layout offsets:

QEMU wants it, so why not?  Trust, but verify.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Most of initialization is device-independent.
Let's move it to common.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Device VQs were getting freed twice: once in every device's removal
functions, and then again in virtio_pci_legacy_remove().  The ones in
devices are called first, so drop the useless second call.
Signed-off-by: NSasha Levin <sasha.levin@oracle.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Some devices might not implement config space access
(e.g. remoteproc used not to - before 3.9).
virtio/balloon needs config space access so make it
fail gracefully if not there.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

The reason we defer kfree until release function is because it's a
general rule for kobjects: kfree of the reference counter itself is only
legal in the release function.

Previous patch didn't make this clear, document this in code.

Cc: stable@vger.kernel.org
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

A struct device which has just been unregistered can live on past the
point at which a driver decides to drop it's initial reference to the
kobject gained on allocation.

This implies that when releasing a virtio device, we can't free a struct
virtio_device until the underlying struct device has been released,
which might not happen immediately on device_unregister().

Unfortunately, this is exactly what virtio pci does:
it has an empty release callback, and frees memory immediately
after unregistering the device.

This causes an easy to reproduce crash if CONFIG_DEBUG_KOBJECT_RELEASE
it enabled.

To fix, free the memory only once we know the device is gone in the release
callback.

Cc: stable@vger.kernel.org
Signed-off-by: NSasha Levin <sasha.levin@oracle.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

It turns out we need to add device-specific code
in release callback. Move it to virtio_pci_legacy.c.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Our code calls del_vqs multiple times, assuming
it's idempotent.

commit 3ec7a77b
    virtio_pci: free up vq->priv
broke this assumption, by adding kfree there,
so multiple calls cause double free.

Fix it up.

Fixes: 3ec7a77bReported-by: NSasha Levin <sasha.levin@oracle.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

When the virtio_pci driver was moved into virtio_pci_legacy.c the module
licence and other attributes went AWOL.  This patch restores them.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

It turns out this make everything easier.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Legacy drivers use virtio_pci_common.h too, we should not
define VIRTIO_PCI_NO_LEGACY there.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

virtio 1.0 devices require that drivers set VIRTIO_CONFIG_S_FEATURES_OK
after finalizing features.
virtio core missed doing this on restore, fix it up.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>

kbuild does not seem to like it when we name source
files same as the module.
Let's rename virtio_pci -> virtio_pci_common,
and get rid of #include-ing c files.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

There's been a lot of changes since 2007.
List main authors, add Red Hat copyright.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Move everything dealing with legacy devices out to virtio_pci_legacy.c.
Expose common code APIs in virtio_pci.h
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

config vector setup is version specific, do it indirectly.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

VQ setup is mostly version-specific, add another level of indirection to
split the version-independent code out.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

VQ deletion is mostly version-specific, add another level of indirection
to split the version-independent code out.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

slightly reduce the amount of pointer chasing this needs to do.
More importantly, this will easily generalize to virtio 1.0.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

We don't need to go from vq to vq info on
data path, so using direct vq->priv pointer for that
seems like a waste.

Let's build an array of vq infos, then we can use vq->index
for that lookup.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

should be

struct foo {
}

not

struct foo
{
}
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Use isr field instead of direct access to ioaddr.
This way generalizes easily to virtio 1.0.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

legacy_only flag is now unused, drop it from core.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Acked-by: NCornelia Huck <cornelia.huck@de.ibm.com>

we have blacklisted balloon in core, no need
for a driver flag.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Acked-by: NCornelia Huck <cornelia.huck@de.ibm.com>

This will make it easy for transports to validate features and return
failure.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

transports need to be able to detect legacy-only
devices (ATM balloon only) to use legacy path
to drive them.

Add a core API to do just that.
The implementation just blacklists balloon:
not too pretty, but let's not over-engineer.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Acked-by: NCornelia Huck <cornelia.huck@de.ibm.com>

Activate VIRTIO_F_VERSION_1 automatically unless legacy_only
is set.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

We have no plans to support virtio 1.0 in balloon driver.  Add an
explicit flag to mark it legacy only.

This will be used by follow-up patches.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

virtio-blk has some legacy feature bits that modern drivers
must not negotiate, but are needed for old legacy hosts
(that e.g. don't support virtio-scsi).
Allow a separate legacy feature table for such cases.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>

Now that we use u64 for bits, we can simply & them together.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>

set FEATURES_OK as per virtio 1.0 spec
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>

For virtio-1, we can theoretically have a more complex virtqueue
layout with avail and used buffers not on a contiguous memory area
with the descriptor table. For now, it's fine for a transport driver
to stay with the old layout: It needs, however, a way to access
the locations of the avail/used rings so it can register them with
the host.
Reviewed-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>