virtio 1.0 spec says:

Drivers MUST NOT assume reads from fields greater than 32 bits wide are
atomic, nor are reads from multiple fields: drivers SHOULD read device
configuration space fields like so:
	u32 before, after;
	do {
		before = get_config_generation(device);
		// read config entry/entries.
		after = get_config_generation(device);
	} while (after != before);

Do exactly this, for transports that support it.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Add macro to disable all legacy register defines.
Helpful to make sure legacy macros don't leak
through into modern code.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

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

virtio_cread_bytes is implemented incorrectly in case length happens to
be 2,4 or 8 bytes: transports and devices will assume it's an integer
value that has to be converted to LE format.

Let's just do multiple 1-byte reads: this also makes life easier
for transports who only need to implement 1,2,4 and 8 byte reads.
Signed-off-by: Michael 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: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>

We previously tried to use device even if finalize_features failed, but
that's wrong since driver and device are now out of sync.

Fail probe if we detect failures during finalize_features.
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

We never negotiate revision > 1, but just to
make this code more likely to work when we do,
require VERSION_1 with any revision >= 1.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Cornelia 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: Michael S. Tsirkin <mst@redhat.com>

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

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

should be

struct foo {
}

not

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

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

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

What does it mean if rev 1 device does not set
VIRTIO_F_VERSION_1? E.g. is it native endian?

Let's not even try to drive such devices:
fail attempts to finalize features.
virtio core will detect this and bail out.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

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

Legacy balloon device doesn't pretend to support revision 1 or 64 bit
features.

But just in case someone implements a broken one that does, let's not
even try to drive legacy only devices using revision 1, and let's not
give them a chance to say they support VIRTIO_F_VERSION_1 by not reading
or writing high feature bits.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.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: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>

CHECK drivers/char/virtio_console.c
drivers/char/virtio_console.c:687:36: warning: incorrect type in
	argument 1 (different address spaces)
drivers/char/virtio_console.c:687:36:    expected void [noderef]
	<asn:1>*to
drivers/char/virtio_console.c:687:36:    got char *out_buf
drivers/char/virtio_console.c:790:35: warning: incorrect type in
	argument 2 (different address spaces)
drivers/char/virtio_console.c:790:35:    expected char *out_buf
drivers/char/virtio_console.c:790:35:    got char [noderef]
	<asn:1>*ubuf

fill_readbuf is reused with both kernel and userspace pointers,
depending on value of to_user flag.

Tag address parameter as __user, and cast to/from regular pointer type
when we know it's safe.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Core activates this bit automatically now,
drop it from drivers that set it explicitly.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

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

Pretty straight-forward, just use accessors for all fields.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

This merely fixes sparse warnings, without actually
adding support for the new APIs.

Still working out the best way to enable the new
functionality.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Include all endian conversions as required by virtio 1.0.
Don't set virtio 1.0 yet, since that requires ANY_LAYOUT
which we don't yet support.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>

Replace uXX by __uXX and _packed by __attribute((packed))
as seems to be the norm for userspace headers.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>

Guests need to use virtio scsi API, so export it to uapi,
nice to e.g. qemu and will help us remember this file
affects ABI.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>

Note: for consistency, and to avoid sparse errors,
  convert all fields, even those no longer in use
  for virtio v1.0.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>

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

Pretty straight-forward: convert all fields to/from
virtio endian-ness.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Jason Wang <jasowang@redhat.com>

virtio 1.0 modified virtio net header format,
making all fields little endian.

Users can tweak header format before submitting it to tun,
but this means more data copies where none were necessary.
And if the iovec is in RO memory, this means we might
need to split iovec also means we might in theory overflow
iovec max size.

This patch adds a simpler way for applications to handle this,
using new "little endian" flag in tun.
As a result, tun simply byte-swaps header fields as appropriate.
This is a NOP on LE architectures.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

It's just as easy to use IFF_ flags directly,
there's no point in adding our own defines.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

TUN_ flags are internal and never exposed
to userspace. Any application using it is almost
certainly buggy.

Move them out to tun.c.

Note: we remove these completely in follow-up patches,
this code movement is split out for ease of review.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>