virtio-serial-bus: use correct lengths in control_out() message

Original code has one thing to process (cur_len), requests to
convert from iovec to buf another thing (len which is actually max_len),
and processes something else (copied).  Whole thing is very difficult
to understand, even if it does a right thing.  The iov_to_buf()
conversion in this case will always return cur_len, because it is
the length of the iovec it was asked to process, and the size we
asked to convert is the same or larger, and iov_to_buf() will stop
at reaching either iov or buf.

Make the code saner by doing the only sane thing: dropping `copied'
which is always the same as `cur_len' but just introduces questions.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
change iov_* function prototypes to be more appropriate

Reorder arguments to be more natural, readable and
consistent with other iov_* functions, and change
argument names, from:
 iov_from_buf(iov, iov_cnt, buf, iov_off, size)
to
 iov_from_buf(iov, iov_cnt, offset, buf, bytes)

The result becomes natural English:

 copy data to this `iov' vector with `iov_cnt'
 elements starting at byte offset `offset'
 from memory buffer `buf', processing `bytes'
 bytes max.

(Try to read the original prototype this way).

Also change iov_clear() to more general iov_memset()
(it uses memset() internally anyway).

While at it, add comments to the header file
describing what the routines actually does.

The patch only renames argumens in the header, but
keeps old names in the implementation.  The next
patch will touch actual code to match.

Now, it might look wrong to pay so much attention
to so small things.  But we've so many badly designed
interfaces already so the whole thing becomes rather
confusing or error prone.  One example of this is
previous commit and small discussion which emerged
from it, with an outcome that the utility functions
like these aren't well-understdandable, leading to
strange usage cases.  That's why I paid quite some
attention to this set of functions and a few
others in subsequent patches.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
rewrite iov_* functions

This changes implementations of all iov_*
functions, completing the previous step.

All iov_* functions now ensure that this offset
argument is within the iovec (using assertion),
but lets to specify `bytes' value larger than
actual length of the iovec - in this case they
stops at the actual end of iovec.  It is also
suggested to use convinient `-1' value as `bytes'
to mean just this -- "up to the end".

There's one very minor semantic change here: new
requiriment is that `offset' points to inside of
iovec.  This is checked just at the end of functions
(assert()), it does not actually need to be enforced,
but using any of these functions with offset pointing
past the end of iovec is wrong anyway.

Note: the new code in iov.c uses arithmetic with
void pointers.  I thought this is not supported
everywhere and is a GCC extension (indeed, the C
standard does not define void arithmetic).  However,
the original code already use void arith in
iov_from_buf() function:
  (memcpy(..., buf + buf_off,...)
which apparently works well so far (it is this
way in qemu 1.0).  So I left it this way and used
it in other places.

While at it, add a unit-test file test-iov.c,
to check various corner cases with iov_from_buf(),
iov_to_buf() and iov_memset().

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
consolidate qemu_iovec_memset{,_skip}() into single function and use existing iov_memset()

This patch combines two functions into one, and replaces
the implementation with already existing iov_memset() from
iov.c.

The new prototype of qemu_iovec_memset():
  size_t qemu_iovec_memset(qiov, size_t offset, int fillc, size_t bytes)
It is different from former qemu_iovec_memset_skip(), and
I want to make other functions to be consistent with it
too: first how much to skip, second what, and 3rd how many
of it.  It also returns actual number of bytes filled in,
which may be less than the requested `bytes' if qiov is
smaller than offset+bytes, in the same way iov_memset()
does.

While at it, use utility function iov_memset() from
iov.h in posix-aio-compat.c, where qiov was used.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
allow qemu_iovec_from_buffer() to specify offset from which to start copying

Similar to
 qemu_iovec_memset(QEMUIOVector *qiov, size_t offset,
                   int c, size_t bytes);
the new prototype is:
 qemu_iovec_from_buf(QEMUIOVector *qiov, size_t offset,
                     const void *buf, size_t bytes);

The processing starts at offset bytes within qiov.

This way, we may copy a bounce buffer directly to
a middle of qiov.

This is exactly the same function as iov_from_buf() from
iov.c, so use the existing implementation and rename it
to qemu_iovec_from_buf() to be shorter and to match the
utility function.

As with utility implementation, we now assert that the
offset is inside actual iovec.  Nothing changed for
current callers, because `offset' parameter is new.

While at it, stop using "bounce-qiov" in block/qcow2.c
and copy decrypted data directly from cluster_data
instead of recreating a temp qiov for doing that.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
consolidate qemu_iovec_copy() and qemu_iovec_concat() and make them consistent

qemu_iovec_concat() is currently a wrapper for
qemu_iovec_copy(), use the former (with extra
"0" arg) in a few places where it is used.

Change skip argument of qemu_iovec_copy() from
uint64_t to size_t, since size of qiov itself
is size_t, so there's no way to skip larger
sizes.  Rename it to soffset, to make it clear
that the offset is applied to src.

Also change the only usage of uint64_t in
hw/9pfs/virtio-9p.c, in v9fs_init_qiov_from_pdu() -
all callers of it actually uses size_t too,
not uint64_t.

One added restriction: as for all other iovec-related
functions, soffset must point inside src.

Order of argumens is already good:
 qemu_iovec_memset(QEMUIOVector *qiov, size_t offset,
                   int c, size_t bytes)
vs:
 qemu_iovec_concat(QEMUIOVector *dst,
                   QEMUIOVector *src,
                   size_t soffset, size_t sbytes)
(note soffset is after _src_ not dst, since it applies to src;
for memset it applies to qiov).

Note that in many places where this function is used,
the previous call is qemu_iovec_reset(), which means
many callers actually want copy (replacing dst content),
not concat.  So we may want to add a wrapper like
qemu_iovec_copy() with the same arguments but which
calls qemu_iovec_reset() before _concat().

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
change qemu_iovec_to_buf() to match other to,from_buf functions

It now allows specifying offset within qiov to start from and
amount of bytes to copy.  Actual implementation is just a call
to iov_to_buf().

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
rename qemu_sendv to iov_send, change proto and move declarations to iov.h

Rename arguments and use size_t for sizes instead of int,
from
 int
 qemu_sendv(int sockfd, struct iovec *iov,
            int len, int iov_offset)
to
 ssize_t
 iov_send(int sockfd, struct iovec *iov,
          size_t offset, size_t bytes)

The main motivation was to make it clear that length
and offset are in _bytes_, not in iov elements: it was
very confusing before, because all standard functions
which deals with iovecs expects number of iovs, not
bytes, even the fact that struct iovec has iov_len and
iov_ prefix does not help.  With "bytes" and "offset",
especially since they're now size_t, it is much more
explicit.  Also change the return type to be ssize_t
instead of int.

This also changes it to match other iov-related functons,
but not _quite_: there's still no argument indicating
where iovec ends, ie, no iov_cnt parameter as used
in iov_size() and friends.  If will be added in subsequent
patch/rewrite.

All callers of qemu_sendv() and qemu_recvv() and
related, like qemu_co_sendv() and qemu_co_recvv(),
were checked to verify that it is safe to use unsigned
datatype instead of int.

Note that the order of arguments is changed to: offset
and bytes (len and iov_offset) are swapped with each
other.  This is to make them consistent with very similar
functions from qemu_iovec family, where offset always
follows qiov, to mean the place in it to start from.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
export iov_send_recv() and use it in iov_send() and iov_recv()

Rename do_sendv_recvv() to iov_send_recv(), change its last arg
(do_send) from int to bool, export it in iov.h, and made the two
callers of it (iov_send() and iov_recv()) to be trivial #defines
just adding 5th arg.

iov_send_recv() will be used later.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
cleanup qemu_co_sendv(), qemu_co_recvv() and friends

The same as for non-coroutine versions in previous
patches: rename arguments to be more obvious, change
type of arguments from int to size_t where appropriate,
and use common code for send and receive paths (with
one extra argument) since these are exactly the same.
Use common iov_send_recv() directly.

qemu_co_sendv(), qemu_co_recvv(), and qemu_co_recv()
are now trivial #define's merely adding one extra arg.

qemu_co_sendv() and qemu_co_recvv() callers are
converted to different argument order and extra
`iov_cnt' argument.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
rewrite iov_send_recv() and move it to iov.c

Make it much more understandable, add a missing
iov_cnt argument (number of iovs in the iov), and
add comments to it.

The new implementation has been extensively tested
by splitting a large buffer into many small
randomly-sized chunks, sending it over socket to
another, slow process and verifying the receiving
data is the same.

Also add a unit test for iov_send_recv(), sending/
receiving data between two processes over a socketpair
using random vectors and random sizes.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
msix: drop unused msix_bar_size, require valid bar_size

No user in sight for msix_bar_size.
bar_size for all users is aligned, let's simply
require this instead of trying to fix up invalid input.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
msix: fix PCIDevice naming inconsistency

msix.h calls the PCIDevice * parameter "dev" almost everywhere except
the msix_write_config declaration. Fix the inconsistency.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
msix: Add simple BAR allocation MSIX setup functions

msi_init() takes over a BAR without really specifying or allowing
specification of how it does so.  Instead, let's split it into
two interfaces, one fully specified, and one trivially easy.  This
implements the latter.  msix_init_exclusive_bar() takes over
allocating and filling a PCI BAR _exclusively_ for the use of MSIX.
When used, the matching msi_uninit_exclusive_bar() should be used
to tear it down.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
ivshmem: Convert to msix_init_exclusive_bar() interface

Trivial conversion, failed to have an uninit before and after.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
virtio: Convert to msix_init_exclusive_bar() interface

Simple conversion.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
msix: Move msix_mmio_read

What's this doing so far from msix_mmio_ops?

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
msix: Note endian TODO item

MSIX, like PCI, is little endian.  Specifying native is wrong here,
but we need to check the rest of the file to determine if it's
as simple as flipping this macro.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
msix: Split PBA into it's own MemoryRegion

These don't have to be contiguous.  Size them to only what
they need and use separate MemoryRegions for the vector
table and PBA.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
msix: Allow full specification of MSIX layout

Finally, complete the fully specified interface.  msix_add_config()
gets folded into msix_init() because we now have quite a few parameters
to pass and rolling it in let's us error earlier, avoiding the ugly
unwind exit path.  msix_mmio_setup() also gets rolled in, just because
it's redundant to rediscover offsets when we already have them for
such a tiny function.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>