libqos/virtio.c: Correct 'flags' reading in qvirtqueue_kick

In qvirtqueue_kick(), the 'flags' were previously being incorrectly read from
vq->avail instead of the correct vq->used location. This upd

libqos/virtio.c: Correct 'flags' reading in qvirtqueue_kick

In qvirtqueue_kick(), the 'flags' were previously being incorrectly read from
vq->avail instead of the correct vq->used location. This update ensures 'flags'
are read from the correct location as per the virtio standard.

Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20240320090442.267525-1-zheyuma97@gmail.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

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libqos/virtio.c: fix 'avail_event' offset in qvring_init()

In qvring_init() we're writing vq->used->avail_event at "vq->used + 2 +
array_size". The struct pointed by vq->used is, from virtio_ring.h

libqos/virtio.c: fix 'avail_event' offset in qvring_init()

In qvring_init() we're writing vq->used->avail_event at "vq->used + 2 +
array_size". The struct pointed by vq->used is, from virtio_ring.h
Linux header):

* // A ring of used descriptor heads with free-running index.
* __virtio16 used_flags;
* __virtio16 used_idx;
* struct vring_used_elem used[num];
* __virtio16 avail_event_idx;

So 'flags' is the word right at vq->used. 'idx' is vq->used + 2. We need
to skip 'used_idx' by adding + 2 bytes, and then sum the vector size, to
reach avail_event_idx. An example on how to properly access this field
can be found in qvirtqueue_kick():

avail_event = qvirtio_readw(d, qts, vq->used + 4 +
sizeof(struct vring_used_elem) * vq->size);

This error was detected when enabling the RISC-V 'virt' libqos machine.
The 'idx' test from vhost-user-blk-test.c errors out with a timeout in
qvirtio_wait_used_elem(). The timeout happens because when processing
the first element, 'avail_event' is read in qvirtqueue_kick() as non-zero
because we didn't initialize it properly (and the memory at that point
happened to be non-zero). 'idx' is 0.

All of this makes this condition fail because "idx - avail_event" will
overflow and be non-zero:

/* < 1 because we add elements to avail queue one by one */
if ((flags & VRING_USED_F_NO_NOTIFY) == 0 &&
(!vq->event || (uint16_t)(idx-avail_event) < 1)) {
d->bus->virtqueue_kick(d, vq);
}

As a result the virtqueue is never kicked and we'll timeout waiting for it.

Fixes: 1053587c3f ("libqos: Added EVENT_IDX support")
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20240217192607.32565-3-dbarboza@ventanamicro.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

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libqos/virtio.c: init all elems in qvring_indirect_desc_setup()

The loop isn't setting the values for the last element. Every other
element is being initialized with addr = 0, flags = VRING_DESC_F_N

libqos/virtio.c: init all elems in qvring_indirect_desc_setup()

The loop isn't setting the values for the last element. Every other
element is being initialized with addr = 0, flags = VRING_DESC_F_NEXT
and next = i + 1. The last elem is never touched.

This became a problem when enabling a RISC-V 'virt' libqos machine in
the 'indirect' test of virti-blk-test.c. The 'flags' for the last
element will end up being an odd number (since we didn't touch it).
Being an odd number it will be mistaken by VRING_DESC_F_NEXT, which
happens to be 1.

Deep into hw/virt/virtio.c, in virtqueue_split_pop(), into
virtqueue_split_read_next_desc(), a check for VRING_DESC_F_NEXT will be
made to see if we're supposed to chain. The code will keep up chaining
in the last element because the uninitialized value happens to be odd.
We'll error out right after that because desc->next (which is also
uninitialized) will be >= max. A VIRTQUEUE_READ_DESC_ERROR will be
returned, with an error message like this in the stderr:

qemu-system-riscv64: Desc next is 49391

Since we never returned, we'll end up timing out at qvirtio_wait_used_elem():

ERROR:../tests/qtest/libqos/virtio.c:236:qvirtio_wait_used_elem:
assertion failed: (g_get_monotonic_time() - start_time <= timeout_us)

The root cause is using uninitialized values from guest_alloc() in
qvring_indirect_desc_setup(). There's no guarantee that the memory pages
retrieved will be zeroed, so we can't make assumptions. In fact, commit
5b4f72f5e8 ("tests/qtest: properly initialise the vring used idx") fixed a
similar problem stating "It is probably not wise to assume guest memory
is zeroed anyway". I concur.

Initialize all elems in qvring_indirect_desc_setup().

Fixes: f294b029aa ("libqos: Added indirect descriptor support to virtio implementation")
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20240217192607.32565-2-dbarboza@ventanamicro.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

show more ...

tests/qtest: enable tests for virtio-gpio

We don't have a virtio-gpio implementation in QEMU and only
support a vhost-user backend. The QEMU side of the code is minimal so
it should be enough to ins

tests/qtest: enable tests for virtio-gpio

We don't have a virtio-gpio implementation in QEMU and only
support a vhost-user backend. The QEMU side of the code is minimal so
it should be enough to instantiate the device and pass some vhost-user
messages over the control socket. To do this we hook into the existing
vhost-user-test code and just add the bits required for gpio.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Eric Auger <eric.auger@redhat.com>
Message-Id: <20220408155704.2777166-1-alex.bennee@linaro.org>

Message-Id: <20220802095010.3330793-23-alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

tests/qtest: add assert to catch bad features

No device driver (which is what the qvirtio_ access functions
represent) should be setting UNUSED(30) in the feature space. Although
existing libqos use

tests/qtest: add assert to catch bad features

No device driver (which is what the qvirtio_ access functions
represent) should be setting UNUSED(30) in the feature space. Although
existing libqos users mask it out lets ensure nothing sneaks through.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220802095010.3330793-20-alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

tests/qtest: enable tests for virtio-gpio

We don't have a virtio-gpio implementation in QEMU and only
support a vhost-user backend. The QEMU side of the code is minimal so
it should be enough to ins

tests/qtest: enable tests for virtio-gpio

We don't have a virtio-gpio implementation in QEMU and only
support a vhost-user backend. The QEMU side of the code is minimal so
it should be enough to instantiate the device and pass some vhost-user
messages over the control socket. To do this we hook into the existing
vhost-user-test code and just add the bits required for gpio.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Eric Auger <eric.auger@redhat.com>
Message-Id: <20220408155704.2777166-1-alex.bennee@linaro.org>

Message-Id: <20220802095010.3330793-23-alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

tests/qtest: add assert to catch bad features

No device driver (which is what the qvirtio_ access functions
represent) should be setting UNUSED(30) in the feature space. Although
existing libqos use

tests/qtest: add assert to catch bad features

No device driver (which is what the qvirtio_ access functions
represent) should be setting UNUSED(30) in the feature space. Although
existing libqos users mask it out lets ensure nothing sneaks through.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220802095010.3330793-20-alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

tests/qtest: enable tests for virtio-gpio

We don't have a virtio-gpio implementation in QEMU and only
support a vhost-user backend. The QEMU side of the code is minimal so
it should be enough to ins

tests/qtest: enable tests for virtio-gpio

We don't have a virtio-gpio implementation in QEMU and only
support a vhost-user backend. The QEMU side of the code is minimal so
it should be enough to instantiate the device and pass some vhost-user
messages over the control socket. To do this we hook into the existing
vhost-user-test code and just add the bits required for gpio.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Eric Auger <eric.auger@redhat.com>
Message-Id: <20220408155704.2777166-1-alex.bennee@linaro.org>

Message-Id: <20220802095010.3330793-23-alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

tests/qtest: add assert to catch bad features

No device driver (which is what the qvirtio_ access functions
represent) should be setting UNUSED(30) in the feature space. Although
existing libqos use

tests/qtest: add assert to catch bad features

No device driver (which is what the qvirtio_ access functions
represent) should be setting UNUSED(30) in the feature space. Although
existing libqos users mask it out lets ensure nothing sneaks through.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220802095010.3330793-20-alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

tests/qtest: enable tests for virtio-gpio

We don't have a virtio-gpio implementation in QEMU and only
support a vhost-user backend. The QEMU side of the code is minimal so
it should be enough to ins

tests/qtest: enable tests for virtio-gpio

We don't have a virtio-gpio implementation in QEMU and only
support a vhost-user backend. The QEMU side of the code is minimal so
it should be enough to instantiate the device and pass some vhost-user
messages over the control socket. To do this we hook into the existing
vhost-user-test code and just add the bits required for gpio.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Eric Auger <eric.auger@redhat.com>
Message-Id: <20220408155704.2777166-1-alex.bennee@linaro.org>

Message-Id: <20220802095010.3330793-23-alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

tests/qtest: add assert to catch bad features

No device driver (which is what the qvirtio_ access functions
represent) should be setting UNUSED(30) in the feature space. Although
existing libqos use

tests/qtest: add assert to catch bad features

No device driver (which is what the qvirtio_ access functions
represent) should be setting UNUSED(30) in the feature space. Although
existing libqos users mask it out lets ensure nothing sneaks through.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220802095010.3330793-20-alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

tests/qtest: enable tests for virtio-gpio

We don't have a virtio-gpio implementation in QEMU and only
support a vhost-user backend. The QEMU side of the code is minimal so
it should be enough to ins

tests/qtest: enable tests for virtio-gpio

We don't have a virtio-gpio implementation in QEMU and only
support a vhost-user backend. The QEMU side of the code is minimal so
it should be enough to instantiate the device and pass some vhost-user
messages over the control socket. To do this we hook into the existing
vhost-user-test code and just add the bits required for gpio.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Eric Auger <eric.auger@redhat.com>
Message-Id: <20220408155704.2777166-1-alex.bennee@linaro.org>

Message-Id: <20220802095010.3330793-23-alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

tests/qtest: add assert to catch bad features

No device driver (which is what the qvirtio_ access functions
represent) should be setting UNUSED(30) in the feature space. Although
existing libqos use

tests/qtest: add assert to catch bad features

No device driver (which is what the qvirtio_ access functions
represent) should be setting UNUSED(30) in the feature space. Although
existing libqos users mask it out lets ensure nothing sneaks through.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220802095010.3330793-20-alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

show more ...

tests: move libqtest.h back under qtest/

Since commit a2ce7dbd917 ("meson: convert tests/qtest to meson"),
libqtest.h is under libqos/ directory, while libqtest.c is still in
qtest/. Move back to it

tests: move libqtest.h back under qtest/

Since commit a2ce7dbd917 ("meson: convert tests/qtest to meson"),
libqtest.h is under libqos/ directory, while libqtest.c is still in
qtest/. Move back to its original location to avoid mixing with libqos/.

Suggested-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>

show more ...

tests/qtest: properly initialise the vring used idx

Eric noticed while attempting to enable the vhost-user-blk-test for
Aarch64 that that things didn't work unless he put in a dummy
guest_malloc() a

tests/qtest: properly initialise the vring used idx

Eric noticed while attempting to enable the vhost-user-blk-test for
Aarch64 that that things didn't work unless he put in a dummy
guest_malloc() at the start of the test. Without it
qvirtio_wait_used_elem() would assert when it reads a junk value for
idx resulting in:

qvirtqueue_get_buf: idx:2401 last_idx:0
qvirtqueue_get_buf: 0x7ffcb6d3fe74, (nil)
qvirtio_wait_used_elem: 3000000/0
ERROR:../../tests/qtest/libqos/virtio.c:226:qvirtio_wait_used_elem: assertion failed (got_desc_idx == desc_idx): (50331648 == 0)
Bail out! ERROR:../../tests/qtest/libqos/virtio.c:226:qvirtio_wait_used_elem: assertion failed (got_desc_idx == desc_idx): (50331648 == 0)

What was actually happening is the guest_malloc() effectively pushed
the allocation of the vring into the next page which just happened to
have clear memory. After much tedious tracing of the code I could see
that qvring_init() does attempt initialise a bunch of the vring
structures but skips the vring->used.idx value. It is probably not
wise to assume guest memory is zeroed anyway. Once the ring is
properly initialised the hack is no longer needed to get things
working.

Thanks-to: John Snow <jsnow@redhat.com> for helping debug
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220406173356.1891500-1-alex.bennee@linaro.org>
Tested-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

show more ...

meson: convert tests/qtest to meson

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tests/libqos: Move the libqos files under tests/qtest/

The qos stuff belongs to qtest, so move it into that directory, too.

Message-Id: <20191218103059.11729-8-thuth@redhat.com>
Reviewed-by: Paolo

tests/libqos: Move the libqos files under tests/qtest/

The qos stuff belongs to qtest, so move it into that directory, too.

Message-Id: <20191218103059.11729-8-thuth@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

show more ...