On 200526 0758, Philippe Mathieu-Daudé wrote:
> We don't need to serialize over QTest chardev when we can
> directly access the MMIO address space via the first
> registered CPU view.
>
> virtio-net-socket gets ~50% performance improvement.
One option might be to write alternate (direct) implemtations for
qtest_out*, qtest_write*, qest_read*, qtest_bufread, qtest_bufwrite and
qtest_memset. Maybe these could even go into qtest.c, alleviating some
of the complexity of qtest_process_command(). Then there can be
a preprocessor option to link against libqtest or against the direct
access functions. In the case of qos-based virtio and scsi fuzzers
below, this would also mean that abstract functions such as
qvirtqueue_add would also go through the direct access layer, instead of
mixing direct access and qtest commands.
I don't think this is something we need right now, but it would be
useful for building qtest reproducers.
> Signed-off-by: Philippe Mathieu-Daudé <f4...@amsat.org>
Reviewed-by: Alexander Bulekov <alx...@bu.edu>
> ---
> tests/qtest/fuzz/virtio_net_fuzz.c | 6 ++++--
> tests/qtest/fuzz/virtio_scsi_fuzz.c | 6 +++++-
> 2 files changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/tests/qtest/fuzz/virtio_net_fuzz.c
> b/tests/qtest/fuzz/virtio_net_fuzz.c
> index d08a47e278..ec993c9d5f 100644
> --- a/tests/qtest/fuzz/virtio_net_fuzz.c
> +++ b/tests/qtest/fuzz/virtio_net_fuzz.c
> @@ -19,6 +19,8 @@
> #include "fork_fuzz.h"
> #include "qos_fuzz.h"
>
> +#include "exec/address-spaces.h"
> +#include "hw/core/cpu.h"
>
> #define QVIRTIO_NET_TIMEOUT_US (30 * 1000 * 1000)
> #define QVIRTIO_RX_VQ 0
> @@ -69,8 +71,8 @@ static void virtio_net_fuzz_multi(QTestState *s,
> * If checking used ring, ensure that the fuzzer doesn't trigger
> * trivial asserion failure on zero-zied buffer
> */
> - qtest_memwrite(s, req_addr, Data, vqa.length);
> -
> + address_space_write(first_cpu->as, req_addr,
> MEMTXATTRS_UNSPECIFIED,
> + &Data, vqa.length);
>
> free_head = qvirtqueue_add(s, q, req_addr, vqa.length,
> vqa.write, vqa.next);
> diff --git a/tests/qtest/fuzz/virtio_scsi_fuzz.c
> b/tests/qtest/fuzz/virtio_scsi_fuzz.c
> index 3b95247f12..5096a5a730 100644
> --- a/tests/qtest/fuzz/virtio_scsi_fuzz.c
> +++ b/tests/qtest/fuzz/virtio_scsi_fuzz.c
> @@ -23,6 +23,9 @@
> #include "fork_fuzz.h"
> #include "qos_fuzz.h"
>
> +#include "exec/address-spaces.h"
> +#include "hw/core/cpu.h"
> +
> #define PCI_SLOT 0x02
> #define PCI_FN 0x00
> #define QVIRTIO_SCSI_TIMEOUT_US (1 * 1000 * 1000)
> @@ -108,7 +111,8 @@ static void virtio_scsi_fuzz(QTestState *s,
> QVirtioSCSIQueues* queues,
>
> /* Copy the data into ram, and place it on the virtqueue */
> uint64_t req_addr = guest_alloc(t_alloc, vqa.length);
> - qtest_memwrite(s, req_addr, Data, vqa.length);
> + address_space_write(first_cpu->as, req_addr, MEMTXATTRS_UNSPECIFIED,
> + &Data, vqa.length);
> if (vq_touched[vqa.queue] == 0) {
> vq_touched[vqa.queue] = 1;
> free_head[vqa.queue] = qvirtqueue_add(s, q, req_addr, vqa.length,
> --
> 2.21.3
>
