Re: [PATCH v4 1/3] drm/dp_mst: Add self-tests for up requests

[Lyude Paul <lyude@redhat.com>]

On Wed, 2021-05-19 at 13:51 +1000, Sam McNally wrote:
> On Wed, 19 May 2021 at 08:01, Lyude Paul <lyude@redhat.com> wrote:
> > 
> > Looks like these tests might still need to be fixed up a bit:
> > 
> > [   34.785042]  (null): [drm:drm_dp_sideband_parse_req [drm_kms_helper]]
> > connection status reply parse length fail 2 1
> > [   34.785082]  (null): [drm:drm_dp_sideband_parse_req [drm_kms_helper]]
> > resource status reply parse length fail 2 1
> > [   34.785114]  (null): [drm:drm_dp_sideband_parse_req [drm_kms_helper]]
> > sink event notify parse length fail 2 1
> > [   34.785146]  (null): [drm] *ERROR* Got unknown request 0x23
> > (REMOTE_I2C_WRITE)
> > 
> 
> Those are expected parse failures - testing that parse rejects
> messages that are too short or are unsupported. I'll set the mock
> device name to make this clearer in the next version, producing
> logging like:
> [   25.163682]  [drm_dp_mst_helper] expected parse failure:
> [drm:drm_dp_sideband_parse_req] connection status reply parse length
> fail 2 1
> [   25.163706]  [drm_dp_mst_helper] expected parse failure:
> [drm:drm_dp_sideband_parse_req] resource status reply parse length
> fail 2 1
> [   25.163719]  [drm_dp_mst_helper] expected parse failure:
> [drm:drm_dp_sideband_parse_req] sink event notify parse length fail 2
> 1
> [   25.163730]  [drm_dp_mst_helper] expected parse failure: [drm]
> *ERROR* Got unknown request 0x23 (REMOTE_I2C_WRITE)
> 

sgtm

> > 
> > On Tue, 2021-05-18 at 22:35 +1000, Sam McNally wrote:
> > Up requests are decoded by drm_dp_sideband_parse_req(), which operates
> > on a drm_dp_sideband_msg_rx, unlike down requests. Expand the existing
> > self-test helper sideband_msg_req_encode_decode() to copy the message
> > contents and length from a drm_dp_sideband_msg_tx to
> > drm_dp_sideband_msg_rx and use the parse function under test in place of
> > decode.
> > 
> > Add support for currently-supported up requests to
> > drm_dp_dump_sideband_msg_req_body(); add support to
> > drm_dp_encode_sideband_req() to allow encoding for the self-tests.
> > 
> > Add self-tests for CONNECTION_STATUS_NOTIFY and RESOURCE_STATUS_NOTIFY.
> > 
> > Signed-off-by: Sam McNally <sammc@chromium.org>
> > ---
> > 
> > Changes in v4:
> > - New in v4
> > 
> >  drivers/gpu/drm/drm_dp_mst_topology.c         |  54 ++++++-
> >  .../gpu/drm/drm_dp_mst_topology_internal.h    |   4 +
> >  .../drm/selftests/test-drm_dp_mst_helper.c    | 147 ++++++++++++++++--
> >  3 files changed, 190 insertions(+), 15 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c
> > b/drivers/gpu/drm/drm_dp_mst_topology.c
> > index 54604633e65c..573f39a3dc16 100644
> > --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> > +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> > @@ -442,6 +442,37 @@ drm_dp_encode_sideband_req(const struct
> > drm_dp_sideband_msg_req_body *req,
> >                 idx++;
> >                 }
> >                 break;
> > +       case DP_CONNECTION_STATUS_NOTIFY: {
> > +               const struct drm_dp_connection_status_notify *msg;
> > +
> > +               msg = &req->u.conn_stat;
> > +               buf[idx] = (msg->port_number & 0xf) << 4;
> > +               idx++;
> > +               memcpy(&raw->msg[idx], msg->guid, 16);
> > +               idx += 16;
> > +               raw->msg[idx] = 0;
> > +               raw->msg[idx] |= msg->legacy_device_plug_status ? BIT(6) :
> > 0;
> > +               raw->msg[idx] |= msg->displayport_device_plug_status ?
> > BIT(5) :
> > 0;
> > +               raw->msg[idx] |= msg->message_capability_status ? BIT(4) :
> > 0;
> > +               raw->msg[idx] |= msg->input_port ? BIT(3) : 0;
> > +               raw->msg[idx] |= FIELD_PREP(GENMASK(2, 0), msg-
> > > peer_device_type);
> > +               idx++;
> > +               break;
> > +       }
> > +       case DP_RESOURCE_STATUS_NOTIFY: {
> > +               const struct drm_dp_resource_status_notify *msg;
> > +
> > +               msg = &req->u.resource_stat;
> > +               buf[idx] = (msg->port_number & 0xf) << 4;
> > +               idx++;
> > +               memcpy(&raw->msg[idx], msg->guid, 16);
> > +               idx += 16;
> > +               buf[idx] = (msg->available_pbn & 0xff00) >> 8;
> > +               idx++;
> > +               buf[idx] = (msg->available_pbn & 0xff);
> > +               idx++;
> > +               break;
> > +       }
> >         }
> >         raw->cur_len = idx;
> >  }
> > @@ -672,6 +703,22 @@ drm_dp_dump_sideband_msg_req_body(const struct
> > drm_dp_sideband_msg_req_body *req
> >                   req->u.enc_status.stream_behavior,
> >                   req->u.enc_status.valid_stream_behavior);
> >                 break;
> > +       case DP_CONNECTION_STATUS_NOTIFY:
> > +               P("port=%d guid=%*ph legacy=%d displayport=%d messaging=%d
> > input=%d peer_type=%d",
> > +                 req->u.conn_stat.port_number,
> > +                 (int)ARRAY_SIZE(req->u.conn_stat.guid), req-
> > >u.conn_stat.guid,
> > +                 req->u.conn_stat.legacy_device_plug_status,
> > +                 req->u.conn_stat.displayport_device_plug_status,
> > +                 req->u.conn_stat.message_capability_status,
> > +                 req->u.conn_stat.input_port,
> > +                 req->u.conn_stat.peer_device_type);
> > +               break;
> > +       case DP_RESOURCE_STATUS_NOTIFY:
> > +               P("port=%d guid=%*ph pbn=%d",
> > +                 req->u.resource_stat.port_number,
> > +                 (int)ARRAY_SIZE(req->u.resource_stat.guid), req-
> > > u.resource_stat.guid,
> > +                 req->u.resource_stat.available_pbn);
> > +               break;
> >         default:
> >                 P("???\n");
> >                 break;
> > @@ -1116,9 +1163,9 @@ static bool
> > drm_dp_sideband_parse_resource_status_notify(const struct drm_dp_mst
> >         return false;
> >  }
> > 
> > -static bool drm_dp_sideband_parse_req(const struct drm_dp_mst_topology_mgr
> > *mgr,
> > -                                     struct drm_dp_sideband_msg_rx *raw,
> > -                                     struct drm_dp_sideband_msg_req_body
> > *msg)
> > +bool drm_dp_sideband_parse_req(const struct drm_dp_mst_topology_mgr *mgr,
> > +                              struct drm_dp_sideband_msg_rx *raw,
> > +                              struct drm_dp_sideband_msg_req_body *msg)
> >  {
> >         memset(msg, 0, sizeof(*msg));
> >         msg->req_type = (raw->msg[0] & 0x7f);
> > @@ -1134,6 +1181,7 @@ static bool drm_dp_sideband_parse_req(const struct
> > drm_dp_mst_topology_mgr *mgr,
> >                 return false;
> >         }
> >  }
> > +EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_sideband_parse_req);
> > 
> >  static void build_dpcd_write(struct drm_dp_sideband_msg_tx *msg,
> >                              u8 port_num, u32 offset, u8 num_bytes, u8
> > *bytes)
> > diff --git a/drivers/gpu/drm/drm_dp_mst_topology_internal.h
> > b/drivers/gpu/drm/drm_dp_mst_topology_internal.h
> > index eeda9a61c657..0356a2e0dba1 100644
> > --- a/drivers/gpu/drm/drm_dp_mst_topology_internal.h
> > +++ b/drivers/gpu/drm/drm_dp_mst_topology_internal.h
> > @@ -21,4 +21,8 @@ void
> >  drm_dp_dump_sideband_msg_req_body(const struct drm_dp_sideband_msg_req_body
> > *req,
> >                                   int indent, struct drm_printer *printer);
> > 
> > +bool
> > +drm_dp_sideband_parse_req(const struct drm_dp_mst_topology_mgr *mgr,
> > +                         struct drm_dp_sideband_msg_rx *raw,
> > +                         struct drm_dp_sideband_msg_req_body *msg);
> >  #endif /* !_DRM_DP_MST_HELPER_INTERNAL_H_ */
> > diff --git a/drivers/gpu/drm/selftests/test-drm_dp_mst_helper.c
> > b/drivers/gpu/drm/selftests/test-drm_dp_mst_helper.c
> > index 6b4759ed6bfd..22aaedc63aec 100644
> > --- a/drivers/gpu/drm/selftests/test-drm_dp_mst_helper.c
> > +++ b/drivers/gpu/drm/selftests/test-drm_dp_mst_helper.c
> > @@ -13,6 +13,10 @@
> >  #include "../drm_dp_mst_topology_internal.h"
> >  #include "test-drm_modeset_common.h"
> > 
> > +static void mock_release(struct device *dev)
> > +{
> > +}
> > +
> >  int igt_dp_mst_calc_pbn_mode(void *ignored)
> >  {
> >         int pbn, i;
> > @@ -120,27 +124,59 @@ sideband_msg_req_equal(const struct
> > drm_dp_sideband_msg_req_body *in,
> >  static bool
> >  sideband_msg_req_encode_decode(struct drm_dp_sideband_msg_req_body *in)
> >  {
> > -       struct drm_dp_sideband_msg_req_body *out;
> > +       struct drm_dp_sideband_msg_req_body *out = NULL;
> >         struct drm_printer p = drm_err_printer(PREFIX_STR);
> > -       struct drm_dp_sideband_msg_tx *txmsg;
> > +       struct drm_dp_sideband_msg_tx *txmsg = NULL;
> > +       struct drm_dp_sideband_msg_rx *rxmsg = NULL;
> > +       struct drm_dp_mst_topology_mgr *mgr = NULL;
> >         int i, ret;
> > -       bool result = true;
> > +       bool result = false;
> > 
> >         out = kzalloc(sizeof(*out), GFP_KERNEL);
> >         if (!out)
> > -               return false;
> > +               goto out;
> > 
> >         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
> >         if (!txmsg)
> > -               return false;
> > +               goto out;
> > 
> > -       drm_dp_encode_sideband_req(in, txmsg);
> > -       ret = drm_dp_decode_sideband_req(txmsg, out);
> > -       if (ret < 0) {
> > -               drm_printf(&p, "Failed to decode sideband request: %d\n",
> > -                          ret);
> > -               result = false;
> > +       rxmsg = kzalloc(sizeof(*rxmsg), GFP_KERNEL);
> > +       if (!rxmsg)
> >                 goto out;
> > +
> > +       mgr = kzalloc(sizeof(*mgr), GFP_KERNEL);
> > +       if (!mgr)
> > +               goto out;
> > +
> > +       mgr->dev = kzalloc(sizeof(*mgr->dev), GFP_KERNEL);
> > +       if (!mgr->dev)
> > +               goto out;
> > +
> > +       mgr->dev->dev = kzalloc(sizeof(*mgr->dev->dev), GFP_KERNEL);
> > +       if (!mgr->dev->dev)
> > +               goto out;
> > +
> > +       mgr->dev->dev->release = mock_release;
> > +       device_initialize(mgr->dev->dev);
> > +
> > +       drm_dp_encode_sideband_req(in, txmsg);
> > +       switch (in->req_type) {
> > +       case DP_CONNECTION_STATUS_NOTIFY:
> > +       case DP_RESOURCE_STATUS_NOTIFY:
> > +               memcpy(&rxmsg->msg, txmsg->msg, ARRAY_SIZE(rxmsg->msg));
> > +               rxmsg->curlen = txmsg->cur_len;
> > +               if (!drm_dp_sideband_parse_req(mgr, rxmsg, out)) {
> > +                       drm_printf(&p, "Failed to decode sideband
> > request\n");
> > +                       goto out;
> > +               }
> > +               break;
> > +       default:
> > +               ret = drm_dp_decode_sideband_req(txmsg, out);
> > +               if (ret < 0) {
> > +                       drm_printf(&p, "Failed to decode sideband request:
> > %d\n", ret);
> > +                       goto out;
> > +               }
> > +               break;
> >         }
> > 
> >         if (!sideband_msg_req_equal(in, out)) {
> > @@ -148,9 +184,9 @@ sideband_msg_req_encode_decode(struct
> > drm_dp_sideband_msg_req_body *in)
> >                 drm_dp_dump_sideband_msg_req_body(in, 1, &p);
> >                 drm_printf(&p, "Got:\n");
> >                 drm_dp_dump_sideband_msg_req_body(out, 1, &p);
> > -               result = false;
> >                 goto out;
> >         }
> > +       result = true;
> > 
> >         switch (in->req_type) {
> >         case DP_REMOTE_DPCD_WRITE:
> > @@ -171,6 +207,65 @@ sideband_msg_req_encode_decode(struct
> > drm_dp_sideband_msg_req_body *in)
> >  out:
> >         kfree(out);
> >         kfree(txmsg);
> > +       kfree(rxmsg);
> > +       if (mgr) {
> > +               if (mgr->dev) {
> > +                       put_device(mgr->dev->dev);
> > +                       kfree(mgr->dev);
> > +               }
> > +               kfree(mgr);
> > +       }
> > +       return result;
> > +}
> > +
> > +static bool
> > +sideband_msg_req_parse(int req_type)
> > +{
> > +       struct drm_dp_sideband_msg_req_body *out = NULL;
> > +       struct drm_printer p = drm_err_printer(PREFIX_STR);
> > +       struct drm_dp_sideband_msg_rx *rxmsg = NULL;
> > +       struct drm_dp_mst_topology_mgr *mgr = NULL;
> > +       bool result = false;
> > +
> > +       out = kzalloc(sizeof(*out), GFP_KERNEL);
> > +       if (!out)
> > +               goto out;
> > +
> > +       rxmsg = kzalloc(sizeof(*rxmsg), GFP_KERNEL);
> > +       if (!rxmsg)
> > +               goto out;
> > +
> > +       mgr = kzalloc(sizeof(*mgr), GFP_KERNEL);
> > +       if (!mgr)
> > +               goto out;
> > +
> > +       mgr->dev = kzalloc(sizeof(*mgr->dev), GFP_KERNEL);
> > +       if (!mgr->dev)
> > +               goto out;
> > +
> > +       mgr->dev->dev = kzalloc(sizeof(*mgr->dev->dev), GFP_KERNEL);
> > +       if (!mgr->dev->dev)
> > +               goto out;
> > +
> > +       mgr->dev->dev->release = mock_release;
> > +       device_initialize(mgr->dev->dev);
> > +
> > +       rxmsg->curlen = 1;
> > +       rxmsg->msg[0] = req_type & 0x7f;
> > +       if (drm_dp_sideband_parse_req(mgr, rxmsg, out))
> > +               drm_printf(&p, "Unexpectedly decoded invalid sideband
> > request\n");
> > +       else
> > +               result = true;
> > +out:
> > +       kfree(out);
> > +       kfree(rxmsg);
> > +       if (mgr) {
> > +               if (mgr->dev) {
> > +                       put_device(mgr->dev->dev);
> > +                       kfree(mgr->dev);
> > +               }
> > +               kfree(mgr);
> > +       }
> >         return result;
> >  }
> > 
> > @@ -268,6 +363,34 @@ int igt_dp_mst_sideband_msg_req_decode(void *unused)
> >         in.u.enc_status.valid_stream_behavior = 1;
> >         DO_TEST();
> > 
> > +       in.req_type = DP_CONNECTION_STATUS_NOTIFY;
> > +       in.u.conn_stat.port_number = 0xf;
> > +       get_random_bytes(in.u.conn_stat.guid, sizeof(in.u.conn_stat.guid));
> > +       in.u.conn_stat.legacy_device_plug_status = 1;
> > +       in.u.conn_stat.displayport_device_plug_status = 0;
> > +       in.u.conn_stat.message_capability_status = 0;
> > +       in.u.conn_stat.input_port = 0;
> > +       in.u.conn_stat.peer_device_type = 7;
> > +       DO_TEST();
> > +       in.u.conn_stat.displayport_device_plug_status = 1;
> > +       DO_TEST();
> > +       in.u.conn_stat.message_capability_status = 1;
> > +       DO_TEST();
> > +       in.u.conn_stat.input_port = 1;
> > +       DO_TEST();
> > +
> > +       in.req_type = DP_RESOURCE_STATUS_NOTIFY;
> > +       in.u.resource_stat.port_number = 0xf;
> > +       get_random_bytes(in.u.resource_stat.guid,
> > sizeof(in.u.resource_stat.guid));
> > +       in.u.resource_stat.available_pbn = 0xcdef;
> > +       DO_TEST();
> > +
> > +#undef DO_TEST
> > +#define DO_TEST(req_type) FAIL_ON(!sideband_msg_req_parse(req_type))
> > +       DO_TEST(DP_CONNECTION_STATUS_NOTIFY);
> > +       DO_TEST(DP_RESOURCE_STATUS_NOTIFY);
> > +
> > +       DO_TEST(DP_REMOTE_I2C_WRITE);
> >  #undef DO_TEST
> >         return 0;
> >  }
> > 
> > --
> > Sincerely,
> >    Lyude Paul (she/her)
> >    Software Engineer at Red Hat
> > 
> > Note: I deal with a lot of emails and have a lot of bugs on my plate. If
> > you've
> > asked me a question, are waiting for a review/merge on a patch, etc. and I
> > haven't responded in a while, please feel free to send me another email to
> > check
> > on my status. I don't bite!
> > 
> 

-- 
Sincerely,
   Lyude Paul (she/her)
   Software Engineer at Red Hat
   
Note: I deal with a lot of emails and have a lot of bugs on my plate. If you've
asked me a question, are waiting for a review/merge on a patch, etc. and I
haven't responded in a while, please feel free to send me another email to check
on my status. I don't bite!