From 1d628c330fa6e1fe58b00624d46b4ce0a2502f54 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Mon, 7 Sep 2020 15:47:30 +0200 Subject: xen/events: defer eoi in case of excessive number of events commit e99502f76271d6bc4e374fe368c50c67a1fd3070 upstream. In case rogue guests are sending events at high frequency it might happen that xen_evtchn_do_upcall() won't stop processing events in dom0. As this is done in irq handling a crash might be the result. In order to avoid that, delay further inter-domain events after some time in xen_evtchn_do_upcall() by forcing eoi processing into a worker on the same cpu, thus inhibiting new events coming in. The time after which eoi processing is to be delayed is configurable via a new module parameter "event_loop_timeout" which specifies the maximum event loop time in jiffies (default: 2, the value was chosen after some tests showing that a value of 2 was the lowest with an only slight drop of dom0 network throughput while multiple guests performed an event storm). How long eoi processing will be delayed can be specified via another parameter "event_eoi_delay" (again in jiffies, default 10, again the value was chosen after testing with different delay values). This is part of XSA-332. Cc: stable@vger.kernel.org Reported-by: Julien Grall Signed-off-by: Juergen Gross Reviewed-by: Stefano Stabellini Reviewed-by: Wei Liu Signed-off-by: Greg Kroah-Hartman --- Documentation/admin-guide/kernel-parameters.txt | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'Documentation') diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 988a0d2535b2..5b4753e602de 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -5462,6 +5462,14 @@ as generic guest with no PV drivers. Currently support XEN HVM, KVM, HYPER_V and VMWARE guest. + xen.event_eoi_delay= [XEN] + How long to delay EOI handling in case of event + storms (jiffies). Default is 10. + + xen.event_loop_timeout= [XEN] + After which time (jiffies) the event handling loop + should start to delay EOI handling. Default is 2. + xirc2ps_cs= [NET,PCMCIA] Format: ,,,,,[,[,[,]]] -- cgit v1.2.3 From 3a85688062852cb2dec93dfda83239fd400ac8a2 Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Thu, 20 Aug 2020 12:47:16 +0200 Subject: media: videodev2.h: RGB BT2020 and HSV are always full range [ Upstream commit b305dfe2e93434b12d438434461b709641f62af4 ] The default RGB quantization range for BT.2020 is full range (just as for all the other RGB pixel encodings), not limited range. Update the V4L2_MAP_QUANTIZATION_DEFAULT macro and documentation accordingly. Also mention that HSV is always full range and cannot be limited range. When RGB BT2020 was introduced in V4L2 it was not clear whether it should be limited or full range, but full range is the right (and consistent) choice. Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Sasha Levin --- Documentation/media/uapi/v4l/colorspaces-defs.rst | 9 ++++----- Documentation/media/uapi/v4l/colorspaces-details.rst | 5 ++--- 2 files changed, 6 insertions(+), 8 deletions(-) (limited to 'Documentation') diff --git a/Documentation/media/uapi/v4l/colorspaces-defs.rst b/Documentation/media/uapi/v4l/colorspaces-defs.rst index e122bbe3d799..aabb08130354 100644 --- a/Documentation/media/uapi/v4l/colorspaces-defs.rst +++ b/Documentation/media/uapi/v4l/colorspaces-defs.rst @@ -36,8 +36,7 @@ whole range, 0-255, dividing the angular value by 1.41. The enum :c:type:`v4l2_hsv_encoding` specifies which encoding is used. .. note:: The default R'G'B' quantization is full range for all - colorspaces except for BT.2020 which uses limited range R'G'B' - quantization. + colorspaces. HSV formats are always full range. .. tabularcolumns:: |p{6.7cm}|p{10.8cm}| @@ -169,8 +168,8 @@ whole range, 0-255, dividing the angular value by 1.41. The enum - Details * - ``V4L2_QUANTIZATION_DEFAULT`` - Use the default quantization encoding as defined by the - colorspace. This is always full range for R'G'B' (except for the - BT.2020 colorspace) and HSV. It is usually limited range for Y'CbCr. + colorspace. This is always full range for R'G'B' and HSV. + It is usually limited range for Y'CbCr. * - ``V4L2_QUANTIZATION_FULL_RANGE`` - Use the full range quantization encoding. I.e. the range [0…1] is mapped to [0…255] (with possible clipping to [1…254] to avoid the @@ -180,4 +179,4 @@ whole range, 0-255, dividing the angular value by 1.41. The enum * - ``V4L2_QUANTIZATION_LIM_RANGE`` - Use the limited range quantization encoding. I.e. the range [0…1] is mapped to [16…235]. Cb and Cr are mapped from [-0.5…0.5] to - [16…240]. + [16…240]. Limited Range cannot be used with HSV. diff --git a/Documentation/media/uapi/v4l/colorspaces-details.rst b/Documentation/media/uapi/v4l/colorspaces-details.rst index 8b0ba3668101..fd0cf57691d8 100644 --- a/Documentation/media/uapi/v4l/colorspaces-details.rst +++ b/Documentation/media/uapi/v4l/colorspaces-details.rst @@ -377,9 +377,8 @@ Colorspace BT.2020 (V4L2_COLORSPACE_BT2020) The :ref:`itu2020` standard defines the colorspace used by Ultra-high definition television (UHDTV). The default transfer function is ``V4L2_XFER_FUNC_709``. The default Y'CbCr encoding is -``V4L2_YCBCR_ENC_BT2020``. The default R'G'B' quantization is limited -range (!), and so is the default Y'CbCr quantization. The chromaticities -of the primary colors and the white reference are: +``V4L2_YCBCR_ENC_BT2020``. The default Y'CbCr quantization is limited range. +The chromaticities of the primary colors and the white reference are: -- cgit v1.2.3