* [PATCH v13 12/27] drm/i915/dp: Add YCBCR444 handling for sink formats
From: Nicolas Frattaroli @ 2026-04-13 10:07 UTC (permalink / raw)
To: Harry Wentland, Leo Li, Rodrigo Siqueira, Alex Deucher,
Christian König, David Airlie, Simona Vetter,
Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
Andrzej Hajda, Neil Armstrong, Robert Foss, Laurent Pinchart,
Jonas Karlman, Jernej Skrabec, Sandy Huang, Heiko Stübner,
Andy Yan, Jani Nikula, Rodrigo Vivi, Joonas Lahtinen,
Tvrtko Ursulin, Dmitry Baryshkov, Sascha Hauer, Rob Herring,
Jonathan Corbet, Shuah Khan
Cc: kernel, amd-gfx, dri-devel, linux-kernel, linux-arm-kernel,
linux-rockchip, intel-gfx, intel-xe, linux-doc,
Nicolas Frattaroli
In-Reply-To: <20260413-color-format-v13-0-ab37d4dfba48@collabora.com>
In anticipation of userspace being able to explicitly select supported
sink formats, add handling of the YCBCR444 sink format. The AUTO path
does not choose this format, but with explicit format selection added to
the driver, it becomes a possibility.
Check for sink support of YCBCR444 to intel_dp_sink_format_valid.
Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
---
drivers/gpu/drm/i915/display/intel_dp.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 35b8fb5740aa..47bd3d59ea93 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -1364,6 +1364,11 @@ intel_dp_sink_format_valid(struct intel_connector *connector,
return MODE_OK;
case INTEL_OUTPUT_FORMAT_RGB:
+ return MODE_OK;
+ case INTEL_OUTPUT_FORMAT_YCBCR444:
+ if (!(info->color_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR444)))
+ return MODE_BAD;
+
return MODE_OK;
default:
MISSING_CASE(sink_format);
--
2.53.0
^ permalink raw reply related
* [PATCH v13 11/27] drm/i915/hdmi: Add YCBCR444 handling for sink formats
From: Nicolas Frattaroli @ 2026-04-13 10:07 UTC (permalink / raw)
To: Harry Wentland, Leo Li, Rodrigo Siqueira, Alex Deucher,
Christian König, David Airlie, Simona Vetter,
Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
Andrzej Hajda, Neil Armstrong, Robert Foss, Laurent Pinchart,
Jonas Karlman, Jernej Skrabec, Sandy Huang, Heiko Stübner,
Andy Yan, Jani Nikula, Rodrigo Vivi, Joonas Lahtinen,
Tvrtko Ursulin, Dmitry Baryshkov, Sascha Hauer, Rob Herring,
Jonathan Corbet, Shuah Khan
Cc: kernel, amd-gfx, dri-devel, linux-kernel, linux-arm-kernel,
linux-rockchip, intel-gfx, intel-xe, linux-doc,
Nicolas Frattaroli
In-Reply-To: <20260413-color-format-v13-0-ab37d4dfba48@collabora.com>
In anticipation of userspace being able to explicitly select supported
sink formats, add handling of the YCBCR444 sink format. The AUTO path
does not choose this format, but with explicit format selection added to
the driver, it becomes a possibility.
Check for YCBCR444 support on the sink in both sink_bpc_possible, and
sink_format_valid.
Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
---
drivers/gpu/drm/i915/display/intel_hdmi.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/gpu/drm/i915/display/intel_hdmi.c b/drivers/gpu/drm/i915/display/intel_hdmi.c
index 874076a29da4..5ab5b5f85cde 100644
--- a/drivers/gpu/drm/i915/display/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/display/intel_hdmi.c
@@ -1966,6 +1966,8 @@ static bool intel_hdmi_sink_bpc_possible(struct drm_connector *_connector,
if (sink_format == INTEL_OUTPUT_FORMAT_YCBCR420)
return hdmi->y420_dc_modes & DRM_EDID_YCBCR420_DC_36;
+ else if (sink_format == INTEL_OUTPUT_FORMAT_YCBCR444)
+ return info->edid_hdmi_ycbcr444_dc_modes & DRM_EDID_HDMI_DC_36;
else
return info->edid_hdmi_rgb444_dc_modes & DRM_EDID_HDMI_DC_36;
case 10:
@@ -1974,6 +1976,8 @@ static bool intel_hdmi_sink_bpc_possible(struct drm_connector *_connector,
if (sink_format == INTEL_OUTPUT_FORMAT_YCBCR420)
return hdmi->y420_dc_modes & DRM_EDID_YCBCR420_DC_30;
+ else if (sink_format == INTEL_OUTPUT_FORMAT_YCBCR444)
+ return info->edid_hdmi_ycbcr444_dc_modes & DRM_EDID_HDMI_DC_30;
else
return info->edid_hdmi_rgb444_dc_modes & DRM_EDID_HDMI_DC_30;
case 8:
@@ -2038,6 +2042,11 @@ intel_hdmi_sink_format_valid(struct intel_connector *connector,
return MODE_OK;
case INTEL_OUTPUT_FORMAT_RGB:
+ return MODE_OK;
+ case INTEL_OUTPUT_FORMAT_YCBCR444:
+ if (!(info->color_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR444)))
+ return MODE_BAD;
+
return MODE_OK;
default:
MISSING_CASE(sink_format);
--
2.53.0
^ permalink raw reply related
* [PATCH v13 10/27] drm/amdgpu: Implement "color format" DRM property
From: Nicolas Frattaroli @ 2026-04-13 10:07 UTC (permalink / raw)
To: Harry Wentland, Leo Li, Rodrigo Siqueira, Alex Deucher,
Christian König, David Airlie, Simona Vetter,
Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
Andrzej Hajda, Neil Armstrong, Robert Foss, Laurent Pinchart,
Jonas Karlman, Jernej Skrabec, Sandy Huang, Heiko Stübner,
Andy Yan, Jani Nikula, Rodrigo Vivi, Joonas Lahtinen,
Tvrtko Ursulin, Dmitry Baryshkov, Sascha Hauer, Rob Herring,
Jonathan Corbet, Shuah Khan
Cc: kernel, amd-gfx, dri-devel, linux-kernel, linux-arm-kernel,
linux-rockchip, intel-gfx, intel-xe, linux-doc,
Nicolas Frattaroli, Werner Sembach, Andri Yngvason, Marius Vlad
In-Reply-To: <20260413-color-format-v13-0-ab37d4dfba48@collabora.com>
The "color format" DRM property allows userspace to explicitly pick a
color format to use. If an unsupported color format is requested,
userspace will be given an error instead of silently having its request
disobeyed.
The default case, which is AUTO, picks YCbCr 4:2:0 if it's a 4:2:0-only
mode, and RGB in all other cases.
Co-developed-by: Werner Sembach <wse@tuxedocomputers.com>
Signed-off-by: Werner Sembach <wse@tuxedocomputers.com>
Co-developed-by: Andri Yngvason <andri@yngvason.is>
Signed-off-by: Andri Yngvason <andri@yngvason.is>
Co-developed-by: Marius Vlad <marius.vlad@collabora.com>
Signed-off-by: Marius Vlad <marius.vlad@collabora.com>
Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
---
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 90 ++++++++++++++++++++---
1 file changed, 79 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index ad9714382d5f..ef9c60c49001 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -6762,11 +6762,14 @@ static void fill_stream_properties_from_drm_display_mode(
const struct dc_stream_state *old_stream,
int requested_bpc)
{
+ bool is_dp_or_hdmi = dc_is_hdmi_signal(stream->signal) || dc_is_dp_signal(stream->signal);
struct dc_crtc_timing *timing_out = &stream->timing;
const struct drm_display_info *info = &connector->display_info;
struct amdgpu_dm_connector *aconnector = NULL;
struct hdmi_vendor_infoframe hv_frame;
struct hdmi_avi_infoframe avi_frame;
+ bool want_420;
+ bool want_422;
ssize_t err;
if (connector->connector_type != DRM_MODE_CONNECTOR_WRITEBACK)
@@ -6779,20 +6782,41 @@ static void fill_stream_properties_from_drm_display_mode(
timing_out->h_border_right = 0;
timing_out->v_border_top = 0;
timing_out->v_border_bottom = 0;
- /* TODO: un-hardcode */
- if (drm_mode_is_420_only(info, mode_in) ||
- (aconnector && aconnector->force_yuv420_output &&
- drm_mode_is_420_also(info, mode_in)))
+
+ want_420 = (aconnector && aconnector->force_yuv420_output) ||
+ (connector_state->color_format == DRM_CONNECTOR_COLOR_FORMAT_YCBCR420);
+ want_422 = (aconnector && aconnector->force_yuv422_output) ||
+ (connector_state->color_format == DRM_CONNECTOR_COLOR_FORMAT_YCBCR422);
+
+ if (drm_mode_is_420_only(info, mode_in) &&
+ (want_420 || connector_state->color_format == DRM_CONNECTOR_COLOR_FORMAT_AUTO)) {
timing_out->pixel_encoding = PIXEL_ENCODING_YCBCR420;
- else if ((connector->display_info.color_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR422))
- && aconnector
- && aconnector->force_yuv422_output)
+ } else if (drm_mode_is_420_also(info, mode_in) && want_420) {
+ timing_out->pixel_encoding = PIXEL_ENCODING_YCBCR420;
+ } else if ((info->color_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR422)) &&
+ want_422 && is_dp_or_hdmi) {
timing_out->pixel_encoding = PIXEL_ENCODING_YCBCR422;
- else if ((connector->display_info.color_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR444))
- && stream->signal == SIGNAL_TYPE_HDMI_TYPE_A)
+ } else if (connector_state->color_format == DRM_CONNECTOR_COLOR_FORMAT_YCBCR444 &&
+ (info->color_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR444)) &&
+ is_dp_or_hdmi) {
timing_out->pixel_encoding = PIXEL_ENCODING_YCBCR444;
- else
+ } else if (connector_state->color_format == DRM_CONNECTOR_COLOR_FORMAT_RGB444 ||
+ connector_state->color_format == DRM_CONNECTOR_COLOR_FORMAT_AUTO) {
timing_out->pixel_encoding = PIXEL_ENCODING_RGB;
+ } else {
+ /*
+ * If a format was explicitly requested but the requested format
+ * can't be satisfied, set it to an invalid value so that an
+ * error bubbles up to userspace. This way, userspace knows it
+ * needs to make a better choice.
+ */
+ if (connector_state->color_format != DRM_CONNECTOR_COLOR_FORMAT_AUTO)
+ timing_out->pixel_encoding = PIXEL_ENCODING_UNDEFINED;
+ else if (drm_mode_is_420_only(info, mode_in))
+ timing_out->pixel_encoding = PIXEL_ENCODING_YCBCR420;
+ else
+ timing_out->pixel_encoding = PIXEL_ENCODING_RGB;
+ }
timing_out->timing_3d_format = TIMING_3D_FORMAT_NONE;
timing_out->display_color_depth = convert_color_depth_from_display_info(
@@ -8142,6 +8166,38 @@ static enum dc_status dm_validate_stream_and_context(struct dc *dc,
return dc_result;
}
+static enum dc_status
+dm_validate_stream_color_format(const struct drm_connector_state *drm_state,
+ const struct dc_stream_state *stream)
+{
+ enum dc_pixel_encoding encoding;
+
+ if (!drm_state->color_format)
+ return DC_OK;
+
+ switch (drm_state->color_format) {
+ case DRM_CONNECTOR_COLOR_FORMAT_AUTO:
+ case DRM_CONNECTOR_COLOR_FORMAT_RGB444:
+ encoding = PIXEL_ENCODING_RGB;
+ break;
+ case DRM_CONNECTOR_COLOR_FORMAT_YCBCR444:
+ encoding = PIXEL_ENCODING_YCBCR444;
+ break;
+ case DRM_CONNECTOR_COLOR_FORMAT_YCBCR422:
+ encoding = PIXEL_ENCODING_YCBCR422;
+ break;
+ case DRM_CONNECTOR_COLOR_FORMAT_YCBCR420:
+ encoding = PIXEL_ENCODING_YCBCR420;
+ break;
+ default:
+ encoding = PIXEL_ENCODING_UNDEFINED;
+ break;
+ }
+
+ return encoding == stream->timing.pixel_encoding ?
+ DC_OK : DC_UNSUPPORTED_VALUE;
+}
+
struct dc_stream_state *
create_validate_stream_for_sink(struct drm_connector *connector,
const struct drm_display_mode *drm_mode,
@@ -8188,6 +8244,9 @@ create_validate_stream_for_sink(struct drm_connector *connector,
if (dc_result == DC_OK)
dc_result = dm_validate_stream_and_context(adev->dm.dc, stream);
+ if (dc_result == DC_OK)
+ dc_result = dm_validate_stream_color_format(drm_state, stream);
+
if (dc_result != DC_OK) {
drm_dbg_kms(connector->dev, "Pruned mode %d x %d (clk %d) %s %s -- %s\n",
drm_mode->hdisplay,
@@ -9017,6 +9076,12 @@ static const u32 supported_colorspaces =
BIT(DRM_MODE_COLORIMETRY_BT2020_RGB) |
BIT(DRM_MODE_COLORIMETRY_BT2020_YCC);
+static const u32 supported_colorformats =
+ BIT(DRM_OUTPUT_COLOR_FORMAT_RGB444) |
+ BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR444) |
+ BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR422) |
+ BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR420);
+
void amdgpu_dm_connector_init_helper(struct amdgpu_display_manager *dm,
struct amdgpu_dm_connector *aconnector,
int connector_type,
@@ -9133,8 +9198,11 @@ void amdgpu_dm_connector_init_helper(struct amdgpu_display_manager *dm,
connector_type == DRM_MODE_CONNECTOR_eDP) {
drm_connector_attach_hdr_output_metadata_property(&aconnector->base);
- if (!aconnector->mst_root)
+ if (!aconnector->mst_root) {
drm_connector_attach_vrr_capable_property(&aconnector->base);
+ drm_connector_attach_color_format_property(&aconnector->base,
+ supported_colorformats);
+ }
if (adev->dm.hdcp_workqueue)
drm_connector_attach_content_protection_property(&aconnector->base, true);
--
2.53.0
^ permalink raw reply related
* [PATCH v13 09/27] drm/display: hdmi-state-helper: Try subsampling in mode_valid
From: Nicolas Frattaroli @ 2026-04-13 10:07 UTC (permalink / raw)
To: Harry Wentland, Leo Li, Rodrigo Siqueira, Alex Deucher,
Christian König, David Airlie, Simona Vetter,
Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
Andrzej Hajda, Neil Armstrong, Robert Foss, Laurent Pinchart,
Jonas Karlman, Jernej Skrabec, Sandy Huang, Heiko Stübner,
Andy Yan, Jani Nikula, Rodrigo Vivi, Joonas Lahtinen,
Tvrtko Ursulin, Dmitry Baryshkov, Sascha Hauer, Rob Herring,
Jonathan Corbet, Shuah Khan
Cc: kernel, amd-gfx, dri-devel, linux-kernel, linux-arm-kernel,
linux-rockchip, intel-gfx, intel-xe, linux-doc,
Nicolas Frattaroli, Dmitry Baryshkov
In-Reply-To: <20260413-color-format-v13-0-ab37d4dfba48@collabora.com>
drm_hdmi_connector_mode_valid assumes modes are only valid if they work
with RGB. The reality is more complex however: YCbCr 4:2:0
chroma-subsampled modes only require half the pixel clock that the same
mode would require in RGB.
This leads to drm_hdmi_connector_mode_valid rejecting perfectly valid
420-only or 420-also modes.
Fix this by checking whether the mode is 420-capable first. If so, then
proceed by checking it with DRM_OUTPUT_COLOR_FORMAT_YCBCR420 so long as
the connector has legalized 420, otherwise error out. If the mode is not
420-capable, check with RGB as was previously always the case.
Fixes: 47368ab437fd ("drm/display: hdmi: add generic mode_valid helper")
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
---
drivers/gpu/drm/display/drm_hdmi_state_helper.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/display/drm_hdmi_state_helper.c b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
index 954f8b2973fc..5cc30da30989 100644
--- a/drivers/gpu/drm/display/drm_hdmi_state_helper.c
+++ b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
@@ -942,8 +942,21 @@ drm_hdmi_connector_mode_valid(struct drm_connector *connector,
const struct drm_display_mode *mode)
{
unsigned long long clock;
+ enum drm_output_color_format fmt;
+
+ if (drm_mode_is_420_only(&connector->display_info, mode)) {
+ if (connector->ycbcr_420_allowed)
+ fmt = DRM_OUTPUT_COLOR_FORMAT_YCBCR420;
+ else
+ return MODE_NO_420;
+ } else if (drm_mode_is_420_also(&connector->display_info, mode) &&
+ connector->ycbcr_420_allowed) {
+ fmt = DRM_OUTPUT_COLOR_FORMAT_YCBCR420;
+ } else {
+ fmt = DRM_OUTPUT_COLOR_FORMAT_RGB444;
+ }
- clock = drm_hdmi_compute_mode_clock(mode, 8, DRM_OUTPUT_COLOR_FORMAT_RGB444);
+ clock = drm_hdmi_compute_mode_clock(mode, 8, fmt);
if (!clock)
return MODE_ERROR;
--
2.53.0
^ permalink raw reply related
* [PATCH v13 08/27] drm/display: hdmi-state-helper: Act on color format DRM property
From: Nicolas Frattaroli @ 2026-04-13 10:07 UTC (permalink / raw)
To: Harry Wentland, Leo Li, Rodrigo Siqueira, Alex Deucher,
Christian König, David Airlie, Simona Vetter,
Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
Andrzej Hajda, Neil Armstrong, Robert Foss, Laurent Pinchart,
Jonas Karlman, Jernej Skrabec, Sandy Huang, Heiko Stübner,
Andy Yan, Jani Nikula, Rodrigo Vivi, Joonas Lahtinen,
Tvrtko Ursulin, Dmitry Baryshkov, Sascha Hauer, Rob Herring,
Jonathan Corbet, Shuah Khan
Cc: kernel, amd-gfx, dri-devel, linux-kernel, linux-arm-kernel,
linux-rockchip, intel-gfx, intel-xe, linux-doc,
Nicolas Frattaroli, Dmitry Baryshkov
In-Reply-To: <20260413-color-format-v13-0-ab37d4dfba48@collabora.com>
With the introduction of the "color format" DRM property, which allows
userspace to request a specific color format, the HDMI state helper
should implement this.
Implement it by translating the requested drm_connector_color_format to
a drm_output_color_format enum value as per the logic HDMI should use
for this: Auto is translated to RGB, and a fallback to YUV420 is only
performed if the original color format was auto.
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
---
drivers/gpu/drm/display/drm_hdmi_state_helper.c | 31 +++++++++++++++++++++++++
1 file changed, 31 insertions(+)
diff --git a/drivers/gpu/drm/display/drm_hdmi_state_helper.c b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
index a0d88701d236..954f8b2973fc 100644
--- a/drivers/gpu/drm/display/drm_hdmi_state_helper.c
+++ b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
@@ -670,8 +670,39 @@ hdmi_compute_config(const struct drm_connector *connector,
unsigned int max_bpc = clamp_t(unsigned int,
conn_state->max_bpc,
8, connector->max_bpc);
+ enum drm_output_color_format fmt;
int ret;
+ if (conn_state->color_format != DRM_CONNECTOR_COLOR_FORMAT_AUTO) {
+ switch (conn_state->color_format) {
+ case DRM_CONNECTOR_COLOR_FORMAT_AUTO:
+ drm_warn(connector->dev, "AUTO format in non-AUTO path.\n");
+ fallthrough;
+ case DRM_CONNECTOR_COLOR_FORMAT_RGB444:
+ fmt = DRM_OUTPUT_COLOR_FORMAT_RGB444;
+ break;
+ case DRM_CONNECTOR_COLOR_FORMAT_YCBCR444:
+ fmt = DRM_OUTPUT_COLOR_FORMAT_YCBCR444;
+ break;
+ case DRM_CONNECTOR_COLOR_FORMAT_YCBCR422:
+ fmt = DRM_OUTPUT_COLOR_FORMAT_YCBCR422;
+ break;
+ case DRM_CONNECTOR_COLOR_FORMAT_YCBCR420:
+ fmt = DRM_OUTPUT_COLOR_FORMAT_YCBCR420;
+ break;
+ default:
+ drm_dbg_kms(connector->dev, "HDMI does not support color format '%d'.\n",
+ conn_state->color_format);
+ return -EINVAL;
+ }
+
+ return hdmi_compute_format_bpc(connector, conn_state, mode, max_bpc, fmt);
+ }
+
+ /*
+ * For %DRM_CONNECTOR_COLOR_FORMAT_AUTO, try RGB first, and fall back
+ * to the less bandwidth-intensive YCBCR420 if RGB fails.
+ */
ret = hdmi_compute_format_bpc(connector, conn_state, mode, max_bpc,
DRM_OUTPUT_COLOR_FORMAT_RGB444);
if (ret) {
--
2.53.0
^ permalink raw reply related
* [PATCH v13 07/27] drm/atomic-helper: Add HDMI bridge output bus formats helper
From: Nicolas Frattaroli @ 2026-04-13 10:07 UTC (permalink / raw)
To: Harry Wentland, Leo Li, Rodrigo Siqueira, Alex Deucher,
Christian König, David Airlie, Simona Vetter,
Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
Andrzej Hajda, Neil Armstrong, Robert Foss, Laurent Pinchart,
Jonas Karlman, Jernej Skrabec, Sandy Huang, Heiko Stübner,
Andy Yan, Jani Nikula, Rodrigo Vivi, Joonas Lahtinen,
Tvrtko Ursulin, Dmitry Baryshkov, Sascha Hauer, Rob Herring,
Jonathan Corbet, Shuah Khan
Cc: kernel, amd-gfx, dri-devel, linux-kernel, linux-arm-kernel,
linux-rockchip, intel-gfx, intel-xe, linux-doc,
Nicolas Frattaroli
In-Reply-To: <20260413-color-format-v13-0-ab37d4dfba48@collabora.com>
The drm_bridge_funcs atomic_get_output_bus_fmts operation should be the
same for likely every HDMI connector bridge, unless such an HDMI
connector bridge has some special hardware restrictions that I cannot
envision yet.
To avoid code duplication and standardize on a set of media bus formats
that the HDMI output color formats translate to, add a common helper
function that implements this operation to the drm bridge helpers.
The function returns a list of output bus formats based on the HDMI
bridge's current output bits-per-component, and its bitmask of supported
color formats.
To guard against future expansion of DRM_OUTPUT_COLOR_FORMAT outgrowing
the hweight8 call, add a BUILD_BUG_ON statement where it's used that
checks for DRM_OUTPUT_COLOR_FORMAT_COUNT. The justification for not
using hweight32 in all cases is that not all ISAs have a popcount
instruction, and will benefit from a smaller/faster software
implementation that doesn't have to operate across all bits.
The justification for not defining an hweight_color depending on the
value of DRM_OUTPUT_COLOR_FORMAT_COUNT is that this count enum value is
only known at compile time, not at preprocessor time.
Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
---
drivers/gpu/drm/drm_atomic_helper.c | 81 +++++++++++++++++++++++++++++++++++++
include/drm/drm_atomic_helper.h | 7 ++++
2 files changed, 88 insertions(+)
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 0de9748a82c6..9e62a24ab4b4 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -28,6 +28,7 @@
#include <linux/export.h>
#include <linux/dma-fence.h>
#include <linux/ktime.h>
+#include <linux/media-bus-format.h>
#include <drm/drm_atomic.h>
#include <drm/drm_atomic_helper.h>
@@ -4095,3 +4096,83 @@ drm_atomic_helper_bridge_propagate_bus_fmt(struct drm_bridge *bridge,
return input_fmts;
}
EXPORT_SYMBOL(drm_atomic_helper_bridge_propagate_bus_fmt);
+
+/**
+ * drm_atomic_helper_bridge_get_hdmi_output_bus_fmts - helper implementing
+ * atomic_get_output_bus_fmts for HDMI
+ * @bridge: pointer to &struct drm_bridge
+ * @bridge_state: pointer to the current bridge state
+ * @crtc_state: pointer to the current CRTC state
+ * @conn_state: pointer to the current connector state
+ * @num_output_fmts: pointer to where the number of entries in the returned array
+ * will be stored. Set to 0 if unsuccessful.
+ *
+ * Common implementation for the &drm_bridge_funcs.atomic_get_output_bus_fmts
+ * operation that's applicable to HDMI connectors.
+ *
+ * Returns: a newly allocated array of u32 values of length \*@num_output_fmts,
+ * representing all the MEDIA_BUS_FMTS\_ for the current connector state's
+ * chosen HDMI output bits per compoennt, or %NULL if it fails to allocate one.
+ */
+u32 *
+drm_atomic_helper_bridge_get_hdmi_output_bus_fmts(struct drm_bridge *bridge,
+ struct drm_bridge_state *bridge_state,
+ struct drm_crtc_state *crtc_state,
+ struct drm_connector_state *conn_state,
+ unsigned int *num_output_fmts)
+{
+ unsigned int num_fmts = 0;
+ u32 *out_fmts;
+
+ /*
+ * bridge->supported_formats is a bit field of BIT(enum drm_output_color_format)
+ * values. The smallest hweight that is smaller than or equal to
+ * %DRM_OUTPUT_COLOR_FORMAT_COUNT will do for counting set bits here.
+ */
+ BUILD_BUG_ON(const_true(DRM_OUTPUT_COLOR_FORMAT_COUNT > 8));
+ out_fmts = kmalloc_array(hweight8(bridge->supported_formats),
+ sizeof(u32), GFP_KERNEL);
+ if (!out_fmts) {
+ *num_output_fmts = 0;
+ return NULL;
+ }
+
+ switch (conn_state->hdmi.output_bpc) {
+ case 12:
+ if (bridge->supported_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_RGB444))
+ out_fmts[num_fmts++] = MEDIA_BUS_FMT_RGB121212_1X36;
+ if (bridge->supported_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR444))
+ out_fmts[num_fmts++] = MEDIA_BUS_FMT_YUV12_1X36;
+ if (bridge->supported_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR422))
+ out_fmts[num_fmts++] = MEDIA_BUS_FMT_UYVY12_1X24;
+ if (bridge->supported_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR420))
+ out_fmts[num_fmts++] = MEDIA_BUS_FMT_UYYVYY12_0_5X36;
+ break;
+ case 10:
+ if (bridge->supported_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_RGB444))
+ out_fmts[num_fmts++] = MEDIA_BUS_FMT_RGB101010_1X30;
+ if (bridge->supported_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR444))
+ out_fmts[num_fmts++] = MEDIA_BUS_FMT_YUV10_1X30;
+ if (bridge->supported_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR422))
+ out_fmts[num_fmts++] = MEDIA_BUS_FMT_UYVY10_1X20;
+ if (bridge->supported_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR420))
+ out_fmts[num_fmts++] = MEDIA_BUS_FMT_UYYVYY10_0_5X30;
+ break;
+ default:
+ if (bridge->supported_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_RGB444))
+ out_fmts[num_fmts++] = MEDIA_BUS_FMT_RGB888_1X24;
+ if (bridge->supported_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR444))
+ out_fmts[num_fmts++] = MEDIA_BUS_FMT_YUV8_1X24;
+ if (bridge->supported_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR422))
+ out_fmts[num_fmts++] = MEDIA_BUS_FMT_UYVY8_1X16;
+ if (bridge->supported_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR420))
+ out_fmts[num_fmts++] = MEDIA_BUS_FMT_UYYVYY8_0_5X24;
+ break;
+ }
+
+ *num_output_fmts = num_fmts;
+
+ return out_fmts;
+}
+EXPORT_SYMBOL(drm_atomic_helper_bridge_get_hdmi_output_bus_fmts);
+
diff --git a/include/drm/drm_atomic_helper.h b/include/drm/drm_atomic_helper.h
index e154ee4f0696..7256eaca109b 100644
--- a/include/drm/drm_atomic_helper.h
+++ b/include/drm/drm_atomic_helper.h
@@ -295,4 +295,11 @@ drm_atomic_helper_bridge_propagate_bus_fmt(struct drm_bridge *bridge,
u32 output_fmt,
unsigned int *num_input_fmts);
+u32 *
+drm_atomic_helper_bridge_get_hdmi_output_bus_fmts(struct drm_bridge *bridge,
+ struct drm_bridge_state *bridge_state,
+ struct drm_crtc_state *crtc_state,
+ struct drm_connector_state *conn_state,
+ unsigned int *num_output_fmts);
+
#endif /* DRM_ATOMIC_HELPER_H_ */
--
2.53.0
^ permalink raw reply related
* [PATCH v13 06/27] drm/bridge: Act on the DRM color format property
From: Nicolas Frattaroli @ 2026-04-13 10:07 UTC (permalink / raw)
To: Harry Wentland, Leo Li, Rodrigo Siqueira, Alex Deucher,
Christian König, David Airlie, Simona Vetter,
Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
Andrzej Hajda, Neil Armstrong, Robert Foss, Laurent Pinchart,
Jonas Karlman, Jernej Skrabec, Sandy Huang, Heiko Stübner,
Andy Yan, Jani Nikula, Rodrigo Vivi, Joonas Lahtinen,
Tvrtko Ursulin, Dmitry Baryshkov, Sascha Hauer, Rob Herring,
Jonathan Corbet, Shuah Khan
Cc: kernel, amd-gfx, dri-devel, linux-kernel, linux-arm-kernel,
linux-rockchip, intel-gfx, intel-xe, linux-doc,
Nicolas Frattaroli
In-Reply-To: <20260413-color-format-v13-0-ab37d4dfba48@collabora.com>
The new DRM color format property allows userspace to request a specific
color format on a connector. In turn, this fills the connector state's
color_format member to switch color formats.
Make drm_bridges consider the color_format set in the connector state
during the atomic bridge check. Call into the connector function to get
the connector state's connector color format. For bridge connectors
including an HDMI bridge, this will make use of whatever the HDMI
implementation set as output formats, and AUTO will never be part of the
rejection logic.
Reject any output bus formats that do not correspond to the requested
color format. DRM_CONNECTOR_COLOR_FORMAT_AUTO is always accepted as a
matching color format for a bus format, meaning that non-HDMI bridge
chains will end up picking the first bus format choice that works, as
has already been the case previously.
Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
---
drivers/gpu/drm/drm_bridge.c | 64 +++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 63 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index ba80bebb5685..5acd6bf84ae2 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -1150,6 +1150,47 @@ static int select_bus_fmt_recursive(struct drm_bridge *first_bridge,
return ret;
}
+static bool __pure bus_format_is_color_fmt(u32 bus_fmt, enum drm_connector_color_format fmt)
+{
+ if (fmt == DRM_CONNECTOR_COLOR_FORMAT_AUTO)
+ return true;
+
+ switch (bus_fmt) {
+ case MEDIA_BUS_FMT_FIXED:
+ return true;
+ case MEDIA_BUS_FMT_RGB888_1X24:
+ case MEDIA_BUS_FMT_RGB101010_1X30:
+ case MEDIA_BUS_FMT_RGB121212_1X36:
+ case MEDIA_BUS_FMT_RGB161616_1X48:
+ return fmt == DRM_CONNECTOR_COLOR_FORMAT_RGB444;
+ case MEDIA_BUS_FMT_YUV8_1X24:
+ case MEDIA_BUS_FMT_YUV10_1X30:
+ case MEDIA_BUS_FMT_YUV12_1X36:
+ case MEDIA_BUS_FMT_YUV16_1X48:
+ return fmt == DRM_CONNECTOR_COLOR_FORMAT_YCBCR444;
+ case MEDIA_BUS_FMT_UYVY8_1X16:
+ case MEDIA_BUS_FMT_VYUY8_1X16:
+ case MEDIA_BUS_FMT_YUYV8_1X16:
+ case MEDIA_BUS_FMT_YVYU8_1X16:
+ case MEDIA_BUS_FMT_UYVY10_1X20:
+ case MEDIA_BUS_FMT_YUYV10_1X20:
+ case MEDIA_BUS_FMT_VYUY10_1X20:
+ case MEDIA_BUS_FMT_YVYU10_1X20:
+ case MEDIA_BUS_FMT_UYVY12_1X24:
+ case MEDIA_BUS_FMT_VYUY12_1X24:
+ case MEDIA_BUS_FMT_YUYV12_1X24:
+ case MEDIA_BUS_FMT_YVYU12_1X24:
+ return fmt == DRM_CONNECTOR_COLOR_FORMAT_YCBCR422;
+ case MEDIA_BUS_FMT_UYYVYY8_0_5X24:
+ case MEDIA_BUS_FMT_UYYVYY10_0_5X30:
+ case MEDIA_BUS_FMT_UYYVYY12_0_5X36:
+ case MEDIA_BUS_FMT_UYYVYY16_0_5X48:
+ return fmt == DRM_CONNECTOR_COLOR_FORMAT_YCBCR420;
+ default:
+ return false;
+ }
+}
+
/*
* This function is called by &drm_atomic_bridge_chain_check() just before
* calling &drm_bridge_funcs.atomic_check() on all elements of the chain.
@@ -1193,6 +1234,7 @@ drm_atomic_bridge_chain_select_bus_fmts(struct drm_bridge *bridge,
struct drm_encoder *encoder = bridge->encoder;
struct drm_bridge_state *last_bridge_state;
unsigned int i, num_out_bus_fmts = 0;
+ enum drm_connector_color_format fmt;
u32 *out_bus_fmts;
int ret = 0;
@@ -1234,11 +1276,31 @@ drm_atomic_bridge_chain_select_bus_fmts(struct drm_bridge *bridge,
out_bus_fmts[0] = MEDIA_BUS_FMT_FIXED;
}
+ /*
+ * Instead of directly accessing conn_state.color_format, call into a
+ * connector function that allows connector implementations (e.g. for
+ * bridge connectors including HDMI bridges, where the HDMI helpers will
+ * have already chosen an appropriate output format) to override the
+ * selected format.
+ */
+ fmt = drm_connector_get_color_format(conn_state);
+
for (i = 0; i < num_out_bus_fmts; i++) {
+ if (!bus_format_is_color_fmt(out_bus_fmts[i], fmt)) {
+ drm_dbg_kms(last_bridge->dev,
+ "Skipping bus format 0x%04x as it doesn't match format %d\n",
+ out_bus_fmts[i], fmt);
+ ret = -ENOTSUPP;
+ continue;
+ }
ret = select_bus_fmt_recursive(bridge, last_bridge, crtc_state,
conn_state, out_bus_fmts[i]);
- if (ret != -ENOTSUPP)
+ if (ret != -ENOTSUPP) {
+ drm_dbg_kms(last_bridge->dev,
+ "Found bridge chain ending with bus format 0x%04x\n",
+ out_bus_fmts[i]);
break;
+ }
}
kfree(out_bus_fmts);
--
2.53.0
^ permalink raw reply related
* [PATCH v13 05/27] drm/display: bridge_connector: Use HDMI color format for HDMI conns
From: Nicolas Frattaroli @ 2026-04-13 10:07 UTC (permalink / raw)
To: Harry Wentland, Leo Li, Rodrigo Siqueira, Alex Deucher,
Christian König, David Airlie, Simona Vetter,
Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
Andrzej Hajda, Neil Armstrong, Robert Foss, Laurent Pinchart,
Jonas Karlman, Jernej Skrabec, Sandy Huang, Heiko Stübner,
Andy Yan, Jani Nikula, Rodrigo Vivi, Joonas Lahtinen,
Tvrtko Ursulin, Dmitry Baryshkov, Sascha Hauer, Rob Herring,
Jonathan Corbet, Shuah Khan
Cc: kernel, amd-gfx, dri-devel, linux-kernel, linux-arm-kernel,
linux-rockchip, intel-gfx, intel-xe, linux-doc,
Nicolas Frattaroli
In-Reply-To: <20260413-color-format-v13-0-ab37d4dfba48@collabora.com>
For bridge connectors which contain an HDMI bridge at some stage, the
HDMI state helpers' format selection logic should be involved.
Add an implementation for the drm_bridge_funcs color_format function,
which translates from the HDMI state's output format to a connector
format for bridge connectors involving an HDMI bridge, but return the
connector state's color_format member unchanged otherwise.
Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
---
drivers/gpu/drm/display/drm_bridge_connector.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/drivers/gpu/drm/display/drm_bridge_connector.c b/drivers/gpu/drm/display/drm_bridge_connector.c
index 39cc18f78eda..bcfa4f2ca3e4 100644
--- a/drivers/gpu/drm/display/drm_bridge_connector.c
+++ b/drivers/gpu/drm/display/drm_bridge_connector.c
@@ -276,6 +276,29 @@ static void drm_bridge_connector_reset(struct drm_connector *connector)
connector->state);
}
+static enum drm_connector_color_format
+drm_bridge_connector_color_format(const struct drm_connector_state *conn_state)
+{
+ struct drm_bridge_connector *bridge_connector =
+ to_drm_bridge_connector(conn_state->connector);
+
+ if (bridge_connector->bridge_hdmi) {
+ switch (conn_state->hdmi.output_format) {
+ default:
+ case DRM_OUTPUT_COLOR_FORMAT_RGB444:
+ return DRM_CONNECTOR_COLOR_FORMAT_RGB444;
+ case DRM_OUTPUT_COLOR_FORMAT_YCBCR444:
+ return DRM_CONNECTOR_COLOR_FORMAT_YCBCR444;
+ case DRM_OUTPUT_COLOR_FORMAT_YCBCR422:
+ return DRM_CONNECTOR_COLOR_FORMAT_YCBCR422;
+ case DRM_OUTPUT_COLOR_FORMAT_YCBCR420:
+ return DRM_CONNECTOR_COLOR_FORMAT_YCBCR420;
+ }
+ }
+
+ return conn_state->color_format;
+}
+
static const struct drm_connector_funcs drm_bridge_connector_funcs = {
.reset = drm_bridge_connector_reset,
.detect = drm_bridge_connector_detect,
@@ -285,6 +308,7 @@ static const struct drm_connector_funcs drm_bridge_connector_funcs = {
.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
.debugfs_init = drm_bridge_connector_debugfs_init,
.oob_hotplug_event = drm_bridge_connector_oob_hotplug_event,
+ .color_format = drm_bridge_connector_color_format,
};
/* -----------------------------------------------------------------------------
--
2.53.0
^ permalink raw reply related
* [PATCH v13 04/27] drm/connector: Let connectors have a say in their color format
From: Nicolas Frattaroli @ 2026-04-13 10:07 UTC (permalink / raw)
To: Harry Wentland, Leo Li, Rodrigo Siqueira, Alex Deucher,
Christian König, David Airlie, Simona Vetter,
Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
Andrzej Hajda, Neil Armstrong, Robert Foss, Laurent Pinchart,
Jonas Karlman, Jernej Skrabec, Sandy Huang, Heiko Stübner,
Andy Yan, Jani Nikula, Rodrigo Vivi, Joonas Lahtinen,
Tvrtko Ursulin, Dmitry Baryshkov, Sascha Hauer, Rob Herring,
Jonathan Corbet, Shuah Khan
Cc: kernel, amd-gfx, dri-devel, linux-kernel, linux-arm-kernel,
linux-rockchip, intel-gfx, intel-xe, linux-doc,
Nicolas Frattaroli
In-Reply-To: <20260413-color-format-v13-0-ab37d4dfba48@collabora.com>
Add a function to get the connector color format from a connector state,
and a new function pointer in drm_connector_funcs to allow connectors to
override what connector color format it returns.
This is useful for the bridge chain recursive bus format selection code,
which does not wish to implement connector implementation specific
checks like whether it involves HDMI.
Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
---
drivers/gpu/drm/drm_connector.c | 16 ++++++++++++++++
include/drm/drm_connector.h | 12 ++++++++++++
2 files changed, 28 insertions(+)
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index 1c4f3ff7d84f..d354ab77d3b8 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -3690,6 +3690,22 @@ void drm_connector_oob_hotplug_event(struct fwnode_handle *connector_fwnode,
}
EXPORT_SYMBOL(drm_connector_oob_hotplug_event);
+/**
+ * drm_connector_get_color_format - Return connector color format of @conn_state
+ * @conn_state: pointer to the &struct drm_connector_state to go check
+ *
+ */
+enum drm_connector_color_format
+drm_connector_get_color_format(const struct drm_connector_state *conn_state)
+{
+ struct drm_connector *connector = conn_state->connector;
+
+ if (connector->funcs->color_format)
+ return connector->funcs->color_format(conn_state);
+
+ return conn_state->color_format;
+}
+EXPORT_SYMBOL(drm_connector_get_color_format);
/**
* DOC: Tile group
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index 620f700fbe76..21767fffcba4 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -1811,6 +1811,16 @@ struct drm_connector_funcs {
* Allows connectors to create connector-specific debugfs files.
*/
void (*debugfs_init)(struct drm_connector *connector, struct dentry *root);
+
+ /**
+ * @color_format:
+ *
+ * Allows connectors to return a connector color format other than
+ * @conn_state.color_format for purposes of e.g. display protocol
+ * specific helper logic having already mapped it to an output format.
+ */
+ enum drm_connector_color_format (*color_format)(
+ const struct drm_connector_state *conn_state);
};
/**
@@ -2627,6 +2637,8 @@ drm_connector_is_unregistered(struct drm_connector *connector)
void drm_connector_oob_hotplug_event(struct fwnode_handle *connector_fwnode,
enum drm_connector_status status);
+enum drm_connector_color_format
+drm_connector_get_color_format(const struct drm_connector_state *conn_state);
const char *drm_get_connector_type_name(unsigned int connector_type);
const char *drm_get_connector_status_name(enum drm_connector_status status);
const char *drm_get_subpixel_order_name(enum subpixel_order order);
--
2.53.0
^ permalink raw reply related
* [PATCH v13 03/27] drm: Add new general DRM property "color format"
From: Nicolas Frattaroli @ 2026-04-13 10:07 UTC (permalink / raw)
To: Harry Wentland, Leo Li, Rodrigo Siqueira, Alex Deucher,
Christian König, David Airlie, Simona Vetter,
Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
Andrzej Hajda, Neil Armstrong, Robert Foss, Laurent Pinchart,
Jonas Karlman, Jernej Skrabec, Sandy Huang, Heiko Stübner,
Andy Yan, Jani Nikula, Rodrigo Vivi, Joonas Lahtinen,
Tvrtko Ursulin, Dmitry Baryshkov, Sascha Hauer, Rob Herring,
Jonathan Corbet, Shuah Khan
Cc: kernel, amd-gfx, dri-devel, linux-kernel, linux-arm-kernel,
linux-rockchip, intel-gfx, intel-xe, linux-doc,
Nicolas Frattaroli, Werner Sembach, Andri Yngvason, Marius Vlad
In-Reply-To: <20260413-color-format-v13-0-ab37d4dfba48@collabora.com>
Add a new general DRM property named "color format" which can be used by
userspace to request the display driver to output a particular color
format.
Possible string values for the new enum property are:
- "AUTO" (setup by default, driver internally picks the color format)
- "RGB"
- "YUV 4:4:4"
- "YUV 4:2:2"
- "YUV 4:2:0"
Drivers should advertise from this list the formats they support in an
optimistic best-case scenario. EDID data from the sink can then be used
in the kernel's atomic check phase to restrict this set of formats, as
well as by userspace to make a correct choice in the first place.
Co-developed-by: Werner Sembach <wse@tuxedocomputers.com>
Signed-off-by: Werner Sembach <wse@tuxedocomputers.com>
Co-developed-by: Andri Yngvason <andri@yngvason.is>
Signed-off-by: Andri Yngvason <andri@yngvason.is>
Signed-off-by: Marius Vlad <marius.vlad@collabora.com>
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
---
Documentation/gpu/drm-kms.rst | 6 ++
drivers/gpu/drm/drm_atomic_helper.c | 5 ++
drivers/gpu/drm/drm_atomic_uapi.c | 11 +++
drivers/gpu/drm/drm_connector.c | 155 ++++++++++++++++++++++++++++++++++++
include/drm/drm_connector.h | 108 +++++++++++++++++++++++++
5 files changed, 285 insertions(+)
diff --git a/Documentation/gpu/drm-kms.rst b/Documentation/gpu/drm-kms.rst
index 2292e65f044c..da5133b672d3 100644
--- a/Documentation/gpu/drm-kms.rst
+++ b/Documentation/gpu/drm-kms.rst
@@ -599,6 +599,12 @@ Color Management Properties
.. kernel-doc:: drivers/gpu/drm/drm_color_mgmt.c
:doc: overview
+Color Format Property
+---------------------
+
+.. kernel-doc:: drivers/gpu/drm/drm_connector.c
+ :doc: Color format
+
Tile Group Property
-------------------
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 2e7e8ed8ad7f..0de9748a82c6 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -737,6 +737,11 @@ drm_atomic_helper_check_modeset(struct drm_device *dev,
if (old_connector_state->max_requested_bpc !=
new_connector_state->max_requested_bpc)
new_crtc_state->connectors_changed = true;
+
+ if (old_connector_state->color_format !=
+ new_connector_state->color_format)
+ new_crtc_state->connectors_changed = true;
+
}
if (funcs->atomic_check)
diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c
index 5bd5bf6661df..dee510c85e59 100644
--- a/drivers/gpu/drm/drm_atomic_uapi.c
+++ b/drivers/gpu/drm/drm_atomic_uapi.c
@@ -935,6 +935,15 @@ static int drm_atomic_connector_set_property(struct drm_connector *connector,
state->privacy_screen_sw_state = val;
} else if (property == connector->broadcast_rgb_property) {
state->hdmi.broadcast_rgb = val;
+ } else if (property == connector->color_format_property) {
+ if (val > INT_MAX || !drm_connector_color_format_valid(val)) {
+ drm_dbg_atomic(connector->dev,
+ "[CONNECTOR:%d:%s] unknown color format %llu\n",
+ connector->base.id, connector->name, val);
+ return -EINVAL;
+ }
+
+ state->color_format = val;
} else if (connector->funcs->atomic_set_property) {
return connector->funcs->atomic_set_property(connector,
state, property, val);
@@ -1020,6 +1029,8 @@ drm_atomic_connector_get_property(struct drm_connector *connector,
*val = state->privacy_screen_sw_state;
} else if (property == connector->broadcast_rgb_property) {
*val = state->hdmi.broadcast_rgb;
+ } else if (property == connector->color_format_property) {
+ *val = state->color_format;
} else if (connector->funcs->atomic_get_property) {
return connector->funcs->atomic_get_property(connector,
state, property, val);
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index 47dc53c4a738..1c4f3ff7d84f 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -1388,6 +1388,18 @@ static const u32 hdmi_colorspaces =
BIT(DRM_MODE_COLORIMETRY_DCI_P3_RGB_D65) |
BIT(DRM_MODE_COLORIMETRY_DCI_P3_RGB_THEATER);
+static const u32 hdmi_colorformats =
+ BIT(DRM_OUTPUT_COLOR_FORMAT_RGB444) |
+ BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR444) |
+ BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR422) |
+ BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR420);
+
+static const u32 dp_colorformats =
+ BIT(DRM_OUTPUT_COLOR_FORMAT_RGB444) |
+ BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR444) |
+ BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR422) |
+ BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR420);
+
/*
* As per DP 1.4a spec, 2.2.5.7.5 VSC SDP Payload for Pixel Encoding/Colorimetry
* Format Table 2-120
@@ -2940,6 +2952,149 @@ int drm_connector_attach_colorspace_property(struct drm_connector *connector)
}
EXPORT_SYMBOL(drm_connector_attach_colorspace_property);
+/**
+ * DOC: Color format
+ *
+ * The connector "color format" property allows userspace to request a specific
+ * color model on the output of the connector. Not all values listed by the
+ * property are guaranteed to work for every sink; rather, it is an optimistic
+ * listing of color formats that the source could output depending on
+ * circumstances.
+ *
+ * Whether it actually can output a certain color format is determined during
+ * the atomic check phase. Consequently, a userspace application that sets the
+ * color format to a value other than "AUTO" should check whether its atomic
+ * commit succeeded.
+ *
+ * Possible values for "color format":
+ *
+ * "AUTO":
+ * The driver or display protocol helpers should pick a suitable color
+ * format. All implementations of a specific display protocol will behave
+ * the same way with "AUTO", but different display protocols do not
+ * necessarily have the same "AUTO" semantics.
+ *
+ * For HDMI connectors, "AUTO" picks RGB, but falls back to YUV 4:2:0 if
+ * the bandwidth required for full-scale RGB is not available, or the mode
+ * is YUV 4:2:0-only, as long as the mode, source, and sink all support
+ * YUV 4:2:0.
+ * "RGB":
+ * RGB output format. The quantization range (limited/full) depends on the
+ * value of the "Broadcast RGB" property if it is present on the connector.
+ * "YUV 4:4:4":
+ * YUV 4:4:4 (a.k.a. YCbCr 4:4:4) output format. Chroma is not subsampled.
+ * The quantization range defaults to limited.
+ * "YUV 4:2:2":
+ * YUV 4:2:2 (a.k.a. YCbCr 4:2:2) output format. Chroma has half the
+ * horizontal resolution of Luma. The quantization range defaults to
+ * limited.
+ * "YUV 4:2:0":
+ * YUV 4:2:0 (a.k.a. YCbCr 4:2:0) output format. Chroma has half the
+ * horizontal and vertical resolution of Luma. The quantization range
+ * defaults to limited.
+ *
+ * A sink may only support some color formats in specific modes and at specific
+ * bit depths. The atomic modesetting API should be used to set a working
+ * configuration in one go, as an unsupported combination of parameters is
+ * rejected.
+ */
+
+/**
+ * drm_connector_attach_color_format_property - create and attach color format property
+ * @connector: connector to create the color format property on
+ * @supported_color_formats: bitmask of bit-shifted &enum drm_output_color_format
+ * values the connector supports
+ *
+ * Called by a driver to create a color format property. The property is
+ * attached to the connector automatically on success.
+ *
+ * @supported_color_formats should only include color formats the connector
+ * type can actually support.
+ *
+ * Returns:
+ * 0 on success, negative errno on error
+ */
+int drm_connector_attach_color_format_property(struct drm_connector *connector,
+ unsigned long supported_color_formats)
+{
+ struct drm_device *dev = connector->dev;
+ struct drm_prop_enum_list enum_list[DRM_CONNECTOR_COLOR_FORMAT_COUNT];
+ unsigned int i = 0;
+ unsigned long fmt;
+
+ if (connector->color_format_property)
+ return 0;
+
+ if (!supported_color_formats) {
+ drm_err(dev, "No supported color formats provided on [CONNECTOR:%d:%s]\n",
+ connector->base.id, connector->name);
+ return -EINVAL;
+ }
+
+ if (supported_color_formats & ~GENMASK(DRM_OUTPUT_COLOR_FORMAT_COUNT - 1, 0)) {
+ drm_err(dev, "Unknown color formats provided on [CONNECTOR:%d:%s]\n",
+ connector->base.id, connector->name);
+ return -EINVAL;
+ }
+
+ switch (connector->connector_type) {
+ case DRM_MODE_CONNECTOR_HDMIA:
+ case DRM_MODE_CONNECTOR_HDMIB:
+ if (supported_color_formats & ~hdmi_colorformats) {
+ drm_err(dev, "Color formats not allowed for HDMI on [CONNECTOR:%d:%s]\n",
+ connector->base.id, connector->name);
+ return -EINVAL;
+ }
+ break;
+ case DRM_MODE_CONNECTOR_DisplayPort:
+ case DRM_MODE_CONNECTOR_eDP:
+ if (supported_color_formats & ~dp_colorformats) {
+ drm_err(dev, "Color formats not allowed for DP on [CONNECTOR:%d:%s]\n",
+ connector->base.id, connector->name);
+ return -EINVAL;
+ }
+ break;
+ }
+
+ enum_list[0].name = "AUTO";
+ enum_list[0].type = DRM_CONNECTOR_COLOR_FORMAT_AUTO;
+
+ for_each_set_bit(fmt, &supported_color_formats, DRM_OUTPUT_COLOR_FORMAT_COUNT) {
+ switch (fmt) {
+ case DRM_OUTPUT_COLOR_FORMAT_RGB444:
+ enum_list[++i].type = DRM_CONNECTOR_COLOR_FORMAT_RGB444;
+ break;
+ case DRM_OUTPUT_COLOR_FORMAT_YCBCR444:
+ enum_list[++i].type = DRM_CONNECTOR_COLOR_FORMAT_YCBCR444;
+ break;
+ case DRM_OUTPUT_COLOR_FORMAT_YCBCR422:
+ enum_list[++i].type = DRM_CONNECTOR_COLOR_FORMAT_YCBCR422;
+ break;
+ case DRM_OUTPUT_COLOR_FORMAT_YCBCR420:
+ enum_list[++i].type = DRM_CONNECTOR_COLOR_FORMAT_YCBCR420;
+ break;
+ default:
+ drm_warn(dev, "Unknown supported format %ld on [CONNECTOR:%d:%s]\n",
+ fmt, connector->base.id, connector->name);
+ continue;
+ }
+ enum_list[i].name = drm_hdmi_connector_get_output_format_name(fmt);
+ }
+
+ connector->color_format_property =
+ drm_property_create_enum(dev, DRM_MODE_PROP_ENUM, "color format",
+ enum_list, i + 1);
+
+ if (!connector->color_format_property)
+ return -ENOMEM;
+
+ drm_object_attach_property(&connector->base, connector->color_format_property,
+ DRM_CONNECTOR_COLOR_FORMAT_AUTO);
+
+ return 0;
+}
+EXPORT_SYMBOL(drm_connector_attach_color_format_property);
+
/**
* drm_connector_atomic_hdr_metadata_equal - checks if the hdr metadata changed
* @old_state: old connector state to compare
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index f83f28cae207..620f700fbe76 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -571,14 +571,106 @@ enum drm_colorspace {
* YCbCr 4:2:2 output format (ie. with horizontal subsampling)
* @DRM_OUTPUT_COLOR_FORMAT_YCBCR420:
* YCbCr 4:2:0 output format (ie. with horizontal and vertical subsampling)
+ * @DRM_OUTPUT_COLOR_FORMAT_COUNT:
+ * Number of valid output color format values in this enum
*/
enum drm_output_color_format {
DRM_OUTPUT_COLOR_FORMAT_RGB444 = 0,
DRM_OUTPUT_COLOR_FORMAT_YCBCR444,
DRM_OUTPUT_COLOR_FORMAT_YCBCR422,
DRM_OUTPUT_COLOR_FORMAT_YCBCR420,
+ DRM_OUTPUT_COLOR_FORMAT_COUNT,
};
+/**
+ * enum drm_connector_color_format - Connector Color Format Request
+ *
+ * This enum, unlike &enum drm_output_color_format, is used to specify requests
+ * for a specific color format on a connector through the DRM "color format"
+ * property. The difference is that it has an "AUTO" value to specify that
+ * no specific choice has been made.
+ */
+enum drm_connector_color_format {
+ /**
+ * @DRM_CONNECTOR_COLOR_FORMAT_AUTO: The driver or display protocol
+ * helpers should pick a suitable color format. All implementations of a
+ * specific display protocol must behave the same way with "AUTO", but
+ * different display protocols do not necessarily have the same "AUTO"
+ * semantics.
+ *
+ * For HDMI, "AUTO" picks RGB, but falls back to YCbCr 4:2:0 if the
+ * bandwidth required for full-scale RGB is not available, or the mode
+ * is YCbCr 4:2:0-only, as long as the mode and output both support
+ * YCbCr 4:2:0.
+ *
+ * For display protocols other than HDMI, the recursive bridge chain
+ * format selection picks the first chain of bridge formats that works,
+ * as has already been the case before the introduction of the "color
+ * format" property. Non-HDMI bridges should therefore either sort their
+ * bus output formats by preference, or agree on a unified auto format
+ * selection logic that's implemented in a common state helper (like
+ * how HDMI does it).
+ */
+ DRM_CONNECTOR_COLOR_FORMAT_AUTO = 0,
+
+ /**
+ * @DRM_CONNECTOR_COLOR_FORMAT_RGB444: RGB output format. The
+ * quantization range depends on the value of the "Broadcast RGB"
+ * property if it is present on the connector.
+ */
+ DRM_CONNECTOR_COLOR_FORMAT_RGB444,
+
+ /**
+ * @DRM_CONNECTOR_COLOR_FORMAT_YCBCR444: YCbCr 4:4:4 output format (ie.
+ * not subsampled). Quantization range is "Limited" by default.
+ */
+ DRM_CONNECTOR_COLOR_FORMAT_YCBCR444,
+
+ /**
+ * @DRM_CONNECTOR_COLOR_FORMAT_YCBCR422: YCbCr 4:2:2 output format (ie.
+ * with horizontal subsampling). Quantization range is "Limited" by
+ * default.
+ */
+ DRM_CONNECTOR_COLOR_FORMAT_YCBCR422,
+
+ /**
+ * @DRM_CONNECTOR_COLOR_FORMAT_YCBCR420: YCbCr 4:2:0 output format (ie.
+ * with horizontal and vertical subsampling). Quantization range is
+ * "Limited" by default.
+ */
+ DRM_CONNECTOR_COLOR_FORMAT_YCBCR420,
+
+ /**
+ * @DRM_CONNECTOR_COLOR_FORMAT_COUNT: Number of valid connector color
+ * format values in this enum
+ */
+ DRM_CONNECTOR_COLOR_FORMAT_COUNT,
+};
+
+/**
+ * drm_connector_color_format_valid - Validate drm_connector_color_format value
+ * @fmt: value to check against all values of &enum drm_connector_color_format
+ *
+ * Checks whether the passed in value of @fmt is one of the allowable values in
+ * &enum drm_connector_color_format.
+ *
+ * Returns: %true if it's a valid value for the enum, %false otherwise.
+ */
+static inline bool __pure
+drm_connector_color_format_valid(enum drm_connector_color_format fmt)
+{
+ switch (fmt) {
+ case DRM_CONNECTOR_COLOR_FORMAT_AUTO:
+ case DRM_CONNECTOR_COLOR_FORMAT_RGB444:
+ case DRM_CONNECTOR_COLOR_FORMAT_YCBCR444:
+ case DRM_CONNECTOR_COLOR_FORMAT_YCBCR422:
+ case DRM_CONNECTOR_COLOR_FORMAT_YCBCR420:
+ return true;
+ default:
+ return false;
+ }
+}
+
const char *
drm_hdmi_connector_get_output_format_name(enum drm_output_color_format fmt);
@@ -1167,6 +1259,13 @@ struct drm_connector_state {
*/
enum drm_colorspace colorspace;
+ /**
+ * @color_format: State variable for Connector property to request
+ * color format change on Sink. This is most commonly used to switch
+ * between RGB to YUV and vice-versa.
+ */
+ enum drm_connector_color_format color_format;
+
/**
* @writeback_job: Writeback job for writeback connectors
*
@@ -2165,6 +2264,12 @@ struct drm_connector {
*/
struct drm_property *colorspace_property;
+ /**
+ * @color_format_property: Connector property to set the suitable
+ * color format supported by the sink.
+ */
+ struct drm_property *color_format_property;
+
/**
* @path_blob_ptr:
*
@@ -2648,6 +2753,9 @@ bool drm_connector_has_possible_encoder(struct drm_connector *connector,
struct drm_encoder *encoder);
const char *drm_get_colorspace_name(enum drm_colorspace colorspace);
+int drm_connector_attach_color_format_property(struct drm_connector *connector,
+ unsigned long supported_color_formats);
+
/**
* drm_for_each_connector_iter - connector_list iterator macro
* @connector: &struct drm_connector pointer used as cursor
--
2.53.0
^ permalink raw reply related
* [PATCH v13 00/27] Add new general DRM property "color format"
From: Nicolas Frattaroli @ 2026-04-13 10:07 UTC (permalink / raw)
To: Harry Wentland, Leo Li, Rodrigo Siqueira, Alex Deucher,
Christian König, David Airlie, Simona Vetter,
Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
Andrzej Hajda, Neil Armstrong, Robert Foss, Laurent Pinchart,
Jonas Karlman, Jernej Skrabec, Sandy Huang, Heiko Stübner,
Andy Yan, Jani Nikula, Rodrigo Vivi, Joonas Lahtinen,
Tvrtko Ursulin, Dmitry Baryshkov, Sascha Hauer, Rob Herring,
Jonathan Corbet, Shuah Khan
Cc: kernel, amd-gfx, dri-devel, linux-kernel, linux-arm-kernel,
linux-rockchip, intel-gfx, intel-xe, linux-doc,
Nicolas Frattaroli, Werner Sembach, Andri Yngvason,
Cristian Ciocaltea, Marius Vlad, Dmitry Baryshkov, Andy Yan
Hello,
this is a follow-up to
https://lore.kernel.org/all/20250911130739.4936-1-marius.vlad@collabora.com/
which in of itself is a follow-up to
https://lore.kernel.org/dri-devel/20240115160554.720247-1-andri@yngvason.is/ where
a new DRM connector property has been added allowing users to
force a particular color format.
That in turn was actually also a follow-up from Werner Sembach's posted at
https://lore.kernel.org/dri-devel/20210630151018.330354-1-wse@tuxedocomputers.com/
As the number of cooks have reached critical mass, I'm hoping I'll be
the last person to touch this particular series.
We have an implementation in Weston at
https://gitlab.freedesktop.org/wayland/weston/-/merge_requests/1825 that
adds support for this property. This patch series has been tested
against that MR on i915 (HDMI, DP), amdgpu (HDMI, DP) and on rockchip
(HDMI).
You can also manually test this with modetest like so, but beware that
this is a non-atomic invocation, so testing YUV420 like this will result
in weird outcomes if only some of the modes support YUV420:
$ modetest -s 115:1920x1080-60@NV12 -w 115:'color format':4
where 115 is the connector ID and '4' is the enum value for a particular
color format.
General notes on the approach taken by me: instead of silently switching
to a different format than was explicitly requested, or even worse,
outputting something to the sink the sink doesn't support, bubble up an
error to userspace instead. "color format" is a "I want this" type
property, not a "force this" type property, i.e. the kernel will respect
the limits imposed by the hardware.
Things I've tested:
- HDMI (YCbCr 4:4:4 + YCbCr 4:2:2 (8-bit) + RGB + Auto) on RK3588
- HDMI (YCbCr 4:4:4 + YCbCr 4:2:2 (8-bit) + RGB + Auto) on RK3576
- HDMI + DP (YCbCr 4:4:4, YCbCr 4:2:0, RGB, Auto) on Intel N97 (i915).
- HDMI (YCbCr 4:4:4, YCbCr 4:2:2, YCbCr 4:2:0, RGB, Auto) + DP (YCbCr
4:4:4, RGB, Auto) on an AMD Radeon RX 550 (amdgpu).
Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
---
Changes in v13:
- Introduce a new drm_connector_funcs member that returns the
connector state's color format with additional bells and whistles.
- Implement this new func in drm_bridge_connector to return whatever the
HDMI implementation did if an HDMI bridge is present.
- Call into the drm_connector.h function wrapping this new func in the
recursive bridge chain bus format selection code.
- Link to v12: https://patch.msgid.link/20260409-color-format-v12-0-ce84e1817a27@collabora.com
Changes in v12:
- Rebase on top of Ville's i915 format selection cleanup series
- i915: Reimplement based on new format selection code. Drop the DP-MST
implementation, as sinks with different sets of supported formats
complicate the matter.
- Adjust documentation on drm_connector_color_format enum values to
mention quantization ranges.
- Add documentation to drm-kms page to document the string values for
the property. Mostly the same documentation as the enum values, but
from a more userspace-centric perspective. This is done in the patch
that introduces the property, but I didn't drop the existing R-b as
it isn't a functional change.
- Update documentation of "colorspace" property to mention that "color
format" property controls the output format.
- amdgpu: Remove property from DP-MST, as it's unclear whether it'd work
properly with sinks that have different sets of supported formats
- Link to v11: https://patch.msgid.link/20260324-color-format-v11-0-605559af4fb4@collabora.com
Changes in v11:
- amdgpu: fix property registration on DP-MST
- i915: fix property registration on DP-MST
- rebase on drm-tip, which includes Maxime's refactor series that was
previously declared a dependency of this series
- Link to v10: https://lore.kernel.org/r/20260305-color-format-v10-0-a58c68a11868@collabora.com
Changes in v10:
- Make DRM_OUTPUT_COLOR_FORMAT_COUNT and
DRM_CONNECTOR_COLOR_FORMAT_COUNT part of the enum definition (thanks
to Maxime)
- Preemptively avoid the warning that would be generated by the
enumification of DRM_OUTPUT_COLOR_FORMAT_COUNT by modifying the
problematic switch statement in drm_hdmi_state_helper's
sink_supports_format_bpc.
- drm/bridge: Change HDMI check from checking for the last bridge having
a DRM_BRIDGE_OP_HDMI in ops to checking if last_bridge->type is HDMIA.
This is not quite the suggestion Dmitry had, but according to the
documentation of the drm_bridge.type member, and the
display-connector.c code, it should be correct.
- Combine drm_mode_create_color_format_property and
drm_connector_attach_color_format_property into one function named the
latter. (thanks to Dmitry Baryshkov)
- Change author of 'drm: Add new general DRM property "color format"'
to myself as it has by now changed quite a bit, and add Andri and
Werner as Co-developed-by, as per Andri's suggestion.
- hdmi-state-helper: Rework hdmi_compute_config to make code flow more
obvious, and drop Dmitry's R-b as a consequence (thanks to Maxime)
- Move dw-hdmi-qp's atomic_get_output_bus_fmts into
drm_bridge_helper.c, along with kernel doc string (thanks to Dmitry)
- Future-proof the aforementioned get_output_bus_fmts use of hweight8 on
the supported_formats bitmask with a BUILD_BUG_ON.
- Add a KUnit test for the HDMI output bus formats helper
- Link to v9: https://lore.kernel.org/r/20260227-color-format-v9-0-658c3b9db7ef@collabora.com
Changes in v9:
- Document what the "AUTO" behaviour is in the color format enum (thanks
to Maxime)
- drm/bridge: dw-hdmi-qp: Fix a rebase oopsie that reintroduced some
functions that were dropped. (thanks to Cristian)
- drm/bridge: Shuffle "1:1" in the bridge fmt selection docs to earlier
in the sentence. (thanks to Randy Dunlap)
- i915: Check chosen output format against requested format for dp-mst
- All color format driver implementations: rebase and rework on top of
Maxime's series
- As part of this rework, rename drm_color_format_enum to
drm_connector_color_format
- drm kunit tests: rework for the new enums. Changes were trivial, so
trailers were kept
- Link to v8: https://lore.kernel.org/r/20260216-color-format-v8-0-5722ce175dd5@collabora.com
Changes in v8:
- Drop "drm/rockchip: vop2: Fix YUV444 output", as the original problem
could not be reproduced anymore, and the justification did not make
sense.
- Remove the 12-bit format from "drm/rockchip: vop2: Recognise 10/12-bit
YUV422 as YUV formats".
- Refactor to keep the original DRM_COLOR_FORMAT bitshifted defines
as-is, but introduce a new drm_color_format_enum enum.
- Adjust conversion functions for the newly refactored enum, ensuring
they only return valid enum values, and only convert in directions
that open up no error value cans of worms.
- Rework the property uapi code for the newly refactored enum, since
it no longer needs to do any bitshifting or ffs().
- Rework all the device drivers for the new enum.
- Rework all the tests for the refactored enum.
- Rework the hdmi state helper for the new enum, and also make it more
explicit about the auto behaviour by not relying on a conversion
function to map AUTO to RGB, but do this in the framework itself.
- rockchip dw_hdmi_qp: Fix the GRF value to check for color >= 0 instead
of color > 0, as the latter broke switching back to RGB.
- Rebase onto a recent drm-tip. This necessitated blindly reworking some
of the i915 dp-mst code.
- Drop the __maybe_unused edid test patch, as I could no longer
reproduce the build warnings I added it for. I blame ghosts.
- drm_bridge tests: remove "destroyed" member from struct
drm_bridge_chain_priv and all associated code, as it was not used in
any test.
- Link to v7: https://lore.kernel.org/r/20260121-color-format-v7-0-ef790dae780c@collabora.com
Changes in v7:
- Fix drm_bridge kunit test build failure caused by rebasing across an
API change.
- Make compilers shut up about unused EDID definitions in the test
suites.
- Empty line checkpatch fixes that b4 prep --check didn't catch.
- Link to v6: https://lore.kernel.org/r/20260121-color-format-v6-0-7b81a771cd0b@collabora.com
Changes in v6:
- Checkpatch fixes
- Add drm_bridge.c kerneldoc fix patch to b4 deps so the kernel docs
required for every contribution to the subsystem can be built
- dw-hdmi-qp core has gained the atomic_get_output_bus_fmts bridge func,
which allows it to participate in the drm_bridge chain recursive format
selection code properly.
- The Rockchip dw-hdmi-qp integration now no longer reimplements the
color format logic (improperly), but reads the bus format of the first
bridge as set by the recursive bridge format selection. If the input
format is FIXED, it'll use the output format. Otherwise, the input
format is used.
- In the synopsys drivers, YUV422 uses the same bus format as the non-qp
hdmi encoder driver. Probably correcter this way. The Rockchip vop2
is_yuv function has been extended to recognise this format as well.
- KUnit tests for drm_bridge chains are now included, which exercise the
chain's recursive bus format selection.
- On HDMI connectors, the drm_bridge bus format selection will try to target
the color format that the HDMI layer came up with. This means the AUTO
logic is not duplicated for HDMI connectors.
- The enum conversion function commit gained a function for converting
from hdmi_colorspace to drm_color_format, and its author changed as no
original code remains anyway. Marius is still included as a
Co-developer.
- Some tests for the HDMI state helper's mode_valid have been written.
They are incomplete as we lack a test EDID for a 420-also mode that
would violate the clock constraints on RGB. I hacked one together with
a hex editor, but it reports a too high of a clock rate, and there's
no EDID editor I could find which supports these extension blocks.
- The color_format KUnit tests have been more heavily parameterised, the
auto case absorbed into other tests, and the comments around them
rewritten.
- Add a few paragraphs of documentation that explain the bridge format
selection, and how to make use of it in a display driver.
- Link to v5: https://lore.kernel.org/r/20251128-color-format-v5-0-63e82f1db1e1@collabora.com
Changes in v5:
- Rebase onto drm-tip
- Drop DRM_MODE_COLOR_FORMAT_* as an enum
- Unify DRM_COLOR_FORMAT_NONE and DRM_COLOR_FORMAT_AUTO, with AUTO being
0. This makes conversion and general logic much easier.
- Adjust the drm_color_format enum to not needlessly renumber the
existing defines, as it doesn't need to correspond to how HDMI numbers
them.
- Make the DRM-to-HDMI conversion function static inline __pure, because
the assembly it generates is tiny, and the function is pure.
- Don't accept nothing as the list of supported color formats for
registration of the property.
- Drop the per-connector variants of the color format registration
function, as it's not needed.
- drm_hdmi_state_helper: Fix mode_valid rejecting 420-only modes.
- drm_hdmi_state_helper: Only fall back to YUV420 with
DRM_COLOR_FORMAT_AUTO.
- drm_hdmi_state_helper: Remove redundant AUTO->RGB condition, as the
conversion already does this.
- Add KUnit tests for hdmi_compute_config.
- drm/bridge: Refactor bus_format_is_color_fmt and add a few more YUV422
formats.
- Register the color format property in drmm_connector_hdmi_init based
on the supported HDMI formats passed to it. This means rockchip
dw_hdmi_qp no longer needs to register it.
- amdgpu: Simplify YUV420 logic
- amdgpu: Don't try to pick YUV444 on YUV420-only modes
- i915: Try to make behaviour more or less the same as that of the drm
hdmi state helper.
- rockchip dw_hdmi_qp: Set supported HDMI formats
- rockchip dw_hdmi_qp: Set the right VO GRF values depending on color
format.
- rockchip dw_hdmi_qp: Act on the color format property in this driver,
rather than in VOP2, by setting the bus_format appropriately.
- rockchip VOP2: Can the BCSH-based implementation. BCSH isn't available
on all video ports of the hardware, and the code was extremely
suspect. Instead, plug into the existing YUV-to-RGB/RGB-to-YUV code,
which can be done now that the HDMI driver sets the bus format.
- A whole bunch of Rockchip VOP2 fixes.
- Link to v4: https://lore.kernel.org/r/20251117-color-format-v4-0-0ded72bd1b00@collabora.com
Changes in v4:
- Rebase onto next-20251117
- Get rid of HDMI_COLORSPACE_AUTO
- Split hdmi_compute_config change into separate patch
- Add missing symbol export for color_format_to_hdmi_colorspace to fix
builds in certain configurations
- Drop "drm: Pass supported color formats straight onto drm_bridge"
- Make dw-hdmi-qp set the platform data's supported color formats as
the bridge's supported HDMI color formats
- drm_hdmi_state_helper: pass requested color format to
hdmi_compute_format_bpc if set.
- drm_bridge: limit the bus formats to those explicitly requested with
the color format property during the atomic bridge check call,
specifically in drm_atomic_bridge_chain_select_bus_fmts.
- i915: Remove INTEL_OUTPUT_FORMAT_AUTO, as automatic format selection
does not need to involve the hardware state
- i915: Deduplicate ntel_output_format_to_drm_color_format code by
moving it as a static inline __pure function into a shared header
- i915: rework logic in HDMI, DP and DP-MST output config functions to
remove redundant locals, simplify execution flow, and return an error
to userspace if an explicit color_format request can't be satisfied.
- i915: assign myself as the author and make the others Co-developers,
so that they don't get the blame for any of my bugs.
- amdgpu: refactor fill_stream_properties_from_drm_display_mode to
improve readability and ensure that impossible color format requests
get bubbled up to userspace as errors
- amdgpu: don't pick YUV444 over RGB.
- amdgpu: assign authorship to myself, with others as Co-developers, as
logic was modified and the blame should fall on me
- dw_hdmi_qp-rockchip: set the supported color formats platform data
member
- rockchip: remove drm property registration for rk3066_hdmi and
inno_hdmi. None of the platforms that use these use vop2 as the
video output processor.
- Link to v3: https://lore.kernel.org/all/20250911130739.4936-1-marius.vlad@collabora.com/
Changes in v3 by mvlad compared to Andri's v2 series:
- renamed the property to just 'color format'
- the property is added dynamically similar to the Colorspace property
- a key point from previous comments was that drivers should advertise
the color formats they support and userspace would query EDID and
perform an intersection from those color formats which users can
further use. With this patch set each driver that adds this property
has such list of hard-coded color formats, but fundamentally the idea
is that driver can query the HW and do that on its own. The
infrastructure is now in place to allow to do that
- by default the 'AUTO' color format is set. With this patch series that
has been introduced as a fallback to RGB. Drivers could further
customize this behavour and could perform additional checks on the sink
to pick another suitable color format they'd like for AUTO
- drm_bridge bridge code has been improved to allow initialization with
the same color formats list as the DRM connector property. Similarly, bpc
pick-up now takes the color format into consideration when deciding
which bpc to choose from
- The new DRM color format re-uses HDMI_COLORPSACE enum and provides an
enum translations between the two to avoid touching all other drivers that
use HDMI_COLORPSACE enum. I believe at this point that this allows the
least amount of disruption and avoids a massive bike shedding around
that part
- a rockchip implementation has been by my colleague Derek Foreman
- YUV444 color format has been added in i915
- address comment about "Remove unnecessary SIGNAL_TYPE_HDMI_TYPE_A
check" where aconnector might be invalid
- Link to v2: https://lore.kernel.org/dri-devel/20240115160554.720247-1-andri@yngvason.is/
---
Nicolas Frattaroli (26):
drm/display: hdmi-state-helper: Use default case for unsupported formats
drm: Add new general DRM property "color format"
drm/connector: Let connectors have a say in their color format
drm/display: bridge_connector: Use HDMI color format for HDMI conns
drm/bridge: Act on the DRM color format property
drm/atomic-helper: Add HDMI bridge output bus formats helper
drm/display: hdmi-state-helper: Act on color format DRM property
drm/display: hdmi-state-helper: Try subsampling in mode_valid
drm/amdgpu: Implement "color format" DRM property
drm/i915/hdmi: Add YCBCR444 handling for sink formats
drm/i915/dp: Add YCBCR444 handling for sink formats
drm/i915: Implement the "color format" DRM property
drm/rockchip: Add YUV422 output mode constants for VOP2
drm/rockchip: vop2: Add RK3576 to the RG swap special case
drm/rockchip: vop2: Recognise 10-bit YUV422 as YUV format
drm/rockchip: vop2: Set correct output format for RK3576 YUV422
drm/bridge: dw-hdmi-qp: Use common HDMI output bus fmts helper
drm/rockchip: dw_hdmi_qp: Implement "color format" DRM property
drm/rockchip: dw_hdmi_qp: Set supported_formats platdata
drm/connector: Register color format property on HDMI connectors
drm/tests: hdmi: Add tests for the color_format property
drm/tests: hdmi: Add tests for HDMI helper's mode_valid
drm/tests: bridge: Add KUnit tests for bridge chain format selection
drm/tests: bridge: Add test for HDMI output bus formats helper
drm/bridge: Document bridge chain format selection
drm/connector: Update docs of "colorspace" for color format prop
Werner Sembach (1):
drm/amd/display: Remove unnecessary SIGNAL_TYPE_HDMI_TYPE_A check
Documentation/gpu/drm-kms-helpers.rst | 6 +
Documentation/gpu/drm-kms.rst | 6 +
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 91 +-
drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c | 1 +
drivers/gpu/drm/display/drm_bridge_connector.c | 24 +
drivers/gpu/drm/display/drm_hdmi_state_helper.c | 53 +-
drivers/gpu/drm/drm_atomic_helper.c | 86 ++
drivers/gpu/drm/drm_atomic_uapi.c | 11 +
drivers/gpu/drm/drm_bridge.c | 104 ++-
drivers/gpu/drm/drm_connector.c | 178 +++-
drivers/gpu/drm/i915/display/intel_connector.c | 10 +
drivers/gpu/drm/i915/display/intel_connector.h | 1 +
drivers/gpu/drm/i915/display/intel_dp.c | 43 +-
drivers/gpu/drm/i915/display/intel_hdmi.c | 47 +-
drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c | 111 ++-
drivers/gpu/drm/rockchip/rockchip_drm_drv.h | 4 +
drivers/gpu/drm/rockchip/rockchip_drm_vop2.c | 21 +-
drivers/gpu/drm/tests/drm_bridge_test.c | 971 +++++++++++++++++++++
drivers/gpu/drm/tests/drm_hdmi_state_helper_test.c | 345 ++++++++
include/drm/drm_atomic_helper.h | 7 +
include/drm/drm_connector.h | 120 +++
21 files changed, 2203 insertions(+), 37 deletions(-)
---
base-commit: e3dc6072028a594d5e9bfc6476165842602d5307
change-id: 20251028-color-format-49fd202b7183
prerequisite-message-id: <20260409101539.22032-1-ville.syrjala@linux.intel.com>
prerequisite-patch-id: f382aeb5da5f2b8f6e2cb22b88eb47f490f2c724
prerequisite-patch-id: 20570aeb28e3c31353e6f697b193b23d8b47c47c
prerequisite-patch-id: 1b7e24034883b22cd82be025a1cf82ae77170fd0
prerequisite-patch-id: 6ec2dc2c05a75391b67cb12d93168f5e8da8ec55
prerequisite-patch-id: 32e84581998ef4eef05e1681c7ec36b90f2a6bb7
prerequisite-patch-id: 99c2187a846b0c9ac2ea1a892c17483120cb7da1
prerequisite-patch-id: fb41b4668a3b7c8c375c67ffd6b178fa3273e86a
prerequisite-patch-id: 4c115a36eea0d5f80643dc34310690894ac80e0e
prerequisite-patch-id: 6fdec0832cd6062de3cc5c2f363c5d624d8a00f9
Best regards,
--
Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
^ permalink raw reply
* [PATCH v13 02/27] drm/display: hdmi-state-helper: Use default case for unsupported formats
From: Nicolas Frattaroli @ 2026-04-13 10:07 UTC (permalink / raw)
To: Harry Wentland, Leo Li, Rodrigo Siqueira, Alex Deucher,
Christian König, David Airlie, Simona Vetter,
Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
Andrzej Hajda, Neil Armstrong, Robert Foss, Laurent Pinchart,
Jonas Karlman, Jernej Skrabec, Sandy Huang, Heiko Stübner,
Andy Yan, Jani Nikula, Rodrigo Vivi, Joonas Lahtinen,
Tvrtko Ursulin, Dmitry Baryshkov, Sascha Hauer, Rob Herring,
Jonathan Corbet, Shuah Khan
Cc: kernel, amd-gfx, dri-devel, linux-kernel, linux-arm-kernel,
linux-rockchip, intel-gfx, intel-xe, linux-doc,
Nicolas Frattaroli, Cristian Ciocaltea
In-Reply-To: <20260413-color-format-v13-0-ab37d4dfba48@collabora.com>
Switch statements that do not handle all possible values of an
enumeration will generate a warning during compilation. In preparation
for adding a COUNT value to the end of the enum, this needs to be dealt
with.
Add a default case to sink_supports_format_bpc's DRM_OUTPUT_COLOR_FORMAT
switch statement, and move the log-and-return unknown pixel format
handling into it.
No functional change.
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
---
drivers/gpu/drm/display/drm_hdmi_state_helper.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/display/drm_hdmi_state_helper.c b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
index 9f3b696aceeb..a0d88701d236 100644
--- a/drivers/gpu/drm/display/drm_hdmi_state_helper.c
+++ b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
@@ -541,10 +541,11 @@ sink_supports_format_bpc(const struct drm_connector *connector,
drm_dbg_kms(dev, "YUV444 format supported in that configuration.\n");
return true;
- }
- drm_dbg_kms(dev, "Unsupported pixel format.\n");
- return false;
+ default:
+ drm_dbg_kms(dev, "Unsupported pixel format.\n");
+ return false;
+ }
}
static enum drm_mode_status
--
2.53.0
^ permalink raw reply related
* [PATCH v13 01/27] drm/amd/display: Remove unnecessary SIGNAL_TYPE_HDMI_TYPE_A check
From: Nicolas Frattaroli @ 2026-04-13 10:07 UTC (permalink / raw)
To: Harry Wentland, Leo Li, Rodrigo Siqueira, Alex Deucher,
Christian König, David Airlie, Simona Vetter,
Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
Andrzej Hajda, Neil Armstrong, Robert Foss, Laurent Pinchart,
Jonas Karlman, Jernej Skrabec, Sandy Huang, Heiko Stübner,
Andy Yan, Jani Nikula, Rodrigo Vivi, Joonas Lahtinen,
Tvrtko Ursulin, Dmitry Baryshkov, Sascha Hauer, Rob Herring,
Jonathan Corbet, Shuah Khan
Cc: kernel, amd-gfx, dri-devel, linux-kernel, linux-arm-kernel,
linux-rockchip, intel-gfx, intel-xe, linux-doc,
Nicolas Frattaroli, Werner Sembach, Andri Yngvason
In-Reply-To: <20260413-color-format-v13-0-ab37d4dfba48@collabora.com>
From: Werner Sembach <wse@tuxedocomputers.com>
Remove unnecessary SIGNAL_TYPE_HDMI_TYPE_A check that was performed in the
drm_mode_is_420_only() case, but not in the drm_mode_is_420_also() &&
force_yuv420_output case.
Without further knowledge if YCbCr 4:2:0 is supported outside of HDMI,
there is no reason to use RGB when the display
reports drm_mode_is_420_only() even on a non HDMI connection.
This patch also moves both checks in the same if-case. This eliminates an
extra else-if-case.
Signed-off-by: Werner Sembach <wse@tuxedocomputers.com>
Signed-off-by: Andri Yngvason <andri@yngvason.is>
Tested-by: Andri Yngvason <andri@yngvason.is>
Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
---
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index c2066319772b..ad9714382d5f 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -6780,12 +6780,9 @@ static void fill_stream_properties_from_drm_display_mode(
timing_out->v_border_top = 0;
timing_out->v_border_bottom = 0;
/* TODO: un-hardcode */
- if (drm_mode_is_420_only(info, mode_in)
- && stream->signal == SIGNAL_TYPE_HDMI_TYPE_A)
- timing_out->pixel_encoding = PIXEL_ENCODING_YCBCR420;
- else if (drm_mode_is_420_also(info, mode_in)
- && aconnector
- && aconnector->force_yuv420_output)
+ if (drm_mode_is_420_only(info, mode_in) ||
+ (aconnector && aconnector->force_yuv420_output &&
+ drm_mode_is_420_also(info, mode_in)))
timing_out->pixel_encoding = PIXEL_ENCODING_YCBCR420;
else if ((connector->display_info.color_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR422))
&& aconnector
--
2.53.0
^ permalink raw reply related
* [PATCH net-next v2 1/5] net: add dev->bql flag to allow BQL sysfs for IFF_NO_QUEUE devices
From: hawk @ 2026-04-13 9:44 UTC (permalink / raw)
To: netdev
Cc: kernel-team, Jesper Dangaard Brouer, Jonas Köppeler,
Andrew Lunn, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Jonathan Corbet, Shuah Khan,
Kuniyuki Iwashima, Stanislav Fomichev, Frederic Weisbecker,
Yajun Deng, Krishna Kumar, linux-doc, linux-kernel
In-Reply-To: <20260413094442.1376022-1-hawk@kernel.org>
From: Jesper Dangaard Brouer <hawk@kernel.org>
Virtual devices with IFF_NO_QUEUE or lltx are excluded from BQL sysfs
by netdev_uses_bql(), since they traditionally lack real hardware
queues. However, some virtual devices like veth implement a real
ptr_ring FIFO with NAPI processing and benefit from BQL to limit
in-flight bytes and reduce latency.
Add a per-device 'bql' bitfield boolean in the priv_flags_slow section
of struct net_device. When set, it overrides the IFF_NO_QUEUE/lltx
exclusion and exposes BQL sysfs entries (/sys/class/net/<dev>/queues/
tx-<n>/byte_queue_limits/). The flag is still gated on CONFIG_BQL.
This allows drivers that use BQL despite being IFF_NO_QUEUE to opt in
to sysfs visibility for monitoring and debugging.
Signed-off-by: Jesper Dangaard Brouer <hawk@kernel.org>
Tested-by: Jonas Köppeler <j.koeppeler@tu-berlin.de>
---
Documentation/networking/net_cachelines/net_device.rst | 1 +
include/linux/netdevice.h | 2 ++
net/core/net-sysfs.c | 8 +++++++-
3 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/Documentation/networking/net_cachelines/net_device.rst b/Documentation/networking/net_cachelines/net_device.rst
index 1c19bb7705df..b775d3235a2d 100644
--- a/Documentation/networking/net_cachelines/net_device.rst
+++ b/Documentation/networking/net_cachelines/net_device.rst
@@ -170,6 +170,7 @@ unsigned_long:1 see_all_hwtstamp_requests
unsigned_long:1 change_proto_down
unsigned_long:1 netns_immutable
unsigned_long:1 fcoe_mtu
+unsigned_long:1 bql netdev_uses_bql(net-sysfs.c)
struct list_head net_notifier_list
struct macsec_ops* macsec_ops
struct udp_tunnel_nic_info* udp_tunnel_nic_info
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 47417b2d48a4..7a1a491ecdd5 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2048,6 +2048,7 @@ enum netdev_reg_state {
* @change_proto_down: device supports setting carrier via IFLA_PROTO_DOWN
* @netns_immutable: interface can't change network namespaces
* @fcoe_mtu: device supports maximum FCoE MTU, 2158 bytes
+ * @bql: device uses BQL (DQL sysfs) despite having IFF_NO_QUEUE
*
* @net_notifier_list: List of per-net netdev notifier block
* that follow this device when it is moved
@@ -2462,6 +2463,7 @@ struct net_device {
unsigned long change_proto_down:1;
unsigned long netns_immutable:1;
unsigned long fcoe_mtu:1;
+ unsigned long bql:1;
struct list_head net_notifier_list;
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index e430645748a7..4360efc8f241 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -1945,10 +1945,16 @@ static const struct kobj_type netdev_queue_ktype = {
static bool netdev_uses_bql(const struct net_device *dev)
{
+ if (!IS_ENABLED(CONFIG_BQL))
+ return false;
+
+ if (dev->bql)
+ return true;
+
if (dev->lltx || (dev->priv_flags & IFF_NO_QUEUE))
return false;
- return IS_ENABLED(CONFIG_BQL);
+ return true;
}
static int netdev_queue_add_kobject(struct net_device *dev, int index)
--
2.43.0
^ permalink raw reply related
* Re: [PATCH v4 9/9] Documentation: ABI: Add sysfs ABI documentation for DDR training data
From: Kishore Batta @ 2026-04-13 9:05 UTC (permalink / raw)
To: Jeff Hugo, Jonathan Corbet, Shuah Khan, Carl Vanderlip,
Oded Gabbay, Manivannan Sadhasivam, andersson
Cc: linux-doc, linux-kernel, linux-arm-msm, dri-devel, mhi
In-Reply-To: <4bc1363d-5785-4214-8057-4f2a75e0f8a8@oss.qualcomm.com>
On 4/10/2026 3:00 AM, Jeff Hugo wrote:
> On 3/19/2026 12:31 AM, Kishore Batta wrote:
>> Add ABI documentation for the DDR training data sysfs attribute
>> exposed by
>> the sahara MHI driver.
>
> Sahara
>
> Also, this patch should be squashed with the previous patch since that
> is the one that adds this sysfs entry.
ACK. Will correct Sahara keyword and also squash this with previous patch.
^ permalink raw reply
* Re: [PATCH v4 7/9] bus: mhi: Capture DDR training data using command mode
From: Kishore Batta @ 2026-04-13 9:05 UTC (permalink / raw)
To: Jeff Hugo, Jonathan Corbet, Shuah Khan, Carl Vanderlip,
Oded Gabbay, Manivannan Sadhasivam, andersson
Cc: linux-doc, linux-kernel, linux-arm-msm, dri-devel, mhi
In-Reply-To: <031702af-5976-438a-841a-48e95f41eb03@oss.qualcomm.com>
On 4/10/2026 2:57 AM, Jeff Hugo wrote:
> On 3/19/2026 12:31 AM, Kishore Batta wrote:
>> During early boot, devices may perform DDR training and produce training
>> data that can be reused on subsequent boots to reduce initialization
>> time. The sahara protocol provides a command mode flow to transfer this
>
> Sahara
ACK. Will correct it.
>
>> training data to the host, but the driver currently does not handle
>> command mode and drops the training payload.
>>
>> Add Sahara command mode support to retrieve DDR training data from the
>> device. When the device enters command mode and sends CMD_READY, query
>> the support command list and request DDR training data using EXECUTE and
>> EXECUTE_DATA. Allocate receive buffers based on the reported response
>> size and copy the raw payload directly from the MHI DL completion
>> callback.
>>
>> Store the captured training data in controller-scoped memory using
>> devres,
>> so it remains available after sahara channel teardown. Also distinguish
>
> Sahara
ACK. Will correct it.
>
>> raw payload completion from control packets in the DL callback, avoiding
>> misinterpretation of training data as protocol messages, and requeue
>> the RX buffer after switching back to IMAGE_TX_PENDING to allow the
>> boot flow to continue.
>>
>> Signed-off-by: Kishore Batta <kishore.batta@oss.qualcomm.com>
>> ---
>> drivers/bus/mhi/sahara/sahara.c | 328
>> +++++++++++++++++++++++++++++++++++++++-
>> 1 file changed, 320 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/bus/mhi/sahara/sahara.c
>> b/drivers/bus/mhi/sahara/sahara.c
>> index
>> 0a0f578aaa47ab2c4ca0765666b392fb9936ddd5..c88f1220199ac4373d3552167870c19a0d5f23b9
>> 100644
>> --- a/drivers/bus/mhi/sahara/sahara.c
>> +++ b/drivers/bus/mhi/sahara/sahara.c
>> @@ -5,11 +5,14 @@
>> */
>> #include <linux/devcoredump.h>
>> +#include <linux/device.h>
>> +#include <linux/device/devres.h>
>> #include <linux/firmware.h>
>> #include <linux/limits.h>
>> #include <linux/mhi.h>
>> #include <linux/minmax.h>
>> #include <linux/mod_devicetable.h>
>> +#include <linux/mutex.h>
>> #include <linux/overflow.h>
>> #include <linux/sahara.h>
>> #include <linux/types.h>
>> @@ -60,8 +63,16 @@
>> #define SAHARA_RESET_LENGTH 0x8
>> #define SAHARA_MEM_DEBUG64_LENGTH 0x18
>> #define SAHARA_MEM_READ64_LENGTH 0x18
>> -
>> +#define SAHARA_COMMAND_READY_LENGTH 0x8
>> +#define SAHARA_COMMAND_EXEC_RESP_LENGTH 0x10
>> +#define SAHARA_COMMAND_EXECUTE_LENGTH 0xc
>> +#define SAHARA_COMMAND_EXEC_DATA_LENGTH 0xc
>> +#define SAHARA_SWITCH_MODE_LENGTH 0xc
>> +
>> +#define SAHARA_EXEC_CMD_GET_COMMAND_ID_LIST 0x8
>> +#define SAHARA_EXEC_CMD_GET_TRAINING_DATA 0x9
>> #define SAHARA_DDR_TRAINING_IMG_ID 34
>
> Why is the indentation of this line messed up?
ACK. Will correct it.
>
>> +#define SAHARA_NUM_CMD_BUF SAHARA_NUM_TX_BUF
>> struct sahara_packet {
>> __le32 cmd;
>> @@ -97,6 +108,19 @@ struct sahara_packet {
>> __le64 memory_address;
>> __le64 memory_length;
>> } memory_read64;
>> + struct {
>> + __le32 client_command;
>> + } command_execute;
>> + struct {
>> + __le32 client_command;
>> + __le32 response_length;
>> + } command_execute_resp;
>> + struct {
>> + __le32 client_command;
>> + } command_exec_data;
>> + struct {
>> + __le32 mode;
>> + } mode_switch;
>> };
>> };
>> @@ -163,6 +187,7 @@ struct sahara_context {
>> struct work_struct fw_work;
>> struct work_struct dump_work;
>> struct work_struct read_data_work;
>> + struct work_struct cmd_work;
>> struct mhi_device *mhi_dev;
>> const char * const *image_table;
>> u32 table_size;
>> @@ -183,6 +208,24 @@ struct sahara_context {
>> bool is_mem_dump_mode;
>> bool non_streaming;
>> const char *fw_folder;
>> + bool is_cmd_mode;
>> + bool receiving_trng_data;
>
> You already spell out "receiving", spell out "training". I don't
> recall seeing "trng" before so it seems like a really uncommon shortform.
ACK. Will correct it.
>
>> + size_t trng_size;
>> + size_t trng_rcvd;
>> + u32 trng_nbuf;
>> + char *cmd_buff[SAHARA_NUM_CMD_BUF];
>> +};
^ permalink raw reply
* Re: [PATCH v4 4/9] bus: mhi: Centralize firmware image table selection at probe time
From: Kishore Batta @ 2026-04-13 9:04 UTC (permalink / raw)
To: Jeff Hugo, Jonathan Corbet, Shuah Khan, Carl Vanderlip,
Oded Gabbay, Manivannan Sadhasivam, andersson
Cc: linux-doc, linux-kernel, linux-arm-msm, dri-devel, mhi
In-Reply-To: <2eda7d10-e4a9-4ca7-ae73-bf9c0ca8fa33@oss.qualcomm.com>
On 4/10/2026 2:22 AM, Jeff Hugo wrote:
> On 3/19/2026 12:31 AM, Kishore Batta wrote:
>> The Sahara driver currently selects firmware image tables using
>> scattered, device specific conditionals in the probe path, making the
>> logic harder to follow and extend.
>
> "to follow" (remove extra space)
ACK.
>
>> Refactor firmware image table selection into a single, explicit
>> probe-time
>> mechanism by introducing a variant table that captures device matching,
>> firmware image tables, firmware folder names, and streaming behavior in
>> one place.
>>
>> This centralizes device specific decisions, simplifies the probe logic,
>> and avoids ad-hoc conditionals while preserving the existing behavior
>> for
>> all supported AIC devices.
>
> It would probably be useful to mention this is in preparation for
> adding QDU100 support, otherwise this reads like it is just change for
> the sake of change.
Sure. I will mention in next version.
>
>> Signed-off-by: Kishore Batta <kishore.batta@oss.qualcomm.com>
>> ---
>> drivers/bus/mhi/sahara/sahara.c | 66
>> ++++++++++++++++++++++++++++++++++++-----
>> 1 file changed, 58 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/bus/mhi/sahara/sahara.c
>> b/drivers/bus/mhi/sahara/sahara.c
>> index
>> e3499977e7c6b53bc624a8eb00d0636f2ea63307..8f1c0d72066c0cf80c09d78bfc51df2e482133b9
>> 100644
>> --- a/drivers/bus/mhi/sahara/sahara.c
>> +++ b/drivers/bus/mhi/sahara/sahara.c
>> @@ -180,6 +180,16 @@ struct sahara_context {
>> u32 read_data_length;
>> bool is_mem_dump_mode;
>> bool non_streaming;
>> + const char *fw_folder;
>> +};
>> +
>> +struct sahara_variant {
>> + const char *match;
>> + bool match_is_chan;
>
> This is dead code, add it later on when it gets used.
ACK.
>
>> + const char * const *image_table;
>> + size_t table_size;
>> + const char *fw_folder;
>
> This is dead code, add it later on when it gets used.
ACK.
>
>> + bool non_streaming;
>
> Please run pahole on this structure. With the interleaving of types
> for every other member, I'm expecting there would be quite a bit of
> compiler added padding.
Sure. I had ran pahole on this structure and 8 bytes can be saved. I
will rearrange the members of the structure in the next version.
>
>
^ permalink raw reply
* Re: [PATCH v4 3/9] bus: mhi: Match devices exposing the protocol on the SAHARA channel
From: Kishore Batta @ 2026-04-13 9:03 UTC (permalink / raw)
To: Jeff Hugo, Jonathan Corbet, Shuah Khan, Carl Vanderlip,
Oded Gabbay, Manivannan Sadhasivam, andersson
Cc: linux-doc, linux-kernel, linux-arm-msm, dri-devel, mhi
In-Reply-To: <7aeeed43-b458-4c68-98b0-e857f1ed791d@oss.qualcomm.com>
On 4/10/2026 1:53 AM, Jeff Hugo wrote:
> On 3/19/2026 12:31 AM, Kishore Batta wrote:
>> Some Qualcomm devices expose the Sahara protocol on a generic SAHARA MHI
>> channel rather than a QAIC specific channel name. As a result, the
>> sahara
>
> "Sahara"
ACK. I will correct in next version.
>
>> driver does not currently bind to such devices and never probes.
>>
>> Extend the MHI device ID match table to also match the SAHARA channel
>> name. This allows the Sahara protocol driver to bind to devices that
>> expose the protocol directly on a standard sahara MHI channel.
>
> "Sahara"
ACK. I will correct in next version.
>
>>
>> Signed-off-by: Kishore Batta <kishore.batta@oss.qualcomm.com>
>> ---
>> drivers/bus/mhi/sahara/sahara.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/bus/mhi/sahara/sahara.c
>> b/drivers/bus/mhi/sahara/sahara.c
>> index
>> 8ff7b6425ac5423ef8f32117151dca10397686a8..e3499977e7c6b53bc624a8eb00d0636f2ea63307
>> 100644
>> --- a/drivers/bus/mhi/sahara/sahara.c
>> +++ b/drivers/bus/mhi/sahara/sahara.c
>> @@ -911,8 +911,10 @@ static void sahara_mhi_dl_xfer_cb(struct
>> mhi_device *mhi_dev, struct mhi_result
>> static const struct mhi_device_id sahara_mhi_match_table[] = {
>> { .chan = "QAIC_SAHARA", },
>> + { .chan = "SAHARA"},
>
> This doesn't work and breaks bisect. At this point Sahara will bind to
> QDU100, ath12k, or something else but not know how to drive one of
> those devices.
>
> Just add this when you add QDU100 support, which looks to be patch 5.
ACK. I will add this in patch 5.
>
>> {},
>> };
>> +MODULE_DEVICE_TABLE(mhi, sahara_mhi_match_table);
>> static struct mhi_driver sahara_mhi_driver = {
>> .id_table = sahara_mhi_match_table,
>>
>
^ permalink raw reply
* Re: [PATCH v4 2/9] bus: mhi: Move sahara protocol driver under drivers/bus/mhi
From: Kishore Batta @ 2026-04-13 9:03 UTC (permalink / raw)
To: Jeff Hugo, Jonathan Corbet, Shuah Khan, Carl Vanderlip,
Oded Gabbay, Manivannan Sadhasivam, andersson
Cc: linux-doc, linux-kernel, linux-arm-msm, dri-devel, mhi
In-Reply-To: <0a2af0d1-27da-4f60-952a-409a5abc5647@oss.qualcomm.com>
On 4/10/2026 1:50 AM, Jeff Hugo wrote:
> On 3/19/2026 12:31 AM, Kishore Batta wrote:
>> The Sahara protocol driver is currently located under the QAIC
>> accelerator subsystem even though protocol itself is transported over
>> the
>> MHI bus and is used by multiple Qualcomm flashless devices.
>>
>> Relocate the Sahara protocol driver to drivers/bus/mhi and register
>> it as
>> an independent MHI protocol driver. This avoids treating Sahara as QAIC
>> specific and makes it available for reuse by other MHI based devices.
>>
>> As part of this move, introduce a dedicated Kconfig and Makefile
>> under the
>> MHI subsystem and expose the sahara interface via a common header.
>
> I don't think this belongs under MHI. Mani needs to confirm that he
> agrees with the concept of moving this there.
>
> The Sahara protocol as defined by the spec does not require MHI. We
> know that there are Sahara implementations over USB. I don't see a
> dependency or relationship to MHI other than the current in-kernel
> implementation uses MHI, but there are plenty of things that use MHI
> (qaic, mhi-net, ath12k, etc) which are not a part of the MHI bus.
>
> The implementation presented in this series is not well integrated
> into MHI, which also suggests to me that it doesn't belong there. The
> Documentation is not integrated with MHI (which I mentioned over on
> that patch) and I see the header file (sahara.h) is also not integrated.
On Patch 1 series, I have got a review comment from Bjorn to have it
moved to drivers/bus/mhi as this implementation only supports MHI and is
going to be used with MHI. Hence the sahara driver is moved to this
directory. Do i need to move this to a different directory ? I will move
the Sahara documentation once we conclude on where Sahara driver needs
to be moved.
>
>> diff --git a/drivers/accel/qaic/qaic_drv.c
>> b/drivers/accel/qaic/qaic_drv.c
>> index
>> 63fb8c7b4abcbe4f1b76c32106f4e8b9ea5e2c8e..76cc8086825e7949ed756d51fcb56a08f392d228
>> 100644
>> --- a/drivers/accel/qaic/qaic_drv.c
>> +++ b/drivers/accel/qaic/qaic_drv.c
>> @@ -15,6 +15,7 @@
>> #include <linux/msi.h>
>> #include <linux/mutex.h>
>> #include <linux/pci.h>
>> +#include <linux/sahara.h>
>
> What do we need this for? register()/unregister() get removed.
ACK.I will remove it.
>
>> #include <linux/spinlock.h>
>> #include <linux/workqueue.h>
>> #include <linux/wait.h>
>> @@ -32,7 +33,6 @@
>> #include "qaic_ras.h"
>> #include "qaic_ssr.h"
>> #include "qaic_timesync.h"
>> -#include "sahara.h"
>> MODULE_IMPORT_NS("DMA_BUF");
>> @@ -782,18 +782,12 @@ static int __init qaic_init(void)
>> ret = pci_register_driver(&qaic_pci_driver);
>> if (ret) {
>> pr_debug("qaic: pci_register_driver failed %d\n", ret);
>> - return ret;
>> + goto free_pci;
>
> This is wrong, and there should not be a change here.
ACK. I will revert this change.
>
>> ret = mhi_driver_register(&qaic_mhi_driver);
>> if (ret) {
>> pr_debug("qaic: mhi_driver_register failed %d\n", ret);
>> - goto free_pci;
>> - }
>> -
>> - ret = sahara_register();
>> - if (ret) {
>> - pr_debug("qaic: sahara_register failed %d\n", ret);
>> goto free_mhi;
>
> This is also wrong
I want to make sure I understand the concern correctly before changing
the init flow. With Sahara now being a standalone MHI client driver
(moved out of QAIC and self registering), QAIC no longer calling
sahara_register() is intentional. However, removing that call also
removes an implicit init time dependency/failure gate. Is the objection
primarily about losing that gating / ordering guarantee or is there
another issue with removing the call itself ?
Once i understand that, I'll update the patches in the direction you prefer.
>
>> @@ -847,7 +841,6 @@ static void __exit qaic_exit(void)
>> qaic_ras_unregister();
>> qaic_bootlog_unregister();
>> qaic_timesync_deinit();
>> - sahara_unregister();
>> mhi_driver_unregister(&qaic_mhi_driver);
>> pci_unregister_driver(&qaic_pci_driver);
>> }
>> diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig
>> index
>> b39a11e6c624ba00349cca22d74bd876020590ab..4acedb886adccc6f76f69c241d53106da59b491f
>> 100644
>> --- a/drivers/bus/mhi/Kconfig
>> +++ b/drivers/bus/mhi/Kconfig
>> @@ -7,3 +7,4 @@
>> source "drivers/bus/mhi/host/Kconfig"
>> source "drivers/bus/mhi/ep/Kconfig"
>> +source "drivers/bus/mhi/sahara/Kconfig"
>> diff --git a/drivers/bus/mhi/Makefile b/drivers/bus/mhi/Makefile
>> index
>> 354204b0ef3ae4030469a24a659f32429d592aef..e4af535e1bb1bc9481fae60d7eb347700d2e874c
>> 100644
>> --- a/drivers/bus/mhi/Makefile
>> +++ b/drivers/bus/mhi/Makefile
>> @@ -3,3 +3,6 @@ obj-$(CONFIG_MHI_BUS) += host/
>> # Endpoint MHI stack
>> obj-$(CONFIG_MHI_BUS_EP) += ep/
>> +
>> +# Sahara MHI protocol
>> +obj-$(CONFIG_MHI_SAHARA) += sahara/
>> diff --git a/drivers/bus/mhi/sahara/Kconfig
>> b/drivers/bus/mhi/sahara/Kconfig
>> new file mode 100644
>> index
>> 0000000000000000000000000000000000000000..3f1caf6acd979a4af68aaf0e250aa54762e8cda5
>> --- /dev/null
>> +++ b/drivers/bus/mhi/sahara/Kconfig
>> @@ -0,0 +1,18 @@
>> +config MHI_SAHARA
>> + tristate
>> + depends on MHI_BUS
>> + select FW_LOADER_COMPRESS
>
> Why are we selecting this? I don't see anyone else doing this. Sahara
> should work with and without firmware compression.
ACK. I will remove this.
>
>> + select FW_LOADER_COMPRESS_XZ
>> + select FW_LOADER_COMPRESS_ZSTD
>> + help
>> + Enable support for the Sahara protocol transported over the
>> MHI bus.
>> +
>> + The Sahara protocol is used to transfer firmware images, retrieve
>> + memory dumps and exchange command mode DDR calibration data
>> between
>> + host and device. This driver is not tied to a specific SoC and
>> may be
>> + used by multiple MHI based devices.
>> +
>> + If unsure, say N.
>> +
>> + To compile this driver as a module, choose M here: the module
>> will be
>> + called mhi_sahara.
>> diff --git a/drivers/bus/mhi/sahara/Makefile
>> b/drivers/bus/mhi/sahara/Makefile
>> new file mode 100644
>> index
>> 0000000000000000000000000000000000000000..fc02a25935011cbd7138ea8f24b88cf5b032a4ce
>> --- /dev/null
>> +++ b/drivers/bus/mhi/sahara/Makefile
>> @@ -0,0 +1,2 @@
>> +obj-$(CONFIG_MHI_SAHARA) += mhi_sahara.o
>> +mhi_sahara-y := sahara.o
>> diff --git a/drivers/accel/qaic/sahara.c
>> b/drivers/bus/mhi/sahara/sahara.c
>> similarity index 99%
>> rename from drivers/accel/qaic/sahara.c
>> rename to drivers/bus/mhi/sahara/sahara.c
>> index
>> fd3c3b2d1fd3bb698809e6ca669128e2dce06613..8ff7b6425ac5423ef8f32117151dca10397686a8
>> 100644
>> --- a/drivers/accel/qaic/sahara.c
>> +++ b/drivers/bus/mhi/sahara/sahara.c
>> @@ -1,6 +1,8 @@
>> -// SPDX-License-Identifier: GPL-2.0-only
>> -
>> -/* Copyright (c) 2024 Qualcomm Innovation Center, Inc. All rights
>> reserved. */
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.
>> + *
>> + */
>
> What makes you think that changing the copyright markings is
> appropiate when moving a file?
>
> Furthermore, I wrote this code from scratch based on the spec document
> and therefore know beyond a doubt that this file did not exist prior
> to 2024, so what you are changing the markings to is completely invalid.
>
> Also the SPDX marking you are using is long deprecated and should not
> be used.
Sorry. I misunderstood the review comment that was given on v1 patchset.
Only the copyright style needs to match the subsystem where this driver
is moved to. I will make the changes in the next patch set.
>
>> #include <linux/devcoredump.h>
>> #include <linux/firmware.h>
>> @@ -9,12 +11,11 @@
>> #include <linux/minmax.h>
>> #include <linux/mod_devicetable.h>
>> #include <linux/overflow.h>
>> +#include <linux/sahara.h>
>> #include <linux/types.h>
>> #include <linux/vmalloc.h>
>> #include <linux/workqueue.h>
>> -#include "sahara.h"
>> -
>> #define SAHARA_HELLO_CMD 0x1 /* Min protocol version 1.0 */
>> #define SAHARA_HELLO_RESP_CMD 0x2 /* Min protocol version
>> 1.0 */
>> #define SAHARA_READ_DATA_CMD 0x3 /* Min protocol version
>> 1.0 */
>> @@ -928,8 +929,13 @@ int sahara_register(void)
>> {
>> return mhi_driver_register(&sahara_mhi_driver);
>> }
>> +module_init(sahara_register);
>> void sahara_unregister(void)
>> {
>> mhi_driver_unregister(&sahara_mhi_driver);
>> }
>> +module_exit(sahara_unregister);
>> +
>> +MODULE_LICENSE("GPL");
>> +MODULE_DESCRIPTION("Qualcomm Sahara MHI protocol driver");
>> diff --git a/drivers/accel/qaic/sahara.h b/include/linux/sahara.h
>> similarity index 100%
>> rename from drivers/accel/qaic/sahara.h
>> rename to include/linux/sahara.h
>>
>
^ permalink raw reply
* Re: [PATCH v4 1/9] Add documentation for Sahara protocol.
From: Kishore Batta @ 2026-04-13 9:03 UTC (permalink / raw)
To: Jeff Hugo, Jonathan Corbet, Shuah Khan, Carl Vanderlip,
Oded Gabbay, Manivannan Sadhasivam, andersson
Cc: linux-doc, linux-kernel, linux-arm-msm, dri-devel, mhi
In-Reply-To: <a793d256-f0e6-4a95-943d-e5d85c781428@oss.qualcomm.com>
On 4/10/2026 1:17 AM, Jeff Hugo wrote:
> $SUBJECT is not a complete sentence. You should drop the full stop ".".
Sure. I will drop in the next patch.
>
> On 3/19/2026 12:31 AM, Kishore Batta wrote:
>> Introduce documentation for the Sahara protocol, describing its
>> operational modes and their respective functions. The image transfer
>> mode
>> enables firmware transfer from host to device. The memory debug mode
>> allows extraction of device memory contents to host. The command mode
>> facilitates retrieval of DDR training data from the device and also
>> to restore the training data back to device in subsequent boot of device
>> to save boot time.
>
> Thank you for the documentation.
>
>>
>> Signed-off-by: Kishore Batta <kishore.batta@oss.qualcomm.com>
>> ---
>> Documentation/sahara/index.rst | 14 +
>> Documentation/sahara/sahara_protocol.rst | 1241
>> ++++++++++++++++++++++++++++++
>
> I see from the cover letter that the sahara implementation is moving
> under MHI. I expect to have more about that move later in the series,
> but MHI already has a documentation directory. I don't see why Sahara
> should be at the top level if it is considered to be coupled to MHI.
>
Okay. I have shared comments later in the series. Once its concluded, I
will move the documentation to the right directory.
>> 2 files changed, 1255 insertions(+)
>>
>> diff --git a/Documentation/sahara/index.rst
>> b/Documentation/sahara/index.rst
>> new file mode 100644
>> index
>> 0000000000000000000000000000000000000000..073002c15a203344524e258b2aa0a6ce839e064b
>> --- /dev/null
>> +++ b/Documentation/sahara/index.rst
>> @@ -0,0 +1,14 @@
>> +.. SPDX-License-Identifier: GPL-2.0-only
>> +
>> +========================
>> +Qualcomm Sahara protocol
>> +========================
>> +
>> +The Sahara protocol transfers data to and from memory and describes
>> packet
>> +structures, packet flows, and their usage.
>> +
>> +.. toctree::
>> + :maxdepth: 2
>> + :caption: Contents
>> +
>> + sahara_protocol
>> diff --git a/Documentation/sahara/sahara_protocol.rst
>> b/Documentation/sahara/sahara_protocol.rst
>> new file mode 100644
>> index
>> 0000000000000000000000000000000000000000..91204bb7d170be4fc4c85f142b8f0b93d3c421a0
>> --- /dev/null
>> +++ b/Documentation/sahara/sahara_protocol.rst
>> @@ -0,0 +1,1241 @@
>> +.. SPDX-License-Identifier: GPL-2.0-only
>> +
>> +
>> +=============================
>> +Sahara protocol Specification
>> +=============================
>> +
>> +The Qualcomm Sahara protocol driver is primarily designed for
>> transferring
>> +software images from a host device to a target device using a
>> simplified data
>> +transfer mechanism over a link. However, the sahara protocol does
>> not support
>
> "Sahara" should be capital "S" everywhere in this patch.
Sure. I will make changes accordingly.
^ permalink raw reply
* Re: [PATCH v6 4/4] KVM: arm64: selftests: Test PMU_V3_FIXED_COUNTERS_ONLY
From: Akihiko Odaki @ 2026-04-13 8:19 UTC (permalink / raw)
To: Marc Zyngier, Oliver Upton, Joey Gouly, Suzuki K Poulose,
Zenghui Yu, Catalin Marinas, Will Deacon, Kees Cook,
Gustavo A. R. Silva, Paolo Bonzini, Jonathan Corbet, Shuah Khan
Cc: linux-arm-kernel, kvmarm, linux-kernel, linux-hardening, devel,
kvm, linux-doc, linux-kselftest
In-Reply-To: <20260413-hybrid-v6-4-e79d760f7f1b@rsg.ci.i.u-tokyo.ac.jp>
On 2026/04/13 17:07, Akihiko Odaki wrote:
> Assert the following:
> - KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY is unset at initialization.
> - KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY can be set.
> - Setting KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY for the first time
> after setting an event filter results in EBUSY.
> - KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY can be set again even if an
> event filter has already been set.
> - Setting KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY after running a VCPU
> results in EBUSY.
> - The existing test cases pass with
> KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY set.
>
> Signed-off-by: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>
> ---
> .../selftests/kvm/arm64/vpmu_counter_access.c | 147 +++++++++++++++++----
> 1 file changed, 123 insertions(+), 24 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/arm64/vpmu_counter_access.c b/tools/testing/selftests/kvm/arm64/vpmu_counter_access.c
> index ae36325c022f..6e2bf3ad63b2 100644
> --- a/tools/testing/selftests/kvm/arm64/vpmu_counter_access.c
> +++ b/tools/testing/selftests/kvm/arm64/vpmu_counter_access.c
> @@ -403,12 +403,7 @@ static void create_vpmu_vm(void *guest_code)
> {
> struct kvm_vcpu_init init;
> uint8_t pmuver, ec;
> - uint64_t dfr0, irq = 23;
> - struct kvm_device_attr irq_attr = {
> - .group = KVM_ARM_VCPU_PMU_V3_CTRL,
> - .attr = KVM_ARM_VCPU_PMU_V3_IRQ,
> - .addr = (uint64_t)&irq,
> - };
> + uint64_t dfr0;
>
> /* The test creates the vpmu_vm multiple times. Ensure a clean state */
> memset(&vpmu_vm, 0, sizeof(vpmu_vm));
> @@ -434,8 +429,6 @@ static void create_vpmu_vm(void *guest_code)
> TEST_ASSERT(pmuver != ID_AA64DFR0_EL1_PMUVer_IMP_DEF &&
> pmuver >= ID_AA64DFR0_EL1_PMUVer_IMP,
> "Unexpected PMUVER (0x%x) on the vCPU with PMUv3", pmuver);
> -
> - vcpu_ioctl(vpmu_vm.vcpu, KVM_SET_DEVICE_ATTR, &irq_attr);
> }
>
> static void destroy_vpmu_vm(void)
> @@ -461,15 +454,25 @@ static void run_vcpu(struct kvm_vcpu *vcpu, uint64_t pmcr_n)
> }
> }
>
> -static void test_create_vpmu_vm_with_nr_counters(unsigned int nr_counters, bool expect_fail)
> +static void test_create_vpmu_vm_with_nr_counters(unsigned int nr_counters,
> + bool fixed_counters_only,
> + bool expect_fail)
> {
> struct kvm_vcpu *vcpu;
> unsigned int prev;
> int ret;
> + uint64_t irq = 23;
>
> create_vpmu_vm(guest_code);
> vcpu = vpmu_vm.vcpu;
>
> + if (fixed_counters_only)
> + vcpu_device_attr_set(vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
> + KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY, NULL);
> +
> + vcpu_device_attr_set(vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
> + KVM_ARM_VCPU_PMU_V3_IRQ, &irq);
> +
> prev = get_pmcr_n(vcpu_get_reg(vcpu, KVM_ARM64_SYS_REG(SYS_PMCR_EL0)));
>
> ret = __vcpu_device_attr_set(vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
> @@ -489,15 +492,15 @@ static void test_create_vpmu_vm_with_nr_counters(unsigned int nr_counters, bool
> * Create a guest with one vCPU, set the PMCR_EL0.N for the vCPU to @pmcr_n,
> * and run the test.
> */
> -static void run_access_test(uint64_t pmcr_n)
> +static void run_access_test(uint64_t pmcr_n, bool fixed_counters_only)
> {
> uint64_t sp;
> struct kvm_vcpu *vcpu;
> struct kvm_vcpu_init init;
>
> - pr_debug("Test with pmcr_n %lu\n", pmcr_n);
> + pr_debug("Test with pmcr_n %lu, fixed_counters_only %d\n", pmcr_n, fixed_counters_only);
>
> - test_create_vpmu_vm_with_nr_counters(pmcr_n, false);
> + test_create_vpmu_vm_with_nr_counters(pmcr_n, fixed_counters_only, false);
> vcpu = vpmu_vm.vcpu;
>
> /* Save the initial sp to restore them later to run the guest again */
> @@ -531,14 +534,14 @@ static struct pmreg_sets validity_check_reg_sets[] = {
> * Create a VM, and check if KVM handles the userspace accesses of
> * the PMU register sets in @validity_check_reg_sets[] correctly.
> */
> -static void run_pmregs_validity_test(uint64_t pmcr_n)
> +static void run_pmregs_validity_test(uint64_t pmcr_n, bool fixed_counters_only)
> {
> int i;
> struct kvm_vcpu *vcpu;
> uint64_t set_reg_id, clr_reg_id, reg_val;
> uint64_t valid_counters_mask, max_counters_mask;
>
> - test_create_vpmu_vm_with_nr_counters(pmcr_n, false);
> + test_create_vpmu_vm_with_nr_counters(pmcr_n, fixed_counters_only, false);
> vcpu = vpmu_vm.vcpu;
>
> valid_counters_mask = get_counters_mask(pmcr_n);
> @@ -588,11 +591,11 @@ static void run_pmregs_validity_test(uint64_t pmcr_n)
> * the vCPU to @pmcr_n, which is larger than the host value.
> * The attempt should fail as @pmcr_n is too big to set for the vCPU.
> */
> -static void run_error_test(uint64_t pmcr_n)
> +static void run_error_test(uint64_t pmcr_n, bool fixed_counters_only)
> {
> pr_debug("Error test with pmcr_n %lu (larger than the host)\n", pmcr_n);
>
> - test_create_vpmu_vm_with_nr_counters(pmcr_n, true);
> + test_create_vpmu_vm_with_nr_counters(pmcr_n, fixed_counters_only, true);
> destroy_vpmu_vm();
> }
>
> @@ -622,22 +625,118 @@ static bool kvm_supports_nr_counters_attr(void)
> return supported;
> }
>
> +static void test_config(uint64_t pmcr_n, bool fixed_counters_only)
> +{
> + uint64_t i;
> +
> + for (i = 0; i <= pmcr_n; i++) {
> + run_access_test(i, fixed_counters_only);
> + run_pmregs_validity_test(i, fixed_counters_only);
> + }
> +
> + for (i = pmcr_n + 1; i < ARMV8_PMU_MAX_COUNTERS; i++)
> + run_error_test(i, fixed_counters_only);
> +}
> +
> +static void test_fixed_counters_only(uint64_t pmcr_n)
> +{
> + struct kvm_pmu_event_filter filter = { .nevents = 0 };
> + struct kvm_vm *vm;
> + struct kvm_vcpu *running_vcpu;
> + struct kvm_vcpu *stopped_vcpu;
> + struct kvm_vcpu_init init;
> + int ret;
> + uint64_t irq = 23;
> +
> + create_vpmu_vm(guest_code);
> + ret = __vcpu_has_device_attr(vpmu_vm.vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
> + KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY);
> + if (ret) {
> + TEST_ASSERT(ret == -1 && errno == ENXIO,
> + KVM_IOCTL_ERROR(KVM_HAS_DEVICE_ATTR, ret));
> + destroy_vpmu_vm();
> + return;
> + }
> +
> + /* Assert that FIXED_COUNTERS_ONLY is unset at initialization. */
> + ret = __vcpu_device_attr_get(vpmu_vm.vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
> + KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY, NULL);
> + TEST_ASSERT(ret == -1 && errno == ENXIO,
> + KVM_IOCTL_ERROR(KVM_GET_DEVICE_ATTR, ret));
> +
> + /* Assert that setting FIXED_COUNTERS_ONLY succeeds. */
> + vcpu_device_attr_set(vpmu_vm.vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
> + KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY, NULL);
> +
> + /* Assert that getting FIXED_COUNTERS_ONLY succeeds. */
> + vcpu_device_attr_get(vpmu_vm.vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
> + KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY, NULL);
> +
> + /*
> + * Assert that setting FIXED_COUNTERS_ONLY again succeeds even if an
> + * event filter has already been set.
> + */
> + vcpu_device_attr_set(vpmu_vm.vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
> + KVM_ARM_VCPU_PMU_V3_FILTER, &filter);
> +
> + vcpu_device_attr_set(vpmu_vm.vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
> + KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY, NULL);
> +
> + destroy_vpmu_vm();
> +
> + create_vpmu_vm(guest_code);
> +
> + /*
> + * Assert that setting FIXED_COUNTERS_ONLY results in EBUSY if an event
> + * filter has already been set while FIXED_COUNTERS_ONLY has not.
> + */
> + vcpu_device_attr_set(vpmu_vm.vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
> + KVM_ARM_VCPU_PMU_V3_FILTER, &filter);
> +
> + ret = __vcpu_device_attr_set(vpmu_vm.vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
> + KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY, NULL);
> + TEST_ASSERT(ret == -1 && errno == EBUSY,
> + KVM_IOCTL_ERROR(KVM_SET_DEVICE_ATTR, ret));
> +
> + destroy_vpmu_vm();
> +
> + /*
> + * Assert that setting FIXED_COUNTERS_ONLY after running a VCPU results
> + * in EBUSY.
> + */
> + vm = vm_create(2);
> + vm_ioctl(vm, KVM_ARM_PREFERRED_TARGET, &init);
> + init.features[0] |= (1 << KVM_ARM_VCPU_PMU_V3);
> + running_vcpu = aarch64_vcpu_add(vm, 0, &init, guest_code);
> + stopped_vcpu = aarch64_vcpu_add(vm, 1, &init, guest_code);
> + kvm_arch_vm_finalize_vcpus(vm);
> + vcpu_device_attr_set(running_vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
> + KVM_ARM_VCPU_PMU_V3_IRQ, &irq);
> + vcpu_device_attr_set(running_vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
> + KVM_ARM_VCPU_PMU_V3_INIT, NULL);
> + run_vcpu(running_vcpu, pmcr_n);
Sorry, I sent a series before testing by mistake. This hangs the test
and I'll send a fix later. Anything else is fine and ready for review.
Regards,
Akihiko Odaki
> +
> + ret = __vcpu_device_attr_set(stopped_vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
> + KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY, NULL);
> + TEST_ASSERT(ret == -1 && errno == EBUSY,
> + KVM_IOCTL_ERROR(KVM_SET_DEVICE_ATTR, ret));
> +
> + kvm_vm_free(vm);
> +
> + test_config(0, true);
> +}
> +
> int main(void)
> {
> - uint64_t i, pmcr_n;
> + uint64_t pmcr_n;
>
> TEST_REQUIRE(kvm_has_cap(KVM_CAP_ARM_PMU_V3));
> TEST_REQUIRE(kvm_supports_vgic_v3());
> TEST_REQUIRE(kvm_supports_nr_counters_attr());
>
> pmcr_n = get_pmcr_n_limit();
> - for (i = 0; i <= pmcr_n; i++) {
> - run_access_test(i);
> - run_pmregs_validity_test(i);
> - }
> -
> - for (i = pmcr_n + 1; i < ARMV8_PMU_MAX_COUNTERS; i++)
> - run_error_test(i);
> + test_config(pmcr_n, false);
> + test_fixed_counters_only(pmcr_n);
>
> return 0;
> }
>
^ permalink raw reply
* [PATCH v6 2/4] KVM: arm64: PMU: Protect the list of PMUs with RCU
From: Akihiko Odaki @ 2026-04-13 8:07 UTC (permalink / raw)
To: Marc Zyngier, Oliver Upton, Joey Gouly, Suzuki K Poulose,
Zenghui Yu, Catalin Marinas, Will Deacon, Kees Cook,
Gustavo A. R. Silva, Paolo Bonzini, Jonathan Corbet, Shuah Khan
Cc: linux-arm-kernel, kvmarm, linux-kernel, linux-hardening, devel,
kvm, linux-doc, linux-kselftest, Akihiko Odaki
In-Reply-To: <20260413-hybrid-v6-0-e79d760f7f1b@rsg.ci.i.u-tokyo.ac.jp>
Convert the list of PMUs to a RCU-protected list that has primitives to
avoid read-side contention.
Signed-off-by: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>
---
arch/arm64/kvm/pmu-emul.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)
diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
index 59ec96e09321..ef5140bbfe28 100644
--- a/arch/arm64/kvm/pmu-emul.c
+++ b/arch/arm64/kvm/pmu-emul.c
@@ -7,9 +7,9 @@
#include <linux/cpu.h>
#include <linux/kvm.h>
#include <linux/kvm_host.h>
-#include <linux/list.h>
#include <linux/perf_event.h>
#include <linux/perf/arm_pmu.h>
+#include <linux/rculist.h>
#include <linux/uaccess.h>
#include <asm/kvm_emulate.h>
#include <kvm/arm_pmu.h>
@@ -26,7 +26,6 @@ static bool kvm_pmu_counter_is_enabled(struct kvm_pmc *pmc);
bool kvm_supports_guest_pmuv3(void)
{
- guard(mutex)(&arm_pmus_lock);
return !list_empty(&arm_pmus);
}
@@ -808,7 +807,7 @@ void kvm_host_pmu_init(struct arm_pmu *pmu)
return;
entry->arm_pmu = pmu;
- list_add_tail(&entry->entry, &arm_pmus);
+ list_add_tail_rcu(&entry->entry, &arm_pmus);
}
static struct arm_pmu *kvm_pmu_probe_armpmu(void)
@@ -817,7 +816,7 @@ static struct arm_pmu *kvm_pmu_probe_armpmu(void)
struct arm_pmu *pmu;
int cpu;
- guard(mutex)(&arm_pmus_lock);
+ guard(rcu)();
/*
* It is safe to use a stale cpu to iterate the list of PMUs so long as
@@ -837,7 +836,7 @@ static struct arm_pmu *kvm_pmu_probe_armpmu(void)
* carried here.
*/
cpu = raw_smp_processor_id();
- list_for_each_entry(entry, &arm_pmus, entry) {
+ list_for_each_entry_rcu(entry, &arm_pmus, entry) {
pmu = entry->arm_pmu;
if (cpumask_test_cpu(cpu, &pmu->supported_cpus))
@@ -1088,9 +1087,9 @@ static int kvm_arm_pmu_v3_set_pmu(struct kvm_vcpu *vcpu, int pmu_id)
int ret = -ENXIO;
lockdep_assert_held(&kvm->arch.config_lock);
- mutex_lock(&arm_pmus_lock);
+ guard(rcu)();
- list_for_each_entry(entry, &arm_pmus, entry) {
+ list_for_each_entry_rcu(entry, &arm_pmus, entry) {
arm_pmu = entry->arm_pmu;
if (arm_pmu->pmu.type == pmu_id) {
if (kvm_vm_has_ran_once(kvm) ||
@@ -1106,7 +1105,6 @@ static int kvm_arm_pmu_v3_set_pmu(struct kvm_vcpu *vcpu, int pmu_id)
}
}
- mutex_unlock(&arm_pmus_lock);
return ret;
}
--
2.53.0
^ permalink raw reply related
* [PATCH v6 3/4] KVM: arm64: PMU: Introduce FIXED_COUNTERS_ONLY
From: Akihiko Odaki @ 2026-04-13 8:07 UTC (permalink / raw)
To: Marc Zyngier, Oliver Upton, Joey Gouly, Suzuki K Poulose,
Zenghui Yu, Catalin Marinas, Will Deacon, Kees Cook,
Gustavo A. R. Silva, Paolo Bonzini, Jonathan Corbet, Shuah Khan
Cc: linux-arm-kernel, kvmarm, linux-kernel, linux-hardening, devel,
kvm, linux-doc, linux-kselftest, Akihiko Odaki
In-Reply-To: <20260413-hybrid-v6-0-e79d760f7f1b@rsg.ci.i.u-tokyo.ac.jp>
On a heterogeneous arm64 system, KVM's PMU emulation is based on the
features of a single host PMU instance. When a vCPU is migrated to a
pCPU with an incompatible PMU, counters such as PMCCNTR_EL0 stop
incrementing.
Although this behavior is permitted by the architecture, Windows does
not handle it gracefully and may crash with a division-by-zero error.
The current workaround requires VMMs to pin vCPUs to a set of pCPUs
that share a compatible PMU. This is difficult to implement correctly in
QEMU/libvirt, where pinning occurs after vCPU initialization, and it
also restricts the guest to a subset of available pCPUs.
Introduce the KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY attribute to
create a "fixed-counters-only" PMU. When set, KVM exposes a PMU that is
compatible with all pCPUs but that does not support programmable
event counters which may have different feature sets on different PMUs.
This allows Windows guests to run reliably on heterogeneous systems
without crashing, even without vCPU pinning, and enables VMMs to
schedule vCPUs across all available pCPUs, making full use of the host
hardware.
Much like KVM_ARM_VCPU_PMU_V3_IRQ and other read-write attributes, this
attribute provides a getter that facilitates kernel and userspace
debugging/testing.
Signed-off-by: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>
---
Documentation/virt/kvm/devices/vcpu.rst | 29 ++++++
arch/arm64/include/asm/kvm_host.h | 2 +
arch/arm64/include/uapi/asm/kvm.h | 1 +
arch/arm64/kvm/arm.c | 1 +
arch/arm64/kvm/pmu-emul.c | 155 +++++++++++++++++++++++---------
include/kvm/arm_pmu.h | 2 +
6 files changed, 147 insertions(+), 43 deletions(-)
diff --git a/Documentation/virt/kvm/devices/vcpu.rst b/Documentation/virt/kvm/devices/vcpu.rst
index 60bf205cb373..e0aeb1897d77 100644
--- a/Documentation/virt/kvm/devices/vcpu.rst
+++ b/Documentation/virt/kvm/devices/vcpu.rst
@@ -161,6 +161,35 @@ explicitly selected, or the number of counters is out of range for the
selected PMU. Selecting a new PMU cancels the effect of setting this
attribute.
+1.6 ATTRIBUTE: KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY
+------------------------------------------------------
+
+:Parameters: no additional parameter in kvm_device_attr.addr
+
+:Returns:
+
+ ======= =====================================================
+ -EBUSY Attempted to set after initializing PMUv3 or running
+ VCPU, or attempted to set for the first time after
+ setting an event filter
+ -ENXIO Attempted to get before setting
+ -ENODEV Attempted to set while PMUv3 not supported
+ ======= =====================================================
+
+If set, PMUv3 will be emulated without programmable event counters. The VCPU
+will use any compatible hardware PMU. This attribute is particularly useful on
+heterogeneous systems where different hardware PMUs cover different physical
+CPUs. The compatibility of hardware PMUs can be checked with
+KVM_ARM_VCPU_PMU_V3_SET_PMU. All VCPUs in a VM share this attribute. It isn't
+possible to set it for the first time if a PMU event filter is already present.
+
+Note that KVM will not make any attempts to run the VCPU on the physical CPUs
+with compatible hardware PMUs. This is entirely left to userspace. However,
+attempting to run the VCPU on an unsupported CPU will fail and KVM_RUN will
+return with exit_reason = KVM_EXIT_FAIL_ENTRY and populate the fail_entry struct
+by setting hardware_entry_failure_reason field to
+KVM_EXIT_FAIL_ENTRY_CPU_UNSUPPORTED and the cpu field to the processor id.
+
2. GROUP: KVM_ARM_VCPU_TIMER_CTRL
=================================
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 59f25b85be2b..b59e0182472c 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -353,6 +353,8 @@ struct kvm_arch {
#define KVM_ARCH_FLAG_WRITABLE_IMP_ID_REGS 10
/* Unhandled SEAs are taken to userspace */
#define KVM_ARCH_FLAG_EXIT_SEA 11
+ /* PMUv3 is emulated without progammable event counters */
+#define KVM_ARCH_FLAG_PMU_V3_FIXED_COUNTERS_ONLY 12
unsigned long flags;
/* VM-wide vCPU feature set */
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index a792a599b9d6..474c84fa757f 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -436,6 +436,7 @@ enum {
#define KVM_ARM_VCPU_PMU_V3_FILTER 2
#define KVM_ARM_VCPU_PMU_V3_SET_PMU 3
#define KVM_ARM_VCPU_PMU_V3_SET_NR_COUNTERS 4
+#define KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY 5
#define KVM_ARM_VCPU_TIMER_CTRL 1
#define KVM_ARM_VCPU_TIMER_IRQ_VTIMER 0
#define KVM_ARM_VCPU_TIMER_IRQ_PTIMER 1
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 620a465248d1..dca16ca26d32 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -634,6 +634,7 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
if (has_vhe())
kvm_vcpu_load_vhe(vcpu);
kvm_arch_vcpu_load_fp(vcpu);
+ kvm_vcpu_load_pmu(vcpu);
kvm_vcpu_pmu_restore_guest(vcpu);
if (kvm_arm_is_pvtime_enabled(&vcpu->arch))
kvm_make_request(KVM_REQ_RECORD_STEAL, vcpu);
diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
index ef5140bbfe28..d1009c144581 100644
--- a/arch/arm64/kvm/pmu-emul.c
+++ b/arch/arm64/kvm/pmu-emul.c
@@ -326,7 +326,10 @@ u64 kvm_pmu_implemented_counter_mask(struct kvm_vcpu *vcpu)
static void kvm_pmc_enable_perf_event(struct kvm_pmc *pmc)
{
- if (!pmc->perf_event) {
+ struct kvm_vcpu *vcpu = kvm_pmc_to_vcpu(pmc);
+
+ if (!pmc->perf_event ||
+ !cpumask_test_cpu(vcpu->cpu, &to_arm_pmu(pmc->perf_event->pmu)->supported_cpus)) {
kvm_pmu_create_perf_event(pmc);
return;
}
@@ -667,10 +670,8 @@ static bool kvm_pmc_counts_at_el2(struct kvm_pmc *pmc)
return kvm_pmc_read_evtreg(pmc) & ARMV8_PMU_INCLUDE_EL2;
}
-static int kvm_map_pmu_event(struct kvm *kvm, unsigned int eventsel)
+static int kvm_map_pmu_event(struct arm_pmu *pmu, unsigned int eventsel)
{
- struct arm_pmu *pmu = kvm->arch.arm_pmu;
-
/*
* The CPU PMU likely isn't PMUv3; let the driver provide a mapping
* for the guest's PMUv3 event ID.
@@ -681,6 +682,23 @@ static int kvm_map_pmu_event(struct kvm *kvm, unsigned int eventsel)
return eventsel;
}
+static struct arm_pmu *kvm_pmu_probe_armpmu(int cpu)
+{
+ struct arm_pmu_entry *entry;
+ struct arm_pmu *pmu;
+
+ guard(rcu)();
+
+ list_for_each_entry_rcu(entry, &arm_pmus, entry) {
+ pmu = entry->arm_pmu;
+
+ if (cpumask_test_cpu(cpu, &pmu->supported_cpus))
+ return pmu;
+ }
+
+ return NULL;
+}
+
/**
* kvm_pmu_create_perf_event - create a perf event for a counter
* @pmc: Counter context
@@ -694,6 +712,12 @@ static void kvm_pmu_create_perf_event(struct kvm_pmc *pmc)
int eventsel;
u64 evtreg;
+ if (test_bit(KVM_ARCH_FLAG_PMU_V3_FIXED_COUNTERS_ONLY, &vcpu->kvm->arch.flags)) {
+ arm_pmu = kvm_pmu_probe_armpmu(vcpu->cpu);
+ if (!arm_pmu)
+ return;
+ }
+
evtreg = kvm_pmc_read_evtreg(pmc);
kvm_pmu_stop_counter(pmc);
@@ -722,7 +746,7 @@ static void kvm_pmu_create_perf_event(struct kvm_pmc *pmc)
* Don't create an event if we're running on hardware that requires
* PMUv3 event translation and we couldn't find a valid mapping.
*/
- eventsel = kvm_map_pmu_event(vcpu->kvm, eventsel);
+ eventsel = kvm_map_pmu_event(arm_pmu, eventsel);
if (eventsel < 0)
return;
@@ -810,42 +834,6 @@ void kvm_host_pmu_init(struct arm_pmu *pmu)
list_add_tail_rcu(&entry->entry, &arm_pmus);
}
-static struct arm_pmu *kvm_pmu_probe_armpmu(void)
-{
- struct arm_pmu_entry *entry;
- struct arm_pmu *pmu;
- int cpu;
-
- guard(rcu)();
-
- /*
- * It is safe to use a stale cpu to iterate the list of PMUs so long as
- * the same value is used for the entirety of the loop. Given this, and
- * the fact that no percpu data is used for the lookup there is no need
- * to disable preemption.
- *
- * It is still necessary to get a valid cpu, though, to probe for the
- * default PMU instance as userspace is not required to specify a PMU
- * type. In order to uphold the preexisting behavior KVM selects the
- * PMU instance for the core during vcpu init. A dependent use
- * case would be a user with disdain of all things big.LITTLE that
- * affines the VMM to a particular cluster of cores.
- *
- * In any case, userspace should just do the sane thing and use the UAPI
- * to select a PMU type directly. But, be wary of the baggage being
- * carried here.
- */
- cpu = raw_smp_processor_id();
- list_for_each_entry_rcu(entry, &arm_pmus, entry) {
- pmu = entry->arm_pmu;
-
- if (cpumask_test_cpu(cpu, &pmu->supported_cpus))
- return pmu;
- }
-
- return NULL;
-}
-
static u64 __compute_pmceid(struct arm_pmu *pmu, bool pmceid1)
{
u32 hi[2], lo[2];
@@ -888,6 +876,9 @@ u64 kvm_pmu_get_pmceid(struct kvm_vcpu *vcpu, bool pmceid1)
u64 val, mask = 0;
int base, i, nr_events;
+ if (test_bit(KVM_ARCH_FLAG_PMU_V3_FIXED_COUNTERS_ONLY, &vcpu->kvm->arch.flags))
+ return 0;
+
if (!pmceid1) {
val = compute_pmceid0(cpu_pmu);
base = 0;
@@ -915,6 +906,26 @@ u64 kvm_pmu_get_pmceid(struct kvm_vcpu *vcpu, bool pmceid1)
return val & mask;
}
+void kvm_vcpu_load_pmu(struct kvm_vcpu *vcpu)
+{
+ unsigned long mask = kvm_pmu_enabled_counter_mask(vcpu);
+ struct kvm_pmc *pmc;
+ struct arm_pmu *cpu_pmu;
+ int i;
+
+ for_each_set_bit(i, &mask, 32) {
+ pmc = kvm_vcpu_idx_to_pmc(vcpu, i);
+ if (!pmc->perf_event)
+ continue;
+
+ cpu_pmu = to_arm_pmu(pmc->perf_event->pmu);
+ if (!cpumask_test_cpu(vcpu->cpu, &cpu_pmu->supported_cpus)) {
+ kvm_make_request(KVM_REQ_RELOAD_PMU, vcpu);
+ break;
+ }
+ }
+}
+
void kvm_vcpu_reload_pmu(struct kvm_vcpu *vcpu)
{
u64 mask = kvm_pmu_implemented_counter_mask(vcpu);
@@ -1016,6 +1027,9 @@ u8 kvm_arm_pmu_get_max_counters(struct kvm *kvm)
{
struct arm_pmu *arm_pmu = kvm->arch.arm_pmu;
+ if (test_bit(KVM_ARCH_FLAG_PMU_V3_FIXED_COUNTERS_ONLY, &kvm->arch.flags))
+ return 0;
+
/*
* PMUv3 requires that all event counters are capable of counting any
* event, though the same may not be true of non-PMUv3 hardware.
@@ -1070,7 +1084,24 @@ static void kvm_arm_set_pmu(struct kvm *kvm, struct arm_pmu *arm_pmu)
*/
int kvm_arm_set_default_pmu(struct kvm *kvm)
{
- struct arm_pmu *arm_pmu = kvm_pmu_probe_armpmu();
+ /*
+ * It is safe to use a stale cpu to iterate the list of PMUs so long as
+ * the same value is used for the entirety of the loop. Given this, and
+ * the fact that no percpu data is used for the lookup there is no need
+ * to disable preemption.
+ *
+ * It is still necessary to get a valid cpu, though, to probe for the
+ * default PMU instance as userspace is not required to specify a PMU
+ * type. In order to uphold the preexisting behavior KVM selects the
+ * PMU instance for the core during vcpu init. A dependent use
+ * case would be a user with disdain of all things big.LITTLE that
+ * affines the VMM to a particular cluster of cores.
+ *
+ * In any case, userspace should just do the sane thing and use the UAPI
+ * to select a PMU type directly. But, be wary of the baggage being
+ * carried here.
+ */
+ struct arm_pmu *arm_pmu = kvm_pmu_probe_armpmu(raw_smp_processor_id());
if (!arm_pmu)
return -ENODEV;
@@ -1098,6 +1129,7 @@ static int kvm_arm_pmu_v3_set_pmu(struct kvm_vcpu *vcpu, int pmu_id)
break;
}
+ clear_bit(KVM_ARCH_FLAG_PMU_V3_FIXED_COUNTERS_ONLY, &kvm->arch.flags);
kvm_arm_set_pmu(kvm, arm_pmu);
cpumask_copy(kvm->arch.supported_cpus, &arm_pmu->supported_cpus);
ret = 0;
@@ -1108,11 +1140,42 @@ static int kvm_arm_pmu_v3_set_pmu(struct kvm_vcpu *vcpu, int pmu_id)
return ret;
}
+static int kvm_arm_pmu_v3_set_pmu_fixed_counters_only(struct kvm_vcpu *vcpu)
+{
+ struct kvm *kvm = vcpu->kvm;
+ struct arm_pmu_entry *entry;
+ struct arm_pmu *arm_pmu;
+ struct cpumask *supported_cpus = kvm->arch.supported_cpus;
+
+ lockdep_assert_held(&kvm->arch.config_lock);
+
+ if (kvm_vm_has_ran_once(kvm) ||
+ (kvm->arch.pmu_filter &&
+ !test_bit(KVM_ARCH_FLAG_PMU_V3_FIXED_COUNTERS_ONLY, &kvm->arch.flags)))
+ return -EBUSY;
+
+ set_bit(KVM_ARCH_FLAG_PMU_V3_FIXED_COUNTERS_ONLY, &kvm->arch.flags);
+ kvm_arm_set_nr_counters(kvm, 0);
+ cpumask_clear(supported_cpus);
+
+ guard(rcu)();
+
+ list_for_each_entry_rcu(entry, &arm_pmus, entry) {
+ arm_pmu = entry->arm_pmu;
+ cpumask_or(supported_cpus, supported_cpus, &arm_pmu->supported_cpus);
+ }
+
+ return 0;
+}
+
static int kvm_arm_pmu_v3_set_nr_counters(struct kvm_vcpu *vcpu, unsigned int n)
{
struct kvm *kvm = vcpu->kvm;
- if (!kvm->arch.arm_pmu)
+ lockdep_assert_held(&kvm->arch.config_lock);
+
+ if (!kvm->arch.arm_pmu &&
+ !test_bit(KVM_ARCH_FLAG_PMU_V3_FIXED_COUNTERS_ONLY, &kvm->arch.flags))
return -EINVAL;
if (n > kvm_arm_pmu_get_max_counters(kvm))
@@ -1227,6 +1290,8 @@ int kvm_arm_pmu_v3_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
return kvm_arm_pmu_v3_set_nr_counters(vcpu, n);
}
+ case KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY:
+ return kvm_arm_pmu_v3_set_pmu_fixed_counters_only(vcpu);
case KVM_ARM_VCPU_PMU_V3_INIT:
return kvm_arm_pmu_v3_init(vcpu);
}
@@ -1253,6 +1318,9 @@ int kvm_arm_pmu_v3_get_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
irq = vcpu->arch.pmu.irq_num;
return put_user(irq, uaddr);
}
+ case KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY:
+ if (test_bit(KVM_ARCH_FLAG_PMU_V3_FIXED_COUNTERS_ONLY, &vcpu->kvm->arch.flags))
+ return 0;
}
return -ENXIO;
@@ -1266,6 +1334,7 @@ int kvm_arm_pmu_v3_has_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
case KVM_ARM_VCPU_PMU_V3_FILTER:
case KVM_ARM_VCPU_PMU_V3_SET_PMU:
case KVM_ARM_VCPU_PMU_V3_SET_NR_COUNTERS:
+ case KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY:
if (kvm_vcpu_has_pmu(vcpu))
return 0;
}
diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
index 96754b51b411..1375cbaf97b2 100644
--- a/include/kvm/arm_pmu.h
+++ b/include/kvm/arm_pmu.h
@@ -56,6 +56,7 @@ void kvm_pmu_software_increment(struct kvm_vcpu *vcpu, u64 val);
void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u64 val);
void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data,
u64 select_idx);
+void kvm_vcpu_load_pmu(struct kvm_vcpu *vcpu);
void kvm_vcpu_reload_pmu(struct kvm_vcpu *vcpu);
int kvm_arm_pmu_v3_set_attr(struct kvm_vcpu *vcpu,
struct kvm_device_attr *attr);
@@ -161,6 +162,7 @@ static inline u64 kvm_pmu_get_pmceid(struct kvm_vcpu *vcpu, bool pmceid1)
static inline void kvm_pmu_update_vcpu_events(struct kvm_vcpu *vcpu) {}
static inline void kvm_vcpu_pmu_restore_guest(struct kvm_vcpu *vcpu) {}
static inline void kvm_vcpu_pmu_restore_host(struct kvm_vcpu *vcpu) {}
+static inline void kvm_vcpu_load_pmu(struct kvm_vcpu *vcpu) {}
static inline void kvm_vcpu_reload_pmu(struct kvm_vcpu *vcpu) {}
static inline u8 kvm_arm_pmu_get_pmuver_limit(void)
{
--
2.53.0
^ permalink raw reply related
* [PATCH v6 4/4] KVM: arm64: selftests: Test PMU_V3_FIXED_COUNTERS_ONLY
From: Akihiko Odaki @ 2026-04-13 8:07 UTC (permalink / raw)
To: Marc Zyngier, Oliver Upton, Joey Gouly, Suzuki K Poulose,
Zenghui Yu, Catalin Marinas, Will Deacon, Kees Cook,
Gustavo A. R. Silva, Paolo Bonzini, Jonathan Corbet, Shuah Khan
Cc: linux-arm-kernel, kvmarm, linux-kernel, linux-hardening, devel,
kvm, linux-doc, linux-kselftest, Akihiko Odaki
In-Reply-To: <20260413-hybrid-v6-0-e79d760f7f1b@rsg.ci.i.u-tokyo.ac.jp>
Assert the following:
- KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY is unset at initialization.
- KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY can be set.
- Setting KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY for the first time
after setting an event filter results in EBUSY.
- KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY can be set again even if an
event filter has already been set.
- Setting KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY after running a VCPU
results in EBUSY.
- The existing test cases pass with
KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY set.
Signed-off-by: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>
---
.../selftests/kvm/arm64/vpmu_counter_access.c | 147 +++++++++++++++++----
1 file changed, 123 insertions(+), 24 deletions(-)
diff --git a/tools/testing/selftests/kvm/arm64/vpmu_counter_access.c b/tools/testing/selftests/kvm/arm64/vpmu_counter_access.c
index ae36325c022f..6e2bf3ad63b2 100644
--- a/tools/testing/selftests/kvm/arm64/vpmu_counter_access.c
+++ b/tools/testing/selftests/kvm/arm64/vpmu_counter_access.c
@@ -403,12 +403,7 @@ static void create_vpmu_vm(void *guest_code)
{
struct kvm_vcpu_init init;
uint8_t pmuver, ec;
- uint64_t dfr0, irq = 23;
- struct kvm_device_attr irq_attr = {
- .group = KVM_ARM_VCPU_PMU_V3_CTRL,
- .attr = KVM_ARM_VCPU_PMU_V3_IRQ,
- .addr = (uint64_t)&irq,
- };
+ uint64_t dfr0;
/* The test creates the vpmu_vm multiple times. Ensure a clean state */
memset(&vpmu_vm, 0, sizeof(vpmu_vm));
@@ -434,8 +429,6 @@ static void create_vpmu_vm(void *guest_code)
TEST_ASSERT(pmuver != ID_AA64DFR0_EL1_PMUVer_IMP_DEF &&
pmuver >= ID_AA64DFR0_EL1_PMUVer_IMP,
"Unexpected PMUVER (0x%x) on the vCPU with PMUv3", pmuver);
-
- vcpu_ioctl(vpmu_vm.vcpu, KVM_SET_DEVICE_ATTR, &irq_attr);
}
static void destroy_vpmu_vm(void)
@@ -461,15 +454,25 @@ static void run_vcpu(struct kvm_vcpu *vcpu, uint64_t pmcr_n)
}
}
-static void test_create_vpmu_vm_with_nr_counters(unsigned int nr_counters, bool expect_fail)
+static void test_create_vpmu_vm_with_nr_counters(unsigned int nr_counters,
+ bool fixed_counters_only,
+ bool expect_fail)
{
struct kvm_vcpu *vcpu;
unsigned int prev;
int ret;
+ uint64_t irq = 23;
create_vpmu_vm(guest_code);
vcpu = vpmu_vm.vcpu;
+ if (fixed_counters_only)
+ vcpu_device_attr_set(vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
+ KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY, NULL);
+
+ vcpu_device_attr_set(vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
+ KVM_ARM_VCPU_PMU_V3_IRQ, &irq);
+
prev = get_pmcr_n(vcpu_get_reg(vcpu, KVM_ARM64_SYS_REG(SYS_PMCR_EL0)));
ret = __vcpu_device_attr_set(vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
@@ -489,15 +492,15 @@ static void test_create_vpmu_vm_with_nr_counters(unsigned int nr_counters, bool
* Create a guest with one vCPU, set the PMCR_EL0.N for the vCPU to @pmcr_n,
* and run the test.
*/
-static void run_access_test(uint64_t pmcr_n)
+static void run_access_test(uint64_t pmcr_n, bool fixed_counters_only)
{
uint64_t sp;
struct kvm_vcpu *vcpu;
struct kvm_vcpu_init init;
- pr_debug("Test with pmcr_n %lu\n", pmcr_n);
+ pr_debug("Test with pmcr_n %lu, fixed_counters_only %d\n", pmcr_n, fixed_counters_only);
- test_create_vpmu_vm_with_nr_counters(pmcr_n, false);
+ test_create_vpmu_vm_with_nr_counters(pmcr_n, fixed_counters_only, false);
vcpu = vpmu_vm.vcpu;
/* Save the initial sp to restore them later to run the guest again */
@@ -531,14 +534,14 @@ static struct pmreg_sets validity_check_reg_sets[] = {
* Create a VM, and check if KVM handles the userspace accesses of
* the PMU register sets in @validity_check_reg_sets[] correctly.
*/
-static void run_pmregs_validity_test(uint64_t pmcr_n)
+static void run_pmregs_validity_test(uint64_t pmcr_n, bool fixed_counters_only)
{
int i;
struct kvm_vcpu *vcpu;
uint64_t set_reg_id, clr_reg_id, reg_val;
uint64_t valid_counters_mask, max_counters_mask;
- test_create_vpmu_vm_with_nr_counters(pmcr_n, false);
+ test_create_vpmu_vm_with_nr_counters(pmcr_n, fixed_counters_only, false);
vcpu = vpmu_vm.vcpu;
valid_counters_mask = get_counters_mask(pmcr_n);
@@ -588,11 +591,11 @@ static void run_pmregs_validity_test(uint64_t pmcr_n)
* the vCPU to @pmcr_n, which is larger than the host value.
* The attempt should fail as @pmcr_n is too big to set for the vCPU.
*/
-static void run_error_test(uint64_t pmcr_n)
+static void run_error_test(uint64_t pmcr_n, bool fixed_counters_only)
{
pr_debug("Error test with pmcr_n %lu (larger than the host)\n", pmcr_n);
- test_create_vpmu_vm_with_nr_counters(pmcr_n, true);
+ test_create_vpmu_vm_with_nr_counters(pmcr_n, fixed_counters_only, true);
destroy_vpmu_vm();
}
@@ -622,22 +625,118 @@ static bool kvm_supports_nr_counters_attr(void)
return supported;
}
+static void test_config(uint64_t pmcr_n, bool fixed_counters_only)
+{
+ uint64_t i;
+
+ for (i = 0; i <= pmcr_n; i++) {
+ run_access_test(i, fixed_counters_only);
+ run_pmregs_validity_test(i, fixed_counters_only);
+ }
+
+ for (i = pmcr_n + 1; i < ARMV8_PMU_MAX_COUNTERS; i++)
+ run_error_test(i, fixed_counters_only);
+}
+
+static void test_fixed_counters_only(uint64_t pmcr_n)
+{
+ struct kvm_pmu_event_filter filter = { .nevents = 0 };
+ struct kvm_vm *vm;
+ struct kvm_vcpu *running_vcpu;
+ struct kvm_vcpu *stopped_vcpu;
+ struct kvm_vcpu_init init;
+ int ret;
+ uint64_t irq = 23;
+
+ create_vpmu_vm(guest_code);
+ ret = __vcpu_has_device_attr(vpmu_vm.vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
+ KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY);
+ if (ret) {
+ TEST_ASSERT(ret == -1 && errno == ENXIO,
+ KVM_IOCTL_ERROR(KVM_HAS_DEVICE_ATTR, ret));
+ destroy_vpmu_vm();
+ return;
+ }
+
+ /* Assert that FIXED_COUNTERS_ONLY is unset at initialization. */
+ ret = __vcpu_device_attr_get(vpmu_vm.vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
+ KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY, NULL);
+ TEST_ASSERT(ret == -1 && errno == ENXIO,
+ KVM_IOCTL_ERROR(KVM_GET_DEVICE_ATTR, ret));
+
+ /* Assert that setting FIXED_COUNTERS_ONLY succeeds. */
+ vcpu_device_attr_set(vpmu_vm.vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
+ KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY, NULL);
+
+ /* Assert that getting FIXED_COUNTERS_ONLY succeeds. */
+ vcpu_device_attr_get(vpmu_vm.vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
+ KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY, NULL);
+
+ /*
+ * Assert that setting FIXED_COUNTERS_ONLY again succeeds even if an
+ * event filter has already been set.
+ */
+ vcpu_device_attr_set(vpmu_vm.vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
+ KVM_ARM_VCPU_PMU_V3_FILTER, &filter);
+
+ vcpu_device_attr_set(vpmu_vm.vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
+ KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY, NULL);
+
+ destroy_vpmu_vm();
+
+ create_vpmu_vm(guest_code);
+
+ /*
+ * Assert that setting FIXED_COUNTERS_ONLY results in EBUSY if an event
+ * filter has already been set while FIXED_COUNTERS_ONLY has not.
+ */
+ vcpu_device_attr_set(vpmu_vm.vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
+ KVM_ARM_VCPU_PMU_V3_FILTER, &filter);
+
+ ret = __vcpu_device_attr_set(vpmu_vm.vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
+ KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY, NULL);
+ TEST_ASSERT(ret == -1 && errno == EBUSY,
+ KVM_IOCTL_ERROR(KVM_SET_DEVICE_ATTR, ret));
+
+ destroy_vpmu_vm();
+
+ /*
+ * Assert that setting FIXED_COUNTERS_ONLY after running a VCPU results
+ * in EBUSY.
+ */
+ vm = vm_create(2);
+ vm_ioctl(vm, KVM_ARM_PREFERRED_TARGET, &init);
+ init.features[0] |= (1 << KVM_ARM_VCPU_PMU_V3);
+ running_vcpu = aarch64_vcpu_add(vm, 0, &init, guest_code);
+ stopped_vcpu = aarch64_vcpu_add(vm, 1, &init, guest_code);
+ kvm_arch_vm_finalize_vcpus(vm);
+ vcpu_device_attr_set(running_vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
+ KVM_ARM_VCPU_PMU_V3_IRQ, &irq);
+ vcpu_device_attr_set(running_vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
+ KVM_ARM_VCPU_PMU_V3_INIT, NULL);
+ run_vcpu(running_vcpu, pmcr_n);
+
+ ret = __vcpu_device_attr_set(stopped_vcpu, KVM_ARM_VCPU_PMU_V3_CTRL,
+ KVM_ARM_VCPU_PMU_V3_FIXED_COUNTERS_ONLY, NULL);
+ TEST_ASSERT(ret == -1 && errno == EBUSY,
+ KVM_IOCTL_ERROR(KVM_SET_DEVICE_ATTR, ret));
+
+ kvm_vm_free(vm);
+
+ test_config(0, true);
+}
+
int main(void)
{
- uint64_t i, pmcr_n;
+ uint64_t pmcr_n;
TEST_REQUIRE(kvm_has_cap(KVM_CAP_ARM_PMU_V3));
TEST_REQUIRE(kvm_supports_vgic_v3());
TEST_REQUIRE(kvm_supports_nr_counters_attr());
pmcr_n = get_pmcr_n_limit();
- for (i = 0; i <= pmcr_n; i++) {
- run_access_test(i);
- run_pmregs_validity_test(i);
- }
-
- for (i = pmcr_n + 1; i < ARMV8_PMU_MAX_COUNTERS; i++)
- run_error_test(i);
+ test_config(pmcr_n, false);
+ test_fixed_counters_only(pmcr_n);
return 0;
}
--
2.53.0
^ permalink raw reply related
* [PATCH v6 1/4] KVM: arm64: PMU: Add kvm_pmu_enabled_counter_mask()
From: Akihiko Odaki @ 2026-04-13 8:07 UTC (permalink / raw)
To: Marc Zyngier, Oliver Upton, Joey Gouly, Suzuki K Poulose,
Zenghui Yu, Catalin Marinas, Will Deacon, Kees Cook,
Gustavo A. R. Silva, Paolo Bonzini, Jonathan Corbet, Shuah Khan
Cc: linux-arm-kernel, kvmarm, linux-kernel, linux-hardening, devel,
kvm, linux-doc, linux-kselftest, Akihiko Odaki
In-Reply-To: <20260413-hybrid-v6-0-e79d760f7f1b@rsg.ci.i.u-tokyo.ac.jp>
This function will be useful to enumerate enabled counters.
Signed-off-by: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>
---
arch/arm64/kvm/pmu-emul.c | 22 ++++++++++++++--------
1 file changed, 14 insertions(+), 8 deletions(-)
diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
index b03dbda7f1ab..59ec96e09321 100644
--- a/arch/arm64/kvm/pmu-emul.c
+++ b/arch/arm64/kvm/pmu-emul.c
@@ -619,18 +619,24 @@ void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u64 val)
}
}
-static bool kvm_pmu_counter_is_enabled(struct kvm_pmc *pmc)
+static u64 kvm_pmu_enabled_counter_mask(struct kvm_vcpu *vcpu)
{
- struct kvm_vcpu *vcpu = kvm_pmc_to_vcpu(pmc);
- unsigned int mdcr = __vcpu_sys_reg(vcpu, MDCR_EL2);
+ u64 mask = 0;
- if (!(__vcpu_sys_reg(vcpu, PMCNTENSET_EL0) & BIT(pmc->idx)))
- return false;
+ if (__vcpu_sys_reg(vcpu, MDCR_EL2) & MDCR_EL2_HPME)
+ mask |= kvm_pmu_hyp_counter_mask(vcpu);
- if (kvm_pmu_counter_is_hyp(vcpu, pmc->idx))
- return mdcr & MDCR_EL2_HPME;
+ if (kvm_vcpu_read_pmcr(vcpu) & ARMV8_PMU_PMCR_E)
+ mask |= ~kvm_pmu_hyp_counter_mask(vcpu);
+
+ return __vcpu_sys_reg(vcpu, PMCNTENSET_EL0) & mask;
+}
+
+static bool kvm_pmu_counter_is_enabled(struct kvm_pmc *pmc)
+{
+ struct kvm_vcpu *vcpu = kvm_pmc_to_vcpu(pmc);
- return kvm_vcpu_read_pmcr(vcpu) & ARMV8_PMU_PMCR_E;
+ return kvm_pmu_enabled_counter_mask(vcpu) & BIT(pmc->idx);
}
static bool kvm_pmc_counts_at_el0(struct kvm_pmc *pmc)
--
2.53.0
^ permalink raw reply related
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