drm/i915: don't whitelist oacontrol in cmd parser
commit 10ff401df041e57afc2b1619cd252b86d0ae5f30 upstream.
Being able to program OACONTROL from a non-privileged batch buffer is
not sufficient to be able to configure the OA unit. This was originally
allowed to help enable Mesa to expose OA counters via the
INTEL_performance_query extension, but the current implementation based
on programming OACONTROL via a batch buffer isn't able to report useable
data without a more complete OA unit configuration. Mesa handles the
possibility that writes to OACONTROL may not be allowed and so only
advertises the extension after explicitly testing that a write to
OACONTROL succeeds. Based on this; removing OACONTROL from the whitelist
should be ok for userspace.
Removing this simplifies adding a new kernel api for configuring the OA
unit without needing to consider the possibility that userspace might
trample on OACONTROL state which we'd like to start managing within
the kernel instead. In particular running any Mesa based GL application
currently results in clearing OACONTROL when initializing which would
disable the capturing of metrics.
v2:
This bumps the command parser version from 8 to 9, as the change is
visible to userspace.
Signed-off-by: Robert Bragg <robert@sixbynine.org>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Sourab Gupta <sourab.gupta@intel.com>Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jon Bloomfield <jon.bloomfield@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161108125148.25007-1-robert@sixbynine.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/gpu/drm/i915/i915_cmd_parser.c b/drivers/gpu/drm/i915/i915_cmd_parser.c
index a62b05e..2e3e9cd 100644
--- a/drivers/gpu/drm/i915/i915_cmd_parser.c
+++ b/drivers/gpu/drm/i915/i915_cmd_parser.c
@@ -546,7 +546,6 @@
REG64(PS_INVOCATION_COUNT),
REG64(PS_DEPTH_COUNT),
REG64_IDX(RING_TIMESTAMP, RENDER_RING_BASE),
- REG32(OACONTROL), /* Only allowed for LRI and SRM. See below. */
REG64(MI_PREDICATE_SRC0),
REG64(MI_PREDICATE_SRC1),
REG32(GEN7_3DPRIM_END_OFFSET),
@@ -1156,8 +1155,7 @@
static bool check_cmd(const struct intel_engine_cs *engine,
const struct drm_i915_cmd_descriptor *desc,
const u32 *cmd, u32 length,
- const bool is_master,
- bool *oacontrol_set)
+ const bool is_master)
{
if (desc->flags & CMD_DESC_SKIP)
return true;
@@ -1195,31 +1193,6 @@
}
/*
- * OACONTROL requires some special handling for
- * writes. We want to make sure that any batch which
- * enables OA also disables it before the end of the
- * batch. The goal is to prevent one process from
- * snooping on the perf data from another process. To do
- * that, we need to check the value that will be written
- * to the register. Hence, limit OACONTROL writes to
- * only MI_LOAD_REGISTER_IMM commands.
- */
- if (reg_addr == i915_mmio_reg_offset(OACONTROL)) {
- if (desc->cmd.value == MI_LOAD_REGISTER_MEM) {
- DRM_DEBUG_DRIVER("CMD: Rejected LRM to OACONTROL\n");
- return false;
- }
-
- if (desc->cmd.value == MI_LOAD_REGISTER_REG) {
- DRM_DEBUG_DRIVER("CMD: Rejected LRR to OACONTROL\n");
- return false;
- }
-
- if (desc->cmd.value == MI_LOAD_REGISTER_IMM(1))
- *oacontrol_set = (cmd[offset + 1] != 0);
- }
-
- /*
* Check the value written to the register against the
* allowed mask/value pair given in the whitelist entry.
*/
@@ -1310,7 +1283,6 @@
u32 *cmd, *batch_end;
struct drm_i915_cmd_descriptor default_desc = noop_desc;
const struct drm_i915_cmd_descriptor *desc = &default_desc;
- bool oacontrol_set = false; /* OACONTROL tracking. See check_cmd() */
bool needs_clflush_after = false;
int ret = 0;
@@ -1366,8 +1338,7 @@
break;
}
- if (!check_cmd(engine, desc, cmd, length, is_master,
- &oacontrol_set)) {
+ if (!check_cmd(engine, desc, cmd, length, is_master)) {
ret = -EACCES;
break;
}
@@ -1375,11 +1346,6 @@
cmd += length;
}
- if (oacontrol_set) {
- DRM_DEBUG_DRIVER("CMD: batch set OACONTROL but did not clear it\n");
- ret = -EINVAL;
- }
-
if (cmd >= batch_end) {
DRM_DEBUG_DRIVER("CMD: Got to the end of the buffer w/o a BBE cmd!\n");
ret = -EINVAL;
@@ -1431,6 +1397,8 @@
* 8. Don't report cmd_check() failures as EINVAL errors to userspace;
* rely on the HW to NOOP disallowed commands as it would without
* the parser enabled.
+ * 9. Don't whitelist or handle oacontrol specially, as ownership
+ * for oacontrol state is moving to i915-perf.
*/
- return 8;
+ return 9;
}