iris: Add GET_PARAM for protected context capability support

With MTL onwards, creating protected contexts too early
may block for a longer period. To prevent that, use the new
kernel GET_PARAM:I915_PARAM_PXP_STATUS interface to get the
status of PXP support immediately without blocking.

Using this same interface, we can also wait for platform
dependency readiness before attempting to create a protected
context. Use a longer timeout when user explicitly requests
for protected context as the kernel assures readiness will be
achieved.

Reference to kernel change: https://patchwork.freedesktop.org/patch/533241/?series=112647&rev=8

Signed-off-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23382>

src/gallium/drivers/iris/i915/iris_batch.c

@@ -101,6 +101,14 @@ iris_create_hw_context(struct iris_bufmgr *bufmgr, bool protected)
    uint32_t ctx_id;
 
    if (protected) {
+      /* User explicitly requested for PXP so wait for the kernel + firmware
+       * dependencies to complete to avoid a premature PXP context-create failure.
+       */
+      if (!intel_gem_wait_on_get_param(iris_bufmgr_get_fd(bufmgr),
+                                      I915_PARAM_PXP_STATUS, 1,
+                                      8000))
+         DBG("unable to wait for pxp-readiness\n");
+
       if (!intel_gem_create_context_ext(iris_bufmgr_get_fd(bufmgr),
                                         INTEL_GEM_CREATE_CONTEXT_EXT_PROTECTED_FLAG,
                                         &ctx_id)) {
@@ -169,9 +177,18 @@ iris_create_engines_context(struct iris_context *ice)
       engine_classes[IRIS_BATCH_COMPUTE] = INTEL_ENGINE_CLASS_COMPUTE;
 
    enum intel_gem_create_context_flags flags = 0;
-   if (ice->protected)
+   if (ice->protected) {
       flags |= INTEL_GEM_CREATE_CONTEXT_EXT_PROTECTED_FLAG;
 
+      /* User explicitly requested for PXP so wait for the kernel + firmware
+       * dependencies to complete to avoid a premature PXP context-create failure.
+       */
+      if (!intel_gem_wait_on_get_param(fd,
+                                      I915_PARAM_PXP_STATUS, 1,
+                                      8000))
+         DBG("unable to wait for pxp-readiness\n");
+   }
+
    uint32_t engines_ctx;
    if (!intel_gem_create_context_engines(fd, flags, engines_info, num_batches,
                                          engine_classes, &engines_ctx)) {

src/intel/common/i915/intel_gem.c

@@ -235,10 +235,20 @@ i915_gem_create_context_ext(int fd,
 bool
 i915_gem_supports_protected_context(int fd)
 {
+   int val = 0;
    uint32_t ctx_id;
-   bool ret = i915_gem_create_context_ext(fd,
-                                          INTEL_GEM_CREATE_CONTEXT_EXT_PROTECTED_FLAG,
-                                          &ctx_id);
+   bool ret;
+
+   errno = 0;
+   if (!i915_gem_get_param(fd, I915_PARAM_PXP_STATUS, &val) && (errno == ENODEV))
+      return false;
+   else
+      return (val > 0);
+
+   /* failed without ENODEV, so older kernels require a creation test */
+   ret = i915_gem_create_context_ext(fd,
+                                     INTEL_GEM_CREATE_CONTEXT_EXT_PROTECTED_FLAG,
+                                     &ctx_id);
    if (!ret)
       return ret;
 

src/intel/common/intel_gem.c

@@ -27,6 +27,8 @@
 #include "i915/intel_gem.h"
 #include "xe/intel_gem.h"
 
+#include "util/os_time.h"
+
 bool
 intel_gem_supports_syncobj_wait(int fd)
 {
@@ -135,6 +137,26 @@ intel_gem_supports_protected_context(int fd, enum intel_kmd_type kmd_type)
    }
 }
 
+bool
+intel_gem_wait_on_get_param(int fd, uint32_t param, int target_val,
+                            uint32_t timeout_ms)
+{
+   int64_t start_time = os_time_get();
+   int64_t end_time = start_time + (timeout_ms * 1000);
+   int val = -1;
+
+   errno = 0;
+   do {
+      if (!intel_gem_get_param(fd, param, &val))
+         break;
+   } while (val != target_val && !os_time_timeout(start_time, end_time, os_time_get()));
+
+   if (errno || val != target_val)
+      return false;
+
+   return true;
+}
+
 bool
 intel_gem_get_param(int fd, uint32_t param, int *value)
 {

src/intel/common/intel_gem.h

@@ -187,6 +187,8 @@ bool
 intel_gem_get_context_param(int fd, uint32_t context, uint32_t param,
                             uint64_t *value);
 bool intel_gem_get_param(int fd, uint32_t param, int *value);
+bool intel_gem_wait_on_get_param(int fd, uint32_t param, int target_val,
+                                 uint32_t timeout_ms);
 
 #ifdef __cplusplus
 }