[igt-dev] [RFC 3/5] igt/lib: Add wrapper to check if gtt mapping is available

Antonio Argenziano
2019-02-21T19:27:59Z

Add wrapper to get mmap_gtt version number and another to check if
gtt mapping is at all available.

Cc: Katarzyna Dec <katarzyna.dec@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Antonio Argenziano <antonio.argenziano@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
---
lib/ioctl_wrappers.c | 47 ++++++++++++++++++++++++++++++++++++--------
lib/ioctl_wrappers.h | 11 +++++++++++
2 files changed, 50 insertions(+), 8 deletions(-)

diff --git a/lib/ioctl_wrappers.c b/lib/ioctl_wrappers.c
index d9b46088..25dd8ad3 100644
--- a/lib/ioctl_wrappers.c
+++ b/lib/ioctl_wrappers.c
@@ -659,6 +659,42 @@ static bool has_mmap_offset(int fd)
return has_mmap_offset > 0;
}

+/**
+ * gem_mmap__gtt_version:
+ * @fd: open i915 drm file descriptor
+ *
+ * This wraps I915_PARAM_MMAP_GTT_VERSION. It will return the supported feature
+ * set for gtt mapping. Since the mappable aperture in not always present, this
+ * function will return '-1' in case there is none.
+ */
+static int gem_mmap__gtt_version(int fd)
+{
+ static int gtt_version = ~0;
+
+ if (gtt_version == ~0) {
+ struct drm_i915_getparam gp;
+
+ gtt_version = 0;
+
+ memset(&gp, 0, sizeof(gp));
+ gp.param = I915_PARAM_MMAP_GTT_VERSION;
+ gp.value = &gtt_version;
+ ioctl(fd, DRM_IOCTL_I915_GETPARAM, &gp);
+
+ if(errno == -ENODEV)
+ gtt_version = -1; /* No mappable aperture */
+
+ errno = 0;
+ }
+
+ return gtt_version;
+}
+
+bool gem_mmap__has_gtt(int fd)
+{
+ return gem_mmap__gtt_version(fd) >= 0;
+}
+
/**
* __gem_mmap__gtt:
* @fd: open i915 drm file descriptor
@@ -753,7 +789,6 @@ bool gem_mmap__has_wc(int fd)
static int has_wc = -1;

if (has_wc == -1) {
-
has_wc = 0;

/* Do we have the new mmap_offset ioctl? */
@@ -770,12 +805,8 @@ bool gem_mmap__has_wc(int fd)
} else {
struct drm_i915_getparam gp;
int mmap_version = -1;
- int gtt_version = -1;
-
- memset(&gp, 0, sizeof(gp));
- gp.param = I915_PARAM_MMAP_GTT_VERSION;
- gp.value = &gtt_version;
- ioctl(fd, DRM_IOCTL_I915_GETPARAM, &gp);
+ bool compatible_gtt_version =
+ (!gem_mmap__has_gtt(fd) || gem_mmap__gtt_version(fd) >= 2);

memset(&gp, 0, sizeof(gp));
gp.param = I915_PARAM_MMAP_VERSION;
@@ -783,7 +814,7 @@ bool gem_mmap__has_wc(int fd)
ioctl(fd, DRM_IOCTL_I915_GETPARAM, &gp);

/* Do we have the mmap_ioctl with DOMAIN_WC? */
- if (mmap_version >= 1 && gtt_version >= 2) {
+ if (mmap_version >= 1 && compatible_gtt_version) {
struct drm_i915_gem_mmap arg;

/* Does this device support wc-mmaps ? */
diff --git a/lib/ioctl_wrappers.h b/lib/ioctl_wrappers.h
index b22b36b0..693020ed 100644
--- a/lib/ioctl_wrappers.h
+++ b/lib/ioctl_wrappers.h
@@ -90,6 +90,8 @@ void *gem_mmap__cpu(int fd, uint32_t handle, uint64_t offset, uint64_t size, uns
bool gem_mmap__has_wc(int fd);
void *gem_mmap__wc(int fd, uint32_t handle, uint64_t offset, uint64_t size, unsigned prot);

+bool gem_mmap__has_gtt(int fd);
+
#ifndef I915_GEM_DOMAIN_WC
#define I915_GEM_DOMAIN_WC 0x80
#endif
@@ -121,6 +123,15 @@ int gem_munmap(void *ptr, uint64_t size);
*/
#define gem_require_mmap_wc(fd) igt_require(gem_mmap__has_wc(fd))

+/**
+ * gem_require_mmap_gtt:
+ * @fd: open i915 drm file descriptor
+ *
+ * Feature test macro to query whether memory mappings through the mappable
+ * aperture are available. Automatically skips through igt_require() if not.
+ */
+#define gem_require_mmap_gtt(fd) igt_require(gem_mmap__has_gtt(fd))
+
int gem_madvise(int fd, uint32_t handle, int state);

#define LOCAL_I915_GEM_USERPTR 0x33
--
2.20.1