feature: Add PCI barrier mmap logic for xe

Related-To: NEO-13081

Signed-off-by: Filip Hazubski <[email protected]>

Author: fhazubski-Intel

shared/source/os_interface/linux/xe/ioctl_helper_xe.cpp

@@ -1703,4 +1703,16 @@ void IoctlHelperXe::querySupportedFeatures() {
 bool IoctlHelperXe::isEuPerDssTopologyType(uint16_t topologyType) const {
     return topologyType == DRM_XE_TOPO_EU_PER_DSS;
 }
+
+void *IoctlHelperXe::pciBarrierMmap() {
+    GemMmapOffset mmapOffset = {};
+    mmapOffset.flags = DRM_XE_MMAP_OFFSET_FLAG_PCI_BARRIER;
+    auto ret = ioctl(DrmIoctl::gemMmapOffset, &mmapOffset);
+    if (ret != 0) {
+        return false;
+    }
+
+    return SysCalls::mmap(NULL, MemoryConstants::pageSize, PROT_WRITE, MAP_SHARED, drm.getFileDescriptor(), static_cast<off_t>(mmapOffset.offset));
+}
+
 } // namespace NEO

shared/source/os_interface/linux/xe/ioctl_helper_xe.h

@@ -133,6 +133,7 @@ class IoctlHelperXe : public IoctlHelper {
     bool resourceRegistrationEnabled() override { return true; }
     bool isPreemptionSupported() override { return true; }
     virtual bool isEuPerDssTopologyType(uint16_t topologyType) const;
+    void *pciBarrierMmap() override;
 
   protected:
     static constexpr uint32_t maxContextSetProperties = 4;

third_party/uapi/upstream/xe/xe_drm.h

@@ -809,7 +809,18 @@ struct drm_xe_gem_mmap_offset {
 	/** @handle: Handle for the object being mapped. */
 	__u32 handle;
 
-	/** @flags: Must be zero */
+/**
+ * For user to query special offset we are adding special flag in
+ * mmap_offset ioctl which needs to be passed as follows,
+ * struct drm_xe_gem_mmap_offset mmo = {
+ * 	.handle = 0, (this must be set to 0)
+ * 	.flags = DRM_XE_MMAP_OFFSET_FLAG_PCI_BARRIER,
+ * };
+ * igt_ioctl(fd, DRM_IOCTL_XE_GEM_MMAP_OFFSET, &mmo);
+ * map = mmap(NULL, size, PROT_WRITE, MAP_SHARED, fd, mmo);
+*/
+#define DRM_XE_MMAP_OFFSET_FLAG_PCI_BARRIER     (1 << 0)
+	/** @flags: Flag to indicate if any special offset, zero otherwise */
 	__u32 flags;
 
 	/** @offset: The fake offset to use for subsequent mmap call */