KVM: Don't pre-reserve xarray entries when storing empty/NULL attributesgrafted

Skip the xarray reservation loop when clearing all memory attributes, as
storing NULL only erases the entry and never needs to allocate, so no
reservation (and no cleanup of a failed one) is required in that case.

Suggested-by: Sean Christopherson <seanjc@google.com>
Cc: David Ballesteros <davimaba.v@proton.me>
Signed-off-by: Zeng Chi <zengchi@kylinos.cn>
Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com
[sean: split to separate patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>

1 files changed, 65 insertions, 0 deletions

diff --git a/include/soc/qcom/ocmem.h b/include/soc/qcom/ocmem.h
new file mode 100644
index 000000000..02a8bc267
--- /dev/null
+++ b/include/soc/qcom/ocmem.h
@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * The On Chip Memory (OCMEM) allocator allows various clients to allocate
+ * memory from OCMEM based on performance, latency and power requirements.
+ * This is typically used by the GPU, camera/video, and audio components on
+ * some Snapdragon SoCs.
+ *
+ * Copyright (C) 2019 Brian Masney <masneyb@onstation.org>
+ * Copyright (C) 2015 Red Hat. Author: Rob Clark <robdclark@gmail.com>
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+
+#ifndef __OCMEM_H__
+#define __OCMEM_H__
+
+enum ocmem_client {
+	/* GMEM clients */
+	OCMEM_GRAPHICS = 0x0,
+	/*
+	 * TODO add more once ocmem_allocate() is clever enough to
+	 * deal with multiple clients.
+	 */
+	OCMEM_CLIENT_MAX,
+};
+
+struct ocmem;
+
+struct ocmem_buf {
+	unsigned long offset;
+	unsigned long addr;
+	unsigned long len;
+};
+
+#if IS_ENABLED(CONFIG_QCOM_OCMEM)
+
+struct ocmem *of_get_ocmem(struct device *dev);
+struct ocmem_buf *ocmem_allocate(struct ocmem *ocmem, enum ocmem_client client,
+				 unsigned long size);
+void ocmem_free(struct ocmem *ocmem, enum ocmem_client client,
+		struct ocmem_buf *buf);
+
+#else /* IS_ENABLED(CONFIG_QCOM_OCMEM) */
+
+static inline struct ocmem *of_get_ocmem(struct device *dev)
+{
+	return ERR_PTR(-ENODEV);
+}
+
+static inline struct ocmem_buf *ocmem_allocate(struct ocmem *ocmem,
+					       enum ocmem_client client,
+					       unsigned long size)
+{
+	return ERR_PTR(-ENODEV);
+}
+
+static inline void ocmem_free(struct ocmem *ocmem, enum ocmem_client client,
+			      struct ocmem_buf *buf)
+{
+}
+
+#endif /* IS_ENABLED(CONFIG_QCOM_OCMEM) */
+
+#endif /* __OCMEM_H__ */