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, 51 insertions, 0 deletions

diff --git a/include/video/hecubafb.h b/include/video/hecubafb.h
new file mode 100644
index 000000000..7b9952339
--- /dev/null
+++ b/include/video/hecubafb.h
@@ -0,0 +1,51 @@
+/*
+ * hecubafb.h - definitions for the hecuba framebuffer driver
+ *
+ * Copyright (C) 2008 by Jaya Kumar
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file COPYING in the main directory of this archive for
+ * more details.
+ *
+ */
+
+#ifndef _LINUX_HECUBAFB_H_
+#define _LINUX_HECUBAFB_H_
+
+/* Apollo controller specific defines */
+#define APOLLO_START_NEW_IMG	0xA0
+#define APOLLO_STOP_IMG_DATA	0xA1
+#define APOLLO_DISPLAY_IMG	0xA2
+#define APOLLO_ERASE_DISPLAY	0xA3
+#define APOLLO_INIT_DISPLAY	0xA4
+
+/* Hecuba interface specific defines */
+#define HCB_WUP_BIT	0x01
+#define HCB_DS_BIT 	0x02
+#define HCB_RW_BIT 	0x04
+#define HCB_CD_BIT 	0x08
+#define HCB_ACK_BIT 	0x80
+
+/* struct used by hecuba. board specific stuff comes from *board */
+struct hecubafb_par {
+	struct fb_info *info;
+	struct hecuba_board *board;
+	void (*send_command)(struct hecubafb_par *, unsigned char);
+	void (*send_data)(struct hecubafb_par *, unsigned char);
+};
+
+/* board specific routines
+board drivers can implement wait_for_ack with interrupts if desired. if
+wait_for_ack is called with clear=0, then go to sleep and return when ack
+goes hi or if wait_for_ack with clear=1, then return when ack goes lo */
+struct hecuba_board {
+	struct module *owner;
+	void (*remove)(struct hecubafb_par *);
+	void (*set_ctl)(struct hecubafb_par *, unsigned char, unsigned char);
+	void (*set_data)(struct hecubafb_par *, unsigned char);
+	void (*wait_for_ack)(struct hecubafb_par *, int);
+	int (*init)(struct hecubafb_par *);
+};
+
+
+#endif