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, 45 insertions, 0 deletions

diff --git a/arch/powerpc/boot/bamboo.c b/arch/powerpc/boot/bamboo.c
new file mode 100644
index 000000000..dcdfa586a
--- /dev/null
+++ b/arch/powerpc/boot/bamboo.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright IBM Corporation, 2007
+ * Josh Boyer <jwboyer@linux.vnet.ibm.com>
+ *
+ * Based on ebony wrapper:
+ * Copyright 2007 David Gibson, IBM Corporation.
+ *
+ * Clocking code based on code by:
+ * Stefan Roese <sr@denx.de>
+ */
+#include <stdarg.h>
+#include <stddef.h>
+#include "types.h"
+#include "elf.h"
+#include "string.h"
+#include "stdio.h"
+#include "page.h"
+#include "ops.h"
+#include "dcr.h"
+#include "4xx.h"
+#include "44x.h"
+
+static u8 *bamboo_mac0, *bamboo_mac1;
+
+static void bamboo_fixups(void)
+{
+	unsigned long sysclk = 33333333;
+
+	ibm440ep_fixup_clocks(sysclk, 11059200, 25000000);
+	ibm4xx_sdram_fixup_memsize();
+	ibm4xx_quiesce_eth((u32 *)0xef600e00, (u32 *)0xef600f00);
+	dt_fixup_mac_address_by_alias("ethernet0", bamboo_mac0);
+	dt_fixup_mac_address_by_alias("ethernet1", bamboo_mac1);
+}
+
+void bamboo_init(void *mac0, void *mac1)
+{
+	platform_ops.fixups = bamboo_fixups;
+	platform_ops.exit = ibm44x_dbcr_reset;
+	bamboo_mac0 = mac0;
+	bamboo_mac1 = mac1;
+	fdt_init(_dtb_start);
+	serial_console_init();
+}