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, 107 insertions, 0 deletions

diff --git a/include/xen/acpi.h b/include/xen/acpi.h
new file mode 100644
index 000000000..c66a84616
--- /dev/null
+++ b/include/xen/acpi.h
@@ -0,0 +1,107 @@
+/******************************************************************************
+ * acpi.h
+ * acpi file for domain 0 kernel
+ *
+ * Copyright (c) 2011 Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+ * Copyright (c) 2011 Yu Ke <ke.yu@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#ifndef _XEN_ACPI_H
+#define _XEN_ACPI_H
+
+#include <linux/types.h>
+
+typedef int (*get_gsi_from_sbdf_t)(u32 sbdf);
+
+#ifdef CONFIG_XEN_DOM0
+#include <asm/xen/hypervisor.h>
+#include <xen/xen.h>
+#include <linux/acpi.h>
+
+int xen_acpi_notify_hypervisor_sleep(u8 sleep_state,
+				     u32 pm1a_cnt, u32 pm1b_cnd);
+int xen_acpi_notify_hypervisor_extended_sleep(u8 sleep_state,
+				     u32 val_a, u32 val_b);
+
+static inline int xen_acpi_suspend_lowlevel(void)
+{
+	/*
+	* Xen will save and restore CPU context, so
+	* we can skip that and just go straight to
+	* the suspend.
+	*/
+	acpi_enter_sleep_state(ACPI_STATE_S3);
+	return 0;
+}
+
+static inline void xen_acpi_sleep_register(void)
+{
+	if (xen_initial_domain()) {
+		acpi_os_set_prepare_sleep(
+			&xen_acpi_notify_hypervisor_sleep);
+		acpi_os_set_prepare_extended_sleep(
+			&xen_acpi_notify_hypervisor_extended_sleep);
+
+		acpi_suspend_lowlevel = xen_acpi_suspend_lowlevel;
+	}
+}
+int xen_pvh_setup_gsi(int gsi, int trigger, int polarity);
+int xen_acpi_get_gsi_info(struct pci_dev *dev,
+						  int *gsi_out,
+						  int *trigger_out,
+						  int *polarity_out);
+void xen_acpi_register_get_gsi_func(get_gsi_from_sbdf_t func);
+int xen_acpi_get_gsi_from_sbdf(u32 sbdf);
+#else
+static inline void xen_acpi_sleep_register(void)
+{
+}
+
+static inline int xen_pvh_setup_gsi(int gsi, int trigger, int polarity)
+{
+	return -1;
+}
+
+static inline int xen_acpi_get_gsi_info(struct pci_dev *dev,
+						  int *gsi_out,
+						  int *trigger_out,
+						  int *polarity_out)
+{
+	return -1;
+}
+
+static inline void xen_acpi_register_get_gsi_func(get_gsi_from_sbdf_t func)
+{
+}
+
+static inline int xen_acpi_get_gsi_from_sbdf(u32 sbdf)
+{
+	return -1;
+}
+#endif
+
+#endif	/* _XEN_ACPI_H */