From 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d Mon Sep 17 00:00:00 2001 From: Zeng Chi Date: Mon, 21 Sep 2026 18:24:42 +0800 Subject: KVM: Don't pre-reserve xarray entries when storing empty/NULL attributes 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 Cc: David Ballesteros Signed-off-by: Zeng Chi Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com [sean: split to separate patch] Signed-off-by: Sean Christopherson --- drivers/acpi/bgrt.c | 94 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 94 insertions(+) create mode 100644 drivers/acpi/bgrt.c (limited to 'drivers/acpi/bgrt.c') diff --git a/drivers/acpi/bgrt.c b/drivers/acpi/bgrt.c new file mode 100644 index 000000000..0fdd581ef --- /dev/null +++ b/drivers/acpi/bgrt.c @@ -0,0 +1,94 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * BGRT boot graphic support + * Authors: Matthew Garrett, Josh Triplett + * Copyright 2012 Red Hat, Inc + * Copyright 2012 Intel Corporation + */ + +#include +#include +#include +#include +#include + +static void *bgrt_image; +static struct kobject *bgrt_kobj; + +#define BGRT_SHOW(_name, _member) \ + static ssize_t _name##_show(struct kobject *kobj, \ + struct kobj_attribute *attr, char *buf) \ + { \ + return sysfs_emit(buf, "%d\n", bgrt_tab._member); \ + } \ + static struct kobj_attribute bgrt_attr_##_name = __ATTR_RO(_name) + +BGRT_SHOW(version, version); +BGRT_SHOW(status, status); +BGRT_SHOW(type, image_type); +BGRT_SHOW(xoffset, image_offset_x); +BGRT_SHOW(yoffset, image_offset_y); + +static __ro_after_init BIN_ATTR_SIMPLE_RO(image); + +static struct attribute *bgrt_attributes[] = { + &bgrt_attr_version.attr, + &bgrt_attr_status.attr, + &bgrt_attr_type.attr, + &bgrt_attr_xoffset.attr, + &bgrt_attr_yoffset.attr, + NULL, +}; + +static const struct bin_attribute *const bgrt_bin_attributes[] = { + &bin_attr_image, + NULL, +}; + +static const struct attribute_group bgrt_attribute_group = { + .attrs = bgrt_attributes, + .bin_attrs = bgrt_bin_attributes, +}; + +int __init acpi_parse_bgrt(struct acpi_table_header *table) +{ + efi_bgrt_init(table); + return 0; +} + +static int __init bgrt_init(void) +{ + int ret; + + if (!bgrt_tab.image_address) + return -ENODEV; + + bgrt_image = memremap(bgrt_tab.image_address, bgrt_image_size, + MEMREMAP_WB); + if (!bgrt_image) { + pr_notice("Ignoring BGRT: failed to map image memory\n"); + return -ENOMEM; + } + + bin_attr_image.private = bgrt_image; + bin_attr_image.size = bgrt_image_size; + + bgrt_kobj = kobject_create_and_add("bgrt", acpi_kobj); + if (!bgrt_kobj) { + ret = -EINVAL; + goto out_memmap; + } + + ret = sysfs_create_group(bgrt_kobj, &bgrt_attribute_group); + if (ret) + goto out_kobject; + + return 0; + +out_kobject: + kobject_put(bgrt_kobj); +out_memmap: + memunmap(bgrt_image); + return ret; +} +device_initcall(bgrt_init); -- cgit v1.3.1