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/firmware/efi/fdtparams.c | 133 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 133 insertions(+) create mode 100644 drivers/firmware/efi/fdtparams.c (limited to 'drivers/firmware/efi/fdtparams.c') diff --git a/drivers/firmware/efi/fdtparams.c b/drivers/firmware/efi/fdtparams.c new file mode 100644 index 000000000..b815d2a75 --- /dev/null +++ b/drivers/firmware/efi/fdtparams.c @@ -0,0 +1,133 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#define pr_fmt(fmt) "efi: " fmt + +#include +#include +#include +#include +#include + +#include + +enum { + SYSTAB, + MMBASE, + MMSIZE, + DCSIZE, + DCVERS, + + PARAMCOUNT +}; + +static __initconst const char name[][22] = { + [SYSTAB] = "System Table ", + [MMBASE] = "MemMap Address ", + [MMSIZE] = "MemMap Size ", + [DCSIZE] = "MemMap Desc. Size ", + [DCVERS] = "MemMap Desc. Version ", +}; + +static __initconst const struct { + const char path[17]; + u8 paravirt; + const char params[PARAMCOUNT][26]; +} dt_params[] = { + { +#ifdef CONFIG_XEN // <-------17------> + .path = "/hypervisor/uefi", + .paravirt = 1, + .params = { + [SYSTAB] = "xen,uefi-system-table", + [MMBASE] = "xen,uefi-mmap-start", + [MMSIZE] = "xen,uefi-mmap-size", + [DCSIZE] = "xen,uefi-mmap-desc-size", + [DCVERS] = "xen,uefi-mmap-desc-ver", + } + }, { +#endif + .path = "/chosen", + .params = { // <-----------26-----------> + [SYSTAB] = "linux,uefi-system-table", + [MMBASE] = "linux,uefi-mmap-start", + [MMSIZE] = "linux,uefi-mmap-size", + [DCSIZE] = "linux,uefi-mmap-desc-size", + [DCVERS] = "linux,uefi-mmap-desc-ver", + } + } +}; + +static int __init efi_get_fdt_prop(const void *fdt, int node, const char *pname, + const char *rname, void *var, int size) +{ + const void *prop; + int len; + u64 val; + + prop = fdt_getprop(fdt, node, pname, &len); + if (!prop) + return 1; + + val = (len == 4) ? (u64)be32_to_cpup(prop) : get_unaligned_be64(prop); + + if (size == 8) + *(u64 *)var = val; + else + *(u32 *)var = (val < U32_MAX) ? val : U32_MAX; // saturate + + if (efi_enabled(EFI_DBG)) + pr_info(" %s: 0x%0*llx\n", rname, size * 2, val); + + return 0; +} + +u64 __init efi_get_fdt_params(struct efi_memory_map_data *mm) +{ + const void *fdt = initial_boot_params; + unsigned long systab; + int i, j, node; + struct { + void *var; + int size; + } target[] = { + [SYSTAB] = { &systab, sizeof(systab) }, + [MMBASE] = { &mm->phys_map, sizeof(mm->phys_map) }, + [MMSIZE] = { &mm->size, sizeof(mm->size) }, + [DCSIZE] = { &mm->desc_size, sizeof(mm->desc_size) }, + [DCVERS] = { &mm->desc_version, sizeof(mm->desc_version) }, + }; + + BUILD_BUG_ON(ARRAY_SIZE(target) != ARRAY_SIZE(name)); + BUILD_BUG_ON(ARRAY_SIZE(target) != ARRAY_SIZE(dt_params[0].params)); + + if (!fdt) + return 0; + + for (i = 0; i < ARRAY_SIZE(dt_params); i++) { + node = fdt_path_offset(fdt, dt_params[i].path); + if (node < 0) + continue; + + if (efi_enabled(EFI_DBG)) + pr_info("Getting UEFI parameters from %s in DT:\n", + dt_params[i].path); + + for (j = 0; j < ARRAY_SIZE(target); j++) { + const char *pname = dt_params[i].params[j]; + + if (!efi_get_fdt_prop(fdt, node, pname, name[j], + target[j].var, target[j].size)) + continue; + if (!j) + goto notfound; + pr_err("Can't find property '%s' in DT!\n", pname); + return 0; + } + if (dt_params[i].paravirt) + set_bit(EFI_PARAVIRT, &efi.flags); + return systab; + } +notfound: + pr_info("UEFI not found.\n"); + return 0; +} -- cgit v1.3.1