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 --- arch/powerpc/boot/of.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 93 insertions(+) create mode 100644 arch/powerpc/boot/of.c (limited to 'arch/powerpc/boot/of.c') diff --git a/arch/powerpc/boot/of.c b/arch/powerpc/boot/of.c new file mode 100644 index 000000000..2fbd4ae60 --- /dev/null +++ b/arch/powerpc/boot/of.c @@ -0,0 +1,93 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) Paul Mackerras 1997. + */ +#include +#include +#include "types.h" +#include "elf.h" +#include "string.h" +#include "stdio.h" +#include "page.h" +#include "ops.h" + +#include "of.h" + +/* Value picked to match that used by yaboot */ +#define PROG_START 0x01400000 /* only used on 64-bit systems */ +#define RAM_END (512<<20) /* Fixme: use OF */ +#define ONE_MB 0x100000 + + + +static unsigned long claim_base; + +void epapr_platform_init(unsigned long r3, unsigned long r4, unsigned long r5, + unsigned long r6, unsigned long r7); + +static void *of_try_claim(unsigned long size) +{ + unsigned long addr = 0; + + if (claim_base == 0) + claim_base = _ALIGN_UP((unsigned long)_end, ONE_MB); + + for(; claim_base < RAM_END; claim_base += ONE_MB) { +#ifdef DEBUG + printf(" trying: 0x%08lx\n\r", claim_base); +#endif + addr = (unsigned long) of_claim(claim_base, size, 0); + if (addr != PROM_ERROR) + break; + } + if (addr == 0) + return NULL; + claim_base = PAGE_ALIGN(claim_base + size); + return (void *)addr; +} + +static void of_image_hdr(const void *hdr) +{ + const Elf64_Ehdr *elf64 = hdr; + + if (elf64->e_ident[EI_CLASS] == ELFCLASS64) { + /* + * Maintain a "magic" minimum address. This keeps some older + * firmware platforms running. + */ + if (claim_base < PROG_START) + claim_base = PROG_START; + } +} + +static void of_platform_init(unsigned long a1, unsigned long a2, void *promptr) +{ + platform_ops.image_hdr = of_image_hdr; + platform_ops.malloc = of_try_claim; + platform_ops.exit = of_exit; + platform_ops.vmlinux_alloc = of_vmlinux_alloc; + + dt_ops.finddevice = of_finddevice; + dt_ops.getprop = of_getprop; + dt_ops.setprop = of_setprop; + + of_console_init(); + + of_init(promptr); + loader_info.promptr = promptr; + if (a1 && a2 && a2 != 0xdeadbeef) { + loader_info.initrd_addr = a1; + loader_info.initrd_size = a2; + } +} + +void platform_init(unsigned long r3, unsigned long r4, unsigned long r5, + unsigned long r6, unsigned long r7) +{ + /* Detect OF vs. ePAPR boot */ + if (r5) + of_platform_init(r3, r4, (void *)r5); + else + epapr_platform_init(r3, r4, r5, r6, r7); +} + -- cgit v1.3.1