mirror of
https://github.com/yuzu-emu/unicorn.git
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6180cbd477
For KVM to use Transparent Huge Pages (THP) we have to ensure that the alignment of the userspace address of the KVM memory slot and the IPA that the guest sees for a memory region have the same offset from the 2M huge page size boundary. One way to achieve this is to always align the IPA region at a 2M boundary and ensure that the mmap alignment is also at 2M. Unfortunately, we were only doing this for __arm__, not for __aarch64__, so add this simple condition. This fixes a performance regression using KVM/ARM on AArch64 platforms that showed a performance penalty of more than 50%, introduced by the following commit: 9fac18f (oslib: allocate PROT_NONE pages on top of RAM, 2015-09-10) We were only lucky before the above commit, because we were allocating large regions and naturally getting a 2M alignment on those allocations then. Backports commit ee1e0f8e5d3682c561edcdceccff72b9d9b16d8b from qemu
129 lines
3.4 KiB
C
129 lines
3.4 KiB
C
/*
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* os-posix-lib.c
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*
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* Copyright (c) 2003-2008 Fabrice Bellard
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* Copyright (c) 2010 Red Hat, Inc.
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*
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* QEMU library functions on POSIX which are shared between QEMU and
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* the QEMU tools.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#if defined(__linux__) && \
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(defined(__x86_64__) || defined(__arm__) || defined(__aarch64__))
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/* Use 2 MiB alignment so transparent hugepages can be used by KVM.
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Valgrind does not support alignments larger than 1 MiB,
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therefore we need special code which handles running on Valgrind. */
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# define QEMU_VMALLOC_ALIGN (512 * 4096)
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#elif defined(__linux__) && defined(__s390x__)
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/* Use 1 MiB (segment size) alignment so gmap can be used by KVM. */
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# define QEMU_VMALLOC_ALIGN (256 * 4096)
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#else
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# define QEMU_VMALLOC_ALIGN getpagesize()
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#endif
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#define HUGETLBFS_MAGIC 0x958458f6
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#include "qemu/osdep.h"
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#include "qapi/error.h"
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#include "unicorn/platform.h"
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#include "sysemu/sysemu.h"
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#include <sys/mman.h>
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#include <libgen.h>
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#include <setjmp.h>
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#include <sys/signal.h>
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#include "qemu/cutils.h"
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#ifdef CONFIG_LINUX
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#if !defined(__CYGWIN__)
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#include <sys/syscall.h>
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#endif
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#include <sys/vfs.h>
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#endif
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#ifdef __FreeBSD__
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#include <sys/sysctl.h>
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#endif
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#include <qemu/mmap-alloc.h>
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void *qemu_oom_check(void *ptr)
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{
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if (ptr == NULL) {
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fprintf(stderr, "Failed to allocate memory: %s\n", strerror(errno));
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abort();
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}
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return ptr;
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}
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void *qemu_try_memalign(size_t alignment, size_t size)
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{
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void *ptr;
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if (alignment < sizeof(void*)) {
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alignment = sizeof(void*);
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}
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#if defined(_POSIX_C_SOURCE) && !defined(__sun__)
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int ret;
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ret = posix_memalign(&ptr, alignment, size);
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if (ret != 0) {
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errno = ret;
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ptr = NULL;
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}
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#elif defined(CONFIG_BSD)
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ptr = valloc(size);
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#else
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ptr = memalign(alignment, size);
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#endif
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return ptr;
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}
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void *qemu_memalign(size_t alignment, size_t size)
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{
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return qemu_oom_check(qemu_try_memalign(alignment, size));
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}
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/* alloc shared memory pages */
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void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment)
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{
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size_t align = QEMU_VMALLOC_ALIGN;
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void *ptr = qemu_ram_mmap(-1, size, align, false);
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if (ptr == MAP_FAILED) {
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return NULL;
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}
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if (alignment) {
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*alignment = align;
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}
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return ptr;
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}
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void qemu_vfree(void *ptr)
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{
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free(ptr);
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}
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void qemu_anon_ram_free(void *ptr, size_t size)
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{
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qemu_ram_munmap(ptr, size);
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}
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