2016-06-29 13:47:03 +02:00
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#ifndef QEMU_MMAP_ALLOC_H
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#define QEMU_MMAP_ALLOC_H
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2015-09-24 13:41:17 +02:00
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util/mmap-alloc: fix hugetlb support on ppc64
Since commit 8561c9244ddf1122d "exec: allocate PROT_NONE pages on top of
RAM", it is no longer possible to back guest RAM with hugepages on ppc64
hosts:
mmap(NULL, 285212672, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
0x3fff57000000
mmap(0x3fff57000000, 268435456, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED, 19, 0) = -1 EBUSY (Device or resource busy)
This is because on ppc64, Linux fixes a page size for a virtual address
at mmap time, so we can't switch a range of memory from anonymous
small pages to hugetlbs with MAP_FIXED.
See commit d0f13e3c20b6fb73ccb467bdca97fa7cf5a574cd
("[POWERPC] Introduce address space "slices"") in Linux
history for the details.
Detect this and create the PROT_NONE mapping using the same fd.
Naturally, this makes the guard page bigger with hugetlbfs.
Based on patch by Greg Kurz.
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Tested-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2015-12-02 20:14:12 +01:00
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size_t qemu_fd_getpagesize(int fd);
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2017-03-02 03:36:11 +01:00
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size_t qemu_mempath_getpagesize(const char *mem_path);
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2019-02-08 11:10:37 +01:00
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/**
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* qemu_ram_mmap: mmap the specified file or device.
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*
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* Parameters:
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* @fd: the file or the device to mmap
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* @size: the number of bytes to be mmaped
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* @align: if not zero, specify the alignment of the starting mapping address;
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* otherwise, the alignment in use will be determined by QEMU.
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2021-01-04 18:13:18 +01:00
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* @readonly: true for a read-only mapping, false for read/write.
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2019-02-08 11:10:37 +01:00
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* @shared: map has RAM_SHARED flag.
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* @is_pmem: map has RAM_PMEM flag.
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2021-01-29 17:46:04 +01:00
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* @map_offset: map starts at offset of map_offset from the start of fd
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2019-02-08 11:10:37 +01:00
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*
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* Return:
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* On success, return a pointer to the mapped area.
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* On failure, return MAP_FAILED.
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*/
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void *qemu_ram_mmap(int fd,
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size_t size,
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size_t align,
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2021-01-04 18:13:18 +01:00
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bool readonly,
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2019-02-08 11:10:37 +01:00
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bool shared,
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2021-01-29 17:46:04 +01:00
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bool is_pmem,
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off_t map_offset);
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2015-09-24 13:41:17 +02:00
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2019-01-31 00:36:05 +01:00
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void qemu_ram_munmap(int fd, void *ptr, size_t size);
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2015-09-24 13:41:17 +02:00
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#endif
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