From: William Roche <william.roche@xxxxxxxxxx> Repair poisoned memory location(s), calling ram_block_discard_range(): punching a hole in the backend file when necessary and regenerating a usable memory. If the kernel doesn't support the madvise calls used by this function and we are dealing with anonymous memory, fall back to remapping the location(s). Signed-off-by: William Roche <william.roche@xxxxxxxxxx> --- system/physmem.c | 63 ++++++++++++++++++++++++++++++++---------------- 1 file changed, 42 insertions(+), 21 deletions(-) diff --git a/system/physmem.c b/system/physmem.c index 2c90cc2d78..b228a692f8 100644 --- a/system/physmem.c +++ b/system/physmem.c @@ -2180,13 +2180,37 @@ void qemu_ram_free(RAMBlock *block) } #ifndef _WIN32 +/* Try to simply remap the given location */ +static void qemu_ram_remap_mmap(RAMBlock *block, void* vaddr, size_t size, + ram_addr_t offset) +{ + int flags, prot; + void *area; + + flags = MAP_FIXED; + flags |= block->flags & RAM_SHARED ? MAP_SHARED : MAP_PRIVATE; + flags |= block->flags & RAM_NORESERVE ? MAP_NORESERVE : 0; + prot = PROT_READ; + prot |= block->flags & RAM_READONLY ? 0 : PROT_WRITE; + if (block->fd >= 0) { + area = mmap(vaddr, size, prot, flags, block->fd, + offset + block->fd_offset); + } else { + flags |= MAP_ANONYMOUS; + area = mmap(vaddr, size, prot, flags, -1, 0); + } + if (area != vaddr) { + error_report("Could not remap addr: " RAM_ADDR_FMT "@" RAM_ADDR_FMT "", + size, block->offset + offset); + exit(1); + } +} + void qemu_ram_remap(ram_addr_t addr) { RAMBlock *block; ram_addr_t offset; - int flags; - void *area, *vaddr; - int prot; + void *vaddr; size_t page_size; RAMBLOCK_FOREACH(block) { @@ -2202,24 +2226,21 @@ void qemu_ram_remap(ram_addr_t addr) } else if (xen_enabled()) { abort(); } else { - flags = MAP_FIXED; - flags |= block->flags & RAM_SHARED ? - MAP_SHARED : MAP_PRIVATE; - flags |= block->flags & RAM_NORESERVE ? MAP_NORESERVE : 0; - prot = PROT_READ; - prot |= block->flags & RAM_READONLY ? 0 : PROT_WRITE; - if (block->fd >= 0) { - area = mmap(vaddr, page_size, prot, flags, block->fd, - offset + block->fd_offset); - } else { - flags |= MAP_ANONYMOUS; - area = mmap(vaddr, page_size, prot, flags, -1, 0); - } - if (area != vaddr) { - error_report("Could not remap addr: " - RAM_ADDR_FMT "@" RAM_ADDR_FMT "", - page_size, addr); - exit(1); + if (ram_block_discard_range(block, offset + block->fd_offset, + page_size) != 0) { + /* + * Fold back to using mmap() only for anonymous mapping, + * as if a backing file is associated we may not be able + * to recover the memory in all cases. + * So don't take the risk of using only mmap and fail now. + */ + if (block->fd >= 0) { + error_report("Memory poison recovery failure addr: " + RAM_ADDR_FMT "@" RAM_ADDR_FMT "", + page_size, addr); + exit(1); + } + qemu_ram_remap_mmap(block, vaddr, page_size, offset); } memory_try_enable_merging(vaddr, page_size); qemu_ram_setup_dump(vaddr, page_size); -- 2.43.5