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https://gitlab.com/qemu-project/qemu
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4d6b23f7e2
Currently, if a file does not exist yet, file_ram_open() will create new empty file and open it writable. However, it even does that when readonly=true was specified. Specifying O_RDONLY instead to create a new readonly file would theoretically work, however, ftruncate() will refuse to resize the new empty file and we'll get a warning: ftruncate: Invalid argument And later eventually more problems when actually mmap'ing that file and accessing it. If someone intends to let QEMU open+mmap a file read-only, better create+resize+fill that file ahead of time outside of QEMU context. We'll now fail with: ./qemu-system-x86_64 \ -object memory-backend-file,id=ram0,mem-path=tmp,readonly=true,size=1g qemu-system-x86_64: can't open backing store tmp for guest RAM: No such file or directory All use cases of readonly files (R/O NVDIMMs, VM templating) work on existing files, so silently creating new files might just hide user errors when accidentally specifying a non-existent file. Note that the only memory-backend-file will end up calling memory_region_init_ram_from_file() -> qemu_ram_alloc_from_file() -> file_ram_open(). Move error reporting to the single caller. Message-ID: <20230906120503.359863-7-david@redhat.com> Acked-by: Peter Xu <peterx@redhat.com> Signed-off-by: David Hildenbrand <david@redhat.com> |
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.. | ||
arch_init.c | ||
async-teardown.c | ||
balloon.c | ||
bootdevice.c | ||
cpu-throttle.c | ||
cpu-timers.c | ||
cpus.c | ||
datadir.c | ||
device_tree.c | ||
dirtylimit.c | ||
dma-helpers.c | ||
globals.c | ||
icount.c | ||
ioport.c | ||
main.c | ||
memory_mapping.c | ||
memory.c | ||
meson.build | ||
physmem.c | ||
qdev-monitor.c | ||
qemu-seccomp.c | ||
qtest.c | ||
rtc.c | ||
runstate-action.c | ||
runstate-hmp-cmds.c | ||
runstate.c | ||
timers-state.h | ||
tpm-hmp-cmds.c | ||
tpm.c | ||
trace-events | ||
trace.h | ||
vl.c | ||
watchpoint.c |