In user-mode emulation there is a small race between preexit_cleanup
and exit_group() which means we may end up calling instrumented
instructions before the kernel reaps child threads. To solve this we
implement a new helper which ensures the callbacks are flushed along
with any translations before we let the host do it's a thing.
While we are at it make the documentation of
qemu_plugin_register_atexit_cb clearer as to what the user can expect.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Mahmoud Mandour <ma.mandourr@gmail.com>
Acked-by: Warner Losh <imp@bsdimp.com>
Message-Id: <20210720232703.10650-21-alex.bennee@linaro.org>
Use it to avoid some clang-12 -Watomic-alignment errors,
forcing some structures to be aligned and as a pointer when
we have ensured that the address is aligned.
Tested-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
We now require c11, so the fallbacks are now dead code
Tested-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Clang warnings about questionable atomic usage get localized
to the inline function in atomic.h. By using a macro, we get
the full traceback to the original use that caused the warning.
Tested-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
The compiler rightly complains when we build on 32 bit that casting
uint64_t into a void is a bad idea. We are really dealing with a host
pointer at this point so treat it as such. This does involve
a uintptr_t cast of the result of the TLB addend as we know that has
to point to the host memory.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210709143005.1554-28-alex.bennee@linaro.org>
Add module_allow_arch() to set the target architecture.
In case a module is limited to some arch verify arches
match and ignore the module if not.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Jose R. Ziviani <jziviani@suse.de>
Message-Id: <20210624103836.2382472-19-kraxel@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add script to generate C source with a small
database containing the module meta-data.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Jose R. Ziviani <jziviani@suse.de>
Message-Id: <20210624103836.2382472-4-kraxel@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add macros for module info annotations.
Instead of having that module meta-data stored in lists in util/module.c
place directly in the module source code.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Jose R. Ziviani <jziviani@suse.de>
Message-Id: <20210624103836.2382472-2-kraxel@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
While config-host.mak entries are expanded to "1" for compatibility with
create-config.sh, tests done directly in meson.build expand to the empty
string and cannot be placed to the right of the && operator. Adjust
osdep.h after commit e46bd55d9c ("configure: convert HAVE_BROKEN_SIZE_MAX
to meson", 2021-07-06) changed the way HAVE_BROKEN_SIZE_MAX is defined.
Reported-by: Frederic Bezies <fredbezies@gmail.com>
Fixes: e46bd55d9c ("configure: convert HAVE_BROKEN_SIZE_MAX to meson", 2021-07-06)
Resolves: #463
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-M was the sole user of qemu_opts_set and qemu_opts_set_defaults,
remove them and the arguments that they used.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Allow parsing multiple keyval sequences into the same dictionary.
This will be used to simplify the parsing of the -M command line
option, which is currently a .merge_lists = true QemuOpts group.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This patch introduces a function that merges two keyval-produced
(or keyval-like) QDicts. It can be used to emulate the behavior of
.merge_lists = true QemuOpts groups, merging -readconfig sections and
command-line options in a single QDict, and also to implement -set.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
It can be difficult to debug issues with BHs in production environments.
Although BHs can usually be identified by looking up their ->cb()
function pointer, this requires debug information for the program. It is
also not possible to print human-readable diagnostics about BHs because
they have no identifier.
This patch adds a name to each BH. The name is not unique per instance
but differentiates between cb() functions, which is usually enough. It's
done by changing aio_bh_new() and friends to macros that stringify cb.
The next patch will use the name field when reporting leaked BHs.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20210414200247.917496-2-stefanha@redhat.com>
- Extract nanoMIPS, microMIPS, Code Compaction from translate.c
- Allow PCI config accesses smaller than 32-bit on Bonito64 device
- Fix migration of g364fb device on Jazz Magnum
- Fix dp8393x PROM checksum on Jazz Magnum and Quadra 800
- Map the UART devices unconditionally on Jazz Magnum
- Add functional test booting Linux on the Fuloong 2E
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Merge remote-tracking branch 'remotes/philmd/tags/mips-20210702' into staging
MIPS patches queue
- Extract nanoMIPS, microMIPS, Code Compaction from translate.c
- Allow PCI config accesses smaller than 32-bit on Bonito64 device
- Fix migration of g364fb device on Jazz Magnum
- Fix dp8393x PROM checksum on Jazz Magnum and Quadra 800
- Map the UART devices unconditionally on Jazz Magnum
- Add functional test booting Linux on the Fuloong 2E
# gpg: Signature made Fri 02 Jul 2021 16:36:19 BST
# gpg: using RSA key FAABE75E12917221DCFD6BB2E3E32C2CDEADC0DE
# gpg: Good signature from "Philippe Mathieu-Daudé (F4BUG) <f4bug@amsat.org>" [full]
# Primary key fingerprint: FAAB E75E 1291 7221 DCFD 6BB2 E3E3 2C2C DEAD C0DE
* remotes/philmd/tags/mips-20210702:
hw/mips/jazz: Map the UART devices unconditionally
hw/mips/jazz: specify correct endian for dp8393x device
hw/m68k/q800: fix PROM checksum and MAC address storage
qemu/bitops.h: add bitrev8 implementation
dp8393x: remove onboard PROM containing MAC address and checksum
hw/m68k/q800: move PROM and checksum calculation from dp8393x device to board
hw/mips/jazz: move PROM and checksum calculation from dp8393x device to board
dp8393x: convert to trace-events
dp8393x: checkpatch fixes
g364fb: add VMStateDescription for G364SysBusState
g364fb: use RAM memory region for framebuffer
tests/acceptance: Test Linux on the Fuloong 2E machine
hw/pci-host/bonito: Allow PCI config accesses smaller than 32-bit
hw/pci-host/bonito: Trace PCI config accesses smaller than 32-bit
target/mips: Extract nanoMIPS ISA translation routines
target/mips: Extract the microMIPS ISA translation routines
target/mips: Extract Code Compaction ASE translation routines
target/mips: Add declarations for generic TCG helpers
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This will be required for an upcoming checksum calculation.
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Tested-by: Finn Thain <fthain@linux-m68k.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20210625065401.30170-7-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Introduce a convenient macro, that works for qemu_memalign() like
g_autofree works with g_malloc.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210628121133.193984-2-vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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Merge remote-tracking branch 'remotes/vsementsov/tags/pull-jobs-2021-06-25' into staging
block: Make block-copy API thread-safe
# gpg: Signature made Fri 25 Jun 2021 13:40:24 BST
# gpg: using RSA key 8B9C26CDB2FD147C880E86A1561F24C1F19F79FB
# gpg: Good signature from "Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>" [unknown]
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg: There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 8B9C 26CD B2FD 147C 880E 86A1 561F 24C1 F19F 79FB
* remotes/vsementsov/tags/pull-jobs-2021-06-25:
block-copy: atomic .cancelled and .finished fields in BlockCopyCallState
block-copy: add CoMutex lock
block-copy: move progress_set_remaining in block_copy_task_end
block-copy: streamline choice of copy_range vs. read/write
block-copy: small refactor in block_copy_task_entry and block_copy_common
co-shared-resource: protect with a mutex
progressmeter: protect with a mutex
blockjob: let ratelimit handle a speed of 0
block-copy: let ratelimit handle a speed of 0
ratelimit: treat zero speed as unlimited
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
co-shared-resource is currently not thread-safe, as also reported
in co-shared-resource.h. Add a QemuMutex because co_try_get_from_shres
can also be invoked from non-coroutine context.
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20210614081130.22134-6-eesposit@redhat.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Progressmeter is protected by the AioContext mutex, which
is taken by the block jobs and their caller (like blockdev).
We would like to remove the dependency of block layer code on the
AioContext mutex, since most drivers and the core I/O code are already
not relying on it.
Create a new C file to implement the ProgressMeter API, but keep the
struct as public, to avoid forcing allocation on the heap.
Also add a mutex to be able to provide an accurate snapshot of the
progress values to the caller.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20210614081130.22134-5-eesposit@redhat.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Both users of RateLimit, block-copy.c and blockjob.c, treat
a speed of zero as unlimited, while RateLimit treats it as
"as slow as possible". The latter is nicer from the code
point of view but pretty useless, so disable rate limiting
if a speed of zero is provided.
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20210614081130.22134-2-eesposit@redhat.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
This is a quality of life helper for plugins so they don't need to
re-implement symbol lookup when dumping an address. The strings are
constant so don't need to be duplicated. One minor tweak is to return
NULL instead of a zero length string to show lookup failed.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Mahmoud Mandour <ma.mandourr@gmail.com>
Message-Id: <20210608040532.56449-2-ma.mandourr@gmail.com>
Message-Id: <20210623102749.25686-8-alex.bennee@linaro.org>
osdep.h provides a ROUND_UP macro to hide bitwise operations for the
purpose of rounding a number up to a power of two; add a ROUND_DOWN
macro that does the same with truncation towards zero.
While at it, change the formatting of some comments.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Leading underscores followed by a capital letter or underscore are
reserved by the C standard.
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/369
Signed-off-by: Ahmed Abouzied <email@aabouzied.com>
Message-Id: <20210605174938.13782-1-email@aabouzied.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
As noted by qemu-plugins.h, enum qemu_plugin_cb_flags is
currently unused -- plugins can neither read nor write
guest registers.
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Add function that transforms named fd inside SocketAddress structure
into number representation. This way it may be then used in a context
where current monitor is not available.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210610100802.5888-6-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: comment tweak]
Signed-off-by: Eric Blake <eblake@redhat.com>
qemu_co_queue_next() and qemu_co_queue_restart_all() just call
aio_co_wake() which works well in non-coroutine context. So these
functions can be called from non-coroutine context as well. And
actually qemu_co_queue_restart_all() is called from
nbd_cancel_in_flight(), which is called from non-coroutine context.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210610100802.5888-2-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
int128_make64() creates an Int128 from an unsigned 64 bit value; add
a function int128_makes64() creating an Int128 from a signed 64 bit
value.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20210614151007.4545-34-peter.maydell@linaro.org
Currently the ARM SVE helper code defines locally some utility
functions for swapping 16-bit halfwords within 32-bit or 64-bit
values and for swapping 32-bit words within 64-bit values,
parallel to the byte-swapping bswap16/32/64 functions.
We want these also for the ARM MVE code, and they're potentially
generally useful for other targets, so move them to bitops.h.
(We don't put them in bswap.h with the bswap* functions because
they are implemented in terms of the rotate operations also
defined in bitops.h, and including bitops.h from bswap.h seems
better avoided.)
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20210614151007.4545-17-peter.maydell@linaro.org
_Static_assert is part of C11, which is now required.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20210614233143.1221879-9-richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
All previous users now use C11 _Generic.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210614233143.1221879-8-richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This is both more and less complicated than our expansion
using __builtin_choose_expr and __builtin_types_compatible_p.
The expansion through QEMU_MAKE_LOCKABLE_ doesn't work because
we're not emumerating all of the types within the same _Generic,
which results in errors about unhandled cases. We must also
handle void* explicitly, so that the NULL constant can be used.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210614233143.1221879-7-richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
We will shortly convert lockable.h to _Generic, and we cannot
have two compatible types in the same expansion. Wrap QemuMutex
in a struct, and unwrap in qemu-thread-posix.c.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20210614233143.1221879-6-richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Create macros for file+line expansion in qemu_rec_mutex_unlock
like we have for qemu_mutex_unlock.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20210614233143.1221879-5-richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Move the declarations from thread-win32.h into thread.h
and remove the macro redirection from thread-posix.h.
This will be required by following cleanups.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20210614233143.1221879-4-richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
_Static_assert is part of C11, which is now required.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210614233143.1221879-9-richard.henderson@linaro.org>
All previous users now use C11 _Generic.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210614233143.1221879-8-richard.henderson@linaro.org>
This is both more and less complicated than our expansion
using __builtin_choose_expr and __builtin_types_compatible_p.
The expansion through QEMU_MAKE_LOCKABLE_ doesn't work because
we're not emumerating all of the types within the same _Generic,
which results in errors about unhandled cases. We must also
handle void* explicitly, so that the NULL constant can be used.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210614233143.1221879-7-richard.henderson@linaro.org>
We will shortly convert lockable.h to _Generic, and we cannot
have two compatible types in the same expansion. Wrap QemuMutex
in a struct, and unwrap in qemu-thread-posix.c.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210614233143.1221879-6-richard.henderson@linaro.org>
Create macros for file+line expansion in qemu_rec_mutex_unlock
like we have for qemu_mutex_unlock.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210614233143.1221879-5-richard.henderson@linaro.org>
Move the declarations from thread-win32.h into thread.h
and remove the macro redirection from thread-posix.h.
This will be required by following cleanups.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210614233143.1221879-4-richard.henderson@linaro.org>
Let's support RAM_NORESERVE via MAP_NORESERVE on Linux. The flag has no
effect on most shared mappings - except for hugetlbfs and anonymous memory.
Linux man page:
"MAP_NORESERVE: Do not reserve swap space for this mapping. When swap
space is reserved, one has the guarantee that it is possible to modify
the mapping. When swap space is not reserved one might get SIGSEGV
upon a write if no physical memory is available. See also the discussion
of the file /proc/sys/vm/overcommit_memory in proc(5). In kernels before
2.6, this flag had effect only for private writable mappings."
Note that the "guarantee" part is wrong with memory overcommit in Linux.
Also, in Linux hugetlbfs is treated differently - we configure reservation
of huge pages from the pool, not reservation of swap space (huge pages
cannot be swapped).
The rough behavior is [1]:
a) !Hugetlbfs:
1) Without MAP_NORESERVE *or* with memory overcommit under Linux
disabled ("/proc/sys/vm/overcommit_memory == 2"), the following
accounting/reservation happens:
For a file backed map
SHARED or READ-only - 0 cost (the file is the map not swap)
PRIVATE WRITABLE - size of mapping per instance
For an anonymous or /dev/zero map
SHARED - size of mapping
PRIVATE READ-only - 0 cost (but of little use)
PRIVATE WRITABLE - size of mapping per instance
2) With MAP_NORESERVE, no accounting/reservation happens.
b) Hugetlbfs:
1) Without MAP_NORESERVE, huge pages are reserved.
2) With MAP_NORESERVE, no huge pages are reserved.
Note: With "/proc/sys/vm/overcommit_memory == 0", we were already able
to configure it for !hugetlbfs globally; this toggle now allows
configuring it more fine-grained, not for the whole system.
The target use case is virtio-mem, which dynamically exposes memory
inside a large, sparse memory area to the VM.
[1] https://www.kernel.org/doc/Documentation/vm/overcommit-accounting
Reviewed-by: Peter Xu <peterx@redhat.com>
Acked-by: Eduardo Habkost <ehabkost@redhat.com> for memory backend and machine core
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20210510114328.21835-10-david@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Let's introduce RAM_NORESERVE, allowing mmap'ing with MAP_NORESERVE. The
new flag has the following semantics:
"
RAM is mmap-ed with MAP_NORESERVE. When set, reserving swap space (or huge
pages if applicable) is skipped: will bail out if not supported. When not
set, the OS will do the reservation, if supported for the memory type.
"
Allow passing it into:
- memory_region_init_ram_nomigrate()
- memory_region_init_resizeable_ram()
- memory_region_init_ram_from_file()
... and teach qemu_ram_mmap() and qemu_anon_ram_alloc() about the flag.
Bail out if the flag is not supported, which is the case right now for
both, POSIX and win32. We will add Linux support next and allow specifying
RAM_NORESERVE via memory backends.
The target use case is virtio-mem, which dynamically exposes memory
inside a large, sparse memory area to the VM.
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Acked-by: Eduardo Habkost <ehabkost@redhat.com> for memory backend and machine core
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20210510114328.21835-9-david@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Let's pass flags instead of bools to prepare for passing other flags and
update the documentation of qemu_ram_mmap(). Introduce new QEMU_MAP_
flags that abstract the mmap() PROT_ and MAP_ flag handling and simplify
it.
We expose only flags that are currently supported by qemu_ram_mmap().
Maybe, we'll see qemu_mmap() in the future as well that can implement these
flags.
Note: We don't use MAP_ flags as some flags (e.g., MAP_SYNC) are only
defined for some systems and we want to always be able to identify
these flags reliably inside qemu_ram_mmap() -- for example, to properly
warn when some future flags are not available or effective on a system.
Also, this way we can simplify PROT_ handling as well.
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Acked-by: Eduardo Habkost <ehabkost@redhat.com> for memory backend and machine core
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20210510114328.21835-8-david@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
We can create shared anonymous memory via
"-object memory-backend-ram,share=on,..."
which is, for example, required by PVRDMA for mremap() to work.
Shared anonymous memory is weird, though. Instead of MADV_DONTNEED, we
have to use MADV_REMOVE: MADV_DONTNEED will only remove / zap all
relevant page table entries of the current process, the backend storage
will not get removed, resulting in no reduced memory consumption and
a repopulation of previous content on next access.
Shared anonymous memory is internally really just shmem, but without a
fd exposed. As we cannot use fallocate() without the fd to discard the
backing storage, MADV_REMOVE gets the same job done without a fd as
documented in "man 2 madvise". Removing backing storage implicitly
invalidates all page table entries with relevant mappings - an additional
MADV_DONTNEED is not required.
Fixes: 06329ccecf ("mem: add share parameter to memory-backend-ram")
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20210406080126.24010-3-david@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
