2 Commits

Author	SHA1	Message	Date
Ilya Leoshkevich	892a4f6a75	linux-user: Add partial support for MADV_DONTNEED ... Currently QEMU ignores madvise(MADV_DONTNEED), which break apps that rely on this for zeroing out memory [1]. Improve the situation by doing a passthrough when the range in question is a host-page-aligned anonymous mapping. This is based on the patches from Simon Hausmann [2] and Chris Fallin [3]. The structure is taken from Simon's patch. The PAGE_MAP_ANONYMOUS bits are superseded by commit 26bab757d4 ("linux-user: Introduce PAGE_ANON"). In the end the patch acts like the one from Chris: we either pass-through the entire syscall, or do nothing, since doing this only partially would not help the affected applications much. Finally, add some extra checks to match the behavior of the Linux kernel [4]. [1] https://gitlab.com/qemu-project/qemu/-/issues/326 [2] https://patchew.org/QEMU/20180827084037.25316-1-simon.hausmann@qt.io/ [3] https://github.com/bytecodealliance/wasmtime/blob/v0.37.0/ci/qemu-madvise.patch [4] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/mm/madvise.c?h=v5.19-rc3#n1368 Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Reviewed-by: Laurent Vivier <laurent@vivier.eu> Message-Id: <20220621144205.158452-1-iii@linux.ibm.com> Signed-off-by: Laurent Vivier <laurent@vivier.eu>	2022-06-24 10:00:00 +02:00
Peter Maydell	5423e6d3a4	linux-user: Split mmap prototypes into user-mmap.h ... Split out the mmap prototypes into a new header user-mmap.h which we only include where required. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20210908154405.15417-6-peter.maydell@linaro.org> Signed-off-by: Laurent Vivier <laurent@vivier.eu>	2021-09-13 20:35:45 +02:00