diff options
| author | Richard Henderson <richard.henderson@linaro.org> | 2019-05-19 13:19:52 -0700 |
|---|---|---|
| committer | Laurent Vivier <laurent@vivier.eu> | 2019-05-24 13:16:21 +0200 |
| commit | 30ab9ef2967dde22193f609b6ec56101c156b061 (patch) | |
| tree | 128863abc52b116065b5d5c162e0335592e60254 /linux-user/elfload.c | |
| parent | abcac736c1505254ec3f9587aff04fbe4705a55e (diff) | |
linux-user: Fix shmat emulation by honoring host SHMLBA
For those hosts with SHMLBA > getpagesize, we don't automatically
select a guest address that is compatible with the host. We can
achieve this by boosting the alignment of guest_base and by adding
an extra alignment argument to mmap_find_vma.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20190519201953.20161-13-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Diffstat (limited to 'linux-user/elfload.c')
| -rw-r--r-- | linux-user/elfload.c | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/linux-user/elfload.c b/linux-user/elfload.c index 02832adfbc..a23aa4493e 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -3,6 +3,7 @@ #include <sys/param.h> #include <sys/resource.h> +#include <sys/shm.h> #include "qemu.h" #include "disas/disas.h" @@ -2012,6 +2013,8 @@ unsigned long init_guest_space(unsigned long host_start, unsigned long guest_start, bool fixed) { + /* In order to use host shmat, we must be able to honor SHMLBA. */ + unsigned long align = MAX(SHMLBA, qemu_host_page_size); unsigned long current_start, aligned_start; int flags; @@ -2029,7 +2032,7 @@ unsigned long init_guest_space(unsigned long host_start, } /* Setup the initial flags and start address. */ - current_start = host_start & qemu_host_page_mask; + current_start = host_start & -align; flags = MAP_ANONYMOUS | MAP_PRIVATE | MAP_NORESERVE; if (fixed) { flags |= MAP_FIXED; @@ -2065,8 +2068,8 @@ unsigned long init_guest_space(unsigned long host_start, return (unsigned long)-1; } munmap((void *)real_start, host_full_size); - if (real_start & ~qemu_host_page_mask) { - /* The same thing again, but with an extra qemu_host_page_size + if (real_start & (align - 1)) { + /* The same thing again, but with extra * so that we can shift around alignment. */ unsigned long real_size = host_full_size + qemu_host_page_size; @@ -2079,7 +2082,7 @@ unsigned long init_guest_space(unsigned long host_start, return (unsigned long)-1; } munmap((void *)real_start, real_size); - real_start = HOST_PAGE_ALIGN(real_start); + real_start = ROUND_UP(real_start, align); } current_start = real_start; } @@ -2106,7 +2109,7 @@ unsigned long init_guest_space(unsigned long host_start, } /* Ensure the address is properly aligned. */ - if (real_start & ~qemu_host_page_mask) { + if (real_start & (align - 1)) { /* Ideally, we adjust like * * pages: [ ][ ][ ][ ][ ] @@ -2134,7 +2137,7 @@ unsigned long init_guest_space(unsigned long host_start, if (real_start == (unsigned long)-1) { return (unsigned long)-1; } - aligned_start = HOST_PAGE_ALIGN(real_start); + aligned_start = ROUND_UP(real_start, align); } else { aligned_start = real_start; } @@ -2171,7 +2174,7 @@ unsigned long init_guest_space(unsigned long host_start, * because of trouble with ARM commpage setup. */ munmap((void *)real_start, real_size); - current_start += qemu_host_page_size; + current_start += align; if (host_start == current_start) { /* Theoretically possible if host doesn't have any suitably * aligned areas. Normally the first mmap will fail. |