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author | Richard Henderson <richard.henderson@linaro.org> | 2024-02-24 02:29:41 +0000 |
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committer | Richard Henderson <richard.henderson@linaro.org> | 2024-02-29 14:24:24 -1000 |
commit | 4ef1f559f270c66b3ffc23f6c845ff3d008c6356 (patch) | |
tree | 26c62dea77d627f84f0dc9643e5de459737f376e /linux-user/syscall.c | |
parent | ff202817dc2b0b3b42992fa7f1ce503f081068fe (diff) | |
download | qemu-4ef1f559f270c66b3ffc23f6c845ff3d008c6356.zip qemu-4ef1f559f270c66b3ffc23f6c845ff3d008c6356.tar.gz qemu-4ef1f559f270c66b3ffc23f6c845ff3d008c6356.tar.bz2 |
linux-user/x86_64: Handle the vsyscall page in open_self_maps_{2,4}
This is the only case in which we expect to have no host memory backing
for a guest memory page, because in general linux user processes cannot
map any pages in the top half of the 64-bit address space.
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2170
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Diffstat (limited to 'linux-user/syscall.c')
-rw-r--r-- | linux-user/syscall.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/linux-user/syscall.c b/linux-user/syscall.c index e384e14..bc8c065 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -7994,6 +7994,10 @@ static void open_self_maps_4(const struct open_self_maps_data *d, path = "[heap]"; } else if (start == info->vdso) { path = "[vdso]"; +#ifdef TARGET_X86_64 + } else if (start == TARGET_VSYSCALL_PAGE) { + path = "[vsyscall]"; +#endif } /* Except null device (MAP_ANON), adjust offset for this fragment. */ @@ -8082,6 +8086,18 @@ static int open_self_maps_2(void *opaque, target_ulong guest_start, uintptr_t host_start = (uintptr_t)g2h_untagged(guest_start); uintptr_t host_last = (uintptr_t)g2h_untagged(guest_end - 1); +#ifdef TARGET_X86_64 + /* + * Because of the extremely high position of the page within the guest + * virtual address space, this is not backed by host memory at all. + * Therefore the loop below would fail. This is the only instance + * of not having host backing memory. + */ + if (guest_start == TARGET_VSYSCALL_PAGE) { + return open_self_maps_3(opaque, guest_start, guest_end, flags); + } +#endif + while (1) { IntervalTreeNode *n = interval_tree_iter_first(d->host_maps, host_start, host_start); |