From: Richard Henderson <richard.hender...@linaro.org> 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 <phi...@linaro.org> Signed-off-by: Richard Henderson <richard.hender...@linaro.org> (cherry picked from commit 4ef1f559f270c66b3ffc23f6c845ff3d008c6356) Signed-off-by: Michael Tokarev <m...@tls.msk.ru> diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 834a254895..11c75e3b4e 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); -- 2.39.2
