| Message ID | 1280330003-1467-2-git-send-email-gleb@redhat.com |
|---|---|
| State | New |
| Headers | show |
diff --git a/exec.c b/exec.c index 5e9a5b7..5945496 100644 --- a/exec.c +++ b/exec.c @@ -3363,6 +3363,8 @@ static int subpage_register (subpage_t *mmio, uint32_t start, uint32_t end, mmio, start, end, idx, eidx, memory); #endif memory = (memory >> IO_MEM_SHIFT) & (IO_MEM_NB_ENTRIES - 1); + if ((memory & ~TARGET_PAGE_MASK) == IO_MEM_RAM) + memory = IO_MEM_UNASSIGNED; for (; idx <= eidx; idx++) { mmio->sub_io_index[idx] = memory; mmio->region_offset[idx] = region_offset;
It is possible that subpage mmio is registered over existing memory page. When this happens "memory" will have real memory address and not index into io_mem array so next access to the page will generate segfault. It is uncommon to have some part of a page to be accessed as memory and some as mmio, but qemu shouldn't crash even when guest does stupid things. So lets just pretend that the rest of the page is unassigned if guest configure part of the memory page as mmio. Signed-off-by: Gleb Natapov <gleb@redhat.com> --- exec.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-)