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exec: do not clamp accesses to MMIO regions

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It is common for MMIO registers to overlap, for example a 4 byte register
at 0xcf8 (totally random choice... :)) and a 1 byte register at 0xcf9.
If these registers are implemented via separate MemoryRegions, it is
wrong to clamp the accesses as the value written would be truncated.

Hence for these regions the effects of commit 23820db (exec: Respect
as_translate_internal length clamp, 2015-03-16, previously applied as
commit c3c1bb99) must be skipped.

Tested-by: Hervé Poussineau <hpoussin@reactos.org>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2015-06-17 10:40:27 +02:00
parent ae46e23964
commit 965eb2fcdf
1 changed files with 6 additions and 2 deletions
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8
exec.c
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@ -341,6 +341,7 @@ address_space_translate_internal(AddressSpaceDispatch *d, hwaddr addr, hwaddr *x
hwaddr *plen, bool resolve_subpage)
{
MemoryRegionSection *section;
MemoryRegion *mr;
Int128 diff;
section = address_space_lookup_region(d, addr, resolve_subpage);
@ -350,8 +351,11 @@ address_space_translate_internal(AddressSpaceDispatch *d, hwaddr addr, hwaddr *x
/* Compute offset within MemoryRegion */
*xlat = addr + section->offset_within_region;
diff = int128_sub(section->mr->size, int128_make64(addr));
*plen = int128_get64(int128_min(diff, int128_make64(*plen)));
mr = section->mr;
if (memory_region_is_ram(mr)) {
diff = int128_sub(mr->size, int128_make64(addr));
*plen = int128_get64(int128_min(diff, int128_make64(*plen)));
}
return section;
}