Commit 965eb2fc authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

exec: do not clamp accesses to MMIO regions 



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 23820dbf (exec: Respect
as_translate_internal length clamp, 2015-03-16, previously applied as
commit c3c1bb99) must be skipped.

Tested-by: default avatarHervé Poussineau <hpoussin@reactos.org>
Tested-by: default avatarMark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent ae46e239

exec.c

+6 −2
Original line number Diff line number Diff line
@@ -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));

    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;

}