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ioport: reserve the whole range of an I/O port in the AddressSpace

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When an I/O port is more than 1 byte long, ioport.c is currently
creating "short" regions, for example 0x1ce-0x1ce for the 16-bit
Bochs index port.  When I/O ports are memory mapped, and thus
accessed via a subpage_ops memory region, subpage_accepts gets
confused because it finds a hole at 0x1cf and rejects the access.

In order to fix this, modify registration of the region to cover
the whole size of the I/O port.  Attempts to access an invalid
port will be blocked by find_portio returning NULL.

This only affects the VBE DISPI regions.  For all other cases,
the MemoryRegionPortio entries for 2- or 4-byte accesses overlap
an entry for 1-byte accesses, thus the size of the memory region
is not affected.

Reported-by: Zoltan Balaton <balaton@eik.bme.hu>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2015-03-30 12:35:00 +02:00
parent 147ed37983
commit 4080a13c11
1 changed files with 3 additions and 3 deletions
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6
ioport.c
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@ -269,7 +269,7 @@ void portio_list_add(PortioList *piolist,
/* Handle the first entry specially. */
off_last = off_low = pio_start->offset;
off_high = off_low + pio_start->len;
off_high = off_low + pio_start->len + pio_start->size - 1;
count = 1;
for (pio = pio_start + 1; pio->size != 0; pio++, count++) {
@ -284,10 +284,10 @@ void portio_list_add(PortioList *piolist,
/* ... and start collecting anew. */
pio_start = pio;
off_low = off_last;
off_high = off_low + pio->len;
off_high = off_low + pio->len + pio_start->size - 1;
count = 0;
} else if (off_last + pio->len > off_high) {
off_high = off_last + pio->len;
off_high = off_last + pio->len + pio_start->size - 1;
}
}