QEMU emulator version 0.14.50, Copyright (c) 2003-2008 Fabrice Bellard
You are correct, it's not hardcoded to 4. However, when it's allocated the
number of elements IS 4. Also,
there's a comment just above pci_set_irq which says:
/* 0 <= irq_num <= 3. level must be 0 or 1 */
static void pci_set_irq(void *opaque, int irq_num, int level)
so, that implies to me that it's probably always 4... Sorry for the confusion.
From: Richard Henderson
Sent: Tue 9/20/2011 2:57 PM
To: Alan Amaral
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] pci_change_irq_level is broken...
On 09/20/2011 10:24 AM, Alan Amaral wrote:
> I'm not on this mailing list, so please CC me on any replies. Thanks.
>
> I ran qemu with valgrind last night and found an error in the pci emulation
> code, which may,
> or may not, be biting us. So far the effects seem benign, although there
> exists the possibility
> of trashing random memory.
>
> In the function pci_change_irq_level() the argument irq_num is passed in as
> 0-3, and used
> as an index to change bus->irq_count[4].
I don't know what version of qemu you're using, but this is
int *irq_count;
in current sources. There's certainly no hard-coded "4".
> assert(irq_num >= 0);
> assert(irq_num < bus->nirq);
> bus->irq_count[irq_num] += change;
> bus->set_irq(bus->irq_opaque, bus_irq_num, bus->irq_count[irq_num] != 0);
This version with the asserts, though, could be done. The site
that created the bus ought to match up nirq with the map function.
r~
