Re: [Qemu-devel] [PATCH] piix: do not reset APIC base address (0x80) on piix4_reset.

[Paolo Bonzini <pbonzini@redhat.com>]

Il 11/12/2013 10:21, Gal Hammer ha scritto:
> Fix a bug that was introduced in commit c046e8c4. QEMU fails to
> resume from suspend mode (S3).
> 
> Signed-off-by: Gal Hammer <ghammer@redhat.com>
> ---
>  hw/acpi/piix4.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
> index 93849c8..5c736a4 100644
> --- a/hw/acpi/piix4.c
> +++ b/hw/acpi/piix4.c
> @@ -376,7 +376,6 @@ static void piix4_reset(void *opaque)
>      pci_conf[0x5b] = 0;
>  
>      pci_conf[0x40] = 0x01; /* PM io base read only bit */
> -    pci_conf[0x80] = 0;
>  
>      if (s->kvm_enabled) {
>          /* Mark SMM as already inited (until KVM supports SMM). */

Note this is not the APIC base address, that one is 80h on the ISA
bridge (function 0).  You're changing the behavior for 80h on the power
management function, which is function 3.  The register is "PMBA—POWER
MANAGEMENT BASE ADDRESS" and it is indeed initialized by SeaBIOS in
piix4_pm_setup (src/fw/pciinit.c).

Michael, perhaps a part of pci_setup (same file) should run on S3 resume?

Paolo