On Wed, Dec 18, 2013 at 06:55:24PM +0200, Marcel Apfelbaum wrote:
> On Wed, 2013-12-18 at 11:34 -0500, Paolo Bonzini wrote:
> >
> > ----- Messaggio originale -----
> > > Da: "Michael S. Tsirkin" <m...@redhat.com>
> > > A: "marcel a" <marce...@redhat.com>
> > > Cc: "Paolo Bonzini" <pbonz...@redhat.com>, "Gal Hammer"
> > > <gham...@redhat.com>, seabios@seabios.org,
> > > qemu-de...@nongnu.org
> > > Inviato: Mercoledì, 18 dicembre 2013 17:33:06
> > > Oggetto: Re: [Qemu-devel] [PATCH] piix: do not reset APIC base address
> > > (0x80) on piix4_reset.
> > >
> > > On Wed, Dec 18, 2013 at 06:27:12PM +0200, Marcel Apfelbaum wrote:
> > > > On Wed, 2013-12-18 at 17:22 +0200, Michael S. Tsirkin wrote:
> > > > > On Wed, Dec 18, 2013 at 03:22:59PM +0100, Paolo Bonzini wrote:
> > > > > > 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 <gham...@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
> > > > >
> > > > > Seems reasonable: either seabios or guest OS must do it, and
> > > > > guest does not seem to.
> > > > I was looking into this today, but it seems that we have a problem.
> > > > We cannot run pci_setup() in init section:
> > > > .data.varinit.seabios/src/hw/pci.h.66 is VARVERIFY32INIT but used from
> > > > ['.text.runtime.seabios/src/resume.c.150', '.text.pci_setup']
> > > >
> > > > Any thoughts how to get around this?
> > > > Thanks,
> > > > Marcel
> > >
> > > We defintely don't want to do full pci enumeration.
> > > Just pci_bios_init_platform or even less.
> >
> > Or put an array of (bdf, offset, size, value) tuples somewhere in low
> > memory,
> > fill it at startup, and reproduce it blindly at S3 resume time. This is
> > similar
> > to what UEFI does.
> Could you please elaborate a little more?
> Let me see first if I understand the problem:
> PciDevices list is a list of pointers that cannot be used
> inside init code which is 16 bit code, right?
>
> If I got it right, the solution is to find another way to iterate
> over pci devices?
Yes, but I think foreachbdf does this in already.
> If yes, *when* would this data be put in memory and "when"?
> A pointer to the right direction would be appreciated,
>
> Thanks!
> Marcel
>
> >
> > Paolo
> >
>
>
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