Re: [Qemu-devel] Re: EFI console stopped working in Qemu 0.14.0

[vagran]

I am using TianoCore EFI by Tristan Gingold which is published
on http://wiki.qemu.org/download/efi-bios.tar.bz2. If you would try
to load it on Qemu 0.14.0 (built either for i386 or x86_64) you will
see nothing on VGA display or serial console. But it still will be
able to load OS after timeout if you have proper disk image.
> It seems your EFI BIOS doesn't enable memor, io or master bits
> in command register.
>   
>
> or disableintx.
>   
I have checked your guess and figured out that it works only
if both memory and io bits are not cleared. So the following
patch also works:
diff --git a/hw/pci.c b/hw/pci.c
index 8b76cea..bcf9b16 100644
--- a/hw/pci.c
+++ b/hw/pci.c
@@ -163,8 +163,9 @@ void pci_device_reset(PCIDevice *dev)
    pci_device_deassert_intx(dev);
    /* Clear all writeable bits */
    pci_word_test_and_clear_mask(dev->config + PCI_COMMAND,
-                                 pci_get_word(dev->wmask + PCI_COMMAND) |
-                                 pci_get_word(dev->w1cmask + PCI_COMMAND));
+                                 (pci_get_word(dev->wmask + PCI_COMMAND) |
+                                 pci_get_word(dev->w1cmask + 
PCI_COMMAND)) &
+                                 ~(PCI_COMMAND_IO | PCI_COMMAND_MEMORY));
    pci_word_test_and_clear_mask(dev->config + PCI_STATUS,
                                 pci_get_word(dev->wmask + PCI_STATUS) |
                                 pci_get_word(dev->w1cmask + PCI_STATUS));

So probably the problem is in EFI BIOS. But I was not able to find
its source code. Anyone knows how is it built?

Best regards,
Artyom.


Isaku Yamahata wrote:
> On Thu, Mar 03, 2011 at 12:03:53PM +0900, Isaku Yamahata wrote:
>   
> > Hi. Thank you for reporting.
> > Can you elaborate on the changeset that you pointed out and
> > your work around?
> >
> > Regarding to the changeset, it had the issue, but I suppose
> > 80376c3fc2c38fdd45354e4b0eb45031f35587ed fixed it.
> > Do you found any other issue?
> >
> > Regarding to your workaround, what was the problem?
> > What EFI BIOS are you using? Tiano-core derivatives that
> > Tristan Gingold worked on? Or other one?
> > It seems your EFI BIOS doesn't enable memor, io or master bits
> > in command register.
> >     
>
> or disableintx.
>
>   
> > If so, the issue is in the bios, not qemu.
> >
> > thanks,
> >
> > On Wed, Mar 02, 2011 at 11:27:31PM +0200, vagran wrote:
> >     
> > > vagran wrote:
> > >       
> > > > Hi,
> > > > I have noted that Qemu VGA and serial console with EFI BIOS stopped  
> > > > working in
> > > > 0.14.0 (and in latest development snapshot is still not working).  
> > > > Everything was
> > > > fine in 0.13.0. However EFI BIOS itself is able to load kernel if it was
> > > > properly configured on used disk image. The only effect is that  
> > > > neither VGA nor
> > > > serial console is not functioning. After short investigation I have  
> > > > discovered
> > > > that this functionality was broken by this commit:
> > > >
> > > > commit 9bb3358627d87d8de25fb41b7276575539d799a7
> > > > Author: Isaku Yamahata <address@hidden>
> > > > Date:   Fri Nov 19 18:56:02 2010 +0900
> > > >
> > > > Do you have any idea how this change could affect EFI consoles?
> > > >
> > > >         
> > > After further investigation I have found that the following patch provides
> > > a workaround for the problem, may be it could be useful for somebody who
> > > is more familiar with Qemu PCI code:
> > >
> > > diff --git a/hw/pci.c b/hw/pci.c
> > > index 8b76cea..06dd7ab 100644
> > > --- a/hw/pci.c
> > > +++ b/hw/pci.c
> > > @@ -162,9 +162,11 @@ void pci_device_reset(PCIDevice *dev)
> > >     pci_update_irq_status(dev);
> > >     pci_device_deassert_intx(dev);
> > >     /* Clear all writeable bits */
> > > +#if 0
> > >     pci_word_test_and_clear_mask(dev->config + PCI_COMMAND,
> > >                                  pci_get_word(dev->wmask + PCI_COMMAND) |
> > >                                  pci_get_word(dev->w1cmask + PCI_COMMAND));
> > > +#endif
> > >     pci_word_test_and_clear_mask(dev->config + PCI_STATUS,
> > >                                  pci_get_word(dev->wmask + PCI_STATUS) |
> > >                                  pci_get_word(dev->w1cmask + PCI_STATUS));
> > >
> > > Best regards,
> > > Artyom.
> > >
> > >       
> > --
> > yamahata
> >
> >