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

[vagran <vagran.ast@gmail.com>]

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 <yamahata@valinux.co.jp>
> 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.