[Qemu-devel] Re: [PATCH 0/4] pci: interrupt status/interrupt disable support

[Isaku Yamahata]

On Wed, Nov 25, 2009 at 06:58:34PM +0200, Michael S. Tsirkin wrote:
> This patchset adds support for mandatory interupt
> status and interrupt disable bits to all
> PCI devices.  This is required for PCI compliancy.
> 
> These patches are on top of my pci tree,
> including Isaku Yamahata's fixes.
> If this is a problem, let me know and
> I will rebase.
> 
> This works fine for me, but since this touches
> all PCI devices, please review carefully.

Just a curiosity, what OS do you have in your mind?

You introduced new members, irq_status and irq_disabled
and maintain them according configuration space write.
Another approach is to use irq_state[PCI_NUM_PINS] and interrupt disabled
bit in command register.
At least I think irq_disable can be removed by moving !change check
from pci_set_irq() into pci_change_irq_level().

As for irq_status, only user of irq_status is pci_update_irq_status()
so if (irq_statue) can be open coded. On the other hand,
PCIBus already has irq_count member for same purpose.
So probably open coding or introducing irq_count instead of irq_status
would be reasonable.


> 
> Michael S. Tsirkin (4):
>   pci: rearrange code for interrupts
>   pci: track IRQ status
>   pci: interrupt status bit implementation
>   pci: interrupt disable bit support
> 
>  hw/pci.c |   83 
> +++++++++++++++++++++++++++++++++++++++++++++++++++++---------
>  hw/pci.h |    8 ++++++
>  2 files changed, 79 insertions(+), 12 deletions(-)
> 

-- 
yamahata