Il 20/07/2014 21:48, Michael S. Tsirkin ha scritto:
> I guess an alternative is for callers to check before
> invoking msi_notify. Please note is this is only option
> when using e.g. irqfd, so this has some advantages.
> Is there a specific device that is affected by this?
> I would expect drivers to disable msi before clearing
> bus master bit ...
>
>> > ---
>> > hw/pci/msi.c | 4 ++++
>> > hw/pci/msix.c | 4 ++++
>> > 2 files changed, 8 insertions(+)
>> >
>> > diff --git a/hw/pci/msi.c b/hw/pci/msi.c
>> > index a4a3040..36b651b 100644
>> > --- a/hw/pci/msi.c
>> > +++ b/hw/pci/msi.c
>> > @@ -285,6 +285,10 @@ void msi_notify(PCIDevice *dev, unsigned int vector)
>> > return;
>> > }
>> >
>> > + if (!(pci_get_word(dev->config + PCI_COMMAND) & PCI_COMMAND_MASTER)) {
>> > + return;
>> > + }
>> > +
>> > msg = msi_get_message(dev, vector);
>> >
>> > MSI_DEV_PRINTF(dev,
>> > diff --git a/hw/pci/msix.c b/hw/pci/msix.c
>> > index 5c49bfc..c77ae7d 100644
>> > --- a/hw/pci/msix.c
>> > +++ b/hw/pci/msix.c
>> > @@ -437,6 +437,10 @@ void msix_notify(PCIDevice *dev, unsigned vector)
>> > return;
>> > }
>> >
>> > + if (!(pci_get_word(dev->config + PCI_COMMAND) & PCI_COMMAND_MASTER)) {
>> > + return;
>> > + }
>> > +
>> > msg = msix_get_message(dev, vector);
>> >
>> > stl_le_phys(&address_space_memory, msg.address, msg.data);
I think a better way to do this, is to use the PCI bus master address
space instead of address_space_memory.
Even if it doesn't fix irqfd, it will make the MSI write go through the
IOMMU as it should.
Paolo
