Re: [Qemu-devel] [PATCH v2] pci-assign: Add MSI affinity support

[Anthony Liguori <anthony@codemonkey.ws>]

"Michael S. Tsirkin" <mst@redhat.com> writes:

> On Mon, May 13, 2013 at 02:20:02PM -0600, Alex Williamson wrote:
>> To support guest MSI affinity changes update the MSI message any time
>> the guest writes to the address or data fields.
>> 
>> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
>
> Seems the only way we can fix this for 1.5.
>
> Acked-by: Michael S. Tsirkin <mst@redhat.com>

Is this a bug or a feature?  Can someone describe the scenario in which
the bug occurs?

Regards,

Anthony Liguori

>
>> ---
>> 
>> v2: Don't cache MSIMessage
>> 
>>  hw/i386/kvm/pci-assign.c |   18 ++++++++++++++++++
>>  1 file changed, 18 insertions(+)
>> 
>> diff --git a/hw/i386/kvm/pci-assign.c b/hw/i386/kvm/pci-assign.c
>> index c1e08ec..ff85590 100644
>> --- a/hw/i386/kvm/pci-assign.c
>> +++ b/hw/i386/kvm/pci-assign.c
>> @@ -1026,6 +1026,21 @@ static void assigned_dev_update_msi(PCIDevice *pci_dev)
>>      }
>>  }
>>  
>> +static void assigned_dev_update_msi_msg(PCIDevice *pci_dev)
>> +{
>> +    AssignedDevice *assigned_dev = DO_UPCAST(AssignedDevice, dev, pci_dev);
>> +    uint8_t ctrl_byte = pci_get_byte(pci_dev->config + pci_dev->msi_cap +
>> +                                     PCI_MSI_FLAGS);
>> +
>> +    if (assigned_dev->assigned_irq_type != ASSIGNED_IRQ_MSI ||
>> +        !(ctrl_byte & PCI_MSI_FLAGS_ENABLE)) {
>> +        return;
>> +    }
>> +
>> +    kvm_irqchip_update_msi_route(kvm_state, assigned_dev->msi_virq[0],
>> +                                 msi_get_message(pci_dev, 0));
>> +}
>> +
>>  static bool assigned_dev_msix_masked(MSIXTableEntry *entry)
>>  {
>>      return (entry->ctrl & cpu_to_le32(0x1)) != 0;
>> @@ -1201,6 +1216,9 @@ static void assigned_dev_pci_write_config(PCIDevice *pci_dev, uint32_t address,
>>          if (range_covers_byte(address, len,
>>                                pci_dev->msi_cap + PCI_MSI_FLAGS)) {
>>              assigned_dev_update_msi(pci_dev);
>> +        } else if (ranges_overlap(address, len, /* 32bit MSI only */
>> +                                  pci_dev->msi_cap + PCI_MSI_ADDRESS_LO, 6)) {
>> +            assigned_dev_update_msi_msg(pci_dev);
>>          }
>>      }
>>      if (assigned_dev->cap.available & ASSIGNED_DEVICE_CAP_MSIX) {