Re: [Xen-devel] [PATCH v4 18/22] xen/pci: Pay attention to PCI_MSIX_TABLE_OFFSET

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 24.04.13 at 18:34, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote:
> On Mon, Apr 22, 2013 at 5:12 PM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote:
>> The MSI-X Table structure may be at a non-zero offset into the
>> device BAR, and we should account for that.

NAK: The base is just being use to pass to the hypervisor, which
then takes care to add the offset. Recent hypervisors will actually
only consume this to issue a warning if not matching what gets
read from the corresponding BAR. Earlier hypervisors used this
instead of reading the BAR.

Jan

>> Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
>> CC: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
>> ---
>>  arch/x86/pci/xen.c |    4 +++-
>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
>> index 94e7662..0e8a196 100644
>> --- a/arch/x86/pci/xen.c
>> +++ b/arch/x86/pci/xen.c
>> @@ -300,8 +300,10 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev 
>> *dev, int nvec, int type)
>>                         pci_read_config_dword(dev, pos + PCI_MSIX_TABLE,
>>                                               &table_offset);
>>                         bir = (u8)(table_offset & PCI_MSIX_FLAGS_BIRMASK);
>> +                       table_offset &= PCI_MSIX_TABLE_OFFSET;
>>
>> -                       map_irq.table_base = pci_resource_start(dev, bir);
>> +                       map_irq.table_base = pci_resource_start(dev, bir) +
>> +                               table_offset;
>>                         map_irq.entry_nr = msidesc->msi_attrib.entry_nr;
>>                 }
>>
>>



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