Re: [Qemu-devel] [PATCH] qemu msi/msix: added functions to API to set up message address and data

[Alexey Kardashevskiy <aik@ozlabs.ru>]

On 13/06/12 13:22, Benjamin Herrenschmidt wrote:
> On Wed, 2012-06-13 at 12:44 +1000, Alexey Kardashevskiy wrote:
>> Ping?
> 
> FYI. The way it normally works on pseries is that RTAS, which is the
> part of the firmware that lives inside the partition alongside the OS,
> performs the accesses to configure the MSI/MSI-X.
> 
> With qemu "pseries" machine we don't have such an RTAS currently, it's
> all implemented by qemu (or rather we have a tiny 5 instructions RTAS
> which does a hypercall to qemu).
> 
> So we need to be able to do the configuration from within qemu.
> 
> Alexey: Can this be used for supporting MSI/MSI-X with emulated devices
> and virtio as well ?

This is exactly to support MSIX on virtio-pci devices as there were no other MSIX users on power :)
VFIO came up later (and it does not require any change in spapr-msix code).

> Any chance you can do patches for that too ?

I am polishing descriptions now and post them a bit later.



> Cheers,
> Ben.
> 
>>
>> On 12/05/12 16:48, Alexey Kardashevskiy wrote:
>>> Added msi_set_address_data and msix_set_address_data in order to support
>>> sPAPR-specific implementation of MSI/MSIX configuration mechanism.
>>> POWER guest does not initialize these fields, it expects a supervisor to
>>> get them initialized.
>>>
>>> Required for VFIO on POWER.
>>>
>>> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
>>> ---
>>>  hw/msi.c  |   14 ++++++++++++++
>>>  hw/msi.h  |    1 +
>>>  hw/msix.c |   10 ++++++++++
>>>  hw/msix.h |    3 +++
>>>  4 files changed, 28 insertions(+), 0 deletions(-)
>>>
>>> diff --git a/hw/msi.c b/hw/msi.c
>>> index 5d6ceb6..124878a 100644
>>> --- a/hw/msi.c
>>> +++ b/hw/msi.c
>>> @@ -358,3 +358,17 @@ unsigned int msi_nr_vectors_allocated(const PCIDevice *dev)
>>>      uint16_t flags = pci_get_word(dev->config + msi_flags_off(dev));
>>>      return msi_nr_vectors(flags);
>>>  }
>>> +
>>> +void msi_set_address_data(PCIDevice *dev, uint64_t address, uint16_t data)
>>> +{
>>> +    uint16_t flags = pci_get_word(dev->config + msi_flags_off(dev));
>>> +    bool msi64bit = flags & PCI_MSI_FLAGS_64BIT;
>>> +
>>> +    if (msi64bit) {
>>> +        pci_set_quad(dev->config + msi_address_lo_off(dev), address);
>>> +    } else {
>>> +        pci_set_long(dev->config + msi_address_lo_off(dev), address);
>>> +    }
>>> +    pci_set_word(dev->config + msi_data_off(dev, msi64bit), data);
>>> +}
>>> +
>>> diff --git a/hw/msi.h b/hw/msi.h
>>> index 3040bb0..0acf434 100644
>>> --- a/hw/msi.h
>>> +++ b/hw/msi.h
>>> @@ -34,6 +34,7 @@ void msi_reset(PCIDevice *dev);
>>>  void msi_notify(PCIDevice *dev, unsigned int vector);
>>>  void msi_write_config(PCIDevice *dev, uint32_t addr, uint32_t val, int len);
>>>  unsigned int msi_nr_vectors_allocated(const PCIDevice *dev);
>>> +void msi_set_address_data(PCIDevice *dev, uint64_t address, uint16_t data);
>>>
>>>  static inline bool msi_present(const PCIDevice *dev)
>>>  {
>>> diff --git a/hw/msix.c b/hw/msix.c
>>> index 3835eaa..c57c299 100644
>>> --- a/hw/msix.c
>>> +++ b/hw/msix.c
>>> @@ -414,3 +414,13 @@ void msix_unuse_all_vectors(PCIDevice *dev)
>>>          return;
>>>      msix_free_irq_entries(dev);
>>>  }
>>> +
>>> +void msix_set_address_data(PCIDevice *dev, int vector,
>>> +                           uint64_t address, uint32_t data)
>>> +{
>>> +    uint8_t *table_entry = dev->msix_table_page + vector * PCI_MSIX_ENTRY_SIZE;
>>> +    pci_set_quad(table_entry + PCI_MSIX_ENTRY_LOWER_ADDR, address);
>>> +    pci_set_long(table_entry + PCI_MSIX_ENTRY_DATA, data);
>>> +    table_entry[PCI_MSIX_ENTRY_VECTOR_CTRL] &= ~PCI_MSIX_ENTRY_CTRL_MASKBIT;
>>> +}
>>> +
>>> diff --git a/hw/msix.h b/hw/msix.h
>>> index 5aba22b..e6bb696 100644
>>> --- a/hw/msix.h
>>> +++ b/hw/msix.h
>>> @@ -29,4 +29,7 @@ void msix_notify(PCIDevice *dev, unsigned vector);
>>>
>>>  void msix_reset(PCIDevice *dev);
>>>
>>> +void msix_set_address_data(PCIDevice *dev, int vector,
>>> +                           uint64_t address, uint32_t data);
>>> +
>>>  #endif




-- 
Alexey