On Wed, 2012-06-13 at 13:22 +0200, Jan Kiszka wrote:
> On 2012-06-13 13:21, Michael S. Tsirkin wrote:
> > On Wed, Jun 13, 2012 at 12:44:01PM +0200, Jan Kiszka wrote:
> >> On 2012-06-12 22:03, Alex Williamson wrote:
> >>> msix_init has very little configurability as to how it lays out MSIX
> >>> for a device. It claims to resize BARs, but doesn't actually do this
> >>> anymore. This patch allows MSIX to be fully specified, which is
> >>> necessary both for emulated devices trying to match the physical
> >>> layout of a hardware device as well as for any kind of device
> >>> assignment.
> >>>
> >>> New functions msix_init_bar & msix_uninit_bar provide wrappers around
> >>> the more detailed functions for drivers that just want a simple MSIX
> >>> setup.
> >>>
> >>> Signed-off-by: Alex Williamson <alex.william...@redhat.com>
> >>> ---
> >>>
> >>> hw/ivshmem.c | 9 +-
> >>> hw/msix.c | 299
> >>> +++++++++++++++++++++++++++++++------------------------
> >>> hw/msix.h | 11 +-
> >>> hw/pci.h | 12 ++
> >>> hw/virtio-pci.c | 15 +--
> >>> 5 files changed, 192 insertions(+), 154 deletions(-)
> >>>
> >>> diff --git a/hw/ivshmem.c b/hw/ivshmem.c
> >>> index 05559b6..71c84a6 100644
> >>> --- a/hw/ivshmem.c
> >>> +++ b/hw/ivshmem.c
> >>> @@ -563,16 +563,13 @@ static uint64_t ivshmem_get_size(IVShmemState * s) {
> >>>
> >>> static void ivshmem_setup_msi(IVShmemState * s)
> >>> {
> >>> - memory_region_init(&s->msix_bar, "ivshmem-msix", 4096);
> >>> - if (!msix_init(&s->dev, s->vectors, &s->msix_bar, 1, 0)) {
> >>> - pci_register_bar(&s->dev, 1, PCI_BASE_ADDRESS_SPACE_MEMORY,
> >>> - &s->msix_bar);
> >>> - IVSHMEM_DPRINTF("msix initialized (%d vectors)\n", s->vectors);
> >>> - } else {
> >>> + if (msix_init_bar(&s->dev, s->vectors, &s->msix_bar, 1,
> >>> "ivshmem-msix")) {
> >>
> >> I don't think the callers of msix_init_bar should have to provide the
> >> memory region for that bar. That can be embedded into PCIDevice, just
> >> like you did for the table and PBA. That was my idea with msix_init_simple.
> >>
> >> Back then, I only included a generic memory region name. That can be
> >> improved, but without bothering the caller. Just derive it from
> >> PCIDevice::name.
> >>
> >> Jan
> >
> > I think callers must initialize the BAR regions.
> > This is because BAR can include other stuff besides MSI-X.
> > MSI-X adds its own subregion.
>
> That's the non-common case handled by msix_init. I don't see this as
> typical for emulated devices.
Exactly, if the caller wants a more complicated layout, msix_init
handles that. msix_init_bar simplifies exactly how most drivers use it
today. Thanks,
Alex
