Re: [Qemu-devel] [PATCH] msix: Support specifying offsets, BARs, and capability location

[Jan Kiszka <jan.kiszka@siemens.com>]

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.williamson@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

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