Re: [PATCH 01/12] s390x/pci: use a reserved ID for the default PCI group

[Thomas Huth <thuth@redhat.com>]

On 07/12/2021 22.04, Matthew Rosato wrote:
> The current default PCI group being used can technically collide with a
> real group ID passed from a hostdev.  Let's instead use a group ID that
> comes from a special pool (0xF0-0xFF) that is architected to be reserved
> for simulated devices.

Maybe mention that this is not a problem for migration since zPCI currently 
can't be migrated anyway (as mentioned in the discussion of an earlier 
version of this patch)

Acked-by: Thomas Huth <thuth@redhat.com>


> Fixes: 28dc86a072 ("s390x/pci: use a PCI Group structure")
> Reviewed-by: Eric Farman <farman@linux.ibm.com>
> Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
> Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
> ---
>   include/hw/s390x/s390-pci-bus.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/hw/s390x/s390-pci-bus.h b/include/hw/s390x/s390-pci-bus.h
> index aa891c178d..2727e7bdef 100644
> --- a/include/hw/s390x/s390-pci-bus.h
> +++ b/include/hw/s390x/s390-pci-bus.h
> @@ -313,7 +313,7 @@ typedef struct ZpciFmb {
>   } ZpciFmb;
>   QEMU_BUILD_BUG_MSG(offsetof(ZpciFmb, fmt0) != 48, "padding in ZpciFmb");
>   
> -#define ZPCI_DEFAULT_FN_GRP 0x20
> +#define ZPCI_DEFAULT_FN_GRP 0xFF
>   typedef struct S390PCIGroup {
>       ClpRspQueryPciGrp zpci_group;
>       int id;
>