Re: [PATCH 4/4] s390x/pci: add supported DT information to clp response

[Pierre Morel <pmorel@linux.ibm.com>]

On 12/2/21 17:41, Matthew Rosato wrote:
> The DTSM is a mask that specifies which I/O Address Translation designation
> types are supported.  A linux guest today does not look at this field but

Even Linux is the most used guest it is not the only one so may be not 
mention Linux here.

> could in the future; let's advertise what QEMU actually supports.
> 
> Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
> ---
>   hw/s390x/s390-pci-bus.c         | 1 +
>   hw/s390x/s390-pci-vfio.c        | 1 +
>   include/hw/s390x/s390-pci-bus.h | 1 +
>   include/hw/s390x/s390-pci-clp.h | 3 ++-
>   4 files changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c
> index 1b51a72838..01b58ebc70 100644
> --- a/hw/s390x/s390-pci-bus.c
> +++ b/hw/s390x/s390-pci-bus.c
> @@ -782,6 +782,7 @@ static void s390_pci_init_default_group(void)
>       resgrp->i = 128;
>       resgrp->maxstbl = 128;
>       resgrp->version = 0;
> +    resgrp->dtsm = ZPCI_DTSM;

OK

>   }
>   
>   static void set_pbdev_info(S390PCIBusDevice *pbdev)
> diff --git a/hw/s390x/s390-pci-vfio.c b/hw/s390x/s390-pci-vfio.c
> index 2a153fa8c9..6f80a47e29 100644
> --- a/hw/s390x/s390-pci-vfio.c
> +++ b/hw/s390x/s390-pci-vfio.c
> @@ -160,6 +160,7 @@ static void s390_pci_read_group(S390PCIBusDevice *pbdev,
>           resgrp->i = cap->noi;
>           resgrp->maxstbl = cap->maxstbl;
>           resgrp->version = cap->version;
> +        resgrp->dtsm = ZPCI_DTSM;

Is it safe for VFIO whith interpretation?
Shouldn't we extend the capability and use the host DTSM in this case?

...snip...

-- 
Pierre Morel
IBM Lab Boeblingen