Messages in this thread | | | Date | Wed, 19 Jan 2022 12:20:48 -0500 | Subject | Re: [PATCH v2 26/30] vfio-pci/zdev: wire up zPCI adapter interrupt forwarding support | From | Matthew Rosato <> |
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On 1/19/22 12:10 PM, Pierre Morel wrote: > > > On 1/14/22 21:31, Matthew Rosato wrote: ... >> diff --git a/include/uapi/linux/vfio_zdev.h >> b/include/uapi/linux/vfio_zdev.h >> index 575f0410dc66..c574e23f9385 100644 >> --- a/include/uapi/linux/vfio_zdev.h >> +++ b/include/uapi/linux/vfio_zdev.h >> @@ -90,4 +90,24 @@ struct vfio_device_zpci_interp { >> __u32 fh; /* Host device function handle */ >> }; >> +/** >> + * VFIO_DEVICE_FEATURE_ZPCI_AIF >> + * >> + * This feature is used for enabling forwarding of adapter interrupts >> directly >> + * from firmware to the guest. When setting this feature, the flags >> indicate >> + * whether to enable/disable the feature and the structure defined >> below is >> + * used to setup the forwarding structures. When getting this >> feature, only >> + * the flags are used to indicate the current state. >> + */ >> +struct vfio_device_zpci_aif { >> + __u64 flags; >> +#define VFIO_DEVICE_ZPCI_FLAG_AIF_FLOAT 1 >> +#define VFIO_DEVICE_ZPCI_FLAG_AIF_HOST 2 > > Generaly it looks good to me but I miss some explanation on these flags.
I can add a small line comment for each, like:
AIF_FLOAT 1 /* Floating interrupts enabled */ AIF_HOST 2 /* Host delivery forced */
But here's a bit more detail:
On SET: AIF_FLOAT = 1 means enable the interrupt forwarding assist for floating interrupt delivery AIF_FLOAT = 0 means to disable it. AIF_HOST = 1 means the assist will always deliver the interrupt to the host and let the host inject it AIF_HOST = 0 host only gets interrupts when firmware can't deliver
on GET, we just indicate the current settings from the most recent SET, meaning: AIF_FLOAT = 1 interrupt forwarding assist is currently active AIF_FLOAT = 0 interrupt forwarding assist is not currently active AIF_HOST = 1 interrupt forwarding will always go through host AIF_HOST = 0 interrupt forwarding will only go through the host when necessary
> > Which makes me realize that a more complete documentation under > Documentation/S390 for VFIO zPCI as we have for VFIO AP and VFIO CCW > would be of great interest.
You're not wrong -- a similar comment came up for QEMU. I will add this to my todo list as a follow-on.
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