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.
