Re: [RFC v2 3/5] i386/kvm: Support event with select & umask format in KVM PMU filter

[Zhao Liu <zhao1.liu@intel.com>]

> > Do users need to know how to compute the raw event value from @select
> > and @umask?
> 
> Yes, because it's also a unified calculation. AMD and Intel have
> differences in bits for supported select field, but this calculation
> (which follows from the KVM code) makes both compatible.
> 
> > If yes, is C code the best way?

Sorry, I missed this line. In this patch, there's macro:

+#define X86_PMU_RAW_EVENT(eventsel, umask) (((eventsel & 0xf00UL) << 24) | \
+                                            ((eventsel) & 0xff) | \
+                                            ((umask) & 0xff) << 8)

So could I said something like the following?

+##
+# @KVMPMUX86SelectUmaskEvent:
+#
+# x86 PMU event encoding with select and umask.  Using the X86_PMU_RAW_EVENT
+# macro, the select and umask fields will be encoded into raw foramt and
+# delivered to KVM.
+#
+# @select: x86 PMU event select field, which is a 12-bit unsigned
+#     number.
+#
+# @umask: x86 PMU event umask field.
+#
+# Since 10.0
+##
+{ 'struct': 'KVMPMUX86DefalutEvent',
+  'data': { 'select': 'uint16',
+            'umask': 'uint8' } }
+

Thanks very much!

> > Here's another way:
> > 
> >     bits  0..7 : bits 0..7 of @select
> >     bits  8..15: @umask
> >     bits 24..27: bits 8..11 of @select
> >     all other bits: zero
> >
> 
> Thank you! This is what I want.
> 
> 
>