On Thu, Jun 20, 2019 at 10:16:36 +0200, Ján Tomko wrote:
On Thu, Jun 20, 2019 at 12:53:38AM +0200, Jiri Denemark wrote:
This function may be used as a virCPUDefFeatureFilter callback for virCPUDefCheckFeatures, virCPUDefFilerFeatures, and similar functions to filter or pick out features reported via MSR.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com> --- src/cpu/cpu_x86.c | 40 ++++++++++++++++++++++++++++++++++++++++ src/cpu/cpu_x86.h | 3 +++ src/libvirt_private.syms | 1 + 3 files changed, 44 insertions(+)
diff --git a/src/cpu/cpu_x86.c b/src/cpu/cpu_x86.c index 6eef5cef00..a7ec0f7095 100644 --- a/src/cpu/cpu_x86.c +++ b/src/cpu/cpu_x86.c @@ -3362,6 +3362,46 @@ virCPUx86DataAddFeature(virCPUDataPtr cpuData, }
+/** + * virCPUx86FeatureIsMSR: + * @name CPU feature name + * @opaque NULL or a pointer to bool + * + * This is a callback for functions filtering features in virCPUDef. + * + * Checks whether a given CPU feature is reported via MSR. When @opaque is NULL + * or a pointer to true, the function will pick out (return true for) MSR + * features. If @opaque is a pointer to false, the logic will be inverted and + * the function will filter out (return false for) MSR features. + */
Uhm. What? Do I understand it correctly?
@opaque | *opaque | IsMSR | return --------+---------+-------+-------- NULL | SEGV | true | true 0xBEEF | true | true | true 0xBEEF | false | true | false --------+---------+-------+--------
First, it feels odd that 'false' is the value resulting in changed behavior. I'd rather see it act differently when the bool pointer is present and points to true.
I actually tried both variants and could not decide which one is better. And this means both are in fact ugly :-) So when changing virCPUx86FeatureIsMSR into a helper, I created two simple wrappers instead of playing with opaque pointer. Jirka