Re: [PATCH] cpu_x86: Probe host CPU for all MSR features

[Jiri Denemark <jdenemar@xxxxxxxxxx>]

On Thu, Jan 16, 2025 at 14:38:26 +0100, Michal Prívozník wrote:
> On 1/16/25 14:05, Jiri Denemark wrote:
> > The list of CPU features we probe from various MSR grew significantly
> > over time and the CPU map currently mentions 11 distinct MSR indexes.
> > But the code for directly probing host CPU features was still reading
> > only the original 0x10a index. Thus the CPU model in host capabilities
> > was missing a lot of features.
> > 
> > Instead of specifying a static list of indexes to read (which we would
> > forget to update in the future), let's just read all indexes found in
> > the CPU map.
> > 
> > Signed-off-by: Jiri Denemark <jdenemar@xxxxxxxxxx>
> > ---
> >  src/cpu/cpu_x86.c | 62 ++++++++++++++++++++++++++++++++++++++++-------
> >  1 file changed, 53 insertions(+), 9 deletions(-)
> 
> Reviewed-by: Michal Privoznik <mprivozn@xxxxxxxxxx>

Thanks, I was reminded declaring more variables on a single line is bad
so I squashed the following trivial patch before pushing.

Jirka

@@ -2841,7 +2841,7 @@ virCPUx86ListMSRs(virCPUx86Map *map,
                   unsigned long **msrs)
 {
     size_t n = 0;
-    size_t i, j, k;
+    size_t i;

     /* These three nested loops look horrible, but data->len is always 1 here
      * and thanks to grouping features in the CPU map by their MSR index the
@@ -2850,11 +2850,13 @@ virCPUx86ListMSRs(virCPUx86Map *map,
      */
     for (i = 0; i < map->nfeatures; i++) {
         virCPUx86Data *data = &map->features[i]->data;
+        size_t j;

         for (j = 0; j < data->len; j++) {
             virCPUx86DataItem *item = &data->items[j];
             bool found = false;
             unsigned long msr;
+            size_t k;

             if (item->type != VIR_CPU_X86_DATA_MSR)
                 continue;