hw/core: Add a helper to check the cache topology level

Currently, we have no way to expose the arch-specific default cache
model because the cache model is sometimes related to the CPU model
(e.g., i386).

Since the user might configure "default" level, any comparison with
"default" is meaningless before the machine knows the specific level
that "default" refers to.

We can only check the correctness of the cache topology after the arch
loads the user-configured cache model from MachineState.smp_cache and
consumes the special "default" level by replacing it with the specific
level.

Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-ID: <20241101083331.340178-6-zhao1.liu@intel.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

1 files changed, 48 insertions, 0 deletions

diff --git a/hw/core/machine-smp.c b/hw/core/machine-smp.c
index ebb7a134a7..640b2114b4 100644
--- a/hw/core/machine-smp.c
+++ b/hw/core/machine-smp.c
@@ -348,3 +348,51 @@ void machine_set_cache_topo_level(MachineState *ms, CacheLevelAndType cache,
 {
     ms->smp_cache.props[cache].topology = level;
 }
+
+/*
+ * When both cache1 and cache2 are configured with specific topology levels
+ * (not default level), is cache1's topology level higher than cache2?
+ */
+static bool smp_cache_topo_cmp(const SmpCache *smp_cache,
+                               CacheLevelAndType cache1,
+                               CacheLevelAndType cache2)
+{
+    /*
+     * Before comparing, the "default" topology level should be replaced
+     * with the specific level.
+     */
+    assert(smp_cache->props[cache1].topology != CPU_TOPOLOGY_LEVEL_DEFAULT);
+
+    return smp_cache->props[cache1].topology > smp_cache->props[cache2].topology;
+}
+
+/*
+ * Currently, we have no way to expose the arch-specific default cache model
+ * because the cache model is sometimes related to the CPU model (e.g., i386).
+ *
+ * We can only check the correctness of the cache topology after the arch loads
+ * the user-configured cache model from MachineState and consumes the special
+ * "default" level by replacing it with the specific level.
+ */
+bool machine_check_smp_cache(const MachineState *ms, Error **errp)
+{
+    if (smp_cache_topo_cmp(&ms->smp_cache, CACHE_LEVEL_AND_TYPE_L1D,
+                           CACHE_LEVEL_AND_TYPE_L2) ||
+        smp_cache_topo_cmp(&ms->smp_cache, CACHE_LEVEL_AND_TYPE_L1I,
+                           CACHE_LEVEL_AND_TYPE_L2)) {
+        error_setg(errp,
+                   "Invalid smp cache topology. "
+                   "L2 cache topology level shouldn't be lower than L1 cache");
+        return false;
+    }
+
+    if (smp_cache_topo_cmp(&ms->smp_cache, CACHE_LEVEL_AND_TYPE_L2,
+                           CACHE_LEVEL_AND_TYPE_L3)) {
+        error_setg(errp,
+                   "Invalid smp cache topology. "
+                   "L3 cache topology level shouldn't be lower than L2 cache");
+        return false;
+    }
+
+    return true;
+}