dosc/cpu-models-x86: Add documentation for DiamondRapids

Current DiamondRapids hasn't supported cache model. Instead, document
its special CPU & cache topology to allow user emulate with "-smp" &
"-machine smp-cache".

Reviewed-by: Yu Chen <yu.c.chen@intel.com>
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/r/20251215073743.4055227-12-zhao1.liu@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/docs/system/cpu-models-x86.rst.inc b/docs/system/cpu-models-x86.rst.inc
index 6a770ca8351c3a6a90afdedf56435c62452991c9..3605d05a8c47a70e0b311d48b74d132c4b520b3e 100644 (file)
--- a/docs/system/cpu-models-x86.rst.inc
+++ b/docs/system/cpu-models-x86.rst.inc
@@ -71,6 +71,26 @@ mixture of host CPU models between machines, if live migration
 compatibility is required, use the newest CPU model that is compatible
 across all desired hosts.
 
+``DiamondRapids``
+    Intel Xeon Processor.
+
+    Diamond Rapids product has a topology which differs from previous Xeon
+    products. It does not support SMT, but instead features a dual core
+    module (DCM) architecture. It also has core building blocks (CBB - die
+    level in CPU topology). The cache hierarchy is organized as follows:
+    L1 i/d cache is per thread, L2 cache is per DCM, and L3 cache is per
+    CBB. This cache topology can be emulated for DiamondRapids CPU model
+    using the smp-cache configuration as shown below:
+
+    Example:
+
+        ::
+
+            -machine smp-cache.0.cache=l1d,smp-cache.0.topology=thread,\
+                     smp-cache.1.cache=l1i,smp-cache.1.topology=thread,\
+                     smp-cache.2.cache=l2,smp-cache.2.topology=module,\
+                     smp-cache.3.cache=l3,smp-cache.3.topology=die
+
 ``ClearwaterForest``
     Intel Xeon Processor (ClearwaterForest, 2025)