Re: [PATCH v11 04/11] s390x/cpu topology: reporting the CPU topology to the guest

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On 11/15/22 12:21, Cédric Le Goater wrote:
Hello Pierre,

On 11/3/22 18:01, Pierre Morel wrote:
The guest can use the STSI instruction to get a buffer filled
with the CPU topology description.

Let us implement the STSI instruction for the basis CPU topology
level, level 2.

Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
---
  include/hw/s390x/cpu-topology.h |   6 ++
  target/s390x/cpu.h              |  77 ++++++++++++++++++++++++
  hw/s390x/cpu-topology.c         |   1 -
  target/s390x/cpu_topology.c     | 100 ++++++++++++++++++++++++++++++++
  target/s390x/kvm/kvm.c          |   6 +-
  target/s390x/meson.build        |   1 +
  6 files changed, 189 insertions(+), 2 deletions(-)
  create mode 100644 target/s390x/cpu_topology.c

diff --git a/include/hw/s390x/cpu-topology.h b/include/hw/s390x/cpu-topology.h
index 4e16a2153d..6fec10e032 100644
--- a/include/hw/s390x/cpu-topology.h
+++ b/include/hw/s390x/cpu-topology.h
@@ -16,6 +16,11 @@
  #define S390_TOPOLOGY_CPU_IFL 0x03
  #define S390_TOPOLOGY_MAX_ORIGIN ((63 + S390_MAX_CPUS) / 64)
+#define S390_TOPOLOGY_POLARITY_HORIZONTAL      0x00
+#define S390_TOPOLOGY_POLARITY_VERTICAL_LOW    0x01
+#define S390_TOPOLOGY_POLARITY_VERTICAL_MEDIUM 0x02
+#define S390_TOPOLOGY_POLARITY_VERTICAL_HIGH   0x03
+
  typedef struct S390TopoSocket {
      int active_count;
      uint64_t mask[S390_TOPOLOGY_MAX_ORIGIN];
@@ -26,6 +31,7 @@ struct S390Topology {
      uint32_t nr_cpus;
      uint32_t nr_sockets;
      S390TopoSocket *socket;
+    bool topology_needed;


This is unused in this patch. Introduced too soon ?

right, thanks.



  };
  #define TYPE_S390_CPU_TOPOLOGY "s390-topology"
diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
index c9066b2496..69a7523146 100644
--- a/target/s390x/cpu.h
+++ b/target/s390x/cpu.h
@@ -567,6 +567,81 @@ typedef union SysIB {
  } SysIB;
  QEMU_BUILD_BUG_ON(sizeof(SysIB) != 4096);
+/*
+ * CPU Topology List provided by STSI with fc=15 provides a list
+ * of two different Topology List Entries (TLE) types to specify
+ * the topology hierarchy.
+ *
+ * - Container Topology List Entry
+ *   Defines a container to contain other Topology List Entries
+ *   of any type, nested containers or CPU.
+ * - CPU Topology List Entry
+ *   Specifies the CPUs position, type, entitlement and polarization
+ *   of the CPUs contained in the last Container TLE.
+ *
+ * There can be theoretically up to five levels of containers, QEMU
+ * uses only one level, the socket level.
+ *
+ * A container of with a nesting level (NL) greater than 1 can only
+ * contain another container of nesting level NL-1.
+ *
+ * A container of nesting level 1 (socket), contains as many CPU TLE
+ * as needed to describe the position and qualities of all CPUs inside
+ * the container.
+ * The qualities of a CPU are polarization, entitlement and type.
+ *
+ * The CPU TLE defines the position of the CPUs of identical qualities
+ * using a 64bits mask which first bit has its offset defined by
+ * the CPU address orgin field of the CPU TLE like in:
+ * CPU address = origin * 64 + bit position within the mask
+ *
+ */
+/* Container type Topology List Entry */
+typedef struct SysIBTl_container {
+        uint8_t nl;
+        uint8_t reserved[6];
+        uint8_t id;
+} QEMU_PACKED QEMU_ALIGNED(8) SysIBTl_container;
+QEMU_BUILD_BUG_ON(sizeof(SysIBTl_container) != 8);
+
+/* CPU type Topology List Entry */
+typedef struct SysIBTl_cpu {
+        uint8_t nl;
+        uint8_t reserved0[3];
+        uint8_t reserved1:5;
+        uint8_t dedicated:1;
+        uint8_t polarity:2;
+        uint8_t type;
+        uint16_t origin;
+        uint64_t mask;
+} QEMU_PACKED QEMU_ALIGNED(8) SysIBTl_cpu;
+QEMU_BUILD_BUG_ON(sizeof(SysIBTl_cpu) != 16);
+
+#define S390_TOPOLOGY_MAG  6
+#define S390_TOPOLOGY_MAG6 0
+#define S390_TOPOLOGY_MAG5 1
+#define S390_TOPOLOGY_MAG4 2
+#define S390_TOPOLOGY_MAG3 3
+#define S390_TOPOLOGY_MAG2 4
+#define S390_TOPOLOGY_MAG1 5
+/* Configuration topology */
+typedef struct SysIB_151x {
+    uint8_t  reserved0[2];
+    uint16_t length;
+    uint8_t  mag[S390_TOPOLOGY_MAG];
+    uint8_t  reserved1;
+    uint8_t  mnest;
+    uint32_t reserved2;
+    char tle[0];
+} QEMU_PACKED QEMU_ALIGNED(8) SysIB_151x;
+QEMU_BUILD_BUG_ON(sizeof(SysIB_151x) != 16);
+
+/* Max size of a SYSIB structure is when all CPU are alone in a container */ +#define S390_TOPOLOGY_SYSIB_SIZE (sizeof(SysIB_151x) +                         \ +                                  S390_MAX_CPUS * (sizeof(SysIBTl_container) + \
+                                                   sizeof(SysIBTl_cpu)))
+
+
  /* MMU defines */
  #define ASCE_ORIGIN           (~0xfffULL) /* segment table origin             */   #define ASCE_SUBSPACE         0x200       /* subspace group control           */
@@ -845,4 +920,6 @@ S390CPU *s390_cpu_addr2state(uint16_t cpu_addr);
  #include "exec/cpu-all.h"
+void insert_stsi_15_1_x(S390CPU *cpu, int sel2, __u64 addr, uint8_t ar);
+
  #endif
diff --git a/hw/s390x/cpu-topology.c b/hw/s390x/cpu-topology.c
index 6af41d3d7b..9fa8ca1261 100644
--- a/hw/s390x/cpu-topology.c
+++ b/hw/s390x/cpu-topology.c
@@ -44,7 +44,6 @@ void s390_topology_new_cpu(S390CPU *cpu)
      int socket_id;
      socket_id = core_id / topo->nr_cpus;
-

Unnecessary change.

Yes,

thanks,

regards,
Pierre


--
Pierre Morel
IBM Lab Boeblingen



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