[RFC PATCH v2 09/21] pc: Add dimm paravirt SRAT info

[Vasilis Liaskovitis <vasilis.liaskovitis@profitbricks.com>]

The numa_fw_cfg paravirt interface is extended to include SRAT information for
all hotplug-able dimms. There are 3 words for each hotplug-able memory slot,
denoting start address, size and node proximity. The new info is appended after
existing numa info, so that the fw_cfg layout does not break.  This information
is used by Seabios to build hotplug memory device objects at runtime.
nb_numa_nodes is set to 1 by default (not 0), so that we always pass srat info
to SeaBIOS.

v1->v2:
Dimm SRAT info (#dimms) is appended at end of existing numa fw_cfg in order not
to break existing layout
Documentation of the new fwcfg layout is included in docs/specs/fwcfg.txt

Signed-off-by: Vasilis Liaskovitis <vasilis.liaskovitis@profitbricks.com>
---
 docs/specs/fwcfg.txt |   28 ++++++++++++++++++++++++++
 hw/pc.c              |   53 ++++++++++++++++++++++++++++++++++++++++++++++++-
 vl.c                 |    2 +-
 3 files changed, 80 insertions(+), 3 deletions(-)
 create mode 100644 docs/specs/fwcfg.txt

diff --git a/docs/specs/fwcfg.txt b/docs/specs/fwcfg.txt
new file mode 100644
index 0000000..e6fcd8f
--- /dev/null
+++ b/docs/specs/fwcfg.txt
@@ -0,0 +1,28 @@
+QEMU<->BIOS Paravirt Documentation
+--------------------------------------
+
+This document describes paravirt data structures passed from QEMU to BIOS.
+
+fw_cfg SRAT paravirt info
+--------------------
+The SRAT info passed from QEMU to BIOS has the following layout:
+
+-----------------------------------------------------------------------------------------------
+#nodes | cpu0_pxm | cpu1_pxm | ... | cpulast_pxm | node0_mem | node1_mem | ... | nodelast_mem
+
+-----------------------------------------------------------------------------------------------
+#dimms | dimm0_start | dimm0_sz | dimm0_pxm | ... | dimmlast_start | dimmlast_sz | dimmlast_pxm
+
+Entry 0 contains the number of numa nodes (nb_numa_nodes).
+
+Entries 1..max_cpus: The next max_cpus entries describe node proximity for each
+one of the vCPUs in the system.
+
+Entries max_cpus+1..max_cpus+nb_numa_nodes+1:  The next nb_numa_nodes entries
+describe the memory size for each one of the NUMA nodes in the system.
+
+Entry max_cpus+nb_numa_nodes+1 contains the number of memory dimms (nb_hp_dimms)
+
+The last 3 * nb_hp_dimms entries are organized in triplets: Each triplet contains
+the physical address offset, size (in bytes), and node proximity for the
+respective dimm.
diff --git a/hw/pc.c b/hw/pc.c
index ef9901a..cf651d0 100644
--- a/hw/pc.c
+++ b/hw/pc.c
@@ -598,12 +598,15 @@ int e820_add_entry(uint64_t address, uint64_t length, uint32_t type)
     return index;
 }
 
+static void setup_hp_dimms(uint64_t *fw_cfg_slots);
+
 static void *bochs_bios_init(void)
 {
     void *fw_cfg;
     uint8_t *smbios_table;
     size_t smbios_len;
     uint64_t *numa_fw_cfg;
+    uint64_t *hp_dimms_fw_cfg;
     int i, j;
 
     register_ioport_write(0x400, 1, 2, bochs_bios_write, NULL);
@@ -638,8 +641,10 @@ static void *bochs_bios_init(void)
     /* allocate memory for the NUMA channel: one (64bit) word for the number
      * of nodes, one word for each VCPU->node and one word for each node to
      * hold the amount of memory.
+     * Finally one word for the number of hotplug memory slots and three words
+     * for each hotplug memory slot (start address, size and node proximity).
      */
-    numa_fw_cfg = g_malloc0((1 + max_cpus + nb_numa_nodes) * 8);
+    numa_fw_cfg = g_malloc0((2 + max_cpus + nb_numa_nodes + 3 * nb_hp_dimms) * 8);
     numa_fw_cfg[0] = cpu_to_le64(nb_numa_nodes);
     for (i = 0; i < max_cpus; i++) {
         for (j = 0; j < nb_numa_nodes; j++) {
@@ -652,8 +657,15 @@ static void *bochs_bios_init(void)
     for (i = 0; i < nb_numa_nodes; i++) {
         numa_fw_cfg[max_cpus + 1 + i] = cpu_to_le64(node_mem[i]);
     }
+
+    numa_fw_cfg[1 + max_cpus + nb_numa_nodes] = cpu_to_le64(nb_hp_dimms);
+
+    hp_dimms_fw_cfg = numa_fw_cfg + 2 + max_cpus + nb_numa_nodes;
+    if (nb_hp_dimms)
+        setup_hp_dimms(hp_dimms_fw_cfg);
+
     fw_cfg_add_bytes(fw_cfg, FW_CFG_NUMA, (uint8_t *)numa_fw_cfg,
-                     (1 + max_cpus + nb_numa_nodes) * 8);
+                     (2 + max_cpus + nb_numa_nodes + 3 * nb_hp_dimms) * 8);
 
     return fw_cfg;
 }
@@ -1223,3 +1235,40 @@ target_phys_addr_t pc_set_hp_memory_offset(uint64_t size)
 
     return ret;
 }
+
+static void setup_hp_dimms(uint64_t *fw_cfg_slots)
+{
+    int i = 0;
+    Error *err = NULL;
+    DeviceState *dev;
+    DimmState *slot;
+    const char *type;
+    BusChild *kid;
+    BusState *bus = sysbus_get_default();
+
+    QTAILQ_FOREACH(kid, &bus->children, sibling) {
+        dev = kid->child;
+        type = object_property_get_str(OBJECT(dev), "type", &err);
+        if (err) {
+            error_free(err);
+            fprintf(stderr, "error getting device type\n");
+            exit(1);
+        }
+
+        if (!strcmp(type, "dimm")) {
+            if (!dev->id) {
+                fprintf(stderr, "error getting dimm device id\n");
+                exit(1);
+            }
+            slot = DIMM(dev);
+            /* determine starting physical address for this memory slot */
+            assert(slot->start);
+            fw_cfg_slots[3 * slot->idx] = cpu_to_le64(slot->start);
+            fw_cfg_slots[3 * slot->idx + 1] = cpu_to_le64(slot->size);
+            fw_cfg_slots[3 * slot->idx + 2] = cpu_to_le64(slot->node);
+            i++;
+        }
+    }
+    assert(i == nb_hp_dimms);
+}
+
diff --git a/vl.c b/vl.c
index 0ff8818..37c9798 100644
--- a/vl.c
+++ b/vl.c
@@ -2335,7 +2335,7 @@ int main(int argc, char **argv, char **envp)
         node_cpumask[i] = 0;
     }
 
-    nb_numa_nodes = 0;
+    nb_numa_nodes = 1;
     nb_nics = 0;
 
     autostart= 1;
-- 
1.7.9