qemu-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-devel] [RFC 06/15] pc: set FW_CFG data based on APIC ID calcul


From: Igor Mammedov
Subject: Re: [Qemu-devel] [RFC 06/15] pc: set FW_CFG data based on APIC ID calculation
Date: Mon, 13 Aug 2012 21:52:43 +0200
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120717 Thunderbird/14.0

On 08/07/2012 09:56 PM, Eduardo Habkost wrote:
This changes FW_CFG_MAX_CPUS and FW_CFG_NUMA to use apic_id_for_cpu(),
so the NUMA table can be based on the APIC IDs, instead of CPU index
(SeaBIOS knows nothing about CPU indexes, just APIC IDs).

Signed-off-by: Eduardo Habkost <address@hidden>
---
  hw/pc.c           | 23 ++++++++++++++++-------
  target-i386/cpu.h |  7 +++++++
  2 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/hw/pc.c b/hw/pc.c
index 10449bd..9afb838 100644
--- a/hw/pc.c
+++ b/hw/pc.c
@@ -581,6 +581,11 @@ int e820_add_entry(uint64_t address, uint64_t length, 
uint32_t type)
      return index;
  }

+unsigned int apic_id_limit(void)
+{
+    return apic_id_for_cpu(max_cpus - 1) + 1;
+}
+
  static void *bochs_bios_init(void)
  {
      void *fw_cfg;
@@ -588,6 +593,7 @@ static void *bochs_bios_init(void)
      size_t smbios_len;
      uint64_t *numa_fw_cfg;
      int i, j;
+    unsigned int max_apic_id = apic_id_limit();

      register_ioport_write(0x400, 1, 2, bochs_bios_write, NULL);
      register_ioport_write(0x401, 1, 2, bochs_bios_write, NULL);
@@ -602,7 +608,7 @@ static void *bochs_bios_init(void)
      register_ioport_write(0x503, 1, 1, bochs_bios_write, NULL);

      fw_cfg = fw_cfg_init(BIOS_CFG_IOPORT, BIOS_CFG_IOPORT + 1, 0, 0);
-    fw_cfg_add_i16(fw_cfg, FW_CFG_MAX_CPUS, (uint16_t)max_cpus);
+    fw_cfg_add_i16(fw_cfg, FW_CFG_MAX_CPUS, (uint16_t)max_apic_id);
FW_CFG_MAX_CPUS becoming not MAX_CPUS sounds a bit confusing, perhaps short comment should be here to document this and why it's not? So code reader won't make false assumptions?

      fw_cfg_add_i32(fw_cfg, FW_CFG_ID, 1);
      fw_cfg_add_i64(fw_cfg, FW_CFG_RAM_SIZE, (uint64_t)ram_size);
      fw_cfg_add_bytes(fw_cfg, FW_CFG_ACPI_TABLES, (uint8_t *)acpi_tables,
@@ -622,21 +628,24 @@ static void *bochs_bios_init(void)
       * of nodes, one word for each VCPU->node and one word for each node to
       * hold the amount of memory.
       */
-    numa_fw_cfg = g_malloc0((1 + max_cpus + nb_numa_nodes) * 8);
+    numa_fw_cfg = g_malloc0((1 + max_apic_id + nb_numa_nodes) * 8);
      numa_fw_cfg[0] = cpu_to_le64(nb_numa_nodes);
-    for (i = 0; i < max_cpus; i++) {
+    unsigned int cpu_idx;
+    for (cpu_idx = 0; cpu_idx < max_cpus; cpu_idx++) {
+        unsigned int apic_id = apic_id_for_cpu(cpu_idx);
+        assert(apic_id < max_apic_id);
          for (j = 0; j < nb_numa_nodes; j++) {
-            if (test_bit(i, node_cpumask[j])) {
-                numa_fw_cfg[i + 1] = cpu_to_le64(j);
+            if (test_bit(cpu_idx, node_cpumask[j])) {
+                numa_fw_cfg[apic_id + 1] = cpu_to_le64(j);
                  break;
              }
          }
      }
      for (i = 0; i < nb_numa_nodes; i++) {
-        numa_fw_cfg[max_cpus + 1 + i] = cpu_to_le64(node_mem[i]);
+        numa_fw_cfg[max_apic_id + 1 + i] = cpu_to_le64(node_mem[i]);
      }
      fw_cfg_add_bytes(fw_cfg, FW_CFG_NUMA, (uint8_t *)numa_fw_cfg,
-                     (1 + max_cpus + nb_numa_nodes) * 8);
+                     (1 + max_apic_id + nb_numa_nodes) * 8);

      return fw_cfg;
  }
diff --git a/target-i386/cpu.h b/target-i386/cpu.h
index 39ea005..257d6c7 100644
--- a/target-i386/cpu.h
+++ b/target-i386/cpu.h
@@ -919,6 +919,13 @@ void host_cpuid(uint32_t function, uint32_t count,
   */
  unsigned int apic_id_for_cpu(int cpu_index);

+/* Calculate limit for the APIC ID value, based on max_cpus
+ *
+ * On PC, FW_CFG_MAX_CPUS is not max_cpus, but the limit for the APIC IDs
+ * of all CPUs (so that of all CPUs APIC ID < MAX_CPUS).
+ */
+unsigned int apic_id_limit(void);
+

  /* helper.c */
  int cpu_x86_handle_mmu_fault(CPUX86State *env, target_ulong addr,



--
Regards,
  Igor



reply via email to

[Prev in Thread] Current Thread [Next in Thread]