[Qemu-devel] [PATCH 2/2] pseries: Use new hook to correct reset sequence

[David Gibson <david@gibson.dropbear.id.au>]

A number of things need to occur during reset of the PAPR paravirtualized
platform in a specific order.  For example, the hash table needs to be
cleared before the CPUs are reset, so that they initialize their register
state correctly, and the CPUs need to have their main reset called before
we set up the entry point state on the boot cpu.  We also need to have
the main qdev reset happen before the creation and installation of the
device tree for the new boot, because we need the state of the devices
settled to correctly construct the device tree.

Currently reset of pseries is broken in a number of ways, and in other
cases works largely by accident. This patch uses the new QEMUMachine reset
hook to correct these problems, by replacing the several existing spapr
reset hooks with one new machine hook which ensures that the various stages
happen in the correct order.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 hw/spapr.c |   66 +++++++++++++++++++++++++++++++++---------------------------
 1 file changed, 36 insertions(+), 30 deletions(-)

diff --git a/hw/spapr.c b/hw/spapr.c
index 2453bae..1e60ec1 100644
--- a/hw/spapr.c
+++ b/hw/spapr.c
@@ -582,29 +582,22 @@ static void spapr_reset_htab(sPAPREnvironment *spapr)
     }
 }
 
-static void spapr_reset(void *opaque)
+static void spapr_reset_cpu(CPUPPCState *env)
 {
-    sPAPREnvironment *spapr = (sPAPREnvironment *)opaque;
-
-    /* Reset the hash table & recalc the RMA */
-    spapr_reset_htab(spapr);
-
-    /* Load the fdt */
-    spapr_finalize_fdt(spapr, spapr->fdt_addr, spapr->rtas_addr,
-                       spapr->rtas_size);
-}
-
-static void spapr_cpu_reset(void *opaque)
-{
-    PowerPCCPU *cpu = opaque;
-    CPUPPCState *env = &cpu->env;
+    PowerPCCPU *cpu = container_of(env, PowerPCCPU, env);
 
     cpu_reset(CPU(cpu));
 
     env->external_htab = spapr->htab;
     env->htab_base = -1;
     env->htab_mask = HTAB_SIZE(spapr) - 1;
+    /* CPUs need to start halted at reset, the platform reset code
+     * will activate CPU0 then the rest are explicitly started by the
+     * guest using RTAS */
+    env->halted = 1;
 
+    /* Secondary CPUs get the CPU ID in r3 on entry */
+    env->gpr[3] = env->cpu_index;
     env->spr[SPR_SDR1] = (unsigned long)spapr->htab |
         (spapr->htab_shift - 18);
 
@@ -612,14 +605,35 @@ static void spapr_cpu_reset(void *opaque)
         kvmppc_update_sdr1(env);
     }
 
-    /* Set up the entry state */
-    if (env == first_cpu) {
-        env->gpr[3] = spapr->fdt_addr;
-        env->gpr[5] = 0;
-        env->halted = 0;
-        env->nip = spapr->entry_point;
+    tb_flush(env);
+}
+
+static void spapr_reset(bool report)
+{
+    CPUPPCState *env = first_cpu;
+
+    /* Reset the qdevs */
+    qemu_default_system_reset(report);
+
+    /* Reset the hash table & recalc the RMA */
+    spapr_reset_htab(spapr);
+
+    /* Reset the CPUs */
+    for (env = first_cpu; env != NULL; env = env->next_cpu) {
+        spapr_reset_cpu(env);
     }
 
+    /* Load the fdt */
+    spapr_finalize_fdt(spapr, spapr->fdt_addr, spapr->rtas_addr,
+                       spapr->rtas_size);
+
+    /* Set up the entry state on CPU0 */
+    env = first_cpu;
+
+    env->gpr[3] = spapr->fdt_addr;
+    env->gpr[5] = 0;
+    env->halted = 0;
+    env->nip = spapr->entry_point;
     tb_flush(env);
 }
 
@@ -718,8 +732,6 @@ static void ppc_spapr_init(ram_addr_t ram_size,
     /* FIXME: we should change this default based on RAM size */
     spapr->htab_shift = 24;
 
-    qemu_register_reset(spapr_reset, spapr);
-
     /* init CPUs */
     if (cpu_model == NULL) {
         cpu_model = kvm_enabled() ? "host" : "POWER7";
@@ -734,11 +746,9 @@ static void ppc_spapr_init(ram_addr_t ram_size,
 
         /* Set time-base frequency to 512 MHz */
         cpu_ppc_tb_init(env, TIMEBASE_FREQ);
-        qemu_register_reset(spapr_cpu_reset, cpu);
 
         env->hreset_vector = 0x60;
         env->hreset_excp_prefix = 0;
-        env->gpr[3] = env->cpu_index;
     }
 
     /* allocate RAM */
@@ -883,11 +893,6 @@ static void ppc_spapr_init(ram_addr_t ram_size,
 
     spapr->entry_point = 0x100;
 
-    /* SLOF will startup the secondary CPUs using RTAS */
-    for (env = first_cpu; env != NULL; env = env->next_cpu) {
-        env->halted = 1;
-    }
-
     /* Prepare the device tree */
     spapr->fdt_skel = spapr_create_fdt_skel(cpu_model,
                                             initrd_base, initrd_size,
@@ -900,6 +905,7 @@ static QEMUMachine spapr_machine = {
     .name = "pseries",
     .desc = "pSeries Logical Partition (PAPR compliant)",
     .init = ppc_spapr_init,
+    .reset = spapr_reset,
     .max_cpus = MAX_CPUS,
     .no_parallel = 1,
     .use_scsi = 1,
-- 
1.7.10.4