[Qemu-devel] [PATCH v2 4/6] target-arm: add emulation of PSCI calls for system emulation

[Rob Herring]

From: Rob Herring <address@hidden>

Add support for handling PSCI calls in system emulation. Both version
0.1 and 0.2 of the PSCI spec are supported. Platforms can enable support
by setting "psci-method" QOM property on the cpus to SMC or HVC
emulation and having PSCI binding in their dtb.

Signed-off-by: Rob Herring <address@hidden>
---
v2:
- Add reference to PSCI spec
- Add target_cs instead of cs when doing operations on a different core.
- Move arm_cpu_do_hvc/smc contents from previous patch.
- Set context_id on both x0 and r0.

 target-arm/Makefile.objs |   2 +-
 target-arm/cpu-qom.h     |   6 ++
 target-arm/cpu.c         |   1 +
 target-arm/helper.c      |  12 ++++
 target-arm/kvm-consts.h  |   6 ++
 target-arm/psci.c        | 157 +++++++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 183 insertions(+), 1 deletion(-)
 create mode 100644 target-arm/psci.c

diff --git a/target-arm/Makefile.objs b/target-arm/Makefile.objs
index dcd167e..50f6c43 100644
--- a/target-arm/Makefile.objs
+++ b/target-arm/Makefile.objs
@@ -1,5 +1,5 @@
 obj-y += arm-semi.o
-obj-$(CONFIG_SOFTMMU) += machine.o
+obj-$(CONFIG_SOFTMMU) += machine.o psci.o
 obj-$(CONFIG_KVM) += kvm.o
 obj-$(call land,$(CONFIG_KVM),$(call lnot,$(TARGET_AARCH64))) += kvm32.o
 obj-$(call land,$(CONFIG_KVM),$(TARGET_AARCH64)) += kvm64.o
diff --git a/target-arm/cpu-qom.h b/target-arm/cpu-qom.h
index d2ff087..56999f1 100644
--- a/target-arm/cpu-qom.h
+++ b/target-arm/cpu-qom.h
@@ -105,6 +105,11 @@ typedef struct ARMCPU {
     /* CPU currently in PSCI powered-off state */
     bool powered_off;

+    /* PSCI emulation state
+     * 0 - disabled, 1 - smc, 2 - hvc
+     */
+    uint32_t psci_method;
+
     /* [QEMU_]KVM_ARM_TARGET_* constant for this CPU, or
      * QEMU_KVM_ARM_TARGET_NONE if the kernel doesn't support this CPU type.
      */
@@ -195,6 +200,7 @@ extern const struct VMStateDescription vmstate_arm_cpu;
 void register_cp_regs_for_features(ARMCPU *cpu);
 void init_cpreg_list(ARMCPU *cpu);

+bool arm_handle_psci(CPUState *cs);
 bool arm_cpu_do_hvc(CPUState *cs);
 bool arm_cpu_do_smc(CPUState *cs);

diff --git a/target-arm/cpu.c b/target-arm/cpu.c
index a0f9916..64f1157 100644
--- a/target-arm/cpu.c
+++ b/target-arm/cpu.c
@@ -1024,6 +1024,7 @@ static const ARMCPUInfo arm_cpus[] = {

 static Property arm_cpu_properties[] = {
     DEFINE_PROP_BOOL("start-powered-off", ARMCPU, start_powered_off, false),
+    DEFINE_PROP_UINT32("psci-method", ARMCPU, psci_method, 0),
     DEFINE_PROP_UINT32("midr", ARMCPU, midr, 0),
     DEFINE_PROP_END_OF_LIST()
 };
diff --git a/target-arm/helper.c b/target-arm/helper.c
index 552e601..c1be201 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -3257,11 +3257,23 @@ void arm_v7m_cpu_do_interrupt(CPUState *cs)

 bool arm_cpu_do_hvc(CPUState *cs)
 {
+    ARMCPU *cpu = ARM_CPU(cs);
+
+    if (cpu->psci_method == QEMU_PSCI_METHOD_HVC) {
+        return arm_handle_psci(cs);
+    }
+
     return false;
 }

 bool arm_cpu_do_smc(CPUState *cs)
 {
+    ARMCPU *cpu = ARM_CPU(cs);
+
+    if (cpu->psci_method == QEMU_PSCI_METHOD_SMC) {
+        return arm_handle_psci(cs);
+    }
+
     return false;
 }

diff --git a/target-arm/kvm-consts.h b/target-arm/kvm-consts.h
index 6009a33..d25b9b8 100644
--- a/target-arm/kvm-consts.h
+++ b/target-arm/kvm-consts.h
@@ -50,6 +50,12 @@ MISMATCH_CHECK(PSCI_FN_CPU_OFF, KVM_PSCI_FN_CPU_OFF)
 MISMATCH_CHECK(PSCI_FN_CPU_ON, KVM_PSCI_FN_CPU_ON)
 MISMATCH_CHECK(PSCI_FN_MIGRATE, KVM_PSCI_FN_MIGRATE)

+enum {
+    QEMU_PSCI_METHOD_DISABLED = 0,
+    QEMU_PSCI_METHOD_SMC = 1,
+    QEMU_PSCI_METHOD_HVC = 2,
+};
+
 /* Note that KVM uses overlapping values for AArch32 and AArch64
  * target CPU numbers. AArch32 targets:
  */
diff --git a/target-arm/psci.c b/target-arm/psci.c
new file mode 100644
index 0000000..88af3f9
--- /dev/null
+++ b/target-arm/psci.c
@@ -0,0 +1,157 @@
+/*
+ * Copyright (C) 2014 - Linaro
+ * Author: Rob Herring <address@hidden>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+#include <cpu.h>
+#include <cpu-qom.h>
+#include <kvm-consts.h>
+#include <sysemu/sysemu.h>
+#include <linux/psci.h>
+
+/*
+ * This function implements emulation of ARM Power State Coordination
+ * Interface (PSCI) version 0.2. Details of the PSCI functionality can be
+ * found at:
+ * http://infocenter.arm.com/help//topic/com.arm.doc.den0022b/index.html
+ */
+bool arm_handle_psci(CPUState *cs)
+{
+    CPUState *target_cs;
+    CPUClass *cc;
+    ARMCPU *cpu = ARM_CPU(cs);
+    CPUARMState *env = &cpu->env;
+    uint64_t param[4];
+    uint64_t context_id, mpidr;
+    target_ulong entry;
+    int32_t ret = 0;
+    int i;
+
+    for (i = 0; i < 4; i++) {
+        /* Zero extending registers on 32-bit is okay for PSCI */
+        param[i] = is_a64(env) ? env->xregs[i] : env->regs[i];
+    }
+
+    if ((param[0] & PSCI_0_2_64BIT) && !is_a64(env)) {
+        ret = PSCI_RET_INVALID_PARAMS;
+        goto err;
+    }
+
+    switch (param[0]) {
+    case PSCI_0_2_FN_PSCI_VERSION:
+        ret = PSCI_VERSION_MAJOR(0) | PSCI_VERSION_MINOR(2);
+        break;
+    case PSCI_0_2_FN_MIGRATE_INFO_TYPE:
+        ret = PSCI_0_2_TOS_MP;    /* No trusted OS */
+        break;
+    case PSCI_0_2_FN_AFFINITY_INFO:
+    case PSCI_0_2_FN64_AFFINITY_INFO:
+        mpidr = param[1];
+
+        switch (param[2]) {
+        case 0:
+            /* Get the target cpu */
+            target_cs = qemu_get_cpu(mpidr & 0xff);
+            if (!target_cs) {
+                ret = PSCI_RET_INVALID_PARAMS;
+                break;
+            }
+            cpu = ARM_CPU(target_cs);
+            ret = cpu->powered_off ? 1 : 0;
+            break;
+        default:
+            /* Everything above affinity level 0 is always on. */
+            ret = 0;
+        }
+        break;
+    case PSCI_0_2_FN_SYSTEM_RESET:
+        qemu_system_reset_request();
+        break;
+    case PSCI_0_2_FN_SYSTEM_OFF:
+        qemu_system_powerdown_request();
+        break;
+    case PSCI_FN_CPU_ON:
+    case PSCI_0_2_FN_CPU_ON:
+    case PSCI_0_2_FN64_CPU_ON:
+        mpidr = param[1];
+        entry = param[2];
+        context_id = param[3];
+
+        /* change to the cpu we are powering up */
+        target_cs = qemu_get_cpu(mpidr & 0xff);
+        if (!target_cs) {
+            ret = PSCI_RET_INVALID_PARAMS;
+            break;
+        }
+        cpu = ARM_CPU(target_cs);
+
+        if (!cpu->powered_off) {
+            ret = PSCI_RET_ALREADY_ON;
+            break;
+        }
+
+        /* Initialize the cpu we are turning on */
+        cpu_reset(target_cs);
+        cc = CPU_GET_CLASS(target_cs);
+        cc->set_pc(target_cs, entry);
+
+        cpu->powered_off = false;
+        target_cs->interrupt_request |= CPU_INTERRUPT_EXITTB;
+
+        /* Set the context_id in r0/x0 */
+        cpu->env.xregs[0] = cpu->env.regs[0] = context_id;
+
+        ret = 0;
+        break;
+    case PSCI_FN_CPU_OFF:
+    case PSCI_0_2_FN_CPU_OFF:
+        cpu->powered_off = true;
+        cs->exit_request = 1;
+        cs->halted = 1;
+
+        /* CPU_OFF should never return, but if it does return an error */
+        ret = PSCI_RET_DENIED;
+        break;
+    case PSCI_FN_CPU_SUSPEND:
+    case PSCI_0_2_FN_CPU_SUSPEND:
+    case PSCI_0_2_FN64_CPU_SUSPEND:
+        /* Affinity levels are not supported in QEMU */
+        if (param[1] & 0xfffe0000) {
+            ret = PSCI_RET_INVALID_PARAMS;
+            break;
+        }
+        /* Powerdown is not supported, we always go into WFI */
+        cs->halted = 1;
+        cs->exit_request = 1;
+
+        /* Return success when we wakeup */
+        ret = 0;
+        break;
+    case PSCI_FN_MIGRATE:
+    case PSCI_0_2_FN_MIGRATE:
+        ret = PSCI_RET_NOT_SUPPORTED;
+        break;
+    default:
+        return false;
+    }
+
+err:
+    if (is_a64(env)) {
+        env->xregs[0] = ret;
+    } else {
+        env->regs[0] = ret;
+    }
+    return true;
+}
--
1.9.1