ARM/ARM64: KVM: Add base for PSCI v0.2 emulation

Currently, the in-kernel PSCI emulation provides PSCI v0.1 interface to
VCPUs. This patch extends current in-kernel PSCI emulation to provide
PSCI v0.2 interface to VCPUs.

By default, ARM/ARM64 KVM will always provide PSCI v0.1 interface for
keeping the ABI backward-compatible.

To select PSCI v0.2 interface for VCPUs, the user space (i.e. QEMU or
KVMTOOL) will have to set KVM_ARM_VCPU_PSCI_0_2 feature when doing VCPU
init using KVM_ARM_VCPU_INIT ioctl.

Signed-off-by: Anup Patel <anup.patel@linaro.org>
Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

4 files changed, 88 insertions, 21 deletions

diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index 09af14999c9b..193ceaf01bfd 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -36,7 +36,7 @@
 #define KVM_COALESCED_MMIO_PAGE_OFFSET 1
 #define KVM_HAVE_ONE_REG
 
-#define KVM_VCPU_MAX_FEATURES 1
+#define KVM_VCPU_MAX_FEATURES 2
 
 #include <kvm/arm_vgic.h>
 
diff --git a/arch/arm/include/asm/kvm_psci.h b/arch/arm/include/asm/kvm_psci.h
index 9a83d98bf170..4c0e3e1d1597 100644
--- a/arch/arm/include/asm/kvm_psci.h
+++ b/arch/arm/include/asm/kvm_psci.h
@@ -18,6 +18,10 @@
 #ifndef __ARM_KVM_PSCI_H__
 #define __ARM_KVM_PSCI_H__
 
+#define KVM_ARM_PSCI_0_1        1
+#define KVM_ARM_PSCI_0_2        2
+
+int kvm_psci_version(struct kvm_vcpu *vcpu);
 bool kvm_psci_call(struct kvm_vcpu *vcpu);
 
 #endif /* __ARM_KVM_PSCI_H__ */
diff --git a/arch/arm/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h
index ef0c8785ba16..e6ebdd3471e5 100644
--- a/arch/arm/include/uapi/asm/kvm.h
+++ b/arch/arm/include/uapi/asm/kvm.h
@@ -20,6 +20,7 @@
 #define __ARM_KVM_H__
 
 #include <linux/types.h>
+#include <linux/psci.h>
 #include <asm/ptrace.h>
 
 #define __KVM_HAVE_GUEST_DEBUG
@@ -83,6 +84,7 @@ struct kvm_regs {
 #define KVM_VGIC_V2_CPU_SIZE            0x2000
 
 #define KVM_ARM_VCPU_POWER_OFF          0 /* CPU is started in OFF state */
+#define KVM_ARM_VCPU_PSCI_0_2           1 /* CPU uses PSCI v0.2 */
 
 struct kvm_vcpu_init {
         __u32 target;
@@ -201,9 +203,9 @@ struct kvm_arch_memory_slot {
 #define KVM_PSCI_FN_CPU_ON              KVM_PSCI_FN(2)
 #define KVM_PSCI_FN_MIGRATE             KVM_PSCI_FN(3)
 
-#define KVM_PSCI_RET_SUCCESS            0
-#define KVM_PSCI_RET_NI                 ((unsigned long)-1)
-#define KVM_PSCI_RET_INVAL              ((unsigned long)-2)
-#define KVM_PSCI_RET_DENIED             ((unsigned long)-3)
+#define KVM_PSCI_RET_SUCCESS            PSCI_RET_SUCCESS
+#define KVM_PSCI_RET_NI                 PSCI_RET_NOT_SUPPORTED
+#define KVM_PSCI_RET_INVAL              PSCI_RET_INVALID_PARAMS
+#define KVM_PSCI_RET_DENIED             PSCI_RET_DENIED
 
 #endif /* __ARM_KVM_H__ */
diff --git a/arch/arm/kvm/psci.c b/arch/arm/kvm/psci.c
index 448f60e8d23c..8c42596cdbdf 100644
--- a/arch/arm/kvm/psci.c
+++ b/arch/arm/kvm/psci.c
@@ -59,7 +59,7 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
          * turned off.
          */
         if (!vcpu || !vcpu->arch.pause)
-                return KVM_PSCI_RET_INVAL;
+                return PSCI_RET_INVALID_PARAMS;
 
         target_pc = *vcpu_reg(source_vcpu, 2);
 
@@ -82,20 +82,60 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
         wq = kvm_arch_vcpu_wq(vcpu);
         wake_up_interruptible(wq);
 
-        return KVM_PSCI_RET_SUCCESS;
+        return PSCI_RET_SUCCESS;
 }
 
-/**
- * kvm_psci_call - handle PSCI call if r0 value is in range
- * @vcpu: Pointer to the VCPU struct
- *
- * Handle PSCI calls from guests through traps from HVC instructions.
- * The calling convention is similar to SMC calls to the secure world where
- * the function number is placed in r0 and this function returns true if the
- * function number specified in r0 is withing the PSCI range, and false
- * otherwise.
- */
-bool kvm_psci_call(struct kvm_vcpu *vcpu)
+int kvm_psci_version(struct kvm_vcpu *vcpu)
+{
+        if (test_bit(KVM_ARM_VCPU_PSCI_0_2, vcpu->arch.features))
+                return KVM_ARM_PSCI_0_2;
+
+        return KVM_ARM_PSCI_0_1;
+}
+
+static bool kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
+{
+        unsigned long psci_fn = *vcpu_reg(vcpu, 0) & ~((u32) 0);
+        unsigned long val;
+
+        switch (psci_fn) {
+        case PSCI_0_2_FN_PSCI_VERSION:
+                /*
+                 * Bits[31:16] = Major Version = 0
+                 * Bits[15:0] = Minor Version = 2
+                 */
+                val = 2;
+                break;
+        case PSCI_0_2_FN_CPU_OFF:
+                kvm_psci_vcpu_off(vcpu);
+                val = PSCI_RET_SUCCESS;
+                break;
+        case PSCI_0_2_FN_CPU_ON:
+        case PSCI_0_2_FN64_CPU_ON:
+                val = kvm_psci_vcpu_on(vcpu);
+                break;
+        case PSCI_0_2_FN_CPU_SUSPEND:
+        case PSCI_0_2_FN_AFFINITY_INFO:
+        case PSCI_0_2_FN_MIGRATE:
+        case PSCI_0_2_FN_MIGRATE_INFO_TYPE:
+        case PSCI_0_2_FN_MIGRATE_INFO_UP_CPU:
+        case PSCI_0_2_FN_SYSTEM_OFF:
+        case PSCI_0_2_FN_SYSTEM_RESET:
+        case PSCI_0_2_FN64_CPU_SUSPEND:
+        case PSCI_0_2_FN64_AFFINITY_INFO:
+        case PSCI_0_2_FN64_MIGRATE:
+        case PSCI_0_2_FN64_MIGRATE_INFO_UP_CPU:
+                val = PSCI_RET_NOT_SUPPORTED;
+                break;
+        default:
+                return false;
+        }
+
+        *vcpu_reg(vcpu, 0) = val;
+        return true;
+}
+
+static bool kvm_psci_0_1_call(struct kvm_vcpu *vcpu)
 {
         unsigned long psci_fn = *vcpu_reg(vcpu, 0) & ~((u32) 0);
         unsigned long val;
@@ -103,16 +143,15 @@ bool kvm_psci_call(struct kvm_vcpu *vcpu)
         switch (psci_fn) {
         case KVM_PSCI_FN_CPU_OFF:
                 kvm_psci_vcpu_off(vcpu);
-                val = KVM_PSCI_RET_SUCCESS;
+                val = PSCI_RET_SUCCESS;
                 break;
         case KVM_PSCI_FN_CPU_ON:
                 val = kvm_psci_vcpu_on(vcpu);
                 break;
         case KVM_PSCI_FN_CPU_SUSPEND:
         case KVM_PSCI_FN_MIGRATE:
-                val = KVM_PSCI_RET_NI;
+                val = PSCI_RET_NOT_SUPPORTED;
                 break;
-
         default:
                 return false;
         }
@@ -120,3 +159,25 @@ bool kvm_psci_call(struct kvm_vcpu *vcpu)
         *vcpu_reg(vcpu, 0) = val;
         return true;
 }
+
+/**
+ * kvm_psci_call - handle PSCI call if r0 value is in range
+ * @vcpu: Pointer to the VCPU struct
+ *
+ * Handle PSCI calls from guests through traps from HVC instructions.
+ * The calling convention is similar to SMC calls to the secure world where
+ * the function number is placed in r0 and this function returns true if the
+ * function number specified in r0 is withing the PSCI range, and false
+ * otherwise.
+ */
+bool kvm_psci_call(struct kvm_vcpu *vcpu)
+{
+        switch (kvm_psci_version(vcpu)) {
+        case KVM_ARM_PSCI_0_2:
+                return kvm_psci_0_2_call(vcpu);
+        case KVM_ARM_PSCI_0_1:
+                return kvm_psci_0_1_call(vcpu);
+        default:
+                return false;
+        };
+}