This provides a mechanism for querying which paravirtualized features
are available in this hypervisor.

Also add the header file which defines the ABI for the paravirtualized
clock features we're about to add.

Signed-off-by: Steven Price <steven.pr...@arm.com>
---
 arch/arm64/include/asm/pvclock-abi.h | 20 ++++++++++++++++++++
 include/linux/arm-smccc.h            | 14 ++++++++++++++
 virt/kvm/arm/hypercalls.c            |  9 +++++++++
 3 files changed, 43 insertions(+)
 create mode 100644 arch/arm64/include/asm/pvclock-abi.h

diff --git a/arch/arm64/include/asm/pvclock-abi.h 
b/arch/arm64/include/asm/pvclock-abi.h
new file mode 100644
index 000000000000..1f7cdc102691
--- /dev/null
+++ b/arch/arm64/include/asm/pvclock-abi.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2019 Arm Ltd. */
+
+#ifndef __ASM_PVCLOCK_ABI_H
+#define __ASM_PVCLOCK_ABI_H
+
+/* The below structures and constants are defined in ARM DEN0057A */
+
+struct pvclock_vcpu_stolen_time_info {
+       __le32 revision;
+       __le32 attributes;
+       __le64 stolen_time;
+       /* Structure must be 64 byte aligned, pad to that size */
+       u8 padding[48];
+} __packed;
+
+#define PV_VM_TIME_NOT_SUPPORTED       -1
+#define PV_VM_TIME_INVALID_PARAMETERS  -2
+
+#endif
diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h
index 080012a6f025..e7f129f26ebd 100644
--- a/include/linux/arm-smccc.h
+++ b/include/linux/arm-smccc.h
@@ -45,6 +45,7 @@
 #define ARM_SMCCC_OWNER_SIP            2
 #define ARM_SMCCC_OWNER_OEM            3
 #define ARM_SMCCC_OWNER_STANDARD       4
+#define ARM_SMCCC_OWNER_STANDARD_HYP   5
 #define ARM_SMCCC_OWNER_TRUSTED_APP    48
 #define ARM_SMCCC_OWNER_TRUSTED_APP_END        49
 #define ARM_SMCCC_OWNER_TRUSTED_OS     50
@@ -302,5 +303,18 @@ asmlinkage void __arm_smccc_hvc(unsigned long a0, unsigned 
long a1,
 #define SMCCC_RET_NOT_SUPPORTED                        -1
 #define SMCCC_RET_NOT_REQUIRED                 -2
 
+/* Paravirtualised time calls (defined by ARM DEN0057A) */
+#define ARM_SMCCC_HV_PV_FEATURES                               \
+       ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,                 \
+                          ARM_SMCCC_SMC_64,                    \
+                          ARM_SMCCC_OWNER_STANDARD_HYP,        \
+                          0x20)
+
+#define ARM_SMCCC_HV_PV_TIME_ST                                        \
+       ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,                 \
+                          ARM_SMCCC_SMC_64,                    \
+                          ARM_SMCCC_OWNER_STANDARD_HYP,        \
+                          0x22)
+
 #endif /*__ASSEMBLY__*/
 #endif /*__LINUX_ARM_SMCCC_H*/
diff --git a/virt/kvm/arm/hypercalls.c b/virt/kvm/arm/hypercalls.c
index f875241bd030..2906b2df99df 100644
--- a/virt/kvm/arm/hypercalls.c
+++ b/virt/kvm/arm/hypercalls.c
@@ -5,6 +5,7 @@
 #include <linux/kvm_host.h>
 
 #include <asm/kvm_emulate.h>
+#include <asm/pvclock-abi.h>
 
 #include <kvm/arm_hypercalls.h>
 #include <kvm/arm_psci.h>
@@ -48,6 +49,14 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
                                break;
                        }
                        break;
+               case ARM_SMCCC_HV_PV_FEATURES:
+                       val = SMCCC_RET_SUCCESS;
+                       break;
+               }
+               break;
+       case ARM_SMCCC_HV_PV_FEATURES:
+               feature = smccc_get_arg1(vcpu);
+               switch (feature) {
                }
                break;
        default:
-- 
2.20.1

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