[RFC PATCH v9 6/8] psci: Add hvc call service for ptp_kvm.

Jianyong Wu
2019-12-10T03:41:19Z

ptp_kvm modules will call hvc to get this service.
The service offers real time and counter cycle of host for guest.

Signed-off-by: Jianyong Wu <jianyong.wu@arm.com>
---
include/linux/arm-smccc.h | 12 ++++++++++++
virt/kvm/arm/psci.c | 22 ++++++++++++++++++++++
2 files changed, 34 insertions(+)

diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h
index 6f82c87308ed..aafb6bac167d 100644
--- a/include/linux/arm-smccc.h
+++ b/include/linux/arm-smccc.h
@@ -94,6 +94,7 @@

/* KVM "vendor specific" services */
#define ARM_SMCCC_KVM_FUNC_FEATURES 0
+#define ARM_SMCCC_KVM_PTP 1
#define ARM_SMCCC_KVM_FUNC_FEATURES_2 127
#define ARM_SMCCC_KVM_NUM_FUNCS 128

@@ -103,6 +104,17 @@
ARM_SMCCC_OWNER_VENDOR_HYP, \
ARM_SMCCC_KVM_FUNC_FEATURES)

+/*
+ * This ID used for virtual ptp kvm clock and it will pass second value
+ * and nanosecond value of host real time and system counter by vcpu
+ * register to guest.
+ */
+#define ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID \
+ ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \
+ ARM_SMCCC_SMC_32, \
+ ARM_SMCCC_OWNER_VENDOR_HYP, \
+ ARM_SMCCC_KVM_PTP)
+
#ifndef __ASSEMBLY__

#include <linux/linkage.h>
diff --git a/virt/kvm/arm/psci.c b/virt/kvm/arm/psci.c
index 0debf49bf259..682d892d6717 100644
--- a/virt/kvm/arm/psci.c
+++ b/virt/kvm/arm/psci.c
@@ -9,6 +9,7 @@
#include <linux/kvm_host.h>
#include <linux/uaccess.h>
#include <linux/wait.h>
+#include <linux/clocksource_ids.h>

#include <asm/cputype.h>
#include <asm/kvm_emulate.h>
@@ -389,6 +390,8 @@ static int kvm_psci_call(struct kvm_vcpu *vcpu)

int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
{
+ struct system_time_snapshot systime_snapshot;
+ u64 cycles;
u32 func_id = smccc_get_function(vcpu);
u32 val[4] = {};
u32 option;
@@ -431,6 +434,25 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID:
val[0] = BIT(ARM_SMCCC_KVM_FUNC_FEATURES);
break;
+ /*
+ * This will used for virtual ptp kvm clock. three
+ * values will be passed back.
+ * reg0 stores high 32-bit host ktime;
+ * reg1 stores low 32-bit host ktime;
+ * reg2 stores high 32-bit difference of host cycles and cntvoff;
+ * reg3 stores low 32-bit difference of host cycles and cntvoff.
+ */
+ case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID:
+ ktime_get_snapshot(&systime_snapshot);
+ if (systime_snapshot.cs_id != CSID_ARM_ARCH_COUNTER)
+ return kvm_psci_call(vcpu);
+ val[0] = systime_snapshot.real >> 32;
+ val[1] = systime_snapshot.real << 32 >> 32;
+ cycles = systime_snapshot.cycles -
+ vcpu_vtimer(vcpu)->cntvoff;
+ val[2] = cycles >> 32;
+ val[3] = cycles << 32 >> 32;
+ break;
default:
return kvm_psci_call(vcpu);
}
--
2.17.1