KVM: arm64: Support pvsched preempted via shared structure

euleros inclusion
category: feature
bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=35
CVE: NA

--------------------------------

Implement the service call for configuring a shared structure between a
vCPU and the hypervisor in which the hypervisor can tell the vCPU that is
running or not.
Signed-off-by: NZengruan Ye <yezengruan@huawei.com>
Reviewed-by: Nzhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NChaochao Xing <xingchaochao@huawei.com>
Reviewed-by: NZengruan Ye <yezengruan@huawei.com>
Reviewed-by: NXiangyou Xie <xiexiangyou@huawei.com>
Signed-off-by: NCheng Jian <cj.chengjian@huawei.com>

arch/arm/include/asm/kvm_host.h

@@ -303,6 +303,20 @@ static inline int kvm_arch_dev_ioctl_check_extension(struct kvm *kvm, long ext)
 int kvm_perf_init(void);
 int kvm_perf_teardown(void);
 
+static inline void kvm_arm_pvsched_vcpu_init(struct kvm_vcpu_arch *vcpu_arch)
+{
+}
+
+static inline bool kvm_arm_is_pvsched_enabled(struct kvm_vcpu_arch *vcpu_arch)
+{
+	return false;
+}
+
+static inline void kvm_update_pvsched_preempted(struct kvm_vcpu *vcpu,
+						u32 preempted)
+{
+}
+
 static inline int kvm_hypercall_pvsched_features(struct kvm_vcpu *vcpu)
 {
 	return SMCCC_RET_NOT_SUPPORTED;

arch/arm64/include/asm/kvm_host.h

@@ -325,6 +325,11 @@ struct kvm_vcpu_arch {
 	 * see kvm_vcpu_load_sysregs and kvm_vcpu_put_sysregs. */
 	bool sysregs_loaded_on_cpu;
 
+	/* Guest PV sched state */
+	struct {
+		gpa_t base;
+	} pvsched;
+
 	struct id_registers idregs;
 };
 
@@ -430,6 +435,17 @@ void handle_exit_early(struct kvm_vcpu *vcpu, struct kvm_run *run,
 int kvm_perf_init(void);
 int kvm_perf_teardown(void);
 
+static inline void kvm_arm_pvsched_vcpu_init(struct kvm_vcpu_arch *vcpu_arch)
+{
+	vcpu_arch->pvsched.base = GPA_INVALID;
+}
+
+static inline bool kvm_arm_is_pvsched_enabled(struct kvm_vcpu_arch *vcpu_arch)
+{
+	return (vcpu_arch->pvsched.base != GPA_INVALID);
+}
+
+void kvm_update_pvsched_preempted(struct kvm_vcpu *vcpu, u32 preempted);
 int kvm_hypercall_pvsched_features(struct kvm_vcpu *vcpu);
 
 void kvm_set_sei_esr(struct kvm_vcpu *vcpu, u64 syndrome);

include/linux/kvm_types.h

@@ -49,6 +49,8 @@ typedef unsigned long  gva_t;
 typedef u64            gpa_t;
 typedef u64            gfn_t;
 
+#define GPA_INVALID    (~(gpa_t)0)
+
 typedef unsigned long  hva_t;
 typedef u64            hpa_t;
 typedef u64            hfn_t;

virt/kvm/arm/arm.c

@@ -396,6 +396,8 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
 
 	kvm_arm_reset_debug_ptr(vcpu);
 
+	kvm_arm_pvsched_vcpu_init(&vcpu->arch);
+
 	return kvm_vgic_vcpu_init(vcpu);
 }
 
@@ -446,6 +448,9 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 		vcpu_set_wfe_traps(vcpu);
 
 	update_steal_time(vcpu);
+
+	if (kvm_arm_is_pvsched_enabled(&vcpu->arch))
+		kvm_update_pvsched_preempted(vcpu, 0);
 }
 
 void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
@@ -459,6 +464,9 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 	vcpu->cpu = -1;
 
 	kvm_arm_set_running_vcpu(NULL);
+
+	if (kvm_arm_is_pvsched_enabled(&vcpu->arch))
+		kvm_update_pvsched_preempted(vcpu, 1);
 }
 
 static void vcpu_power_off(struct kvm_vcpu *vcpu)

virt/kvm/arm/hypercalls.c

@@ -14,6 +14,7 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
 	u32 func_id = smccc_get_function(vcpu);
 	u32 val = SMCCC_RET_NOT_SUPPORTED;
 	u32 feature;
+	gpa_t gpa;
 
 	switch (func_id) {
 	case ARM_SMCCC_VERSION_FUNC_ID:
@@ -48,6 +49,17 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
 	case ARM_SMCCC_HV_PV_SCHED_FEATURES:
 		val = kvm_hypercall_pvsched_features(vcpu);
 		break;
+	case ARM_SMCCC_HV_PV_SCHED_IPA_INIT:
+		gpa = smccc_get_arg1(vcpu);
+		if (gpa != GPA_INVALID) {
+			vcpu->arch.pvsched.base = gpa;
+			val = SMCCC_RET_SUCCESS;
+		}
+		break;
+	case ARM_SMCCC_HV_PV_SCHED_IPA_RELEASE:
+		vcpu->arch.pvsched.base = GPA_INVALID;
+		val = SMCCC_RET_SUCCESS;
+		break;
 	default:
 		return kvm_psci_call(vcpu);
 	}

virt/kvm/arm/pvsched.c

@@ -5,9 +5,39 @@
  */
 
 #include <linux/arm-smccc.h>
+#include <linux/kvm_host.h>
+
+#include <asm/pvsched-abi.h>
 
 #include <kvm/arm_hypercalls.h>
 
+void kvm_update_pvsched_preempted(struct kvm_vcpu *vcpu, u32 preempted)
+{
+	__le32 preempted_le;
+	u64 offset;
+	int idx;
+	u64 base = vcpu->arch.pvsched.base;
+	struct kvm *kvm = vcpu->kvm;
+
+	if (base == GPA_INVALID)
+		return;
+
+	preempted_le = cpu_to_le32(preempted);
+
+	/*
+	 * This function is called from atomic context, so we need to
+	 * disable page faults.
+	 */
+	pagefault_disable();
+
+	idx = srcu_read_lock(&kvm->srcu);
+	offset = offsetof(struct pvsched_vcpu_state, preempted);
+	kvm_put_guest(kvm, base + offset, preempted_le, u32);
+	srcu_read_unlock(&kvm->srcu, idx);
+
+	pagefault_enable();
+}
+
 int kvm_hypercall_pvsched_features(struct kvm_vcpu *vcpu)
 {
 	u32 feature = smccc_get_arg1(vcpu);
@@ -15,6 +45,8 @@ int kvm_hypercall_pvsched_features(struct kvm_vcpu *vcpu)
 
 	switch (feature) {
 	case ARM_SMCCC_HV_PV_SCHED_FEATURES:
+	case ARM_SMCCC_HV_PV_SCHED_IPA_INIT:
+	case ARM_SMCCC_HV_PV_SCHED_IPA_RELEASE:
 		val = SMCCC_RET_SUCCESS;
 		break;
 	}