arm/arm64: KVM: Add KVM_GET/SET_VCPU_EVENTS

For the migrating VMs, user space may need to know the exception
state. For example, in the machine A, KVM make an SError pending,
when migrate to B, KVM also needs to pend an SError.

This new IOCTL exports user-invisible states related to SError.
Together with appropriate user space changes, user space can get/set
the SError exception state to do migrate/snapshot/suspend.

Signed-off-by: Dongjiu Geng <gengdongjiu@huawei.com>
Reviewed-by: James Morse <james.morse@arm.com>
[expanded documentation wording]
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

3 files changed, 50 insertions, 3 deletions

diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 56a0260ceb11..dd05be96d981 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -289,6 +289,52 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,
 	return -EINVAL;
 }
 
+int kvm_arm_vcpu_get_events(struct kvm_vcpu *vcpu,
+			struct kvm_vcpu_events *events)
+{
+	memset(events, 0, sizeof(*events));
+
+	events->exception.serror_pending = !!(vcpu->arch.hcr_el2 & HCR_VSE);
+	events->exception.serror_has_esr = cpus_have_const_cap(ARM64_HAS_RAS_EXTN);
+
+	if (events->exception.serror_pending && events->exception.serror_has_esr)
+		events->exception.serror_esr = vcpu_get_vsesr(vcpu);
+
+	return 0;
+}
+
+int kvm_arm_vcpu_set_events(struct kvm_vcpu *vcpu,
+			struct kvm_vcpu_events *events)
+{
+	int i;
+	bool serror_pending = events->exception.serror_pending;
+	bool has_esr = events->exception.serror_has_esr;
+
+	/* check whether the reserved field is zero */
+	for (i = 0; i < ARRAY_SIZE(events->reserved); i++)
+		if (events->reserved[i])
+			return -EINVAL;
+
+	/* check whether the pad field is zero */
+	for (i = 0; i < ARRAY_SIZE(events->exception.pad); i++)
+		if (events->exception.pad[i])
+			return -EINVAL;
+
+	if (serror_pending && has_esr) {
+		if (!cpus_have_const_cap(ARM64_HAS_RAS_EXTN))
+			return -EINVAL;
+
+		if (!((events->exception.serror_esr) & ~ESR_ELx_ISS_MASK))
+			kvm_set_sei_esr(vcpu, events->exception.serror_esr);
+		else
+			return -EINVAL;
+	} else if (serror_pending) {
+		kvm_inject_vabt(vcpu);
+	}
+
+	return 0;
+}
+
 int __attribute_const__ kvm_target_cpu(void)
 {
 	unsigned long implementor = read_cpuid_implementor();
diff --git a/arch/arm64/kvm/inject_fault.c b/arch/arm64/kvm/inject_fault.c
index d8e71659ba7e..a55e91dfcf8f 100644
--- a/arch/arm64/kvm/inject_fault.c
+++ b/arch/arm64/kvm/inject_fault.c
@@ -164,9 +164,9 @@ void kvm_inject_undefined(struct kvm_vcpu *vcpu)
 		inject_undef64(vcpu);
 }
 
-static void pend_guest_serror(struct kvm_vcpu *vcpu, u64 esr)
+void kvm_set_sei_esr(struct kvm_vcpu *vcpu, u64 esr)
 {
-	vcpu_set_vsesr(vcpu, esr);
+	vcpu_set_vsesr(vcpu, esr & ESR_ELx_ISS_MASK);
 	*vcpu_hcr(vcpu) |= HCR_VSE;
 }
 
@@ -184,5 +184,5 @@ static void pend_guest_serror(struct kvm_vcpu *vcpu, u64 esr)
  */
 void kvm_inject_vabt(struct kvm_vcpu *vcpu)
 {
-	pend_guest_serror(vcpu, ESR_ELx_ISV);
+	kvm_set_sei_esr(vcpu, ESR_ELx_ISV);
 }
diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index a74311beda35..a3db01a28062 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -79,6 +79,7 @@ int kvm_arch_dev_ioctl_check_extension(struct kvm *kvm, long ext)
 		break;
 	case KVM_CAP_SET_GUEST_DEBUG:
 	case KVM_CAP_VCPU_ATTRIBUTES:
+	case KVM_CAP_VCPU_EVENTS:
 		r = 1;
 		break;
 	default: