[PATCH v16 34/45] KVM: arm64: CCA: Allow userspace to inject aborts

[Steven Price <steven.price@arm.com>]

From: Joey Gouly <joey.gouly@arm.com>

Extend KVM_SET_VCPU_EVENTS to support realms, where KVM cannot set the
system registers, and the RMM must perform it on next REC entry.

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 Documentation/virt/kvm/api.rst |  2 ++
 arch/arm64/kvm/guest.c         | 24 ++++++++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 802601eaf560..1c9488df7e06 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -1317,6 +1317,8 @@ User space may need to inject several types of events to the guest.
 Set the pending SError exception state for this VCPU. It is not possible to
 'cancel' an Serror that has been made pending.
 
+User space cannot inject SErrors into Realms.
+
 If the guest performed an access to I/O memory which could not be handled by
 userspace, for example because of missing instruction syndrome decode
 information or because there is no device mapped at the accessed IPA, then
diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 3e970c4f6214..5469c9a97fad 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -827,6 +827,30 @@ int __kvm_arm_vcpu_set_events(struct kvm_vcpu *vcpu,
 	u64 esr = events->exception.serror_esr;
 	int ret = 0;
 
+	if (vcpu_is_rec(vcpu)) {
+		/* Cannot inject SError into a Realm. */
+		if (serror_pending)
+			return -EINVAL;
+
+		/*
+		 * If a data abort is pending, set the flag and let the RMM
+		 * inject an SEA when the REC is scheduled to be run.
+		 */
+		if (ext_dabt_pending) {
+			/*
+			 * Can only inject SEA into a Realm if the previous exit
+			 * was due to a data abort of an Unprotected IPA.
+			 */
+			if (!(vcpu->arch.rec.run->enter.flags & REC_ENTER_FLAG_EMULATED_MMIO))
+				return -EINVAL;
+
+			vcpu->arch.rec.run->enter.flags &= ~REC_ENTER_FLAG_EMULATED_MMIO;
+			vcpu->arch.rec.run->enter.flags |= REC_ENTER_FLAG_INJECT_SEA;
+		}
+
+		return 0;
+	}
+
 	/*
 	 * Immediately commit the pending SEA to the vCPU's architectural
 	 * state which is necessary since we do not return a pending SEA
-- 
2.43.0