linux-kernel - [PATCH v6 26/43] arm64: rme: allow userspace to inject aborts

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Message-ID: <20241212155610.76522-27-steven.price@arm.com>
Date: Thu, 12 Dec 2024 15:55:51 +0000
From: Steven Price <steven.price@....com>
To: kvm@...r.kernel.org,
	kvmarm@...ts.linux.dev
Cc: Joey Gouly <joey.gouly@....com>,
	Catalin Marinas <catalin.marinas@....com>,
	Marc Zyngier <maz@...nel.org>,
	Will Deacon <will@...nel.org>,
	James Morse <james.morse@....com>,
	Oliver Upton <oliver.upton@...ux.dev>,
	Suzuki K Poulose <suzuki.poulose@....com>,
	Zenghui Yu <yuzenghui@...wei.com>,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	Alexandru Elisei <alexandru.elisei@....com>,
	Christoffer Dall <christoffer.dall@....com>,
	Fuad Tabba <tabba@...gle.com>,
	linux-coco@...ts.linux.dev,
	Ganapatrao Kulkarni <gankulkarni@...amperecomputing.com>,
	Gavin Shan <gshan@...hat.com>,
	Shanker Donthineni <sdonthineni@...dia.com>,
	Alper Gun <alpergun@...gle.com>,
	"Aneesh Kumar K . V" <aneesh.kumar@...nel.org>,
	Steven Price <steven.price@....com>
Subject: [PATCH v6 26/43] arm64: rme: allow userspace to inject aborts

From: Joey Gouly <joey.gouly@....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@....com>
Signed-off-by: Steven Price <steven.price@....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 df4679415a4c..1c622d8ca602 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -1291,6 +1291,8 @@ 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 1ee2fe072f1a..920e0fd73698 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -883,6 +883,30 @@ int __kvm_arm_vcpu_set_events(struct kvm_vcpu *vcpu,
 	bool has_esr = events->exception.serror_has_esr;
 	bool ext_dabt_pending = events->exception.ext_dabt_pending;
 
+	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_EMULATED_MMIO))
+				return -EINVAL;
+
+			vcpu->arch.rec.run->enter.flags &= ~REC_ENTER_EMULATED_MMIO;
+			vcpu->arch.rec.run->enter.flags |= REC_ENTER_INJECT_SEA;
+		}
+
+		return 0;
+	}
+
 	if (serror_pending && has_esr) {
 		if (!cpus_have_final_cap(ARM64_HAS_RAS_EXTN))
 			return -EINVAL;
-- 
2.43.0