[PATCH 1/1] KVM: inject data abort if instruction cannot be decoded

From: Heinrich Schuchardt <xypron.glpk@gmx.de>
To: Marc Zyngier <marc.zyngier@arm.com>
Cc: "James Morse" <james.morse@arm.com>,
	"Julien Thierry" <julien.thierry@arm.com>,
	"Suzuki K Pouloze" <suzuki.poulose@arm.com>,
	"Peter Maydell" <peter.maydell@linaro.org>,
	"Stefan Hajnoczi" <stefanha@redhat.com>,
	"Daniel P . Berrangé" <berrange@redhat.com>,
	linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org,
	"Heinrich Schuchardt" <xypron.glpk@gmx.de>
Subject: [PATCH 1/1] KVM: inject data abort if instruction cannot be decoded
Date: Wed,  4 Sep 2019 20:07:36 +0200	[thread overview]
Message-ID: <20190904180736.29009-1-xypron.glpk@gmx.de> (raw)

If an application tries to access memory that is not mapped, an error
ENOSYS, "load/store instruction decoding not implemented" may occur.
QEMU will hang with a register dump.

Instead create a data abort that can be handled gracefully by the
application running in the virtual environment.

Now the virtual machine can react to the event in the most appropriate
way - by recovering, by writing an informative log, or by rebooting.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
---
 virt/kvm/arm/mmio.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/virt/kvm/arm/mmio.c b/virt/kvm/arm/mmio.c
index a8a6a0c883f1..0cbed7d6a0f4 100644
--- a/virt/kvm/arm/mmio.c
+++ b/virt/kvm/arm/mmio.c
@@ -161,8 +161,8 @@ int io_mem_abort(struct kvm_vcpu *vcpu, struct kvm_run *run,
 		if (ret)
 			return ret;
 	} else {
-		kvm_err("load/store instruction decoding not implemented\n");
-		return -ENOSYS;
+		kvm_inject_dabt(vcpu, kvm_vcpu_get_hfar(vcpu));
+		return 1;
 	}

 	rt = vcpu->arch.mmio_decode.rt;
--
2.23.0.rc1

