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authorPeter Maydell <peter.maydell@linaro.org>2020-02-25 18:07:50 +0000
committerPeter Maydell <peter.maydell@linaro.org>2020-02-25 18:07:50 +0000
commit957b1c136865876fb3234b8d06cb7472b0f69127 (patch)
tree38590c1792849da6ef4f3075ee4242e86c817671
parentdb736e0437aa6fd7c1b7e4599c17f9619ab6b837 (diff)
downloadqemu-arm-handle-gicv3-only.tar.gz
hw/intc/arm_gic_kvm: Don't assume kernel can provide a GICv2handle-gicv3-only
In our KVM GICv2 realize function, we try to cope with old kernels that don't provide the device control API (KVM_CAP_DEVICE_CTRL): we try to use the device control, and if that fails we fall back to assuming that the kernel has the old style KVM_CREATE_IRQCHIP and that it will provide a GICv2. This doesn't cater for the possibility of a kernel and hardware which only provide a GICv3, which is very common now. On that setup we will abort() later on in kvm_arm_pmu_set_irq() when we try to wire up an interrupt to the GIC we failed to create. If the kernel advertises KVM_CAP_DEVICE_CTRL we should trust it if it says it can't create a GICv2, rather than assuming it has one. We can then produce a more helpful error message including a hint about the most probable reason for the failure. If the kernel doesn't advertise KVM_CAP_DEVICE_CTRL then it is truly ancient by this point but we might as well still fall back to a KVM_CREATE_IRQCHIP GICv2. Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
-rw-r--r--hw/intc/arm_gic_kvm.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/hw/intc/arm_gic_kvm.c b/hw/intc/arm_gic_kvm.c
index 9deb15e7e6..d7df423a7a 100644
--- a/hw/intc/arm_gic_kvm.c
+++ b/hw/intc/arm_gic_kvm.c
@@ -551,7 +551,16 @@ static void kvm_arm_gic_realize(DeviceState *dev, Error **errp)
KVM_DEV_ARM_VGIC_CTRL_INIT, NULL, true,
&error_abort);
}
+ } else if (kvm_check_extension(kvm_state, KVM_CAP_DEVICE_CTRL)) {
+ error_setg_errno(errp, -ret, "error creating in-kernel VGIC");
+ error_append_hint(errp,
+ "Perhaps the host CPU does not support GICv2?\n");
} else if (ret != -ENODEV && ret != -ENOTSUP) {
+ /*
+ * Very ancient kernel without KVM_CAP_DEVICE_CTRL: assume that
+ * ENODEV or ENOTSUP mean "can't create GICv2 with KVM_CREATE_DEVICE",
+ * and that we will get a GICv2 via KVM_CREATE_IRQCHIP.
+ */
error_setg_errno(errp, -ret, "error creating in-kernel VGIC");
return;
}