Hi Andre,
On 08/08/2016 18:29, Andre Przywara wrote:
> According to the KVM API documentation a successful MSI injection
> should return a value > 0 on success.
> Return possible errors in vgic_its_trigger_msi() and report a
> successful injection back to userland, while also reporting the
> case where the MSI could not be delivered due to the guest not
> having the LPI mapped, for instance.
>
> Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
> ---
> Changelog v2 .. v3:
> - return Linux errors to userland
>
> Changelog v1 .. v2:
> - properly detect unmapped LPIs and report this to userland
>
> include/linux/irqchip/arm-gic-v3.h | 1 +
> virt/kvm/arm/vgic/vgic-its.c | 56 +++++++++++++++++++++++++-------------
> 2 files changed, 38 insertions(+), 19 deletions(-)
>
> diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
> index 56b0b7e..99ac022 100644
> --- a/include/linux/irqchip/arm-gic-v3.h
> +++ b/include/linux/irqchip/arm-gic-v3.h
> @@ -337,6 +337,7 @@
> */
> #define E_ITS_MOVI_UNMAPPED_INTERRUPT 0x010107
> #define E_ITS_MOVI_UNMAPPED_COLLECTION 0x010109
> +#define E_ITS_INT_UNMAPPED_INTERRUPT 0x010307
> #define E_ITS_CLEAR_UNMAPPED_INTERRUPT 0x010507
> #define E_ITS_MAPD_DEVICE_OOR 0x010801
> #define E_ITS_MAPC_PROCNUM_OOR 0x010902
> diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
> index 7180994..3c029cd 100644
> --- a/virt/kvm/arm/vgic/vgic-its.c
> +++ b/virt/kvm/arm/vgic/vgic-its.c
> @@ -441,39 +441,48 @@ static unsigned long vgic_mmio_read_its_idregs(struct kvm *kvm,
> * Find the target VCPU and the LPI number for a given devid/eventid pair
> * and make this IRQ pending, possibly injecting it.
> * Must be called with the its_lock mutex held.
> + * Returns 0 on success, a positive error value for any ITS mapping
> + * related errors and negative error values for generic errors.
> */
> -static void vgic_its_trigger_msi(struct kvm *kvm, struct vgic_its *its,
> - u32 devid, u32 eventid)
> +static int vgic_its_trigger_msi(struct kvm *kvm, struct vgic_its *its,
> + u32 devid, u32 eventid)
> {
> + struct kvm_vcpu *vcpu;
> struct its_itte *itte;
>
> if (!its->enabled)
> - return;
> + return -EBUSY;
>
> itte = find_itte(its, devid, eventid);
> - /* Triggering an unmapped IRQ gets silently dropped. */
> - if (itte && its_is_collection_mapped(itte->collection)) {
> - struct kvm_vcpu *vcpu;
> -
> - vcpu = kvm_get_vcpu(kvm, itte->collection->target_addr);
> - if (vcpu && vcpu->arch.vgic_cpu.lpis_enabled) {
> - spin_lock(&itte->irq->irq_lock);
> - itte->irq->pending = true;
> - vgic_queue_irq_unlock(kvm, itte->irq);
> - }
> - }
> + if (!itte || !its_is_collection_mapped(itte->collection))
> + return E_ITS_INT_UNMAPPED_INTERRUPT;
> +
> + vcpu = kvm_get_vcpu(kvm, itte->collection->target_addr);
> + if (!vcpu)
> + return E_ITS_INT_UNMAPPED_INTERRUPT;
> +
> + if (!vcpu->arch.vgic_cpu.lpis_enabled)
> + return -EBUSY;
> +
> + spin_lock(&itte->irq->irq_lock);
> + itte->irq->pending = true;
> + vgic_queue_irq_unlock(kvm, itte->irq);
> +
> + return 0;
> }
>
> /*
> * Queries the KVM IO bus framework to get the ITS pointer from the given
> * doorbell address.
> * We then call vgic_its_trigger_msi() with the decoded data.
> + * According to the KVM_SIGNAL_MSI API description returns 1 on success.
> */
> int vgic_its_inject_msi(struct kvm *kvm, struct kvm_msi *msi)
> {
> u64 address;
> struct kvm_io_device *kvm_io_dev;
> struct vgic_io_device *iodev;
> + int ret;
>
> if (!vgic_has_its(kvm))
> return -ENODEV;
> @@ -490,10 +499,21 @@ int vgic_its_inject_msi(struct kvm *kvm, struct kvm_msi *msi)
> iodev = container_of(kvm_io_dev, struct vgic_io_device, dev);
>
> mutex_lock(&iodev->its->its_lock);
> - vgic_its_trigger_msi(kvm, iodev->its, msi->devid, msi->data);
> + ret = vgic_its_trigger_msi(kvm, iodev->its, msi->devid, msi->data);
> mutex_unlock(&iodev->its->its_lock);
>
> - return 0;
> + if (ret < 0)
> + return ret;
> +
> + /*
> + * KVM_SIGNAL_MSI demands a return value > 0 for success and 0
> + * if the guest has blocked the MSI. So we map any LPI mapping
> + * related error to that.
> + */
> + if (ret)
> + return 0;
> + else
> + return 1;
> }
>
> /* Requires the its_lock to be held. */
> @@ -981,9 +1001,7 @@ static int vgic_its_cmd_handle_int(struct kvm *kvm, struct vgic_its *its,
> u32 msi_data = its_cmd_get_id(its_cmd);
> u64 msi_devid = its_cmd_get_deviceid(its_cmd);
>
> - vgic_its_trigger_msi(kvm, its, msi_devid, msi_data);
> -
> - return 0;
> + return vgic_its_trigger_msi(kvm, its, msi_devid, msi_data);
> }
>
> /*
>
Looks good to me
Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx>
Cheers
Eric
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
