[libvirt PATCH] qemu: ramfb video device doesn't support PCI address

Laine Stump laine at redhat.com
Thu Jun 25 03:21:52 UTC 2020


On 6/24/20 6:06 PM, Jonathon Jongsma wrote:
> Although a ramfb video device is not a PCI device, we don't currently
> report an error for ramfb device definitions containing a PCI address.
> However, a guest configured with such a device will fail to start:
>
>      # virsh start test1
>      error: Failed to start domain test1
>      error: internal error: qemu unexpectedly closed the monitor: 2020-06-16T05:23:02.759221Z qemu-kvm: -device ramfb,id=video0,bus=pcie.0,addr=0x1: Device 'ramfb' can't go on PCIE bus
>
> A better approach is to reject any device definitions that contain PCI
> addresses.  While this is a change in behavior, any existing
> configurations were non-functional.
>
> https://bugzilla.redhat.com/show_bug.cgi?id=1847259
>
> Signed-off-by: Jonathon Jongsma <jjongsma at redhat.com>
> ---
>   src/conf/domain_conf.c   | 7 +++++++
>   tests/qemuxml2argvtest.c | 1 +
>   2 files changed, 8 insertions(+)
>
> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> index fc7fcfb0c6..1a06cb3f4b 100644
> --- a/src/conf/domain_conf.c
> +++ b/src/conf/domain_conf.c
> @@ -6608,6 +6608,13 @@ virDomainVideoDefValidate(const virDomainVideoDef *video,
>           return -1;
>       }
>   
> +    if (video->type == VIR_DOMAIN_VIDEO_TYPE_RAMFB &&
> +        video->info.type != VIR_DOMAIN_DEVICE_ADDRESS_TYPE_NONE) {
> +        virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
> +                       _("'address' is not supported for 'ramfb' video devices"));
> +        return -1;
> +    }
> +


There may be disagreement about this, and in practical terms it makes no 
difference (because no domain type other than QEMU is ever going to have 
one of these devices anyway), but since ramfb is a qemu-specific device 
(isn't it?), I think this check would be better put in 
qemu_validate.c:qemuValidateDomainDeviceDevVideo(), which is the 
qemu-specific validation function for video devices.


(I  see there is already validation in virDomainVideoDefValidate() for a 
qemu-specific (afaik) video type - i is even checking for one backend 
that is named VIR_DOMAIN_VIDEO_BACKEND_TYPE_QEMU)


I don't really have a strong opinion though, since the other hypervisor 
drivers don't seem all that concerned about fleshing out their 
validation functions, and what you have works properly for qemu :-P


>       /* it doesn't make sense to pair video device type 'none' with any other
>        * types, there can be only a single video device in such case
>        */
> diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c
> index 1195f9c982..f2522fa530 100644
> --- a/tests/qemuxml2argvtest.c
> +++ b/tests/qemuxml2argvtest.c
> @@ -2276,6 +2276,7 @@ mymain(void)
>               QEMU_CAPS_VIRTIO_GPU_MAX_OUTPUTS);
>       DO_TEST_CAPS_LATEST("video-bochs-display-device");
>       DO_TEST_CAPS_LATEST("video-ramfb-display-device");
> +    DO_TEST_CAPS_LATEST_PARSE_ERROR("video-ramfb-display-device-pci-address");
>       DO_TEST("video-none-device",
>               QEMU_CAPS_VNC);
>       DO_TEST_PARSE_ERROR("video-invalid-multiple-devices", NONE);





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