On Mon, Nov 02, 2015 at 03:28:00 +0530, Shivaprasad G Bhat wrote:
> There could be a delay of 1 or 2 seconds before the vfio-pci driver
> is unbound and the device file /dev/vfio/<iommu> is actually
> removed. If the file exists, the host driver probing the device
> can lead to crash. So, wait and avoid the crash.
>
> Signed-off-by: Shivaprasad G Bhat <sbhat@xxxxxxxxxxxxxxxxxx>
> ---
> src/util/virpci.c | 42 ++++++++++++++++++++++++++++++++++++++++++
> tests/virpcimock.c | 14 ++++++++++++--
> 2 files changed, 54 insertions(+), 2 deletions(-)
>
> diff --git a/src/util/virpci.c b/src/util/virpci.c
> index 0bb465b..68fd54c 100644
> --- a/src/util/virpci.c
> +++ b/src/util/virpci.c
> @@ -1098,6 +1098,43 @@ virPCIIsAKnownStub(char *driver)
> return ret;
> }
>
> +#define VFIO_UNBIND_TIMEOUT 10
> +
> +/* It is not safe to initiate host driver probe if the vfio driver has not
> + * completely unbound the device. Usual wait time is 1 to 2 seconds.
> + * So, return if the unbind didn't complete in 10 seconds.
> + */
> +static int
> +virPCIWaitForVFIOUnbindCompletion(virPCIDevicePtr dev)
> +{
> + int retry = 0;
> + int ret = -1;
> + char *path = NULL;
> +
> + if (!(path = virPCIDeviceGetIOMMUGroupDev(dev)))
> + goto cleanup;
> +
> + while (retry++ < VFIO_UNBIND_TIMEOUT) {
> + if (!virFileExists(path))
> + break;
> + sleep(1);
I don't particularly like the 1 second sleep granularity here. I'd
rather see a 1/10s or 1/100s delay so that if the time will be decreased
in the future we will not have to wait for a full second.
Peter
Attachment:
signature.asc
Description: Digital signature
-- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list