[pve-devel] [PATCH qemu-server] pci: workaround nvidia driver issue on mdev cleanup

[pve-devel] [PATCH qemu-server] pci: workaround nvidia driver issue on mdev cleanup

[Dominik Csapak]

in some nvidia grid drivers (e.g. 14.4 and 15.x), their kernel module
tries to clean up the mdev device when the vm is shutdown and if it
cannot do that (e.g. becaues we already cleaned it up), their removal
process cancels with an error such that the vgpu does still exist inside
their book-keeping, but can't be used/recreated/freed until a reboot.

since there seems no obvious way to detect if thats the case besides
either parsing dmesg (which is racy), or the nvidia kernel module
version(which i'd rather not do), we simply test the pci device vendor
for nvidia and add a 10s sleep. that should give the driver enough time
to clean up and we will not find the path anymore and skip the cleanup.

This way, it works with both the newer and older versions of the driver
(some of the older drivers are LTS releases, so they're still
supported).

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
---
 PVE/QemuServer.pm | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index 40be44db..096e7f0d 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -6161,6 +6161,15 @@ sub cleanup_pci_devices {
 	    # NOTE: avoid PVE::SysFSTools::pci_cleanup_mdev_device as it requires PCI ID and we
 	    # don't want to break ABI just for this two liner
 	    my $dev_sysfs_dir = "/sys/bus/mdev/devices/$uuid";
+
+	    # some nvidia vgpu driver versions want to clean the mdevs up themselves, and error
+	    # out when we do it first. so wait for 10 seconds and then try it
+	    my $pciid = $d->{pciid}->[0]->{id};
+	    my $info = PVE::SysFSTools::pci_device_info("$pciid");
+	    if ($info->{vendor} eq '10de') {
+		sleep 10;
+	    }
+
 	    PVE::SysFSTools::file_write("$dev_sysfs_dir/remove", "1") if -e $dev_sysfs_dir;
 	}
     }
-- 
2.30.2

[pve-devel] applied: [PATCH qemu-server] pci: workaround nvidia driver issue on mdev cleanup

[Wolfgang Bumiller]

applied, though I'm not too happy about it...

The moment those driver versions that don't cleanup by themselves are
"rare" enough I'd like to just drop the cleanup code from our side!

On Fri, Feb 24, 2023 at 02:04:31PM +0100, Dominik Csapak wrote:
> in some nvidia grid drivers (e.g. 14.4 and 15.x), their kernel module
> tries to clean up the mdev device when the vm is shutdown and if it
> cannot do that (e.g. becaues we already cleaned it up), their removal
> process cancels with an error such that the vgpu does still exist inside
> their book-keeping, but can't be used/recreated/freed until a reboot.
> 
> since there seems no obvious way to detect if thats the case besides
> either parsing dmesg (which is racy), or the nvidia kernel module
> version(which i'd rather not do), we simply test the pci device vendor
> for nvidia and add a 10s sleep. that should give the driver enough time
> to clean up and we will not find the path anymore and skip the cleanup.
> 
> This way, it works with both the newer and older versions of the driver
> (some of the older drivers are LTS releases, so they're still
> supported).
> 
> Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
> ---
>  PVE/QemuServer.pm | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
> index 40be44db..096e7f0d 100644
> --- a/PVE/QemuServer.pm
> +++ b/PVE/QemuServer.pm
> @@ -6161,6 +6161,15 @@ sub cleanup_pci_devices {
>  	    # NOTE: avoid PVE::SysFSTools::pci_cleanup_mdev_device as it requires PCI ID and we
>  	    # don't want to break ABI just for this two liner
>  	    my $dev_sysfs_dir = "/sys/bus/mdev/devices/$uuid";
> +
> +	    # some nvidia vgpu driver versions want to clean the mdevs up themselves, and error
> +	    # out when we do it first. so wait for 10 seconds and then try it
> +	    my $pciid = $d->{pciid}->[0]->{id};
> +	    my $info = PVE::SysFSTools::pci_device_info("$pciid");
> +	    if ($info->{vendor} eq '10de') {
> +		sleep 10;
> +	    }
> +
>  	    PVE::SysFSTools::file_write("$dev_sysfs_dir/remove", "1") if -e $dev_sysfs_dir;
>  	}
>      }
> -- 
> 2.30.2