| Message ID | 20240926161641.189193-1-aleksandr.mikhalitsyn@canonical.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | vhost/vsock: specify module version | expand |
On Thu, Sep 26, 2024 at 06:16:40PM +0200, Alexander Mikhalitsyn wrote: > Add an explicit MODULE_VERSION("0.0.1") specification > for a vhost_vsock module. It is useful because it allows > userspace to check if vhost_vsock is there when it is > configured as a built-in. > > Without this change, there is no /sys/module/vhost_vsock directory. > > With this change: > $ ls -la /sys/module/vhost_vsock/ > total 0 > drwxr-xr-x 2 root root 0 Sep 26 15:59 . > drwxr-xr-x 100 root root 0 Sep 26 15:59 .. > --w------- 1 root root 4096 Sep 26 15:59 uevent > -r--r--r-- 1 root root 4096 Sep 26 15:59 version > > Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com> Why not check that the misc device is registered? I'd rather not add a new UAPI until actually necessary. > --- > drivers/vhost/vsock.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c > index 802153e23073..287ea8e480b5 100644 > --- a/drivers/vhost/vsock.c > +++ b/drivers/vhost/vsock.c > @@ -956,6 +956,7 @@ static void __exit vhost_vsock_exit(void) > > module_init(vhost_vsock_init); > module_exit(vhost_vsock_exit); > +MODULE_VERSION("0.0.1"); > MODULE_LICENSE("GPL v2"); > MODULE_AUTHOR("Asias He"); > MODULE_DESCRIPTION("vhost transport for vsock "); > -- > 2.34.1
On Sun, Sep 29, 2024 at 6:56 PM Michael S. Tsirkin <mst@redhat.com> wrote: > > On Thu, Sep 26, 2024 at 06:16:40PM +0200, Alexander Mikhalitsyn wrote: > > Add an explicit MODULE_VERSION("0.0.1") specification > > for a vhost_vsock module. It is useful because it allows > > userspace to check if vhost_vsock is there when it is > > configured as a built-in. > > > > Without this change, there is no /sys/module/vhost_vsock directory. > > > > With this change: > > $ ls -la /sys/module/vhost_vsock/ > > total 0 > > drwxr-xr-x 2 root root 0 Sep 26 15:59 . > > drwxr-xr-x 100 root root 0 Sep 26 15:59 .. > > --w------- 1 root root 4096 Sep 26 15:59 uevent > > -r--r--r-- 1 root root 4096 Sep 26 15:59 version > > > > Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com> > > Dear Michael, > Why not check that the misc device is registered? It is possible to read /proc/misc and check if "241 vhost-vsock" is there, but it means that userspace needs to have a specific logic for vsock. At the same time, it's quite convenient to do something like: if [ ! -d /sys/modules/vhost_vsock ]; then modprobe vhost_vsock fi > I'd rather not add a new UAPI until actually necessary. I don't insist. I decided to send this patch because, while I was debugging a non-related kernel issue on my local dev environment I accidentally discovered that LXD (containers and VM manager) fails to run VMs because it fails to load the vhost_vsock module (but it was built-in in my debug kernel and the module file didn't exist). Then I discovered that before trying to load a module we check if /sys/module/<module name> exists. And found that, for some reason /sys/module/vhost_vsock does not exist when vhost_vsock is configured as a built-in, and /sys/module/vhost_vsock *does* exist when vhost_vsock is loaded as a module. It looks like an inconsistency and I also checked that other modules in drivers/vhost have MODULE_VERSION specified and version is 0.0.1. I thought that this change looks legitimate and convenient for userspace consumers. Kind regards, Alex > > > --- > > drivers/vhost/vsock.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c > > index 802153e23073..287ea8e480b5 100644 > > --- a/drivers/vhost/vsock.c > > +++ b/drivers/vhost/vsock.c > > @@ -956,6 +956,7 @@ static void __exit vhost_vsock_exit(void) > > > > module_init(vhost_vsock_init); > > module_exit(vhost_vsock_exit); > > +MODULE_VERSION("0.0.1"); > > MODULE_LICENSE("GPL v2"); > > MODULE_AUTHOR("Asias He"); > > MODULE_DESCRIPTION("vhost transport for vsock "); > > -- > > 2.34.1 >
On Sun, Sep 29, 2024 at 07:35:35PM +0200, Aleksandr Mikhalitsyn wrote: > On Sun, Sep 29, 2024 at 6:56 PM Michael S. Tsirkin <mst@redhat.com> wrote: > > > > On Thu, Sep 26, 2024 at 06:16:40PM +0200, Alexander Mikhalitsyn wrote: > > > Add an explicit MODULE_VERSION("0.0.1") specification > > > for a vhost_vsock module. It is useful because it allows > > > userspace to check if vhost_vsock is there when it is > > > configured as a built-in. > > > > > > Without this change, there is no /sys/module/vhost_vsock directory. > > > > > > With this change: > > > $ ls -la /sys/module/vhost_vsock/ > > > total 0 > > > drwxr-xr-x 2 root root 0 Sep 26 15:59 . > > > drwxr-xr-x 100 root root 0 Sep 26 15:59 .. > > > --w------- 1 root root 4096 Sep 26 15:59 uevent > > > -r--r--r-- 1 root root 4096 Sep 26 15:59 version > > > > > > Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com> > > > > > > Dear Michael, > > > Why not check that the misc device is registered? > > It is possible to read /proc/misc and check if "241 vhost-vsock" is > there, but it means that userspace > needs to have a specific logic for vsock. At the same time, it's quite > convenient to do something like: > if [ ! -d /sys/modules/vhost_vsock ]; then > modprobe vhost_vsock > fi > > > I'd rather not add a new UAPI until actually necessary. > > I don't insist. I decided to send this patch because, while I was > debugging a non-related kernel issue > on my local dev environment I accidentally discovered that LXD > (containers and VM manager) > fails to run VMs because it fails to load the vhost_vsock module (but > it was built-in in my debug kernel > and the module file didn't exist). Then I discovered that before > trying to load a module we > check if /sys/module/<module name> exists. And found that, for some > reason /sys/module/vhost_vsock > does not exist when vhost_vsock is configured as a built-in, and > /sys/module/vhost_vsock *does* exist when > vhost_vsock is loaded as a module. It looks like an inconsistency and > I also checked that other modules in > drivers/vhost have MODULE_VERSION specified and version is 0.0.1. I > thought that this change looks legitimate > and convenient for userspace consumers. > > Kind regards, > Alex Aha, that's a different matter. Given userspace already depends on this UAPI, it's easier to fix it in the kernel. > > > > > --- > > > drivers/vhost/vsock.c | 1 + > > > 1 file changed, 1 insertion(+) > > > > > > diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c > > > index 802153e23073..287ea8e480b5 100644 > > > --- a/drivers/vhost/vsock.c > > > +++ b/drivers/vhost/vsock.c > > > @@ -956,6 +956,7 @@ static void __exit vhost_vsock_exit(void) > > > > > > module_init(vhost_vsock_init); > > > module_exit(vhost_vsock_exit); > > > +MODULE_VERSION("0.0.1"); > > > MODULE_LICENSE("GPL v2"); > > > MODULE_AUTHOR("Asias He"); > > > MODULE_DESCRIPTION("vhost transport for vsock "); > > > -- > > > 2.34.1 > >
On Sun, Sep 29, 2024 at 07:35:35PM +0200, Aleksandr Mikhalitsyn wrote: > On Sun, Sep 29, 2024 at 6:56 PM Michael S. Tsirkin <mst@redhat.com> wrote: > > > > On Thu, Sep 26, 2024 at 06:16:40PM +0200, Alexander Mikhalitsyn wrote: > > > Add an explicit MODULE_VERSION("0.0.1") specification > > > for a vhost_vsock module. It is useful because it allows > > > userspace to check if vhost_vsock is there when it is > > > configured as a built-in. > > > > > > Without this change, there is no /sys/module/vhost_vsock directory. > > > > > > With this change: > > > $ ls -la /sys/module/vhost_vsock/ > > > total 0 > > > drwxr-xr-x 2 root root 0 Sep 26 15:59 . > > > drwxr-xr-x 100 root root 0 Sep 26 15:59 .. > > > --w------- 1 root root 4096 Sep 26 15:59 uevent > > > -r--r--r-- 1 root root 4096 Sep 26 15:59 version > > > > > > Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com> > > > > > > Dear Michael, > > > Why not check that the misc device is registered? > > It is possible to read /proc/misc and check if "241 vhost-vsock" is > there, but it means that userspace > needs to have a specific logic for vsock. At the same time, it's quite > convenient to do something like: > if [ ! -d /sys/modules/vhost_vsock ]; then > modprobe vhost_vsock > fi > > > I'd rather not add a new UAPI until actually necessary. > > I don't insist. I decided to send this patch because, while I was > debugging a non-related kernel issue > on my local dev environment I accidentally discovered that LXD > (containers and VM manager) > fails to run VMs because it fails to load the vhost_vsock module (but > it was built-in in my debug kernel > and the module file didn't exist). Then I discovered that before > trying to load a module we > check if /sys/module/<module name> exists. And found that, for some > reason /sys/module/vhost_vsock > does not exist when vhost_vsock is configured as a built-in, and > /sys/module/vhost_vsock *does* exist when > vhost_vsock is loaded as a module. It looks like an inconsistency and > I also checked that other modules in > drivers/vhost have MODULE_VERSION specified and version is 0.0.1. I > thought that this change looks legitimate > and convenient for userspace consumers. > > Kind regards, > Alex I'll ask you to put this explanation in the commit log, and I'll pick this up. > > > > > --- > > > drivers/vhost/vsock.c | 1 + > > > 1 file changed, 1 insertion(+) > > > > > > diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c > > > index 802153e23073..287ea8e480b5 100644 > > > --- a/drivers/vhost/vsock.c > > > +++ b/drivers/vhost/vsock.c > > > @@ -956,6 +956,7 @@ static void __exit vhost_vsock_exit(void) > > > > > > module_init(vhost_vsock_init); > > > module_exit(vhost_vsock_exit); > > > +MODULE_VERSION("0.0.1"); > > > MODULE_LICENSE("GPL v2"); > > > MODULE_AUTHOR("Asias He"); > > > MODULE_DESCRIPTION("vhost transport for vsock "); > > > -- > > > 2.34.1 > >
On Sun, Sep 29, 2024 at 7:48 PM Michael S. Tsirkin <mst@redhat.com> wrote: > > On Sun, Sep 29, 2024 at 07:35:35PM +0200, Aleksandr Mikhalitsyn wrote: > > On Sun, Sep 29, 2024 at 6:56 PM Michael S. Tsirkin <mst@redhat.com> wrote: > > > > > > On Thu, Sep 26, 2024 at 06:16:40PM +0200, Alexander Mikhalitsyn wrote: > > > > Add an explicit MODULE_VERSION("0.0.1") specification > > > > for a vhost_vsock module. It is useful because it allows > > > > userspace to check if vhost_vsock is there when it is > > > > configured as a built-in. > > > > > > > > Without this change, there is no /sys/module/vhost_vsock directory. > > > > > > > > With this change: > > > > $ ls -la /sys/module/vhost_vsock/ > > > > total 0 > > > > drwxr-xr-x 2 root root 0 Sep 26 15:59 . > > > > drwxr-xr-x 100 root root 0 Sep 26 15:59 .. > > > > --w------- 1 root root 4096 Sep 26 15:59 uevent > > > > -r--r--r-- 1 root root 4096 Sep 26 15:59 version > > > > > > > > Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com> > > > > > > > > > > Dear Michael, > > > > > Why not check that the misc device is registered? > > > > It is possible to read /proc/misc and check if "241 vhost-vsock" is > > there, but it means that userspace > > needs to have a specific logic for vsock. At the same time, it's quite > > convenient to do something like: > > if [ ! -d /sys/modules/vhost_vsock ]; then > > modprobe vhost_vsock > > fi > > > > > I'd rather not add a new UAPI until actually necessary. > > > > I don't insist. I decided to send this patch because, while I was > > debugging a non-related kernel issue > > on my local dev environment I accidentally discovered that LXD > > (containers and VM manager) > > fails to run VMs because it fails to load the vhost_vsock module (but > > it was built-in in my debug kernel > > and the module file didn't exist). Then I discovered that before > > trying to load a module we > > check if /sys/module/<module name> exists. And found that, for some > > reason /sys/module/vhost_vsock > > does not exist when vhost_vsock is configured as a built-in, and > > /sys/module/vhost_vsock *does* exist when > > vhost_vsock is loaded as a module. It looks like an inconsistency and > > I also checked that other modules in > > drivers/vhost have MODULE_VERSION specified and version is 0.0.1. I > > thought that this change looks legitimate > > and convenient for userspace consumers. > > > > Kind regards, > > Alex > > > I'll ask you to put this explanation in the commit log, > and I'll pick this up. Have done: https://lore.kernel.org/kvm/20240929182103.21882-1-aleksandr.mikhalitsyn@canonical.com Thanks, Michael! Kind regards, Alex > > > > > > > > --- > > > > drivers/vhost/vsock.c | 1 + > > > > 1 file changed, 1 insertion(+) > > > > > > > > diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c > > > > index 802153e23073..287ea8e480b5 100644 > > > > --- a/drivers/vhost/vsock.c > > > > +++ b/drivers/vhost/vsock.c > > > > @@ -956,6 +956,7 @@ static void __exit vhost_vsock_exit(void) > > > > > > > > module_init(vhost_vsock_init); > > > > module_exit(vhost_vsock_exit); > > > > +MODULE_VERSION("0.0.1"); > > > > MODULE_LICENSE("GPL v2"); > > > > MODULE_AUTHOR("Asias He"); > > > > MODULE_DESCRIPTION("vhost transport for vsock "); > > > > -- > > > > 2.34.1 > > > >
diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c index 802153e23073..287ea8e480b5 100644 --- a/drivers/vhost/vsock.c +++ b/drivers/vhost/vsock.c @@ -956,6 +956,7 @@ static void __exit vhost_vsock_exit(void) module_init(vhost_vsock_init); module_exit(vhost_vsock_exit); +MODULE_VERSION("0.0.1"); MODULE_LICENSE("GPL v2"); MODULE_AUTHOR("Asias He"); MODULE_DESCRIPTION("vhost transport for vsock ");
Add an explicit MODULE_VERSION("0.0.1") specification for a vhost_vsock module. It is useful because it allows userspace to check if vhost_vsock is there when it is configured as a built-in. Without this change, there is no /sys/module/vhost_vsock directory. With this change: $ ls -la /sys/module/vhost_vsock/ total 0 drwxr-xr-x 2 root root 0 Sep 26 15:59 . drwxr-xr-x 100 root root 0 Sep 26 15:59 .. --w------- 1 root root 4096 Sep 26 15:59 uevent -r--r--r-- 1 root root 4096 Sep 26 15:59 version Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com> --- drivers/vhost/vsock.c | 1 + 1 file changed, 1 insertion(+)