Following the recommendation in virio spec 1.1, a device offering
VIRTIO_NET_F_MTU should set the mtu to at least 1280 bytes.
Print a warning if this recommendation is not met.
Signed-off-by: Eli Cohen <[email protected]>
---
v0 -> v1:
chage pr_warn to netlink warning to userspace
drivers/vdpa/vdpa.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index 91f4c13c7c7c..0fb4a615f267 100644
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c
@@ -583,6 +583,9 @@ vdpa_nl_cmd_mgmtdev_get_dumpit(struct sk_buff *msg, struct netlink_callback *cb)
BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MTU) | \
BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MAX_VQP))
+/* Recommended virtio spec 1.1 section 5.1.4.1 */
+#define VIRTIO_MIN_PREFERRED_MTU 1280
+
static int vdpa_nl_cmd_dev_add_set_doit(struct sk_buff *skb, struct genl_info *info)
{
struct vdpa_dev_set_config config = {};
@@ -634,6 +637,10 @@ static int vdpa_nl_cmd_dev_add_set_doit(struct sk_buff *skb, struct genl_info *i
err = PTR_ERR(mdev);
goto err;
}
+ if ((mdev->supported_features & BIT_ULL(VIRTIO_NET_F_MTU)) &&
+ (config.mask & BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MTU) &&
+ config.net.mtu < VIRTIO_MIN_PREFERRED_MTU))
+ NL_SET_ERR_MSG_MOD(info->extack, "MTU is below recommended value\n");
if ((config.mask & mdev->config_attr_mask) != config.mask) {
NL_SET_ERR_MSG_MOD(info->extack,
"All provided attributes are not supported");
@@ -1135,7 +1142,7 @@ static const struct nla_policy vdpa_nl_policy[VDPA_ATTR_MAX + 1] = {
[VDPA_ATTR_DEV_NAME] = { .type = NLA_STRING },
[VDPA_ATTR_DEV_NET_CFG_MACADDR] = NLA_POLICY_ETH_ADDR,
/* virtio spec 1.1 section 5.1.4.1 for valid MTU range */
- [VDPA_ATTR_DEV_NET_CFG_MTU] = NLA_POLICY_MIN(NLA_U16, 68),
+ [VDPA_ATTR_DEV_NET_CFG_MTU] = NLA_POLICY_MIN(NLA_U16, ETH_MIN_MTU),
};
static const struct genl_ops vdpa_nl_ops[] = {
--
2.35.1
On Wed, May 11, 2022 at 6:56 PM Eli Cohen <[email protected]> wrote:
>
> Following the recommendation in virio spec 1.1, a device offering
> VIRTIO_NET_F_MTU should set the mtu to at least 1280 bytes.
>
> Print a warning if this recommendation is not met.
>
> Signed-off-by: Eli Cohen <[email protected]>
> ---
> v0 -> v1:
> chage pr_warn to netlink warning to userspace
>
> drivers/vdpa/vdpa.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
> index 91f4c13c7c7c..0fb4a615f267 100644
> --- a/drivers/vdpa/vdpa.c
> +++ b/drivers/vdpa/vdpa.c
> @@ -583,6 +583,9 @@ vdpa_nl_cmd_mgmtdev_get_dumpit(struct sk_buff *msg, struct netlink_callback *cb)
> BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MTU) | \
> BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MAX_VQP))
>
> +/* Recommended virtio spec 1.1 section 5.1.4.1 */
> +#define VIRTIO_MIN_PREFERRED_MTU 1280
> +
> static int vdpa_nl_cmd_dev_add_set_doit(struct sk_buff *skb, struct genl_info *info)
> {
> struct vdpa_dev_set_config config = {};
> @@ -634,6 +637,10 @@ static int vdpa_nl_cmd_dev_add_set_doit(struct sk_buff *skb, struct genl_info *i
> err = PTR_ERR(mdev);
> goto err;
> }
> + if ((mdev->supported_features & BIT_ULL(VIRTIO_NET_F_MTU)) &&
> + (config.mask & BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MTU) &&
> + config.net.mtu < VIRTIO_MIN_PREFERRED_MTU))
> + NL_SET_ERR_MSG_MOD(info->extack, "MTU is below recommended value\n");
Can this function be used for warning? I have a quick cscope that
tells me it's probably used only for error.
Will it be better if we fail only when the device supports VERSION_1?
Thanks
> if ((config.mask & mdev->config_attr_mask) != config.mask) {
> NL_SET_ERR_MSG_MOD(info->extack,
> "All provided attributes are not supported");
> @@ -1135,7 +1142,7 @@ static const struct nla_policy vdpa_nl_policy[VDPA_ATTR_MAX + 1] = {
> [VDPA_ATTR_DEV_NAME] = { .type = NLA_STRING },
> [VDPA_ATTR_DEV_NET_CFG_MACADDR] = NLA_POLICY_ETH_ADDR,
> /* virtio spec 1.1 section 5.1.4.1 for valid MTU range */
> - [VDPA_ATTR_DEV_NET_CFG_MTU] = NLA_POLICY_MIN(NLA_U16, 68),
> + [VDPA_ATTR_DEV_NET_CFG_MTU] = NLA_POLICY_MIN(NLA_U16, ETH_MIN_MTU),
> };
>
> static const struct genl_ops vdpa_nl_ops[] = {
> --
> 2.35.1
>
> -----Original Message-----
> From: Michael S. Tsirkin <[email protected]>
> Sent: Thursday, May 12, 2022 8:57 AM
> To: Eli Cohen <[email protected]>
> Cc: [email protected]; [email protected]; [email protected]; [email protected]
> Subject: Re: [PATCH v1] vdpa: Warn if MTU configured is too low
>
> On Wed, May 11, 2022 at 01:56:42PM +0300, Eli Cohen wrote:
> > Following the recommendation in virio spec 1.1, a device offering
> > VIRTIO_NET_F_MTU should set the mtu to at least 1280 bytes.
> >
> > Print a warning if this recommendation is not met.
> >
> > Signed-off-by: Eli Cohen <[email protected]>
> > ---
> > v0 -> v1:
> > chage pr_warn to netlink warning to userspace
> >
> > drivers/vdpa/vdpa.c | 9 ++++++++-
> > 1 file changed, 8 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
> > index 91f4c13c7c7c..0fb4a615f267 100644
> > --- a/drivers/vdpa/vdpa.c
> > +++ b/drivers/vdpa/vdpa.c
> > @@ -583,6 +583,9 @@ vdpa_nl_cmd_mgmtdev_get_dumpit(struct sk_buff *msg, struct netlink_callback *cb)
> > BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MTU) | \
> > BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MAX_VQP))
> >
> > +/* Recommended virtio spec 1.1 section 5.1.4.1 */
>
> I'd add name of section here too.
Sure
>
> > +#define VIRTIO_MIN_PREFERRED_MTU 1280
> > +
>
> Preferred is kind of confusing here. I guess you are trying to
> say it's not mandatory but I don't think this conveys this information.
>
> Recommended (matching text below)?
Will modify
>
>
> > static int vdpa_nl_cmd_dev_add_set_doit(struct sk_buff *skb, struct genl_info *info)
> > {
> > struct vdpa_dev_set_config config = {};
> > @@ -634,6 +637,10 @@ static int vdpa_nl_cmd_dev_add_set_doit(struct sk_buff *skb, struct genl_info *i
> > err = PTR_ERR(mdev);
> > goto err;
> > }
> > + if ((mdev->supported_features & BIT_ULL(VIRTIO_NET_F_MTU)) &&
> > + (config.mask & BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MTU) &&
> > + config.net.mtu < VIRTIO_MIN_PREFERRED_MTU))
> > + NL_SET_ERR_MSG_MOD(info->extack, "MTU is below recommended value\n");
> > if ((config.mask & mdev->config_attr_mask) != config.mask) {
> > NL_SET_ERR_MSG_MOD(info->extack,
> > "All provided attributes are not supported");
>
>
> Pity we can't include the actual value here, but oh well. At least let's
> include the recommended value, we can do that:
> "MTU is below recommended value of " __stringify(VIRTIO_MIN_PREFERRED_MTU) "\n"
>
Will change
>
> > @@ -1135,7 +1142,7 @@ static const struct nla_policy vdpa_nl_policy[VDPA_ATTR_MAX + 1] = {
> > [VDPA_ATTR_DEV_NAME] = { .type = NLA_STRING },
> > [VDPA_ATTR_DEV_NET_CFG_MACADDR] = NLA_POLICY_ETH_ADDR,
> > /* virtio spec 1.1 section 5.1.4.1 for valid MTU range */
> > - [VDPA_ATTR_DEV_NET_CFG_MTU] = NLA_POLICY_MIN(NLA_U16, 68),
> > + [VDPA_ATTR_DEV_NET_CFG_MTU] = NLA_POLICY_MIN(NLA_U16, ETH_MIN_MTU),
> > };
> >
> > static const struct genl_ops vdpa_nl_ops[] = {
> > --
> > 2.35.1
> -----Original Message-----
> From: Jason Wang <[email protected]>
> Sent: Thursday, May 12, 2022 7:17 AM
> To: Eli Cohen <[email protected]>
> Cc: mst <[email protected]>; virtualization <[email protected]>; linux-kernel <[email protected]>; Si-
> Wei Liu <[email protected]>
> Subject: Re: [PATCH v1] vdpa: Warn if MTU configured is too low
>
> On Wed, May 11, 2022 at 6:56 PM Eli Cohen <[email protected]> wrote:
> >
> > Following the recommendation in virio spec 1.1, a device offering
> > VIRTIO_NET_F_MTU should set the mtu to at least 1280 bytes.
> >
> > Print a warning if this recommendation is not met.
> >
> > Signed-off-by: Eli Cohen <[email protected]>
> > ---
> > v0 -> v1:
> > chage pr_warn to netlink warning to userspace
> >
> > drivers/vdpa/vdpa.c | 9 ++++++++-
> > 1 file changed, 8 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
> > index 91f4c13c7c7c..0fb4a615f267 100644
> > --- a/drivers/vdpa/vdpa.c
> > +++ b/drivers/vdpa/vdpa.c
> > @@ -583,6 +583,9 @@ vdpa_nl_cmd_mgmtdev_get_dumpit(struct sk_buff *msg, struct netlink_callback *cb)
> > BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MTU) | \
> > BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MAX_VQP))
> >
> > +/* Recommended virtio spec 1.1 section 5.1.4.1 */
> > +#define VIRTIO_MIN_PREFERRED_MTU 1280
> > +
> > static int vdpa_nl_cmd_dev_add_set_doit(struct sk_buff *skb, struct genl_info *info)
> > {
> > struct vdpa_dev_set_config config = {};
> > @@ -634,6 +637,10 @@ static int vdpa_nl_cmd_dev_add_set_doit(struct sk_buff *skb, struct genl_info *i
> > err = PTR_ERR(mdev);
> > goto err;
> > }
> > + if ((mdev->supported_features & BIT_ULL(VIRTIO_NET_F_MTU)) &&
> > + (config.mask & BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MTU) &&
> > + config.net.mtu < VIRTIO_MIN_PREFERRED_MTU))
> > + NL_SET_ERR_MSG_MOD(info->extack, "MTU is below recommended value\n");
>
> Can this function be used for warning? I have a quick cscope that
> tells me it's probably used only for error.
Here's what I get:
# vdpa dev add name vdpa-a mgmtdev auxiliary/mlx5_core.sf.1 mtu 1279
Warning: vdpa: MTU is below recommended value
The vdpa device is created fine.
>
> Will it be better if we fail only when the device supports VERSION_1?
>
Why?
> Thanks
>
> > if ((config.mask & mdev->config_attr_mask) != config.mask) {
> > NL_SET_ERR_MSG_MOD(info->extack,
> > "All provided attributes are not supported");
> > @@ -1135,7 +1142,7 @@ static const struct nla_policy vdpa_nl_policy[VDPA_ATTR_MAX + 1] = {
> > [VDPA_ATTR_DEV_NAME] = { .type = NLA_STRING },
> > [VDPA_ATTR_DEV_NET_CFG_MACADDR] = NLA_POLICY_ETH_ADDR,
> > /* virtio spec 1.1 section 5.1.4.1 for valid MTU range */
> > - [VDPA_ATTR_DEV_NET_CFG_MTU] = NLA_POLICY_MIN(NLA_U16, 68),
> > + [VDPA_ATTR_DEV_NET_CFG_MTU] = NLA_POLICY_MIN(NLA_U16, ETH_MIN_MTU),
> > };
> >
> > static const struct genl_ops vdpa_nl_ops[] = {
> > --
> > 2.35.1
> >
On Wed, May 11, 2022 at 01:56:42PM +0300, Eli Cohen wrote:
> Following the recommendation in virio spec 1.1, a device offering
> VIRTIO_NET_F_MTU should set the mtu to at least 1280 bytes.
>
> Print a warning if this recommendation is not met.
>
> Signed-off-by: Eli Cohen <[email protected]>
> ---
> v0 -> v1:
> chage pr_warn to netlink warning to userspace
>
> drivers/vdpa/vdpa.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
> index 91f4c13c7c7c..0fb4a615f267 100644
> --- a/drivers/vdpa/vdpa.c
> +++ b/drivers/vdpa/vdpa.c
> @@ -583,6 +583,9 @@ vdpa_nl_cmd_mgmtdev_get_dumpit(struct sk_buff *msg, struct netlink_callback *cb)
> BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MTU) | \
> BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MAX_VQP))
>
> +/* Recommended virtio spec 1.1 section 5.1.4.1 */
I'd add name of section here too.
> +#define VIRTIO_MIN_PREFERRED_MTU 1280
> +
Preferred is kind of confusing here. I guess you are trying to
say it's not mandatory but I don't think this conveys this information.
Recommended (matching text below)?
> static int vdpa_nl_cmd_dev_add_set_doit(struct sk_buff *skb, struct genl_info *info)
> {
> struct vdpa_dev_set_config config = {};
> @@ -634,6 +637,10 @@ static int vdpa_nl_cmd_dev_add_set_doit(struct sk_buff *skb, struct genl_info *i
> err = PTR_ERR(mdev);
> goto err;
> }
> + if ((mdev->supported_features & BIT_ULL(VIRTIO_NET_F_MTU)) &&
> + (config.mask & BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MTU) &&
> + config.net.mtu < VIRTIO_MIN_PREFERRED_MTU))
> + NL_SET_ERR_MSG_MOD(info->extack, "MTU is below recommended value\n");
> if ((config.mask & mdev->config_attr_mask) != config.mask) {
> NL_SET_ERR_MSG_MOD(info->extack,
> "All provided attributes are not supported");
Pity we can't include the actual value here, but oh well. At least let's
include the recommended value, we can do that:
"MTU is below recommended value of " __stringify(VIRTIO_MIN_PREFERRED_MTU) "\n"
> @@ -1135,7 +1142,7 @@ static const struct nla_policy vdpa_nl_policy[VDPA_ATTR_MAX + 1] = {
> [VDPA_ATTR_DEV_NAME] = { .type = NLA_STRING },
> [VDPA_ATTR_DEV_NET_CFG_MACADDR] = NLA_POLICY_ETH_ADDR,
> /* virtio spec 1.1 section 5.1.4.1 for valid MTU range */
> - [VDPA_ATTR_DEV_NET_CFG_MTU] = NLA_POLICY_MIN(NLA_U16, 68),
> + [VDPA_ATTR_DEV_NET_CFG_MTU] = NLA_POLICY_MIN(NLA_U16, ETH_MIN_MTU),
> };
>
> static const struct genl_ops vdpa_nl_ops[] = {
> --
> 2.35.1