On 2024/3/15 18:27, Jan Karcher wrote:
On 15/03/2024 04:44, Wen Gu wrote:
On 2024/3/14 18:23, Jan Karcher wrote:
On 12/03/2024 15:27, Wen Gu wrote:
The introduction of Emulated-ISM requires adaptation of SMC-D device
dump. Software implemented non-PCI device (loopback-ism) should be
handled correctly and the CHID reserved for Emulated-ISM should be got
from smcd_ops interface instead of PCI information.
Signed-off-by: Wen Gu <guwen@xxxxxxxxxxxxxxxxx>
---
net/smc/smc_ism.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/net/smc/smc_ism.c b/net/smc/smc_ism.c
index ac88de2a06a0..b6eca4231913 100644
--- a/net/smc/smc_ism.c
+++ b/net/smc/smc_ism.c
@@ -252,12 +252,11 @@ static int smc_nl_handle_smcd_dev(struct smcd_dev *smcd,
char smc_pnet[SMC_MAX_PNETID_LEN + 1];
struct smc_pci_dev smc_pci_dev;
struct nlattr *port_attrs;
+ struct device *device;
struct nlattr *attrs;
- struct ism_dev *ism;
int use_cnt = 0;
void *nlh;
- ism = smcd->priv;
nlh = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
&smc_gen_nl_family, NLM_F_MULTI,
SMC_NETLINK_GET_DEV_SMCD);
@@ -272,7 +271,15 @@ static int smc_nl_handle_smcd_dev(struct smcd_dev *smcd,
if (nla_put_u8(skb, SMC_NLA_DEV_IS_CRIT, use_cnt > 0))
goto errattr;
memset(&smc_pci_dev, 0, sizeof(smc_pci_dev));
- smc_set_pci_values(to_pci_dev(ism->dev.parent), &smc_pci_dev);
+ device = smcd->ops->get_dev(smcd);
+ if (device->parent)
+ smc_set_pci_values(to_pci_dev(device->parent), &smc_pci_dev);
+ if (smc_ism_is_emulated(smcd)) {
+ smc_pci_dev.pci_pchid = smc_ism_get_chid(smcd);
+ if (!device->parent)
+ snprintf(smc_pci_dev.pci_id, sizeof(smc_pci_dev.pci_id),
+ "%s", dev_name(device));
+ }
Hi Wen Gu,
playing around with the loopback-ism device and testing it, i developed some concerns regarding this exposure.
Basically this enables us to see the loopback device in the `smcd device` tool without any changes.
E.g.:
```
# smcd device
FID Type PCI-ID PCHID InUse #LGs PNET-ID
0000 0 loopback-ism ffff No 0
102a ISM 0000:00:00.0 07c2 No 0 NET1
```
Now the problem with this is that "loopback-ism" is no valid PCI-ID and should not be there. My first thought was to
put an "n/a" instead, but that opens up another problem. Currently you could set - even if it does not make sense - a
PNET_ID for the loopback device:
```
Yes, and we can exclude loopback-ism in smc_pnet_enter() if necessary.
We could, but we have to make sure we implement those distinctions at the right location. E.g.: if virtio-ism is coming.
Does a PNETID make sense for a virtio-ism device? Do we want to exclude is also there or do we want an abstracted
layer/mechanism to recognize if a device has a PNETId capability or not?
Understand, a long-term view is better.
# smc_pnet -a -D loopback-ism NET1
# smcd device
FID Type PCI-ID PCHID InUse #LGs PNET-ID
0000 0 loopback-ism ffff No 0 *NET1
102a ISM 0000:00:00.0 07c2 No 0 NET1
```
If we would change the PCI-ID to "n/a" it would be a valid input parameter for the tooling which is... to put it
nice... not so beautiful.
FID Type PCI-ID PCHID InUse #LGs PNET-ID
0000 0 n/a ffff No 0
IIUC, the problem is that the 'n/a', which would be an input for other tools, is somewhat strange?
Exactly.
Since PCHID 0xffff is clear defined for loopback-ism, I am wondering if it can be a specific sign
of loopback-ism for tooling to not take PCI-ID into account? Would you also consider that inelegant?
I think deciding on PCHID is the only way we can currently differentiate what kind of device we are talking about. So my
guess would be that PCHID is going to play a big role in future design decisions.
Make sense to me.
I brainstormed this with them team and the problem is more complex.
In theory there shouldn't be PCI information set for the loopback device. There should be a better abstraction in the
netlink interface that creates this output and the tooling should be made aware of it.
Yes, it is better. But I couldn't surely picture how the abstraction looks like, and if it is necessary
to introduce it just for a special case of loopback-ism (note that virtio-ISM also has PCI information),
since we can identify loopback-ism by CHID.
Please take the following with a grain of salt. I just want to give you a bit insight of our current train of thought.
None of it is final or set in stone. The idea would be to have device core information that contain the information
which other fields are important for this device. And corresponding "extensions" that contain the information. The
tooling cvould then decide soley on the core information which features are supported by a device and which are not.
If that is really needed: Not sure yet. Is this the best solution: Propably not.
E.g.:
SMC-D netlink abstraction
+------------------------------------+
| Core information |
| (e.g. PCHID, InUse, isPCI, isS390) |
+------------------------------------+
+----------------+
| s390 extension |
| (e.g.FID) |
+----------------+
+--------------------+
| PCI extension |
| (e.g. PCI-ID, ...) |
+--------------------+
I like this diagram and it is very clear. So core information will be applicable to all ISM devices,
and the extension information will be specific to some certain kinds.
Do you rely on the output currently? What are your thoughts about it?
If not I'd ask you to not fill the netlink interface for the loopback device and refactor it with the next stage when
we create a right interface for it.
Currently we don't rely on the output, and I have no objection to the proposal that not fill the netlink
interface for loopback-ism and refactor it in the next stage.
Thank you! If you have ideas regarding the design of the interface hit us up. As soon as we are going to think about
this further I'm going to invite you to those discussions.
Sure! and thank you very much!
Best regards,
Wen Gu
>>> Since the Merge-Window is closed feel free to send new versions as RFC.
OK, I will send the new version as an RFC.
Thank you!
Thanks!
- Jan
Thank you
- Jan
if (nla_put_u32(skb, SMC_NLA_DEV_PCI_FID, smc_pci_dev.pci_fid))
goto errattr;
if (nla_put_u16(skb, SMC_NLA_DEV_PCI_CHID, smc_pci_dev.pci_pchid))
