Re: [PATCH] KVM: Only display message about bios support disabled once

[Mario Limonciello]

On 5/27/22 11:08, Sean Christopherson wrote:
> On Thu, May 26, 2022, Mario Limonciello wrote:
> > On an OEM laptop I see the following message 10 times in my dmesg:
> > "kvm: support for 'kvm_amd' disabled by bios"
> >
> > This might be useful the first time, but there really isn't a point
> > to showing the error 9 more times.  The BIOS still has it disabled.
> > Change the message to only display one time.
>
> NAK, this has been discussed multiple times in the past[1][2], there are edge cases
> where logging multiple messages is desirable.  Even using a ratelimited printk is
> essentially a workaround for a systemd bug[3], which I'm guessing is the cuplrit here.
>
> [1] https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fall%2F20190826182320.9089-1-tony.luck%40intel.com&data=05%7C01%7Cmario.limonciello%40amd.com%7C2e1eed66ff8a412cec0508da3ffb1c1b%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637892645000687319%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=X3Hs2QwXLsgAEEQkP7WMniywwoCn065sVh8DFagYzLE%3D&reserved=0
> [2] https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fall%2F20200214143035.607115-1-e.velu%40criteo.com&data=05%7C01%7Cmario.limonciello%40amd.com%7C2e1eed66ff8a412cec0508da3ffb1c1b%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637892645000687319%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=EMe2b9Mu7Pc9Z%2FcBmTPZaChUaDlQD%2FKGwK%2BYM%2Fd1VUY%3D&reserved=0
> [3] https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fsystemd%2Fsystemd%2Fissues%2F14906&data=05%7C01%7Cmario.limonciello%40amd.com%7C2e1eed66ff8a412cec0508da3ffb1c1b%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637892645000687319%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=8fMPC1Opl85BmqqoPJ4ASI6Y58h%2BuTM5oFDS76bqPv0%3D&reserved=0

Sean,

Appreciate the pointer at those earlier threads and the userspace issue.

Yes; it's certainly caused by systemd.  I can reproduce another 10 
entries just like the last link via `udevadm trigger --type=devices 
--action=add`.  I'm on a more modern version of systemd (249.11) so even 
though it was claimed to be fixed previously it resurfaced.  I'll leave 
a comment with systemd accordingly.

Thanks,