[PATCH 19/30] panic: Add the panic hypervisor notifier list

2022-04-28 Thread Guilherme G. Piccoli
The goal of this new panic notifier is to allow its users to register callbacks to run very early in the panic path. This aims hypervisor/FW notification mechanisms as well as simple LED functions, and any other simple and safe mechanism that should run early in the panic path; more dangerous callb

Re: [PATCH 19/30] panic: Add the panic hypervisor notifier list

2022-05-18 Thread Guilherme G. Piccoli
On 18/05/2022 04:38, Petr Mladek wrote: > [...] > I have answered this in more detail in the other reply, see > https://lore.kernel.org/r/YoShZVYNAdvvjb7z@alley > > I agree that both notifiers in > > drivers/soc/bcm/brcmstb/pm/pm-arm.c > drivers/firmware/google/gsmi.c > > better fit into

Re: [PATCH 19/30] panic: Add the panic hypervisor notifier list

2022-05-18 Thread Guilherme G. Piccoli
On 18/05/2022 04:58, Petr Mladek wrote: > [...] >> I does similar things like kmsg_dump() so it should be called in >> the same location (after info notifier list and before kdump). >> >> A solution might be to put it at these notifiers at the very >> end of the "info" list or make extra "dump" not

Re: [PATCH 19/30] panic: Add the panic hypervisor notifier list

2022-05-18 Thread Guilherme G. Piccoli
On 18/05/2022 04:33, Petr Mladek wrote: > [...] > Anyway, I would distinguish it the following way. > > + If the notifier is preserving kernel log then it should be ideally > treated as kmsg_dump(). > > + It the notifier is saving another debugging data then it better > fits into the

Re: [PATCH 19/30] panic: Add the panic hypervisor notifier list

2022-05-22 Thread Guilherme G. Piccoli
On 19/05/2022 04:03, Petr Mladek wrote: > [...] > I would ignore it for now. If anyone would want to safe the log > then they would need to read it. They will most likely use > the existing kmsg_dump() infastructure. In fact, they should > use it to avoid a code duplication. > > Best Regards, > Pe

Re: [PATCH 19/30] panic: Add the panic hypervisor notifier list

2022-05-22 Thread Guilherme G. Piccoli
On 18/05/2022 19:17, Scott Branden wrote: > Hi Guilherme, > > +Desmond > [...] I'm afraid it breaks kdump if this device is not reset beforehand - it's a doorbell write, so not high risk I think... But in case the not-reset device can be probed normally in kdump kernel, t

Re: [PATCH 19/30] panic: Add the panic hypervisor notifier list

2022-05-24 Thread Guilherme G. Piccoli
On 19/05/2022 16:20, Scott Branden wrote: > [...] >> Hi Scott / Desmond, thanks for the detailed answer! Is this adapter >> designed to run in x86 only or you have other architectures' use cases? > The adapter may be used in any PCIe design that supports DMA. > So it may be possible to run in arm6

Re: [PATCH 19/30] panic: Add the panic hypervisor notifier list

2022-04-30 Thread Guilherme G. Piccoli
On 29/04/2022 14:30, Michael Kelley (LINUX) wrote: > From: Guilherme G. Piccoli Sent: Wednesday, April 27, > 2022 3:49 PM >> [...] >> >> @@ -2843,7 +2843,7 @@ static void __exit vmbus_exit(void) >> if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) { >> kmsg_dum

Re: [PATCH 19/30] panic: Add the panic hypervisor notifier list

2022-05-09 Thread Guilherme G. Piccoli
On 03/05/2022 14:44, Michael Kelley (LINUX) wrote: > [...] >> >> Hi Michael, thanks for your feedback! I agree that your idea could work, >> but...there is one downside: imagine the kmsg_dump() approach is not set >> in some Hyper-V guest, then we would rely in the regular notification >> mechanism

Re: [PATCH 19/30] panic: Add the panic hypervisor notifier list

2022-05-17 Thread Guilherme G. Piccoli
Thanks for the review! I agree with the blinking stuff, I can rework and add all LED/blinking stuff into the loop list, it does make sense. I'll comment a bit in the others below... On 16/05/2022 11:01, Petr Mladek wrote: > [...] >> --- a/arch/mips/sgi-ip22/ip22-reset.c >> +++ b/arch/mips/sgi-ip2

Re: [PATCH 19/30] panic: Add the panic hypervisor notifier list

2022-05-17 Thread Evan Green
On Mon, May 16, 2022 at 8:07 AM Guilherme G. Piccoli wrote: > > Thanks for the review! > > I agree with the blinking stuff, I can rework and add all LED/blinking > stuff into the loop list, it does make sense. I'll comment a bit in the > others below... > > On 16/05/2022 11:01, Petr Mladek wrote:

Re: [PATCH 19/30] panic: Add the panic hypervisor notifier list

2022-05-17 Thread Guilherme G. Piccoli
On 17/05/2022 10:28, Petr Mladek wrote: > [...] >>> Disagree here. I'm looping Google maintainers, so they can comment. >>> (CCed Evan, David, Julius) >>> >>> This notifier is clearly a hypervisor notification mechanism. I've fixed >>> a locking stuff there (in previous patch), I feel it's low-risk

Re: [PATCH 19/30] panic: Add the panic hypervisor notifier list

2022-05-17 Thread Guilherme G. Piccoli
On 17/05/2022 10:57, Petr Mladek wrote: > [...] --- a/drivers/misc/bcm-vk/bcm_vk_dev.c +++ b/drivers/misc/bcm-vk/bcm_vk_dev.c @@ -1446,7 +1446,7 @@ static int bcm_vk_probe(struct pci_dev *pdev, const struct pci_device_id *ent) >>> [... snip ...] >>> It seems to reset some hardw