Messages in this thread | | | Date | Wed, 28 Sep 2022 15:43:56 +0200 | From | Juergen Gross <> | Subject | Re: [PATCH v3 08/10] x86/mtrr: let cache_aps_delayed_init replace mtrr_aps_delayed_init |
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On 28.09.22 13:22, Borislav Petkov wrote: > On Wed, Sep 28, 2022 at 01:14:11PM +0200, Juergen Gross wrote: >> No, we don't. >> >> Using basically your patch, but with >> >> + mtrr_online = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, >> + "x86/mtrr:online", >> + mtrr_ap_init, NULL); >> >> moved to the end of mtrr_aps_init(), and: >> >> +void mtrr_aps_thaw(void) >> +{ >> + cpuhp_remove_state_nocalls(mtrr_online); >> +} > > Yes, so you said. I'm not sure I like this toggling of notifier > registration like that.
Yeah, especially with having to remember the slot.
Would you feel better with adding a new enum member CPUHP_AP_CACHECTRL_ONLINE?
This would avoid a possible source of failure during resume in case no slot for CPUHP_AP_ONLINE_DYN is found (quite improbable, but in theory possible).
> Optimally, I'd like to be able to query the suspend code whether it is > in the process of resuming. > > This here: > > > static int resume_target_kernel(bool platform_mode) > { > > ... > > Enable_irqs: > system_state = SYSTEM_RUNNING; > local_irq_enable(); > > Enable_cpus: > pm_sleep_enable_secondary_cpus(); > > > but being able to do: > > pm_sleep_enable_secondary_cpus(); > system_state = SYSTEM_RUNNING | SYSTEM_RUNNING_APS_UP; > > which can't work, obviously. But something like that. >
You wouldn't want to do that there, as there are multiple places where pm_sleep_enable_secondary_cpus() is being called. Additionally not all cases are coming in via pm_sleep_enable_secondary_cpus(), as there is e.g. a call of suspend_enable_secondary_cpus() from kernel_kexec(), which wants to have the same handling.
arch_thaw_secondary_cpus_begin() and arch_thaw_secondary_cpus_end() are the functions to mark start and end of the special region where the delayed MTRR setup should happen.
Juergen [unhandled content-type:application/pgp-keys][unhandled content-type:application/pgp-signature] | |