Messages in this thread | | | Date | Tue, 8 Jun 2021 13:58:47 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v3 4/7] x86/sev-es: Run #VC handler in plain IRQ state |
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On Tue, Jun 08, 2021 at 11:54:36AM +0200, Joerg Roedel wrote: > From: Joerg Roedel <jroedel@suse.de> > > Use irqentry_enter() and irqentry_exit() to track the runtime state of > the #VC handler. The reason it ran in NMI mode was solely to make sure > nothing interrupts the handler while the GHCB is in use. > > This is handled now in sev_es_get/put_ghcb() directly, so there is no > reason the #VC handler can not run in normal IRQ mode and enjoy the > benefits like being able to send signals.
You sure?
So #VC cannot happen with IRQs disabled?
raw_spin_lock_irq(&my_lock); <#VC> raw_spin_lock_irqsave(&my_lock); // whoopsie
Every exception that can happen with IRQs disabled must be NMI like.
Again, what you seem to want is to split the handler in a from-user and from-kernel way, just like we did with #DB and MCE. See how exc_debug_user() is IRQ-like and can send signals, while exc_debug_kernel() is NMI like and can not.
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