Re: [PATCH v3 4/7] x86/sev-es: Run #VC handler in plain IRQ state

From: Joerg Roedel
Date: Tue Jun 08 2021 - 09:25:57 EST

Hi Peter,

On Tue, Jun 08, 2021 at 01:58:47PM +0200, Peter Zijlstra wrote:
> 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.

You are right, thanks for pointing this out. I replaced that patch by
one implementing the split in a from-user and from-kernel part. Initial
testing looks good, will send it out later this week.