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

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Tue, Jun 08, 2021 at 11:54:36AM +0200, Joerg Roedel wrote:
> From: Joerg Roedel <jroedel@xxxxxxx>
> 
> 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.


_______________________________________________
Virtualization mailing list
Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linuxfoundation.org/mailman/listinfo/virtualization



[Index of Archives]     [KVM Development]     [Libvirt Development]     [Libvirt Users]     [CentOS Virtualization]     [Netdev]     [Ethernet Bridging]     [Linux Wireless]     [Kernel Newbies]     [Security]     [Linux for Hams]     [Netfilter]     [Bugtraq]     [Yosemite Forum]     [MIPS Linux]     [ARM Linux]     [Linux RAID]     [Linux Admin]     [Samba]

  Powered by Linux