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

Re: [Xen-devel] [PATCH v2 4/6] x86: track when in #NMI context

  • To: Roger Pau Monne <roger.pau@xxxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxxx>
  • From: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
  • Date: Tue, 18 Feb 2020 10:40:02 +0000
  • Authentication-results: esa6.hc3370-68.iphmx.com; dkim=none (message not signed) header.i=none; spf=None smtp.pra=andrew.cooper3@xxxxxxxxxx; spf=Pass smtp.mailfrom=Andrew.Cooper3@xxxxxxxxxx; spf=None smtp.helo=postmaster@xxxxxxxxxxxxxxx
  • Cc: Wei Liu <wl@xxxxxxx>, Jan Beulich <jbeulich@xxxxxxxx>
  • Delivery-date: Tue, 18 Feb 2020 10:40:16 +0000
  • Ironport-sdr: JdSxOj/M7kVVoMOBSxdvuBuLvnsdUP6FY1uY3p7ZW0XVvspbhqgSB+NSEpowsmhic2DsFurDjq 5w6F9hEw6SF+zp4/6v+9BlAq7y1taOW90B5hgv8B1DJv/J6Ct5BsasNR1c57vxuJUL2Y/2lt1Q HixBBQIYldcpFvzvmfdrYVXXOu6PPCL38lot/VxdyXb9ug7OxNTPKVPWxmdh4zZezzYLkOqyYN FTqsL/DWc8tEyX5ysQ9+6eiuop/T32jAqlO4jrts0054QZ+Ru36Gtv1C8viEVMb7PD+Q9D6iFY BWE=
  • List-id: Xen developer discussion <xen-devel.lists.xenproject.org>

On 17/02/2020 18:43, Roger Pau Monne wrote:
> Add helpers to track when running in #MC context. This is modeled
> after the in_irq helpers, but does not support reentry.
> Note that there are no users of in_mc() introduced by the change,
> further users will be added by followup changes.
> Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>

You probably mean s/mc/nmi/ throughout the commit message, but I'm
afraid these are rather problematic.

NMIs can be recursively entered, especially on corner cases in the crash
path.  Asserting that the crash path is not recursive can lead to never
entering the crash kernel.


Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.