Messages in this thread | | | From | Andy Lutomirski <> | Date | Thu, 21 Mar 2019 11:39:47 -0700 | Subject | Re: [RFC][PATCH] tracing/x86: Save CR2 before tracing irqsoff on error_entry |
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On Thu, Mar 21, 2019 at 11:37 AM Peter Zijlstra <peterz@infradead.org> wrote: > > On Thu, Mar 21, 2019 at 11:25:44AM -0700, Linus Torvalds wrote: > > On Thu, Mar 21, 2019 at 11:21 AM Andy Lutomirski <luto@kernel.org> wrote: > > > > > > I dunno. Lots of people at least use to have serious commercial interest in it. > > > > Yes, it used to be a big deal. But full virtualization has gotten a > > lot more common and better. > > > > > Hey Xen folks, how close are we to being able to say "if you want to > > > run a new kernel, you need to switch to PVH or similar"? > > > > I'd also like to know if we could perhaps at least limit PV to just > > the thing that people care most deeply about. > > > > For example, maybe people notice that they really deeply care about > > the PV spinlocks because they help a lot for some loads, but don't > > care so much about the low-level CPU PV stuff any more because modern > > CPUs do _those_ things so well these days. > > > > So it might not be an all-or-nothing thing, but a gradual "let's stop > > supporting xyz under PV, because it causes pain and isn't worth it". > > So Juergen recently introduced PARAVIRT_XXL, which are exactly those > bits of PV we can get rid of. > > This paravirt-me-harder config does indeed include the CR2 bits. > > I recently talked to Andrew Cooper about this, and he said Xen Dom0 > still needs all this :/
There were patches from last year to fix that:
https://lwn.net/Articles/753982/
I have no clue what the status is.
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