Re: [RFC 03/12] KVM/VMX: Use the new host mapping API for virtual_apic_page

[Jim Mattson]

On Fri, Feb 9, 2018 at 4:15 AM, KarimAllah Ahmed <karahmed@xxxxxxxxxx> wrote:

> Can you elaborate a bit? I do not really understand what is the concern.

I can't find the posting that gave me this impression. The only thing
I can find is the following in Documentation/vm/highmem.txt:

 (*) kmap().  This permits a short duration mapping of a single page.  It needs
     global synchronization, but is amortized somewhat.  It is also prone to
     deadlocks when using in a nested fashion, and so it is not recommended for
     new code.

What constitutes a "short duration," and does this new usage qualify?