From: Paolo Bonzini <pbonzini@redhat.com>
Date: Tue, 13 May 2014 12:02:13 +0000 (+0200)
Subject: KVM: x86: use kvm_read_guest_page for emulator accesses
X-Git-Tag: omap-for-v3.17/fixes-against-rc2~184^2~24
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=44583cba9188b29b20ceeefe8ae23ad19e26d9a4;p=pandora-kernel.git

KVM: x86: use kvm_read_guest_page for emulator accesses

Emulator accesses are always done a page at a time, either by the emulator
itself (for fetches) or because we need to query the MMU for address
translations.  Speed up these accesses by using kvm_read_guest_page
and, in the case of fetches, by inlining kvm_read_guest_virt_helper and
dropping the loop around kvm_read_guest_page.

This final tweak saves 30-100 more clock cycles (4-10%), bringing the
count (as measured by kvm-unit-tests) down to 720-1100 clock cycles on
a Sandy Bridge Xeon host, compared to 2300-3200 before the whole series
and 925-1700 after the first two low-hanging fruit changes.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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