From: Paolo Bonzini Date: Thu, 27 Mar 2014 08:51:52 +0000 (+0100) Subject: KVM: vmx: speed up emulation of invalid guest state X-Git-Tag: omap-for-v3.17/fixes-against-rc2~184^2~42 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=98eb2f8b145cee711984d42eff5d6f19b6b1df69;p=pandora-kernel.git KVM: vmx: speed up emulation of invalid guest state About 25% of the time spent in emulation of invalid guest state is wasted in checking whether emulation is required for the next instruction. However, this almost never changes except when a segment register (or TR or LDTR) changes, or when there is a mode transition (i.e. CR0 changes). In fact, vmx_set_segment and vmx_set_cr0 already modify vmx->emulation_required (except that the former for some reason uses |= instead of just an assignment). So there is no need to call guest_state_valid in the emulation loop. Emulation performance test results indicate 1650-2600 cycles for common instructions, versus 2300-3200 before this patch on a Sandy Bridge Xeon. Signed-off-by: Paolo Bonzini --- Reading git-diff-tree failed