Paolo Bonzini 74a497fae7 KVM: nVMX: track dirty state of non-shadowed VMCS fields
VMCS12 fields that are not handled through shadow VMCS are rarely
written, and thus they are also almost constant in the vmcs02.  We can
thus optimize prepare_vmcs02 by skipping all the work for non-shadowed
fields in the common case.

This patch introduces the (pretty simple) tracking infrastructure; the
next patches will move work to prepare_vmcs02_full and save a few hundred
clock cycles per VMRESUME on a Haswell Xeon E5 system:

	                                before  after
	cpuid                           14159   13869
	vmcall                          15290   14951
	inl_from_kernel                 17703   17447
	outl_to_kernel                  16011   14692
	self_ipi_sti_nop                16763   15825
	self_ipi_tpr_sti_nop            17341   15935
	wr_tsc_adjust_msr               14510   14264
	rd_tsc_adjust_msr               15018   14311
	mmio-wildcard-eventfd:pci-mem   16381   14947
	mmio-datamatch-eventfd:pci-mem  18620   17858
	portio-wildcard-eventfd:pci-io  15121   14769
	portio-datamatch-eventfd:pci-io 15761   14831

(average savings 748, stdev 460).

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2018-01-16 16:50:13 +01:00
..
2017-11-16 09:10:59 -08:00
2017-10-03 16:04:44 -07:00
2017-11-15 13:46:33 -08:00
2017-11-15 18:21:04 -08:00