[intel] Exclude time spent in hypervisor from profiling

When profiling, exclude any time spent inside the hypervisor
responding to our MMIO accesses.  This substantially reduces the
variance accumulated on many other profilers.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/drivers/net/intel.c

@@ -496,6 +496,7 @@ void intel_refill_rx ( struct intel_nic *intel ) {
 		profile_start ( &intel_vm_refill_profiler );
 		writel ( rx_tail, intel->regs + intel->rx.reg + INTEL_xDT );
 		profile_stop ( &intel_vm_refill_profiler );
+		profile_exclude ( &intel_vm_refill_profiler );
 	}
 }
 
@@ -634,6 +635,7 @@ int intel_transmit ( struct net_device *netdev, struct io_buffer *iobuf ) {
 	profile_start ( &intel_vm_tx_profiler );
 	writel ( tx_tail, intel->regs + intel->tx.reg + INTEL_xDT );
 	profile_stop ( &intel_vm_tx_profiler );
+	profile_exclude ( &intel_vm_tx_profiler );
 
 	DBGC2 ( intel, "INTEL %p TX %d is [%llx,%llx)\n", intel, tx_idx,
 		( ( unsigned long long ) address ),
@@ -728,6 +730,7 @@ static void intel_poll ( struct net_device *netdev ) {
 	profile_start ( &intel_vm_poll_profiler );
 	icr = readl ( intel->regs + INTEL_ICR );
 	profile_stop ( &intel_vm_poll_profiler );
+	profile_exclude ( &intel_vm_poll_profiler );
 	if ( ! icr )
 		return;