[intel] Profile common virtual machine operations

Operations which are negligible on physical hardware (such as issuing
a posted write to the transmit ring tail register) may involve
substantial amounts of processing within the hypervisor if running in
a virtual machine.

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

src/drivers/net/intel.c

 #include <ipxe/iobuf.h>
 #include <ipxe/malloc.h>
 #include <ipxe/pci.h>
+#include <ipxe/profile.h>
 #include "intel.h"
 
 /** @file
  *
  */
 
+/** VM transmit profiler */
+static struct profiler intel_vm_tx_profiler __profiler =
+	{ .name = "intel.vm_tx" };
+
+/** VM receive refill profiler */
+static struct profiler intel_vm_refill_profiler __profiler =
+	{ .name = "intel.vm_refill" };
+
+/** VM poll profiler */
+static struct profiler intel_vm_poll_profiler __profiler =
+	{ .name = "intel.vm_poll" };
+
 /******************************************************************************
  *
  * EEPROM interface
 		intel->rx_iobuf[rx_idx] = iobuf;
 
 		/* Push descriptor to card */
+		profile_start ( &intel_vm_refill_profiler );
 		writel ( rx_tail, intel->regs + intel->rx.reg + INTEL_xDT );
+		profile_stop ( &intel_vm_refill_profiler );
 
 		DBGC2 ( intel, "INTEL %p RX %d is [%llx,%llx)\n", intel, rx_idx,
 			( ( unsigned long long ) address ),
 	wmb();
 
 	/* Notify card that there are packets ready to transmit */
+	profile_start ( &intel_vm_tx_profiler );
 	writel ( tx_tail, intel->regs + intel->tx.reg + INTEL_xDT );
+	profile_stop ( &intel_vm_tx_profiler );
 
 	DBGC2 ( intel, "INTEL %p TX %d is [%llx,%llx)\n", intel, tx_idx,
 		( ( unsigned long long ) address ),
 	uint32_t icr;
 
 	/* Check for and acknowledge interrupts */
+	profile_start ( &intel_vm_poll_profiler );
 	icr = readl ( intel->regs + INTEL_ICR );
+	profile_stop ( &intel_vm_poll_profiler );
 	if ( ! icr )
 		return;