Implement guest vcpu pinning using 'pthread_setaffinity_np(3)'.

Prior to this change pinning was implemented via an ioctl (VM_SET_PINNING)
that called 'sched_bind()' on behalf of the user thread.

The ULE implementation of 'sched_bind()' bumps up 'td_pinned' which in turn
runs afoul of the assertion '(td_pinned == 0)' in userret().

Using the cpuset affinity to implement pinning of the vcpu threads works with
both 4BSD and ULE schedulers and has the happy side-effect of getting rid
of a bunch of code in vmm.ko.

Discussed with:	grehan

1 files changed, 5 insertions, 1 deletions

diff --git a/usr.sbin/bhyve/bhyverun.c b/usr.sbin/bhyve/bhyverun.c
index 8d03649..ea4b68c 100644
--- a/usr.sbin/bhyve/bhyverun.c
+++ b/usr.sbin/bhyve/bhyverun.c
@@ -520,13 +520,17 @@ static vmexit_handler_t handler[VM_EXITCODE_MAX] = {
 static void
 vm_loop(struct vmctx *ctx, int vcpu, uint64_t rip)
 {
+	cpuset_t mask;
 	int error, rc, prevcpu;
 
 	if (guest_vcpu_mux)
 		setup_timeslice();
 
 	if (pincpu >= 0) {
-		error = vm_set_pinning(ctx, vcpu, pincpu + vcpu);
+		CPU_ZERO(&mask);
+		CPU_SET(pincpu + vcpu, &mask);
+		error = pthread_setaffinity_np(pthread_self(),
+					       sizeof(mask), &mask);
 		assert(error == 0);
 	}