Merge Xen PVHVM support into the GENERIC kernel config for both

amd64 and i386.

Submitted by:	Roger Pau Monné
Sponsored by:	Citrix Systems R&D
Reviewed by:	gibbs
Approved by:	re (blanket Xen)
MFC after:	2 weeks

sys/amd64/amd64/mp_machdep.c:
sys/amd64/include/cpu.h:
sys/i386/i386/mp_machdep.c:
sys/i386/include/cpu.h:
	- Introduce two new CPU hooks for initialization and resume
	  purposes. This allows us to get rid of the XENHVM ifdefs in
	  mp_machdep, and also sets some hooks into common code that can be
	  used by other hypervisor implementations.

sys/amd64/conf/XENHVM:
sys/i386/conf/XENHVM:
	- Remove these configs now that GENERIC has builtin support for Xen
	  HVM.

sys/kern/subr_smp.c:
	- Make sure there are no pending IPIs when suspending a system.

sys/x86/xen/hvm.c:
	- Add cpu init and resume vectors that are called from mp_machdep
	  using the new hooks.
	- Only clear the vcpu_info mapping data on resume.  It is already
	  clear for the BSP on a cold boot and is set correctly as APs
	  are started.
	- Gate xen_hvm_init_cpu only to systems running under Xen.

sys/x86/xen/xen_intr.c:
	 - Gate the setup of event channels only to systems running under Xen.

1 files changed, 5 insertions, 9 deletions

diff --git a/sys/kern/subr_smp.c b/sys/kern/subr_smp.c
index 77d1b2b..86fbebb 100644
--- a/sys/kern/subr_smp.c
+++ b/sys/kern/subr_smp.c
@@ -225,17 +225,15 @@ generic_stop_cpus(cpuset_t map, u_int type)
 	CTR2(KTR_SMP, "stop_cpus(%s) with %u type",
 	    cpusetobj_strprint(cpusetbuf, &map), type);
 
-#ifdef XENHVM
 	/*
-	 * When migrating a PVHVM domain we need to make sure there are
-	 * no IPIs in progress.  IPIs that have been issued, but not
-	 * yet delivered (not pending on a vCPU) will be lost in the
-	 * IPI rebinding process, violating FreeBSD's assumption of
-	 * reliable IPI delivery.
+	 * When suspending, ensure there are are no IPIs in progress.
+	 * IPIs that have been issued, but not yet delivered (e.g.
+	 * not pending on a vCPU when running under virtualization)
+	 * will be lost, violating FreeBSD's assumption of reliable
+	 * IPI delivery.
 	 */
 	if (type == IPI_SUSPEND)
 		mtx_lock_spin(&smp_ipi_mtx);
-#endif
 
 	if (stopping_cpu != PCPU_GET(cpuid))
 		while (atomic_cmpset_int(&stopping_cpu, NOCPU,
@@ -264,10 +262,8 @@ generic_stop_cpus(cpuset_t map, u_int type)
 		}
 	}
 
-#ifdef XENHVM
 	if (type == IPI_SUSPEND)
 		mtx_unlock_spin(&smp_ipi_mtx);
-#endif
 
 	stopping_cpu = NOCPU;
 	return (1);