1 files changed, 93 insertions, 0 deletions
diff --git a/sys/amd64/vmm/vmm_ipi.c b/sys/amd64/vmm/vmm_ipi.c
new file mode 100644
index 0000000..643d326
--- /dev/null
+++ b/sys/amd64/vmm/vmm_ipi.c
@@ -0,0 +1,93 @@
+/*-
+ * Copyright (c) 2011 NetApp, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY NETAPP, INC ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL NETAPP, INC OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/proc.h>
+#include <sys/bus.h>
+
+#include <machine/intr_machdep.h>
+#include <machine/apicvar.h>
+#include <machine/segments.h>
+#include <machine/md_var.h>
+
+#include <machine/vmm.h>
+#include "vmm_ipi.h"
+
+extern inthand_t IDTVEC(rsvd), IDTVEC(justreturn);
+
+/*
+ * The default is to use the IPI_AST to interrupt a vcpu.
+ */
+int vmm_ipinum = IPI_AST;
+
+CTASSERT(APIC_SPURIOUS_INT == 255);
+
+void
+vmm_ipi_init(void)
+{
+	int idx;
+	uintptr_t func;
+	struct gate_descriptor *ip;
+
+	/*
+	 * Search backwards from the highest IDT vector available for use
+	 * as our IPI vector. We install the 'justreturn' handler at that
+	 * vector and use it to interrupt the vcpus.
+	 *
+	 * We do this because the IPI_AST is heavyweight and saves all
+	 * registers in the trapframe. This is overkill for our use case
+	 * which is simply to EOI the interrupt and return.
+	 */
+	idx = APIC_SPURIOUS_INT;
+	while (--idx >= APIC_IPI_INTS) {
+		ip = &idt[idx];
+		func = ((long)ip->gd_hioffset << 16 | ip->gd_looffset);
+		if (func == (uintptr_t)&IDTVEC(rsvd)) {
+			vmm_ipinum = idx;
+			setidt(vmm_ipinum, IDTVEC(justreturn), SDT_SYSIGT,
+			       SEL_KPL, 0);
+			break;
+		}
+	}
+	
+	if (vmm_ipinum != IPI_AST && bootverbose) {
+		printf("vmm_ipi_init: installing ipi handler to interrupt "
+		       "vcpus at vector %d\n", vmm_ipinum);
+	}
+}
+
+void
+vmm_ipi_cleanup(void)
+{
+	if (vmm_ipinum != IPI_AST)
+		setidt(vmm_ipinum, IDTVEC(rsvd), SDT_SYSIGT, SEL_KPL, 0);
+}