Add an explicit exit code 'SPINUP_AP' to tell the controlling process that an

AP needs to be activated by spinning up an execution context for it.

The local apic emulation is now completely done in the hypervisor and it will
detect writes to the ICR_LO register that try to bring up the AP. In response
to such writes it will return to userspace with an exit code of SPINUP_AP.

Reviewed by: grehan

1 files changed, 180 insertions, 0 deletions

diff --git a/usr.sbin/bhyve/spinup_ap.c b/usr.sbin/bhyve/spinup_ap.c
new file mode 100644
index 0000000..e845515
--- /dev/null
+++ b/usr.sbin/bhyve/spinup_ap.c
@@ -0,0 +1,180 @@
+/*-
+ * Copyright (c) 2012 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/types.h>
+
+#include <machine/vmm.h>
+#include <vmmapi.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+
+#include "fbsdrun.h"
+#include "spinup_ap.h"
+
+/*
+ * Trampoline for hypervisor direct 64-bit jump.
+ *
+ *   0  - signature for guest->host verification
+ *   8  - kernel virtual address of trampoline
+ *  16  - instruction virtual address
+ *  24  - stack pointer virtual address
+ *  32  - CR3, physical address of kernel page table
+ *  40  - 24-byte area for null/code/data GDT entries
+ */
+#define MP_V64T_SIG	0xcafebabecafebabeULL
+struct mp_v64tramp {
+	uint64_t	mt_sig;
+	uint64_t	mt_virt;
+	uint64_t	mt_eip;
+	uint64_t	mt_rsp;
+	uint64_t	mt_cr3;
+	uint64_t	mt_gdtr[3];
+};
+
+static void
+spinup_ap_realmode(struct vmctx *ctx, int newcpu, uint64_t *rip)
+{
+	int vector, error;
+	uint16_t cs;
+	uint64_t desc_base;
+	uint32_t desc_limit, desc_access;
+
+	vector = *rip >> PAGE_SHIFT;
+	*rip = 0;
+
+	/*
+	 * Update the %cs and %rip of the guest so that it starts
+	 * executing real mode code at at 'vector << 12'.
+	 */
+	error = vm_set_register(ctx, newcpu, VM_REG_GUEST_RIP, *rip);
+	assert(error == 0);
+
+	error = vm_get_desc(ctx, newcpu, VM_REG_GUEST_CS, &desc_base,
+			    &desc_limit, &desc_access);
+	assert(error == 0);
+
+	desc_base = vector << PAGE_SHIFT;
+	error = vm_set_desc(ctx, newcpu, VM_REG_GUEST_CS,
+			    desc_base, desc_limit, desc_access);
+	assert(error == 0);
+
+	cs = (vector << PAGE_SHIFT) >> 4;
+	error = vm_set_register(ctx, newcpu, VM_REG_GUEST_CS, cs);
+	assert(error == 0);
+}
+
+static void
+spinup_ap_direct64(struct vmctx *ctx, int newcpu, uint64_t *rip)
+{
+	struct mp_v64tramp *mvt;
+	char *errstr;
+	int error;
+	uint64_t gdtbase;
+
+	mvt = paddr_guest2host(*rip);
+
+	assert(mvt->mt_sig == MP_V64T_SIG);
+
+	/*
+	 * Set up the 3-entry GDT using memory supplied in the
+	 * guest's trampoline structure.
+	 */
+	vm_setup_freebsd_gdt(mvt->mt_gdtr);
+
+#define  CHECK_ERROR(msg) \
+	if (error != 0) { \
+		errstr = msg; \
+		goto err_exit; \
+	}
+
+        /* entry point */
+	*rip = mvt->mt_eip;
+
+	/* Get the guest virtual address of the GDT */
+        gdtbase = mvt->mt_virt + __offsetof(struct mp_v64tramp, mt_gdtr);
+
+	error = vm_setup_freebsd_registers(ctx, newcpu, mvt->mt_eip,
+					   mvt->mt_cr3, gdtbase, mvt->mt_rsp);
+	CHECK_ERROR("vm_setup_freebsd_registers");
+
+	return;
+err_exit:
+	printf("spinup_ap_direct64: machine state error: %s", errstr);
+	exit(1);
+}
+
+int
+spinup_ap(struct vmctx *ctx, int vcpu, int newcpu, uint64_t rip)
+{
+	int error;
+
+	assert(newcpu != 0);
+	assert(newcpu < guest_ncpus);
+
+	error = vcpu_reset(ctx, newcpu);
+	assert(error == 0);
+
+	/* Set up capabilities */
+	if (fbsdrun_vmexit_on_hlt()) {
+		error = vm_set_capability(ctx, newcpu, VM_CAP_HALT_EXIT, 1);
+		assert(error == 0);
+	}
+
+	if (fbsdrun_vmexit_on_pause()) {
+		error = vm_set_capability(ctx, newcpu, VM_CAP_PAUSE_EXIT, 1);
+		assert(error == 0);
+	}
+
+	/*
+	 * There are 2 startup modes possible here:
+	 *  - if the CPU supports 'unrestricted guest' mode, the spinup can
+	 *    set up the processor state in power-on 16-bit mode, with the CS:IP
+	 *    init'd to the specified low-mem 4K page.
+	 *  - if the guest has requested a 64-bit trampoline in the low-mem 4K
+	 *    page by placing in the specified signature, set up the register
+	 *    state using register state in the signature. Note that this
+	 *    requires accessing guest physical memory to read the signature
+	 *    while 'unrestricted mode' does not.
+	 */
+	error = vm_set_capability(ctx, newcpu, VM_CAP_UNRESTRICTED_GUEST, 1);
+	if (error) {
+		spinup_ap_direct64(ctx, newcpu, &rip);
+	} else {
+		spinup_ap_realmode(ctx, newcpu, &rip);
+	}
+
+	fbsdrun_addcpu(ctx, newcpu, rip);
+
+	return (newcpu);
+}