x86.c revision 222610 
1/*-
2 * Copyright (c) 2011 NetApp, Inc.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY NETAPP, INC ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL NETAPP, INC OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD$
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD$");
31
32#include <sys/types.h>
33#include <sys/systm.h>
34
35#include <machine/cpufunc.h>
36#include <machine/md_var.h>
37#include <machine/specialreg.h>
38
39#include "x86.h"
40
41#define	CPUID_VM_HIGH		0x40000000
42
43static const char bhyve_id[12] = "BHyVE BHyVE ";
44
45int
46x86_emulate_cpuid(uint32_t *eax, uint32_t *ebx, uint32_t *ecx, uint32_t *edx,
47	uint32_t vcpu_id)
48{
49	unsigned int 	func, regs[4];
50
51	func = *eax;
52
53	/*
54	 * Requests for invalid CPUID levels should map to the highest
55	 * available level instead.
56	 */
57	if (cpu_exthigh != 0 && *eax >= 0x80000000) {
58		if (*eax > cpu_exthigh)
59			*eax = cpu_exthigh;
60	} else if (*eax >= 0x40000000) {
61		if (*eax > CPUID_VM_HIGH)
62			*eax = CPUID_VM_HIGH;
63	} else if (*eax > cpu_high) {
64		*eax = cpu_high;
65	}
66
67	/*
68	 * In general the approach used for CPU topology is to
69	 * advertise a flat topology where all CPUs are packages with
70	 * no multi-core or SMT.
71	 */
72	switch (func) {
73		case CPUID_0000_0000:
74		case CPUID_0000_0002:
75		case CPUID_0000_0003:
76		case CPUID_0000_000A:
77			cpuid_count(*eax, *ecx, regs);
78			break;
79
80		case CPUID_8000_0000:
81		case CPUID_8000_0001:
82		case CPUID_8000_0002:
83		case CPUID_8000_0003:
84		case CPUID_8000_0004:
85		case CPUID_8000_0006:
86		case CPUID_8000_0007:
87		case CPUID_8000_0008:
88			cpuid_count(*eax, *ecx, regs);
89			break;
90
91		case CPUID_0000_0001:
92			do_cpuid(1, regs);
93
94			/*
95			 * Override the APIC ID only in ebx
96			 */
97			regs[1] &= ~(CPUID_LOCAL_APIC_ID);
98			regs[1] |= (vcpu_id << CPUID_0000_0001_APICID_SHIFT);
99
100			/*
101			 * Don't expose VMX, SpeedStep or TME capability.
102			 * Advertise x2APIC capability and Hypervisor guest.
103			 */
104			regs[2] &= ~(CPUID2_VMX | CPUID2_EST | CPUID2_TM2);
105			regs[2] |= CPUID2_X2APIC | CPUID2_HV;
106
107			/*
108			 * Hide thermal monitoring
109			 */
110			regs[3] &= ~(CPUID_ACPI | CPUID_TM);
111
112			/*
113			 * Machine check handling is done in the host.
114			 * Hide MTRR capability.
115			 */
116			regs[3] &= ~(CPUID_MCA | CPUID_MCE | CPUID_MTRR);
117
118			/*
119			 * Disable multi-core.
120			 */
121			regs[1] &= ~CPUID_HTT_CORES;
122			regs[3] &= ~CPUID_HTT;
123			break;
124
125		case CPUID_0000_0004:
126			do_cpuid(4, regs);
127
128			/*
129			 * Do not expose topology.
130			 */
131			regs[0] &= 0xffff8000;
132			regs[0] |= 0x04008000;
133			break;
134
135		case CPUID_0000_0006:
136			/*
137			 * Handle the access, but report 0 for
138			 * all options
139			 */
140			regs[0] = 0;
141			regs[1] = 0;
142			regs[2] = 0;
143			regs[3] = 0;
144			break;
145
146		case CPUID_0000_000B:
147			/*
148			 * Processor topology enumeration
149			 */
150			regs[0] = 0;
151			regs[1] = 0;
152			regs[2] = *ecx & 0xff;
153			regs[3] = vcpu_id;
154			break;
155
156		case 0x40000000:
157			regs[0] = CPUID_VM_HIGH;
158			bcopy(bhyve_id, &regs[1], 4);
159			bcopy(bhyve_id, &regs[2], 4);
160			bcopy(bhyve_id, &regs[3], 4);
161			break;
162		default:
163			/* XXX: Leaf 5? */
164			return (0);
165	}
166
167	*eax = regs[0];
168	*ebx = regs[1];
169	*ecx = regs[2];
170	*edx = regs[3];
171	return (1);
172}
173