bhyve.c

 1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * FreeBSD Bhyve guest enlightenments
 4 *
 5 * Copyright © 2025 Amazon.com, Inc. or its affiliates.
 6 *
 7 * Author: David Woodhouse <dwmw2@infradead.org>
 8 */
 9
10#include <linux/init.h>
11#include <linux/export.h>
12#include <asm/processor.h>
13#include <asm/hypervisor.h>
14
15static uint32_t bhyve_cpuid_base;
16static uint32_t bhyve_cpuid_max;
17
18#define BHYVE_SIGNATURE			"bhyve bhyve "
19
20#define CPUID_BHYVE_FEATURES		0x40000001
21
22/* Features advertised in CPUID_BHYVE_FEATURES %eax */
23
24/* MSI Extended Dest ID */
25#define CPUID_BHYVE_FEAT_EXT_DEST_ID	(1UL << 0)
26
27static uint32_t __init bhyve_detect(void)
28{
29	if (!cpu_feature_enabled(X86_FEATURE_HYPERVISOR))
30                return 0;
31
32	bhyve_cpuid_base = cpuid_base_hypervisor(BHYVE_SIGNATURE, 0);
33	if (!bhyve_cpuid_base)
34		return 0;
35
36	bhyve_cpuid_max = cpuid_eax(bhyve_cpuid_base);
37	return bhyve_cpuid_max;
38}
39
40static uint32_t bhyve_features(void)
41{
42	unsigned int cpuid_leaf = bhyve_cpuid_base | CPUID_BHYVE_FEATURES;
43
44	if (bhyve_cpuid_max < cpuid_leaf)
45		return 0;
46
47	return cpuid_eax(cpuid_leaf);
48}
49
50static bool __init bhyve_ext_dest_id(void)
51{
52	return !!(bhyve_features() & CPUID_BHYVE_FEAT_EXT_DEST_ID);
53}
54
55static bool __init bhyve_x2apic_available(void)
56{
57	return true;
58}
59
60const struct hypervisor_x86 x86_hyper_bhyve __refconst = {
61	.name			= "Bhyve",
62	.detect			= bhyve_detect,
63	.init.init_platform	= x86_init_noop,
64	.init.x2apic_available	= bhyve_x2apic_available,
65	.init.msi_ext_dest_id	= bhyve_ext_dest_id,
66};