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https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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fa1d117162
Detect the Bhyve hypervisor and enable 15-bit MSI support if available. Detecting Bhyve used to be a purely cosmetic issue of the kernel printing 'Hypervisor detected: Bhyve' at boot time. But FreeBSD 15.0 will support¹ the 15-bit MSI enlightenment to support more than 255 vCPUs (http://david.woodhou.se/ExtDestId.pdf) which means there's now actually some functional reason to do so. ¹ https://github.com/freebsd/freebsd-src/commit/313a68ea20b4 [ bp: Massage, move tail comment ontop. ] Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Acked-by: Ahmed S. Darwish <darwi@linutronix.de> Link: https://lore.kernel.org/03802f6f7f5b5cf8c5e8adfe123c397ca8e21093.camel@infradead.org
67 lines
1.5 KiB
C
67 lines
1.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* FreeBSD Bhyve guest enlightenments
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*
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* Copyright © 2025 Amazon.com, Inc. or its affiliates.
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*
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* Author: David Woodhouse <dwmw2@infradead.org>
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*/
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#include <linux/init.h>
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#include <linux/export.h>
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#include <asm/processor.h>
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#include <asm/hypervisor.h>
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static uint32_t bhyve_cpuid_base;
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static uint32_t bhyve_cpuid_max;
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#define BHYVE_SIGNATURE "bhyve bhyve "
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#define CPUID_BHYVE_FEATURES 0x40000001
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/* Features advertised in CPUID_BHYVE_FEATURES %eax */
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/* MSI Extended Dest ID */
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#define CPUID_BHYVE_FEAT_EXT_DEST_ID (1UL << 0)
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static uint32_t __init bhyve_detect(void)
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{
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if (!cpu_feature_enabled(X86_FEATURE_HYPERVISOR))
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return 0;
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bhyve_cpuid_base = cpuid_base_hypervisor(BHYVE_SIGNATURE, 0);
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if (!bhyve_cpuid_base)
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return 0;
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bhyve_cpuid_max = cpuid_eax(bhyve_cpuid_base);
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return bhyve_cpuid_max;
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}
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static uint32_t bhyve_features(void)
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{
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unsigned int cpuid_leaf = bhyve_cpuid_base | CPUID_BHYVE_FEATURES;
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if (bhyve_cpuid_max < cpuid_leaf)
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return 0;
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return cpuid_eax(cpuid_leaf);
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}
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static bool __init bhyve_ext_dest_id(void)
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{
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return !!(bhyve_features() & CPUID_BHYVE_FEAT_EXT_DEST_ID);
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}
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static bool __init bhyve_x2apic_available(void)
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{
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return true;
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}
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const struct hypervisor_x86 x86_hyper_bhyve __refconst = {
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.name = "Bhyve",
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.detect = bhyve_detect,
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.init.init_platform = x86_init_noop,
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.init.x2apic_available = bhyve_x2apic_available,
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.init.msi_ext_dest_id = bhyve_ext_dest_id,
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};
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