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The Hyper-V clocksource driver is best integrated with Hyper-V detection code since: (a) Linux guests running on Hyper-V require it (b) Integration into that code significanly reduces code size Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com> Cc: gregkh@suse.de Cc: devel@linuxdriverproject.org Cc: virtualization@lists.osdl.org Link: http://lkml.kernel.org/r/1315434310-4827-1-git-send-email-kys@microsoft.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
80 lines
2 KiB
C
80 lines
2 KiB
C
/*
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* HyperV Detection code.
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*
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* Copyright (C) 2010, Novell, Inc.
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* Author : K. Y. Srinivasan <ksrinivasan@novell.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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*/
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#include <linux/types.h>
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#include <linux/time.h>
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#include <linux/clocksource.h>
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#include <linux/module.h>
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#include <asm/processor.h>
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#include <asm/hypervisor.h>
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#include <asm/hyperv.h>
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#include <asm/mshyperv.h>
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struct ms_hyperv_info ms_hyperv;
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EXPORT_SYMBOL_GPL(ms_hyperv);
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static bool __init ms_hyperv_platform(void)
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{
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u32 eax;
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u32 hyp_signature[3];
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if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
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return false;
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cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
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&eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);
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return eax >= HYPERV_CPUID_MIN &&
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eax <= HYPERV_CPUID_MAX &&
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!memcmp("Microsoft Hv", hyp_signature, 12);
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}
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static cycle_t read_hv_clock(struct clocksource *arg)
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{
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cycle_t current_tick;
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/*
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* Read the partition counter to get the current tick count. This count
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* is set to 0 when the partition is created and is incremented in
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* 100 nanosecond units.
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*/
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rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
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return current_tick;
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}
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static struct clocksource hyperv_cs = {
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.name = "hyperv_clocksource",
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.rating = 400, /* use this when running on Hyperv*/
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.read = read_hv_clock,
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.mask = CLOCKSOURCE_MASK(64),
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};
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static void __init ms_hyperv_init_platform(void)
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{
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/*
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* Extract the features and hints
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*/
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ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);
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ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);
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printk(KERN_INFO "HyperV: features 0x%x, hints 0x%x\n",
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ms_hyperv.features, ms_hyperv.hints);
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clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100);
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}
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const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
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.name = "Microsoft HyperV",
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.detect = ms_hyperv_platform,
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.init_platform = ms_hyperv_init_platform,
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};
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EXPORT_SYMBOL(x86_hyper_ms_hyperv);
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