https://github.com/torvalds/linux
Tip revision: 4a3928c6f8a53fa1aed28ccba227742486e8ddcb authored by Linus Torvalds on 26 February 2018, 02:50:41 UTC
Linux 4.16-rc3
Linux 4.16-rc3
Tip revision: 4a3928c
hv_init.c
/*
* X86 specific Hyper-V initialization code.
*
* Copyright (C) 2016, Microsoft, Inc.
*
* Author : K. Y. Srinivasan <kys@microsoft.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for more
* details.
*
*/
#include <linux/types.h>
#include <asm/apic.h>
#include <asm/desc.h>
#include <asm/hypervisor.h>
#include <asm/hyperv.h>
#include <asm/mshyperv.h>
#include <linux/version.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <linux/clockchips.h>
#include <linux/hyperv.h>
#include <linux/slab.h>
#include <linux/cpuhotplug.h>
#ifdef CONFIG_HYPERV_TSCPAGE
static struct ms_hyperv_tsc_page *tsc_pg;
struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
{
return tsc_pg;
}
EXPORT_SYMBOL_GPL(hv_get_tsc_page);
static u64 read_hv_clock_tsc(struct clocksource *arg)
{
u64 current_tick = hv_read_tsc_page(tsc_pg);
if (current_tick == U64_MAX)
rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
return current_tick;
}
static struct clocksource hyperv_cs_tsc = {
.name = "hyperv_clocksource_tsc_page",
.rating = 400,
.read = read_hv_clock_tsc,
.mask = CLOCKSOURCE_MASK(64),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
#endif
static u64 read_hv_clock_msr(struct clocksource *arg)
{
u64 current_tick;
/*
* Read the partition counter to get the current tick count. This count
* is set to 0 when the partition is created and is incremented in
* 100 nanosecond units.
*/
rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
return current_tick;
}
static struct clocksource hyperv_cs_msr = {
.name = "hyperv_clocksource_msr",
.rating = 400,
.read = read_hv_clock_msr,
.mask = CLOCKSOURCE_MASK(64),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
void *hv_hypercall_pg;
EXPORT_SYMBOL_GPL(hv_hypercall_pg);
struct clocksource *hyperv_cs;
EXPORT_SYMBOL_GPL(hyperv_cs);
u32 *hv_vp_index;
EXPORT_SYMBOL_GPL(hv_vp_index);
u32 hv_max_vp_index;
static int hv_cpu_init(unsigned int cpu)
{
u64 msr_vp_index;
hv_get_vp_index(msr_vp_index);
hv_vp_index[smp_processor_id()] = msr_vp_index;
if (msr_vp_index > hv_max_vp_index)
hv_max_vp_index = msr_vp_index;
return 0;
}
static void (*hv_reenlightenment_cb)(void);
static void hv_reenlightenment_notify(struct work_struct *dummy)
{
struct hv_tsc_emulation_status emu_status;
rdmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
/* Don't issue the callback if TSC accesses are not emulated */
if (hv_reenlightenment_cb && emu_status.inprogress)
hv_reenlightenment_cb();
}
static DECLARE_DELAYED_WORK(hv_reenlightenment_work, hv_reenlightenment_notify);
void hyperv_stop_tsc_emulation(void)
{
u64 freq;
struct hv_tsc_emulation_status emu_status;
rdmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
emu_status.inprogress = 0;
wrmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq);
tsc_khz = div64_u64(freq, 1000);
}
EXPORT_SYMBOL_GPL(hyperv_stop_tsc_emulation);
static inline bool hv_reenlightenment_available(void)
{
/*
* Check for required features and priviliges to make TSC frequency
* change notifications work.
*/
return ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS &&
ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE &&
ms_hyperv.features & HV_X64_ACCESS_REENLIGHTENMENT;
}
__visible void __irq_entry hyperv_reenlightenment_intr(struct pt_regs *regs)
{
entering_ack_irq();
inc_irq_stat(irq_hv_reenlightenment_count);
schedule_delayed_work(&hv_reenlightenment_work, HZ/10);
exiting_irq();
}
void set_hv_tscchange_cb(void (*cb)(void))
{
struct hv_reenlightenment_control re_ctrl = {
.vector = HYPERV_REENLIGHTENMENT_VECTOR,
.enabled = 1,
.target_vp = hv_vp_index[smp_processor_id()]
};
struct hv_tsc_emulation_control emu_ctrl = {.enabled = 1};
if (!hv_reenlightenment_available()) {
pr_warn("Hyper-V: reenlightenment support is unavailable\n");
return;
}
hv_reenlightenment_cb = cb;
/* Make sure callback is registered before we write to MSRs */
wmb();
wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
wrmsrl(HV_X64_MSR_TSC_EMULATION_CONTROL, *((u64 *)&emu_ctrl));
}
EXPORT_SYMBOL_GPL(set_hv_tscchange_cb);
void clear_hv_tscchange_cb(void)
{
struct hv_reenlightenment_control re_ctrl;
if (!hv_reenlightenment_available())
return;
rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl);
re_ctrl.enabled = 0;
wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl);
hv_reenlightenment_cb = NULL;
}
EXPORT_SYMBOL_GPL(clear_hv_tscchange_cb);
static int hv_cpu_die(unsigned int cpu)
{
struct hv_reenlightenment_control re_ctrl;
unsigned int new_cpu;
if (hv_reenlightenment_cb == NULL)
return 0;
rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
if (re_ctrl.target_vp == hv_vp_index[cpu]) {
/* Reassign to some other online CPU */
new_cpu = cpumask_any_but(cpu_online_mask, cpu);
re_ctrl.target_vp = hv_vp_index[new_cpu];
wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
}
return 0;
}
/*
* This function is to be invoked early in the boot sequence after the
* hypervisor has been detected.
*
* 1. Setup the hypercall page.
* 2. Register Hyper-V specific clocksource.
*/
void hyperv_init(void)
{
u64 guest_id, required_msrs;
union hv_x64_msr_hypercall_contents hypercall_msr;
if (x86_hyper_type != X86_HYPER_MS_HYPERV)
return;
/* Absolutely required MSRs */
required_msrs = HV_X64_MSR_HYPERCALL_AVAILABLE |
HV_X64_MSR_VP_INDEX_AVAILABLE;
if ((ms_hyperv.features & required_msrs) != required_msrs)
return;
/* Allocate percpu VP index */
hv_vp_index = kmalloc_array(num_possible_cpus(), sizeof(*hv_vp_index),
GFP_KERNEL);
if (!hv_vp_index)
return;
if (cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online",
hv_cpu_init, hv_cpu_die) < 0)
goto free_vp_index;
/*
* Setup the hypercall page and enable hypercalls.
* 1. Register the guest ID
* 2. Enable the hypercall and register the hypercall page
*/
guest_id = generate_guest_id(0, LINUX_VERSION_CODE, 0);
wrmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
hv_hypercall_pg = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_RX);
if (hv_hypercall_pg == NULL) {
wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
goto free_vp_index;
}
rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
hypercall_msr.enable = 1;
hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg);
wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
hyper_alloc_mmu();
/*
* Register Hyper-V specific clocksource.
*/
#ifdef CONFIG_HYPERV_TSCPAGE
if (ms_hyperv.features & HV_X64_MSR_REFERENCE_TSC_AVAILABLE) {
union hv_x64_msr_hypercall_contents tsc_msr;
tsc_pg = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL);
if (!tsc_pg)
goto register_msr_cs;
hyperv_cs = &hyperv_cs_tsc;
rdmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
tsc_msr.enable = 1;
tsc_msr.guest_physical_address = vmalloc_to_pfn(tsc_pg);
wrmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
hyperv_cs_tsc.archdata.vclock_mode = VCLOCK_HVCLOCK;
clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100);
return;
}
register_msr_cs:
#endif
/*
* For 32 bit guests just use the MSR based mechanism for reading
* the partition counter.
*/
hyperv_cs = &hyperv_cs_msr;
if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100);
return;
free_vp_index:
kfree(hv_vp_index);
hv_vp_index = NULL;
}
/*
* This routine is called before kexec/kdump, it does the required cleanup.
*/
void hyperv_cleanup(void)
{
union hv_x64_msr_hypercall_contents hypercall_msr;
/* Reset our OS id */
wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
/* Reset the hypercall page */
hypercall_msr.as_uint64 = 0;
wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
/* Reset the TSC page */
hypercall_msr.as_uint64 = 0;
wrmsrl(HV_X64_MSR_REFERENCE_TSC, hypercall_msr.as_uint64);
}
EXPORT_SYMBOL_GPL(hyperv_cleanup);
void hyperv_report_panic(struct pt_regs *regs, long err)
{
static bool panic_reported;
u64 guest_id;
/*
* We prefer to report panic on 'die' chain as we have proper
* registers to report, but if we miss it (e.g. on BUG()) we need
* to report it on 'panic'.
*/
if (panic_reported)
return;
panic_reported = true;
rdmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
wrmsrl(HV_X64_MSR_CRASH_P0, err);
wrmsrl(HV_X64_MSR_CRASH_P1, guest_id);
wrmsrl(HV_X64_MSR_CRASH_P2, regs->ip);
wrmsrl(HV_X64_MSR_CRASH_P3, regs->ax);
wrmsrl(HV_X64_MSR_CRASH_P4, regs->sp);
/*
* Let Hyper-V know there is crash data available
*/
wrmsrl(HV_X64_MSR_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY);
}
EXPORT_SYMBOL_GPL(hyperv_report_panic);
bool hv_is_hyperv_initialized(void)
{
union hv_x64_msr_hypercall_contents hypercall_msr;
/*
* Ensure that we're really on Hyper-V, and not a KVM or Xen
* emulation of Hyper-V
*/
if (x86_hyper_type != X86_HYPER_MS_HYPERV)
return false;
/*
* Verify that earlier initialization succeeded by checking
* that the hypercall page is setup
*/
hypercall_msr.as_uint64 = 0;
rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
return hypercall_msr.enable;
}
EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized);