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/*
* 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/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;
}
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;
}
/*
* 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;
union hv_x64_msr_hypercall_contents hypercall_msr;
if (x86_hyper_type != X86_HYPER_MS_HYPERV)
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, NULL) < 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)
{
static bool panic_reported;
/*
* 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;
wrmsrl(HV_X64_MSR_CRASH_P0, regs->ip);
wrmsrl(HV_X64_MSR_CRASH_P1, regs->ax);
wrmsrl(HV_X64_MSR_CRASH_P2, regs->bx);
wrmsrl(HV_X64_MSR_CRASH_P3, regs->cx);
wrmsrl(HV_X64_MSR_CRASH_P4, regs->dx);
/*
* 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_hypercall_page_setup(void)
{
union hv_x64_msr_hypercall_contents hypercall_msr;
/* Check if the hypercall page is setup */
hypercall_msr.as_uint64 = 0;
rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
if (!hypercall_msr.enable)
return false;
return true;
}
EXPORT_SYMBOL_GPL(hv_is_hypercall_page_setup);
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