linux/arch/x86/hyperv/hv_init.c
K. Y. Srinivasan 1268ed0c47 x86/hyper-v: Fix the circular dependency in IPI enlightenment
The IPI hypercalls depend on being able to map the Linux notion of CPU ID
to the hypervisor's notion of the CPU ID. The array hv_vp_index[] provides
this mapping. Code for populating this array depends on the IPI functionality.
Break this circular dependency.

[ tglx: Use a proper define instead of '-1' with a u32 variable as pointed
  	out by Vitaly ]

Fixes: 68bb7bfb79 ("X86/Hyper-V: Enable IPI enlightenments")
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Cc: gregkh@linuxfoundation.org
Cc: devel@linuxdriverproject.org
Cc: olaf@aepfle.de
Cc: apw@canonical.com
Cc: jasowang@redhat.com
Cc: hpa@zytor.com
Cc: sthemmin@microsoft.com
Cc: Michael.H.Kelley@microsoft.com
Cc: vkuznets@redhat.com
Link: https://lkml.kernel.org/r/20180703230155.15160-1-kys@linuxonhyperv.com
2018-07-06 12:32:59 +02:00

450 lines
11 KiB
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-tlfs.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);
struct hv_vp_assist_page **hv_vp_assist_page;
EXPORT_SYMBOL_GPL(hv_vp_assist_page);
void __percpu **hyperv_pcpu_input_arg;
EXPORT_SYMBOL_GPL(hyperv_pcpu_input_arg);
u32 hv_max_vp_index;
static int hv_cpu_init(unsigned int cpu)
{
u64 msr_vp_index;
struct hv_vp_assist_page **hvp = &hv_vp_assist_page[smp_processor_id()];
void **input_arg;
input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
*input_arg = page_address(alloc_page(GFP_KERNEL));
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;
if (!hv_vp_assist_page)
return 0;
if (!*hvp)
*hvp = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL);
if (*hvp) {
u64 val;
val = vmalloc_to_pfn(*hvp);
val = (val << HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_SHIFT) |
HV_X64_MSR_VP_ASSIST_PAGE_ENABLE;
wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, val);
}
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;
unsigned long flags;
void **input_arg;
void *input_pg = NULL;
local_irq_save(flags);
input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
input_pg = *input_arg;
*input_arg = NULL;
local_irq_restore(flags);
free_page((unsigned long)input_pg);
if (hv_vp_assist_page && hv_vp_assist_page[cpu])
wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, 0);
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.
* 3. Setup Hyper-V specific APIC entry points.
*/
void __init hyperv_init(void)
{
u64 guest_id, required_msrs;
union hv_x64_msr_hypercall_contents hypercall_msr;
int cpuhp, i;
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 the per-CPU state for the hypercall input arg.
* If this allocation fails, we will not be able to setup
* (per-CPU) hypercall input page and thus this failure is
* fatal on Hyper-V.
*/
hyperv_pcpu_input_arg = alloc_percpu(void *);
BUG_ON(hyperv_pcpu_input_arg == NULL);
/* Allocate percpu VP index */
hv_vp_index = kmalloc_array(num_possible_cpus(), sizeof(*hv_vp_index),
GFP_KERNEL);
if (!hv_vp_index)
return;
for (i = 0; i < num_possible_cpus(); i++)
hv_vp_index[i] = VP_INVAL;
hv_vp_assist_page = kcalloc(num_possible_cpus(),
sizeof(*hv_vp_assist_page), GFP_KERNEL);
if (!hv_vp_assist_page) {
ms_hyperv.hints &= ~HV_X64_ENLIGHTENED_VMCS_RECOMMENDED;
goto free_vp_index;
}
cpuhp = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online",
hv_cpu_init, hv_cpu_die);
if (cpuhp < 0)
goto free_vp_assist_page;
/*
* 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 remove_cpuhp_state;
}
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);
hv_apic_init();
/*
* 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;
remove_cpuhp_state:
cpuhp_remove_state(cpuhp);
free_vp_assist_page:
kfree(hv_vp_assist_page);
hv_vp_assist_page = NULL;
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);