swh:1:snp:32555a3fd8878f019c2ebd6c964bc1edcaeff337
Tip revision: 6fbc7275c7a9ba97877050335f290341a1fd8dbf authored by Linus Torvalds on 30 June 2019, 03:25:36 UTC
Linux 5.2-rc7
Linux 5.2-rc7
Tip revision: 6fbc727
hv.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2009, Microsoft Corporation.
*
* Authors:
* Haiyang Zhang <haiyangz@microsoft.com>
* Hank Janssen <hjanssen@microsoft.com>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/hyperv.h>
#include <linux/version.h>
#include <linux/random.h>
#include <linux/clockchips.h>
#include <asm/mshyperv.h>
#include "hyperv_vmbus.h"
/* The one and only */
struct hv_context hv_context;
/*
* If false, we're using the old mechanism for stimer0 interrupts
* where it sends a VMbus message when it expires. The old
* mechanism is used when running on older versions of Hyper-V
* that don't support Direct Mode. While Hyper-V provides
* four stimer's per CPU, Linux uses only stimer0.
*/
static bool direct_mode_enabled;
static int stimer0_irq;
static int stimer0_vector;
#define HV_TIMER_FREQUENCY (10 * 1000 * 1000) /* 100ns period */
#define HV_MAX_MAX_DELTA_TICKS 0xffffffff
#define HV_MIN_DELTA_TICKS 1
/*
* hv_init - Main initialization routine.
*
* This routine must be called before any other routines in here are called
*/
int hv_init(void)
{
hv_context.cpu_context = alloc_percpu(struct hv_per_cpu_context);
if (!hv_context.cpu_context)
return -ENOMEM;
direct_mode_enabled = ms_hyperv.misc_features &
HV_STIMER_DIRECT_MODE_AVAILABLE;
return 0;
}
/*
* hv_post_message - Post a message using the hypervisor message IPC.
*
* This involves a hypercall.
*/
int hv_post_message(union hv_connection_id connection_id,
enum hv_message_type message_type,
void *payload, size_t payload_size)
{
struct hv_input_post_message *aligned_msg;
struct hv_per_cpu_context *hv_cpu;
u64 status;
if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT)
return -EMSGSIZE;
hv_cpu = get_cpu_ptr(hv_context.cpu_context);
aligned_msg = hv_cpu->post_msg_page;
aligned_msg->connectionid = connection_id;
aligned_msg->reserved = 0;
aligned_msg->message_type = message_type;
aligned_msg->payload_size = payload_size;
memcpy((void *)aligned_msg->payload, payload, payload_size);
status = hv_do_hypercall(HVCALL_POST_MESSAGE, aligned_msg, NULL);
/* Preemption must remain disabled until after the hypercall
* so some other thread can't get scheduled onto this cpu and
* corrupt the per-cpu post_msg_page
*/
put_cpu_ptr(hv_cpu);
return status & 0xFFFF;
}
/*
* ISR for when stimer0 is operating in Direct Mode. Direct Mode
* does not use VMbus or any VMbus messages, so process here and not
* in the VMbus driver code.
*/
static void hv_stimer0_isr(void)
{
struct hv_per_cpu_context *hv_cpu;
hv_cpu = this_cpu_ptr(hv_context.cpu_context);
hv_cpu->clk_evt->event_handler(hv_cpu->clk_evt);
add_interrupt_randomness(stimer0_vector, 0);
}
static int hv_ce_set_next_event(unsigned long delta,
struct clock_event_device *evt)
{
u64 current_tick;
WARN_ON(!clockevent_state_oneshot(evt));
current_tick = hyperv_cs->read(NULL);
current_tick += delta;
hv_init_timer(0, current_tick);
return 0;
}
static int hv_ce_shutdown(struct clock_event_device *evt)
{
hv_init_timer(0, 0);
hv_init_timer_config(0, 0);
if (direct_mode_enabled)
hv_disable_stimer0_percpu_irq(stimer0_irq);
return 0;
}
static int hv_ce_set_oneshot(struct clock_event_device *evt)
{
union hv_stimer_config timer_cfg;
timer_cfg.as_uint64 = 0;
timer_cfg.enable = 1;
timer_cfg.auto_enable = 1;
if (direct_mode_enabled) {
/*
* When it expires, the timer will directly interrupt
* on the specified hardware vector/IRQ.
*/
timer_cfg.direct_mode = 1;
timer_cfg.apic_vector = stimer0_vector;
hv_enable_stimer0_percpu_irq(stimer0_irq);
} else {
/*
* When it expires, the timer will generate a VMbus message,
* to be handled by the normal VMbus interrupt handler.
*/
timer_cfg.direct_mode = 0;
timer_cfg.sintx = VMBUS_MESSAGE_SINT;
}
hv_init_timer_config(0, timer_cfg.as_uint64);
return 0;
}
static void hv_init_clockevent_device(struct clock_event_device *dev, int cpu)
{
dev->name = "Hyper-V clockevent";
dev->features = CLOCK_EVT_FEAT_ONESHOT;
dev->cpumask = cpumask_of(cpu);
dev->rating = 1000;
/*
* Avoid settint dev->owner = THIS_MODULE deliberately as doing so will
* result in clockevents_config_and_register() taking additional
* references to the hv_vmbus module making it impossible to unload.
*/
dev->set_state_shutdown = hv_ce_shutdown;
dev->set_state_oneshot = hv_ce_set_oneshot;
dev->set_next_event = hv_ce_set_next_event;
}
int hv_synic_alloc(void)
{
int cpu;
struct hv_per_cpu_context *hv_cpu;
/*
* First, zero all per-cpu memory areas so hv_synic_free() can
* detect what memory has been allocated and cleanup properly
* after any failures.
*/
for_each_present_cpu(cpu) {
hv_cpu = per_cpu_ptr(hv_context.cpu_context, cpu);
memset(hv_cpu, 0, sizeof(*hv_cpu));
}
hv_context.hv_numa_map = kcalloc(nr_node_ids, sizeof(struct cpumask),
GFP_KERNEL);
if (hv_context.hv_numa_map == NULL) {
pr_err("Unable to allocate NUMA map\n");
goto err;
}
for_each_present_cpu(cpu) {
hv_cpu = per_cpu_ptr(hv_context.cpu_context, cpu);
tasklet_init(&hv_cpu->msg_dpc,
vmbus_on_msg_dpc, (unsigned long) hv_cpu);
hv_cpu->clk_evt = kzalloc(sizeof(struct clock_event_device),
GFP_KERNEL);
if (hv_cpu->clk_evt == NULL) {
pr_err("Unable to allocate clock event device\n");
goto err;
}
hv_init_clockevent_device(hv_cpu->clk_evt, cpu);
hv_cpu->synic_message_page =
(void *)get_zeroed_page(GFP_ATOMIC);
if (hv_cpu->synic_message_page == NULL) {
pr_err("Unable to allocate SYNIC message page\n");
goto err;
}
hv_cpu->synic_event_page = (void *)get_zeroed_page(GFP_ATOMIC);
if (hv_cpu->synic_event_page == NULL) {
pr_err("Unable to allocate SYNIC event page\n");
goto err;
}
hv_cpu->post_msg_page = (void *)get_zeroed_page(GFP_ATOMIC);
if (hv_cpu->post_msg_page == NULL) {
pr_err("Unable to allocate post msg page\n");
goto err;
}
INIT_LIST_HEAD(&hv_cpu->chan_list);
}
if (direct_mode_enabled &&
hv_setup_stimer0_irq(&stimer0_irq, &stimer0_vector,
hv_stimer0_isr))
goto err;
return 0;
err:
/*
* Any memory allocations that succeeded will be freed when
* the caller cleans up by calling hv_synic_free()
*/
return -ENOMEM;
}
void hv_synic_free(void)
{
int cpu;
for_each_present_cpu(cpu) {
struct hv_per_cpu_context *hv_cpu
= per_cpu_ptr(hv_context.cpu_context, cpu);
kfree(hv_cpu->clk_evt);
free_page((unsigned long)hv_cpu->synic_event_page);
free_page((unsigned long)hv_cpu->synic_message_page);
free_page((unsigned long)hv_cpu->post_msg_page);
}
kfree(hv_context.hv_numa_map);
}
/*
* hv_synic_init - Initialize the Synthetic Interrupt Controller.
*
* If it is already initialized by another entity (ie x2v shim), we need to
* retrieve the initialized message and event pages. Otherwise, we create and
* initialize the message and event pages.
*/
int hv_synic_init(unsigned int cpu)
{
struct hv_per_cpu_context *hv_cpu
= per_cpu_ptr(hv_context.cpu_context, cpu);
union hv_synic_simp simp;
union hv_synic_siefp siefp;
union hv_synic_sint shared_sint;
union hv_synic_scontrol sctrl;
/* Setup the Synic's message page */
hv_get_simp(simp.as_uint64);
simp.simp_enabled = 1;
simp.base_simp_gpa = virt_to_phys(hv_cpu->synic_message_page)
>> PAGE_SHIFT;
hv_set_simp(simp.as_uint64);
/* Setup the Synic's event page */
hv_get_siefp(siefp.as_uint64);
siefp.siefp_enabled = 1;
siefp.base_siefp_gpa = virt_to_phys(hv_cpu->synic_event_page)
>> PAGE_SHIFT;
hv_set_siefp(siefp.as_uint64);
/* Setup the shared SINT. */
hv_get_synint_state(VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
shared_sint.vector = HYPERVISOR_CALLBACK_VECTOR;
shared_sint.masked = false;
if (ms_hyperv.hints & HV_DEPRECATING_AEOI_RECOMMENDED)
shared_sint.auto_eoi = false;
else
shared_sint.auto_eoi = true;
hv_set_synint_state(VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
/* Enable the global synic bit */
hv_get_synic_state(sctrl.as_uint64);
sctrl.enable = 1;
hv_set_synic_state(sctrl.as_uint64);
/*
* Register the per-cpu clockevent source.
*/
if (ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE)
clockevents_config_and_register(hv_cpu->clk_evt,
HV_TIMER_FREQUENCY,
HV_MIN_DELTA_TICKS,
HV_MAX_MAX_DELTA_TICKS);
return 0;
}
/*
* hv_synic_clockevents_cleanup - Cleanup clockevent devices
*/
void hv_synic_clockevents_cleanup(void)
{
int cpu;
if (!(ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE))
return;
if (direct_mode_enabled)
hv_remove_stimer0_irq(stimer0_irq);
for_each_present_cpu(cpu) {
struct hv_per_cpu_context *hv_cpu
= per_cpu_ptr(hv_context.cpu_context, cpu);
clockevents_unbind_device(hv_cpu->clk_evt, cpu);
}
}
/*
* hv_synic_cleanup - Cleanup routine for hv_synic_init().
*/
int hv_synic_cleanup(unsigned int cpu)
{
union hv_synic_sint shared_sint;
union hv_synic_simp simp;
union hv_synic_siefp siefp;
union hv_synic_scontrol sctrl;
struct vmbus_channel *channel, *sc;
bool channel_found = false;
unsigned long flags;
hv_get_synic_state(sctrl.as_uint64);
if (sctrl.enable != 1)
return -EFAULT;
/*
* Search for channels which are bound to the CPU we're about to
* cleanup. In case we find one and vmbus is still connected we need to
* fail, this will effectively prevent CPU offlining. There is no way
* we can re-bind channels to different CPUs for now.
*/
mutex_lock(&vmbus_connection.channel_mutex);
list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
if (channel->target_cpu == cpu) {
channel_found = true;
break;
}
spin_lock_irqsave(&channel->lock, flags);
list_for_each_entry(sc, &channel->sc_list, sc_list) {
if (sc->target_cpu == cpu) {
channel_found = true;
break;
}
}
spin_unlock_irqrestore(&channel->lock, flags);
if (channel_found)
break;
}
mutex_unlock(&vmbus_connection.channel_mutex);
if (channel_found && vmbus_connection.conn_state == CONNECTED)
return -EBUSY;
/* Turn off clockevent device */
if (ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE) {
struct hv_per_cpu_context *hv_cpu
= this_cpu_ptr(hv_context.cpu_context);
clockevents_unbind_device(hv_cpu->clk_evt, cpu);
hv_ce_shutdown(hv_cpu->clk_evt);
}
hv_get_synint_state(VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
shared_sint.masked = 1;
/* Need to correctly cleanup in the case of SMP!!! */
/* Disable the interrupt */
hv_set_synint_state(VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
hv_get_simp(simp.as_uint64);
simp.simp_enabled = 0;
simp.base_simp_gpa = 0;
hv_set_simp(simp.as_uint64);
hv_get_siefp(siefp.as_uint64);
siefp.siefp_enabled = 0;
siefp.base_siefp_gpa = 0;
hv_set_siefp(siefp.as_uint64);
/* Disable the global synic bit */
sctrl.enable = 0;
hv_set_synic_state(sctrl.as_uint64);
return 0;
}