blob: 40e0e322161d7bbc4b88e854c4a4e6f503e627f9 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
/*
* Hyper-V specific APIC code.
*
* Copyright (C) 2018, 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 <linux/vmalloc.h>
#include <linux/mm.h>
#include <linux/clockchips.h>
#include <linux/hyperv.h>
#include <linux/slab.h>
#include <linux/cpuhotplug.h>
#include <asm/hypervisor.h>
#include <asm/mshyperv.h>
#include <asm/apic.h>
#include <asm/trace/hyperv.h>
static struct apic orig_apic;
static u64 hv_apic_icr_read(void)
{
u64 reg_val;
rdmsrl(HV_X64_MSR_ICR, reg_val);
return reg_val;
}
static void hv_apic_icr_write(u32 low, u32 id)
{
u64 reg_val;
reg_val = SET_APIC_DEST_FIELD(id);
reg_val = reg_val << 32;
reg_val |= low;
wrmsrl(HV_X64_MSR_ICR, reg_val);
}
static u32 hv_apic_read(u32 reg)
{
u32 reg_val, hi;
switch (reg) {
case APIC_EOI:
rdmsr(HV_X64_MSR_EOI, reg_val, hi);
return reg_val;
case APIC_TASKPRI:
rdmsr(HV_X64_MSR_TPR, reg_val, hi);
return reg_val;
default:
return native_apic_mem_read(reg);
}
}
static void hv_apic_write(u32 reg, u32 val)
{
switch (reg) {
case APIC_EOI:
wrmsr(HV_X64_MSR_EOI, val, 0);
break;
case APIC_TASKPRI:
wrmsr(HV_X64_MSR_TPR, val, 0);
break;
default:
native_apic_mem_write(reg, val);
}
}
static void hv_apic_eoi_write(u32 reg, u32 val)
{
struct hv_vp_assist_page *hvp = hv_vp_assist_page[smp_processor_id()];
if (hvp && (xchg(&hvp->apic_assist, 0) & 0x1))
return;
wrmsr(HV_X64_MSR_EOI, val, 0);
}
/*
* IPI implementation on Hyper-V.
*/
static bool __send_ipi_mask_ex(const struct cpumask *mask, int vector)
{
struct hv_send_ipi_ex **arg;
struct hv_send_ipi_ex *ipi_arg;
unsigned long flags;
int nr_bank = 0;
int ret = 1;
if (!(ms_hyperv.hints & HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED))
return false;
local_irq_save(flags);
arg = (struct hv_send_ipi_ex **)this_cpu_ptr(hyperv_pcpu_input_arg);
ipi_arg = *arg;
if (unlikely(!ipi_arg))
goto ipi_mask_ex_done;
ipi_arg->vector = vector;
ipi_arg->reserved = 0;
ipi_arg->vp_set.valid_bank_mask = 0;
if (!cpumask_equal(mask, cpu_present_mask)) {
ipi_arg->vp_set.format = HV_GENERIC_SET_SPARSE_4K;
nr_bank = cpumask_to_vpset(&(ipi_arg->vp_set), mask);
}
if (nr_bank < 0)
goto ipi_mask_ex_done;
if (!nr_bank)
ipi_arg->vp_set.format = HV_GENERIC_SET_ALL;
ret = hv_do_rep_hypercall(HVCALL_SEND_IPI_EX, 0, nr_bank,
ipi_arg, NULL);
ipi_mask_ex_done:
local_irq_restore(flags);
return ((ret == 0) ? true : false);
}
static bool __send_ipi_mask(const struct cpumask *mask, int vector)
{
int cur_cpu, vcpu;
struct hv_send_ipi ipi_arg;
int ret = 1;
trace_hyperv_send_ipi_mask(mask, vector);
if (cpumask_empty(mask))
return true;
if (!hv_hypercall_pg)
return false;
if ((vector < HV_IPI_LOW_VECTOR) || (vector > HV_IPI_HIGH_VECTOR))
return false;
/*
* From the supplied CPU set we need to figure out if we can get away
* with cheaper HVCALL_SEND_IPI hypercall. This is possible when the
* highest VP number in the set is < 64. As VP numbers are usually in
* ascending order and match Linux CPU ids, here is an optimization:
* we check the VP number for the highest bit in the supplied set first
* so we can quickly find out if using HVCALL_SEND_IPI_EX hypercall is
* a must. We will also check all VP numbers when walking the supplied
* CPU set to remain correct in all cases.
*/
if (hv_cpu_number_to_vp_number(cpumask_last(mask)) >= 64)
goto do_ex_hypercall;
ipi_arg.vector = vector;
ipi_arg.cpu_mask = 0;
for_each_cpu(cur_cpu, mask) {
vcpu = hv_cpu_number_to_vp_number(cur_cpu);
if (vcpu == VP_INVAL)
return false;
/*
* This particular version of the IPI hypercall can
* only target upto 64 CPUs.
*/
if (vcpu >= 64)
goto do_ex_hypercall;
__set_bit(vcpu, (unsigned long *)&ipi_arg.cpu_mask);
}
ret = hv_do_fast_hypercall16(HVCALL_SEND_IPI, ipi_arg.vector,
ipi_arg.cpu_mask);
return ((ret == 0) ? true : false);
do_ex_hypercall:
return __send_ipi_mask_ex(mask, vector);
}
static bool __send_ipi_one(int cpu, int vector)
{
int vp = hv_cpu_number_to_vp_number(cpu);
trace_hyperv_send_ipi_one(cpu, vector);
if (!hv_hypercall_pg || (vp == VP_INVAL))
return false;
if ((vector < HV_IPI_LOW_VECTOR) || (vector > HV_IPI_HIGH_VECTOR))
return false;
if (vp >= 64)
return __send_ipi_mask_ex(cpumask_of(cpu), vector);
return !hv_do_fast_hypercall16(HVCALL_SEND_IPI, vector, BIT_ULL(vp));
}
static void hv_send_ipi(int cpu, int vector)
{
if (!__send_ipi_one(cpu, vector))
orig_apic.send_IPI(cpu, vector);
}
static void hv_send_ipi_mask(const struct cpumask *mask, int vector)
{
if (!__send_ipi_mask(mask, vector))
orig_apic.send_IPI_mask(mask, vector);
}
static void hv_send_ipi_mask_allbutself(const struct cpumask *mask, int vector)
{
unsigned int this_cpu = smp_processor_id();
struct cpumask new_mask;
const struct cpumask *local_mask;
cpumask_copy(&new_mask, mask);
cpumask_clear_cpu(this_cpu, &new_mask);
local_mask = &new_mask;
if (!__send_ipi_mask(local_mask, vector))
orig_apic.send_IPI_mask_allbutself(mask, vector);
}
static void hv_send_ipi_allbutself(int vector)
{
hv_send_ipi_mask_allbutself(cpu_online_mask, vector);
}
static void hv_send_ipi_all(int vector)
{
if (!__send_ipi_mask(cpu_online_mask, vector))
orig_apic.send_IPI_all(vector);
}
static void hv_send_ipi_self(int vector)
{
if (!__send_ipi_one(smp_processor_id(), vector))
orig_apic.send_IPI_self(vector);
}
void __init hv_apic_init(void)
{
if (ms_hyperv.hints & HV_X64_CLUSTER_IPI_RECOMMENDED) {
pr_info("Hyper-V: Using IPI hypercalls\n");
/*
* Set the IPI entry points.
*/
orig_apic = *apic;
apic->send_IPI = hv_send_ipi;
apic->send_IPI_mask = hv_send_ipi_mask;
apic->send_IPI_mask_allbutself = hv_send_ipi_mask_allbutself;
apic->send_IPI_allbutself = hv_send_ipi_allbutself;
apic->send_IPI_all = hv_send_ipi_all;
apic->send_IPI_self = hv_send_ipi_self;
}
if (ms_hyperv.hints & HV_X64_APIC_ACCESS_RECOMMENDED) {
pr_info("Hyper-V: Using enlightened APIC (%s mode)",
x2apic_enabled() ? "x2apic" : "xapic");
/*
* With x2apic, architectural x2apic MSRs are equivalent to the
* respective synthetic MSRs, so there's no need to override
* the apic accessors. The only exception is
* hv_apic_eoi_write, because it benefits from lazy EOI when
* available, but it works for both xapic and x2apic modes.
*/
apic_set_eoi_write(hv_apic_eoi_write);
if (!x2apic_enabled()) {
apic->read = hv_apic_read;
apic->write = hv_apic_write;
apic->icr_write = hv_apic_icr_write;
apic->icr_read = hv_apic_icr_read;
}
}
}