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![Tianyu Lan](/assets/img/avatar_default.png)
hyperv provides ghcb hvcall to handle VMBus HVCALL_SIGNAL_EVENT and HVCALL_POST_MESSAGE msg in SNP Isolation VM. Add such support. Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com> Link: https://lore.kernel.org/r/20211025122116.264793-8-ltykernel@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
442 lines
12 KiB
C
442 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (c) 2009, Microsoft Corporation.
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*
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* Authors:
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* Haiyang Zhang <haiyangz@microsoft.com>
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* Hank Janssen <hjanssen@microsoft.com>
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <linux/hyperv.h>
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#include <linux/random.h>
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#include <linux/clockchips.h>
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#include <linux/delay.h>
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#include <linux/interrupt.h>
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#include <clocksource/hyperv_timer.h>
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#include <asm/mshyperv.h>
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#include "hyperv_vmbus.h"
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/* The one and only */
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struct hv_context hv_context;
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/*
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* hv_init - Main initialization routine.
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*
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* This routine must be called before any other routines in here are called
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*/
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int hv_init(void)
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{
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hv_context.cpu_context = alloc_percpu(struct hv_per_cpu_context);
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if (!hv_context.cpu_context)
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return -ENOMEM;
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return 0;
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}
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/*
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* Functions for allocating and freeing memory with size and
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* alignment HV_HYP_PAGE_SIZE. These functions are needed because
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* the guest page size may not be the same as the Hyper-V page
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* size. We depend upon kmalloc() aligning power-of-two size
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* allocations to the allocation size boundary, so that the
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* allocated memory appears to Hyper-V as a page of the size
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* it expects.
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*/
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void *hv_alloc_hyperv_page(void)
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{
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BUILD_BUG_ON(PAGE_SIZE < HV_HYP_PAGE_SIZE);
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if (PAGE_SIZE == HV_HYP_PAGE_SIZE)
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return (void *)__get_free_page(GFP_KERNEL);
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else
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return kmalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
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}
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void *hv_alloc_hyperv_zeroed_page(void)
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{
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if (PAGE_SIZE == HV_HYP_PAGE_SIZE)
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return (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
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else
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return kzalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
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}
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void hv_free_hyperv_page(unsigned long addr)
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{
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if (PAGE_SIZE == HV_HYP_PAGE_SIZE)
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free_page(addr);
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else
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kfree((void *)addr);
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}
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/*
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* hv_post_message - Post a message using the hypervisor message IPC.
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*
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* This involves a hypercall.
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*/
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int hv_post_message(union hv_connection_id connection_id,
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enum hv_message_type message_type,
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void *payload, size_t payload_size)
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{
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struct hv_input_post_message *aligned_msg;
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struct hv_per_cpu_context *hv_cpu;
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u64 status;
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if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT)
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return -EMSGSIZE;
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hv_cpu = get_cpu_ptr(hv_context.cpu_context);
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aligned_msg = hv_cpu->post_msg_page;
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aligned_msg->connectionid = connection_id;
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aligned_msg->reserved = 0;
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aligned_msg->message_type = message_type;
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aligned_msg->payload_size = payload_size;
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memcpy((void *)aligned_msg->payload, payload, payload_size);
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if (hv_isolation_type_snp())
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status = hv_ghcb_hypercall(HVCALL_POST_MESSAGE,
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(void *)aligned_msg, NULL,
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sizeof(*aligned_msg));
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else
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status = hv_do_hypercall(HVCALL_POST_MESSAGE,
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aligned_msg, NULL);
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/* Preemption must remain disabled until after the hypercall
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* so some other thread can't get scheduled onto this cpu and
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* corrupt the per-cpu post_msg_page
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*/
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put_cpu_ptr(hv_cpu);
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return hv_result(status);
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}
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int hv_synic_alloc(void)
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{
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int cpu;
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struct hv_per_cpu_context *hv_cpu;
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/*
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* First, zero all per-cpu memory areas so hv_synic_free() can
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* detect what memory has been allocated and cleanup properly
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* after any failures.
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*/
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for_each_present_cpu(cpu) {
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hv_cpu = per_cpu_ptr(hv_context.cpu_context, cpu);
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memset(hv_cpu, 0, sizeof(*hv_cpu));
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}
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hv_context.hv_numa_map = kcalloc(nr_node_ids, sizeof(struct cpumask),
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GFP_KERNEL);
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if (hv_context.hv_numa_map == NULL) {
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pr_err("Unable to allocate NUMA map\n");
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goto err;
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}
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for_each_present_cpu(cpu) {
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hv_cpu = per_cpu_ptr(hv_context.cpu_context, cpu);
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tasklet_init(&hv_cpu->msg_dpc,
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vmbus_on_msg_dpc, (unsigned long) hv_cpu);
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/*
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* Synic message and event pages are allocated by paravisor.
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* Skip these pages allocation here.
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*/
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if (!hv_isolation_type_snp()) {
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hv_cpu->synic_message_page =
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(void *)get_zeroed_page(GFP_ATOMIC);
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if (hv_cpu->synic_message_page == NULL) {
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pr_err("Unable to allocate SYNIC message page\n");
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goto err;
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}
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hv_cpu->synic_event_page =
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(void *)get_zeroed_page(GFP_ATOMIC);
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if (hv_cpu->synic_event_page == NULL) {
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pr_err("Unable to allocate SYNIC event page\n");
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goto err;
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}
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}
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hv_cpu->post_msg_page = (void *)get_zeroed_page(GFP_ATOMIC);
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if (hv_cpu->post_msg_page == NULL) {
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pr_err("Unable to allocate post msg page\n");
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goto err;
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}
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}
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return 0;
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err:
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/*
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* Any memory allocations that succeeded will be freed when
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* the caller cleans up by calling hv_synic_free()
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*/
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return -ENOMEM;
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}
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void hv_synic_free(void)
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{
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int cpu;
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for_each_present_cpu(cpu) {
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struct hv_per_cpu_context *hv_cpu
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= per_cpu_ptr(hv_context.cpu_context, cpu);
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free_page((unsigned long)hv_cpu->synic_event_page);
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free_page((unsigned long)hv_cpu->synic_message_page);
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free_page((unsigned long)hv_cpu->post_msg_page);
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}
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kfree(hv_context.hv_numa_map);
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}
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/*
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* hv_synic_init - Initialize the Synthetic Interrupt Controller.
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*
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* If it is already initialized by another entity (ie x2v shim), we need to
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* retrieve the initialized message and event pages. Otherwise, we create and
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* initialize the message and event pages.
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*/
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void hv_synic_enable_regs(unsigned int cpu)
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{
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struct hv_per_cpu_context *hv_cpu
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= per_cpu_ptr(hv_context.cpu_context, cpu);
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union hv_synic_simp simp;
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union hv_synic_siefp siefp;
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union hv_synic_sint shared_sint;
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union hv_synic_scontrol sctrl;
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/* Setup the Synic's message page */
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simp.as_uint64 = hv_get_register(HV_REGISTER_SIMP);
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simp.simp_enabled = 1;
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if (hv_isolation_type_snp()) {
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hv_cpu->synic_message_page
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= memremap(simp.base_simp_gpa << HV_HYP_PAGE_SHIFT,
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HV_HYP_PAGE_SIZE, MEMREMAP_WB);
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if (!hv_cpu->synic_message_page)
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pr_err("Fail to map syinc message page.\n");
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} else {
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simp.base_simp_gpa = virt_to_phys(hv_cpu->synic_message_page)
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>> HV_HYP_PAGE_SHIFT;
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}
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hv_set_register(HV_REGISTER_SIMP, simp.as_uint64);
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/* Setup the Synic's event page */
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siefp.as_uint64 = hv_get_register(HV_REGISTER_SIEFP);
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siefp.siefp_enabled = 1;
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if (hv_isolation_type_snp()) {
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hv_cpu->synic_event_page =
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memremap(siefp.base_siefp_gpa << HV_HYP_PAGE_SHIFT,
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HV_HYP_PAGE_SIZE, MEMREMAP_WB);
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if (!hv_cpu->synic_event_page)
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pr_err("Fail to map syinc event page.\n");
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} else {
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siefp.base_siefp_gpa = virt_to_phys(hv_cpu->synic_event_page)
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>> HV_HYP_PAGE_SHIFT;
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}
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hv_set_register(HV_REGISTER_SIEFP, siefp.as_uint64);
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/* Setup the shared SINT. */
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if (vmbus_irq != -1)
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enable_percpu_irq(vmbus_irq, 0);
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shared_sint.as_uint64 = hv_get_register(HV_REGISTER_SINT0 +
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VMBUS_MESSAGE_SINT);
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shared_sint.vector = vmbus_interrupt;
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shared_sint.masked = false;
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/*
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* On architectures where Hyper-V doesn't support AEOI (e.g., ARM64),
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* it doesn't provide a recommendation flag and AEOI must be disabled.
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*/
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#ifdef HV_DEPRECATING_AEOI_RECOMMENDED
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shared_sint.auto_eoi =
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!(ms_hyperv.hints & HV_DEPRECATING_AEOI_RECOMMENDED);
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#else
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shared_sint.auto_eoi = 0;
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#endif
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hv_set_register(HV_REGISTER_SINT0 + VMBUS_MESSAGE_SINT,
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shared_sint.as_uint64);
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/* Enable the global synic bit */
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sctrl.as_uint64 = hv_get_register(HV_REGISTER_SCONTROL);
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sctrl.enable = 1;
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hv_set_register(HV_REGISTER_SCONTROL, sctrl.as_uint64);
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}
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int hv_synic_init(unsigned int cpu)
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{
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hv_synic_enable_regs(cpu);
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hv_stimer_legacy_init(cpu, VMBUS_MESSAGE_SINT);
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return 0;
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}
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/*
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* hv_synic_cleanup - Cleanup routine for hv_synic_init().
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*/
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void hv_synic_disable_regs(unsigned int cpu)
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{
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struct hv_per_cpu_context *hv_cpu
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= per_cpu_ptr(hv_context.cpu_context, cpu);
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union hv_synic_sint shared_sint;
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union hv_synic_simp simp;
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union hv_synic_siefp siefp;
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union hv_synic_scontrol sctrl;
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shared_sint.as_uint64 = hv_get_register(HV_REGISTER_SINT0 +
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VMBUS_MESSAGE_SINT);
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shared_sint.masked = 1;
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/* Need to correctly cleanup in the case of SMP!!! */
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/* Disable the interrupt */
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hv_set_register(HV_REGISTER_SINT0 + VMBUS_MESSAGE_SINT,
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shared_sint.as_uint64);
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simp.as_uint64 = hv_get_register(HV_REGISTER_SIMP);
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/*
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* In Isolation VM, sim and sief pages are allocated by
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* paravisor. These pages also will be used by kdump
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* kernel. So just reset enable bit here and keep page
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* addresses.
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*/
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simp.simp_enabled = 0;
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if (hv_isolation_type_snp())
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memunmap(hv_cpu->synic_message_page);
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else
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simp.base_simp_gpa = 0;
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hv_set_register(HV_REGISTER_SIMP, simp.as_uint64);
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siefp.as_uint64 = hv_get_register(HV_REGISTER_SIEFP);
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siefp.siefp_enabled = 0;
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if (hv_isolation_type_snp())
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memunmap(hv_cpu->synic_event_page);
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else
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siefp.base_siefp_gpa = 0;
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hv_set_register(HV_REGISTER_SIEFP, siefp.as_uint64);
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/* Disable the global synic bit */
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sctrl.as_uint64 = hv_get_register(HV_REGISTER_SCONTROL);
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sctrl.enable = 0;
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hv_set_register(HV_REGISTER_SCONTROL, sctrl.as_uint64);
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if (vmbus_irq != -1)
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disable_percpu_irq(vmbus_irq);
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}
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#define HV_MAX_TRIES 3
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/*
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* Scan the event flags page of 'this' CPU looking for any bit that is set. If we find one
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* bit set, then wait for a few milliseconds. Repeat these steps for a maximum of 3 times.
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* Return 'true', if there is still any set bit after this operation; 'false', otherwise.
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*
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* If a bit is set, that means there is a pending channel interrupt. The expectation is
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* that the normal interrupt handling mechanism will find and process the channel interrupt
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* "very soon", and in the process clear the bit.
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*/
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static bool hv_synic_event_pending(void)
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{
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struct hv_per_cpu_context *hv_cpu = this_cpu_ptr(hv_context.cpu_context);
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union hv_synic_event_flags *event =
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(union hv_synic_event_flags *)hv_cpu->synic_event_page + VMBUS_MESSAGE_SINT;
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unsigned long *recv_int_page = event->flags; /* assumes VMBus version >= VERSION_WIN8 */
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bool pending;
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u32 relid;
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int tries = 0;
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retry:
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pending = false;
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for_each_set_bit(relid, recv_int_page, HV_EVENT_FLAGS_COUNT) {
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/* Special case - VMBus channel protocol messages */
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if (relid == 0)
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continue;
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pending = true;
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break;
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}
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if (pending && tries++ < HV_MAX_TRIES) {
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usleep_range(10000, 20000);
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goto retry;
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}
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return pending;
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}
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int hv_synic_cleanup(unsigned int cpu)
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{
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struct vmbus_channel *channel, *sc;
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bool channel_found = false;
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if (vmbus_connection.conn_state != CONNECTED)
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goto always_cleanup;
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/*
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* Hyper-V does not provide a way to change the connect CPU once
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* it is set; we must prevent the connect CPU from going offline
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* while the VM is running normally. But in the panic or kexec()
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* path where the vmbus is already disconnected, the CPU must be
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* allowed to shut down.
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*/
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if (cpu == VMBUS_CONNECT_CPU)
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return -EBUSY;
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/*
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* Search for channels which are bound to the CPU we're about to
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* cleanup. In case we find one and vmbus is still connected, we
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* fail; this will effectively prevent CPU offlining.
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*
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* TODO: Re-bind the channels to different CPUs.
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*/
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mutex_lock(&vmbus_connection.channel_mutex);
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list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
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if (channel->target_cpu == cpu) {
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channel_found = true;
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break;
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}
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list_for_each_entry(sc, &channel->sc_list, sc_list) {
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if (sc->target_cpu == cpu) {
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channel_found = true;
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break;
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}
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}
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if (channel_found)
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break;
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}
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mutex_unlock(&vmbus_connection.channel_mutex);
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if (channel_found)
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return -EBUSY;
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/*
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* channel_found == false means that any channels that were previously
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* assigned to the CPU have been reassigned elsewhere with a call of
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* vmbus_send_modifychannel(). Scan the event flags page looking for
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* bits that are set and waiting with a timeout for vmbus_chan_sched()
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* to process such bits. If bits are still set after this operation
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* and VMBus is connected, fail the CPU offlining operation.
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*/
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if (vmbus_proto_version >= VERSION_WIN10_V4_1 && hv_synic_event_pending())
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return -EBUSY;
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always_cleanup:
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hv_stimer_legacy_cleanup(cpu);
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hv_synic_disable_regs(cpu);
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return 0;
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}
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