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![Michael Ellerman](/assets/img/avatar_default.png)
As part of the support for split core on POWER8, we want to be able to block splitting of the core while KVM VMs are active. The logic to do that would be exactly the same as the code we currently have for inhibiting onlining of secondaries. Instead of adding an identical mechanism to block split core, rework the secondary inhibit code to be a "HV KVM is active" check. We can then use that in both the cpu hotplug code and the upcoming split core code. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Neuling <mikey@neuling.org> Acked-by: Alexander Graf <agraf@suse.de> Acked-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
214 lines
5.7 KiB
C
214 lines
5.7 KiB
C
/*
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* Copyright 2011 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License, version 2, as
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* published by the Free Software Foundation.
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*/
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#include <linux/cpu.h>
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#include <linux/kvm_host.h>
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#include <linux/preempt.h>
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#include <linux/export.h>
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#include <linux/sched.h>
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#include <linux/spinlock.h>
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#include <linux/bootmem.h>
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#include <linux/init.h>
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#include <linux/memblock.h>
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#include <linux/sizes.h>
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#include <asm/cputable.h>
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#include <asm/kvm_ppc.h>
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#include <asm/kvm_book3s.h>
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#include "book3s_hv_cma.h"
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/*
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* Hash page table alignment on newer cpus(CPU_FTR_ARCH_206)
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* should be power of 2.
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*/
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#define HPT_ALIGN_PAGES ((1 << 18) >> PAGE_SHIFT) /* 256k */
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/*
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* By default we reserve 5% of memory for hash pagetable allocation.
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*/
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static unsigned long kvm_cma_resv_ratio = 5;
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/*
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* We allocate RMAs (real mode areas) for KVM guests from the KVM CMA area.
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* Each RMA has to be physically contiguous and of a size that the
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* hardware supports. PPC970 and POWER7 support 64MB, 128MB and 256MB,
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* and other larger sizes. Since we are unlikely to be allocate that
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* much physically contiguous memory after the system is up and running,
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* we preallocate a set of RMAs in early boot using CMA.
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* should be power of 2.
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*/
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unsigned long kvm_rma_pages = (1 << 27) >> PAGE_SHIFT; /* 128MB */
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EXPORT_SYMBOL_GPL(kvm_rma_pages);
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/* Work out RMLS (real mode limit selector) field value for a given RMA size.
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Assumes POWER7 or PPC970. */
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static inline int lpcr_rmls(unsigned long rma_size)
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{
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switch (rma_size) {
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case 32ul << 20: /* 32 MB */
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if (cpu_has_feature(CPU_FTR_ARCH_206))
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return 8; /* only supported on POWER7 */
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return -1;
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case 64ul << 20: /* 64 MB */
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return 3;
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case 128ul << 20: /* 128 MB */
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return 7;
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case 256ul << 20: /* 256 MB */
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return 4;
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case 1ul << 30: /* 1 GB */
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return 2;
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case 16ul << 30: /* 16 GB */
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return 1;
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case 256ul << 30: /* 256 GB */
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return 0;
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default:
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return -1;
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}
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}
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static int __init early_parse_rma_size(char *p)
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{
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unsigned long kvm_rma_size;
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pr_debug("%s(%s)\n", __func__, p);
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if (!p)
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return -EINVAL;
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kvm_rma_size = memparse(p, &p);
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/*
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* Check that the requested size is one supported in hardware
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*/
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if (lpcr_rmls(kvm_rma_size) < 0) {
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pr_err("RMA size of 0x%lx not supported\n", kvm_rma_size);
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return -EINVAL;
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}
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kvm_rma_pages = kvm_rma_size >> PAGE_SHIFT;
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return 0;
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}
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early_param("kvm_rma_size", early_parse_rma_size);
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struct kvm_rma_info *kvm_alloc_rma()
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{
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struct page *page;
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struct kvm_rma_info *ri;
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ri = kmalloc(sizeof(struct kvm_rma_info), GFP_KERNEL);
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if (!ri)
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return NULL;
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page = kvm_alloc_cma(kvm_rma_pages, kvm_rma_pages);
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if (!page)
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goto err_out;
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atomic_set(&ri->use_count, 1);
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ri->base_pfn = page_to_pfn(page);
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return ri;
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err_out:
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kfree(ri);
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return NULL;
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}
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EXPORT_SYMBOL_GPL(kvm_alloc_rma);
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void kvm_release_rma(struct kvm_rma_info *ri)
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{
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if (atomic_dec_and_test(&ri->use_count)) {
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kvm_release_cma(pfn_to_page(ri->base_pfn), kvm_rma_pages);
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kfree(ri);
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}
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}
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EXPORT_SYMBOL_GPL(kvm_release_rma);
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static int __init early_parse_kvm_cma_resv(char *p)
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{
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pr_debug("%s(%s)\n", __func__, p);
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if (!p)
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return -EINVAL;
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return kstrtoul(p, 0, &kvm_cma_resv_ratio);
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}
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early_param("kvm_cma_resv_ratio", early_parse_kvm_cma_resv);
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struct page *kvm_alloc_hpt(unsigned long nr_pages)
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{
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unsigned long align_pages = HPT_ALIGN_PAGES;
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/* Old CPUs require HPT aligned on a multiple of its size */
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if (!cpu_has_feature(CPU_FTR_ARCH_206))
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align_pages = nr_pages;
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return kvm_alloc_cma(nr_pages, align_pages);
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}
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EXPORT_SYMBOL_GPL(kvm_alloc_hpt);
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void kvm_release_hpt(struct page *page, unsigned long nr_pages)
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{
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kvm_release_cma(page, nr_pages);
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}
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EXPORT_SYMBOL_GPL(kvm_release_hpt);
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/**
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* kvm_cma_reserve() - reserve area for kvm hash pagetable
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*
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* This function reserves memory from early allocator. It should be
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* called by arch specific code once the early allocator (memblock or bootmem)
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* has been activated and all other subsystems have already allocated/reserved
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* memory.
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*/
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void __init kvm_cma_reserve(void)
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{
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unsigned long align_size;
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struct memblock_region *reg;
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phys_addr_t selected_size = 0;
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/*
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* We cannot use memblock_phys_mem_size() here, because
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* memblock_analyze() has not been called yet.
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*/
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for_each_memblock(memory, reg)
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selected_size += memblock_region_memory_end_pfn(reg) -
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memblock_region_memory_base_pfn(reg);
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selected_size = (selected_size * kvm_cma_resv_ratio / 100) << PAGE_SHIFT;
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if (selected_size) {
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pr_debug("%s: reserving %ld MiB for global area\n", __func__,
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(unsigned long)selected_size / SZ_1M);
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/*
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* Old CPUs require HPT aligned on a multiple of its size. So for them
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* make the alignment as max size we could request.
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*/
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if (!cpu_has_feature(CPU_FTR_ARCH_206))
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align_size = __rounddown_pow_of_two(selected_size);
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else
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align_size = HPT_ALIGN_PAGES << PAGE_SHIFT;
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align_size = max(kvm_rma_pages << PAGE_SHIFT, align_size);
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kvm_cma_declare_contiguous(selected_size, align_size);
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}
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}
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/*
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* When running HV mode KVM we need to block certain operations while KVM VMs
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* exist in the system. We use a counter of VMs to track this.
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*
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* One of the operations we need to block is onlining of secondaries, so we
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* protect hv_vm_count with get/put_online_cpus().
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*/
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static atomic_t hv_vm_count;
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void kvm_hv_vm_activated(void)
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{
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get_online_cpus();
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atomic_inc(&hv_vm_count);
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put_online_cpus();
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}
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EXPORT_SYMBOL_GPL(kvm_hv_vm_activated);
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void kvm_hv_vm_deactivated(void)
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{
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get_online_cpus();
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atomic_dec(&hv_vm_count);
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put_online_cpus();
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}
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EXPORT_SYMBOL_GPL(kvm_hv_vm_deactivated);
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bool kvm_hv_mode_active(void)
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{
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return atomic_read(&hv_vm_count) != 0;
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}
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