262 lines
6.8 KiB
C
262 lines
6.8 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/init.h>
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#include <linux/memblock.h>
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#include <linux/sizes.h>
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#include <linux/cma.h>
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#include <linux/bitops.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 <asm/archrandom.h>
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#include <asm/xics.h>
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#include <asm/dbell.h>
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#include <asm/cputhreads.h>
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#define KVM_CMA_CHUNK_ORDER 18
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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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static struct cma *kvm_cma;
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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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VM_BUG_ON(order_base_2(nr_pages) < KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
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return cma_alloc(kvm_cma, nr_pages, order_base_2(HPT_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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cma_release(kvm_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 memblock allocator
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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 need CMA reservation only when we are in HV mode
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*/
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if (!cpu_has_feature(CPU_FTR_HVMODE))
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return;
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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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align_size = HPT_ALIGN_PAGES << PAGE_SHIFT;
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cma_declare_contiguous(0, selected_size, 0, align_size,
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KVM_CMA_CHUNK_ORDER - PAGE_SHIFT, false, &kvm_cma);
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}
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}
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/*
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* Real-mode H_CONFER implementation.
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* We check if we are the only vcpu out of this virtual core
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* still running in the guest and not ceded. If so, we pop up
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* to the virtual-mode implementation; if not, just return to
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* the guest.
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*/
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long int kvmppc_rm_h_confer(struct kvm_vcpu *vcpu, int target,
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unsigned int yield_count)
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{
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struct kvmppc_vcore *vc = vcpu->arch.vcore;
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int threads_running;
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int threads_ceded;
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int threads_conferring;
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u64 stop = get_tb() + 10 * tb_ticks_per_usec;
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int rv = H_SUCCESS; /* => don't yield */
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set_bit(vcpu->arch.ptid, &vc->conferring_threads);
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while ((get_tb() < stop) && !VCORE_IS_EXITING(vc)) {
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threads_running = VCORE_ENTRY_MAP(vc);
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threads_ceded = vc->napping_threads;
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threads_conferring = vc->conferring_threads;
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if ((threads_ceded | threads_conferring) == threads_running) {
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rv = H_TOO_HARD; /* => do yield */
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break;
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}
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}
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clear_bit(vcpu->arch.ptid, &vc->conferring_threads);
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return rv;
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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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extern int hcall_real_table[], hcall_real_table_end[];
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int kvmppc_hcall_impl_hv_realmode(unsigned long cmd)
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{
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cmd /= 4;
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if (cmd < hcall_real_table_end - hcall_real_table &&
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hcall_real_table[cmd])
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return 1;
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return 0;
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}
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EXPORT_SYMBOL_GPL(kvmppc_hcall_impl_hv_realmode);
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int kvmppc_hwrng_present(void)
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{
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return powernv_hwrng_present();
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}
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EXPORT_SYMBOL_GPL(kvmppc_hwrng_present);
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long kvmppc_h_random(struct kvm_vcpu *vcpu)
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{
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if (powernv_get_random_real_mode(&vcpu->arch.gpr[4]))
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return H_SUCCESS;
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return H_HARDWARE;
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}
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static inline void rm_writeb(unsigned long paddr, u8 val)
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{
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__asm__ __volatile__("stbcix %0,0,%1"
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: : "r" (val), "r" (paddr) : "memory");
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}
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/*
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* Send an interrupt or message to another CPU.
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* This can only be called in real mode.
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* The caller needs to include any barrier needed to order writes
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* to memory vs. the IPI/message.
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*/
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void kvmhv_rm_send_ipi(int cpu)
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{
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unsigned long xics_phys;
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/* On POWER8 for IPIs to threads in the same core, use msgsnd */
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if (cpu_has_feature(CPU_FTR_ARCH_207S) &&
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cpu_first_thread_sibling(cpu) ==
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cpu_first_thread_sibling(raw_smp_processor_id())) {
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unsigned long msg = PPC_DBELL_TYPE(PPC_DBELL_SERVER);
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msg |= cpu_thread_in_core(cpu);
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__asm__ __volatile__ (PPC_MSGSND(%0) : : "r" (msg));
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return;
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}
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/* Else poke the target with an IPI */
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xics_phys = paca[cpu].kvm_hstate.xics_phys;
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rm_writeb(xics_phys + XICS_MFRR, IPI_PRIORITY);
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}
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/*
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* The following functions are called from the assembly code
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* in book3s_hv_rmhandlers.S.
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*/
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static void kvmhv_interrupt_vcore(struct kvmppc_vcore *vc, int active)
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{
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int cpu = vc->pcpu;
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/* Order setting of exit map vs. msgsnd/IPI */
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smp_mb();
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for (; active; active >>= 1, ++cpu)
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if (active & 1)
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kvmhv_rm_send_ipi(cpu);
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}
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void kvmhv_commence_exit(int trap)
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{
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struct kvmppc_vcore *vc = local_paca->kvm_hstate.kvm_vcore;
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int ptid = local_paca->kvm_hstate.ptid;
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int me, ee;
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/* Set our bit in the threads-exiting-guest map in the 0xff00
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bits of vcore->entry_exit_map */
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me = 0x100 << ptid;
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do {
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ee = vc->entry_exit_map;
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} while (cmpxchg(&vc->entry_exit_map, ee, ee | me) != ee);
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/* Are we the first here? */
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if ((ee >> 8) != 0)
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return;
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/*
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* Trigger the other threads in this vcore to exit the guest.
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* If this is a hypervisor decrementer interrupt then they
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* will be already on their way out of the guest.
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*/
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if (trap != BOOK3S_INTERRUPT_HV_DECREMENTER)
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kvmhv_interrupt_vcore(vc, ee & ~(1 << ptid));
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}
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