760 lines
20 KiB
C
760 lines
20 KiB
C
/*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* KVM/MIPS MMU handling in the KVM module.
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*
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* Copyright (C) 2012 MIPS Technologies, Inc. All rights reserved.
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* Authors: Sanjay Lal <sanjayl@kymasys.com>
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*/
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#include <linux/highmem.h>
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#include <linux/kvm_host.h>
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#include <linux/uaccess.h>
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#include <asm/mmu_context.h>
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#include <asm/pgalloc.h>
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/*
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* KVM_MMU_CACHE_MIN_PAGES is the number of GPA page table translation levels
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* for which pages need to be cached.
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*/
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#if defined(__PAGETABLE_PMD_FOLDED)
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#define KVM_MMU_CACHE_MIN_PAGES 1
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#else
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#define KVM_MMU_CACHE_MIN_PAGES 2
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#endif
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void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu)
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{
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kvm_mmu_free_memory_cache(&vcpu->arch.mmu_page_cache);
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}
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/**
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* kvm_pgd_init() - Initialise KVM GPA page directory.
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* @page: Pointer to page directory (PGD) for KVM GPA.
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*
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* Initialise a KVM GPA page directory with pointers to the invalid table, i.e.
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* representing no mappings. This is similar to pgd_init(), however it
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* initialises all the page directory pointers, not just the ones corresponding
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* to the userland address space (since it is for the guest physical address
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* space rather than a virtual address space).
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*/
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static void kvm_pgd_init(void *page)
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{
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unsigned long *p, *end;
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unsigned long entry;
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#ifdef __PAGETABLE_PMD_FOLDED
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entry = (unsigned long)invalid_pte_table;
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#else
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entry = (unsigned long)invalid_pmd_table;
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#endif
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p = (unsigned long *)page;
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end = p + PTRS_PER_PGD;
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do {
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p[0] = entry;
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p[1] = entry;
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p[2] = entry;
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p[3] = entry;
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p[4] = entry;
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p += 8;
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p[-3] = entry;
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p[-2] = entry;
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p[-1] = entry;
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} while (p != end);
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}
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/**
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* kvm_pgd_alloc() - Allocate and initialise a KVM GPA page directory.
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*
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* Allocate a blank KVM GPA page directory (PGD) for representing guest physical
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* to host physical page mappings.
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*
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* Returns: Pointer to new KVM GPA page directory.
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* NULL on allocation failure.
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*/
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pgd_t *kvm_pgd_alloc(void)
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{
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pgd_t *ret;
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ret = (pgd_t *)__get_free_pages(GFP_KERNEL, PGD_ORDER);
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if (ret)
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kvm_pgd_init(ret);
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return ret;
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}
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/**
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* kvm_mips_walk_pgd() - Walk page table with optional allocation.
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* @pgd: Page directory pointer.
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* @addr: Address to index page table using.
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* @cache: MMU page cache to allocate new page tables from, or NULL.
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*
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* Walk the page tables pointed to by @pgd to find the PTE corresponding to the
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* address @addr. If page tables don't exist for @addr, they will be created
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* from the MMU cache if @cache is not NULL.
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*
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* Returns: Pointer to pte_t corresponding to @addr.
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* NULL if a page table doesn't exist for @addr and !@cache.
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* NULL if a page table allocation failed.
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*/
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static pte_t *kvm_mips_walk_pgd(pgd_t *pgd, struct kvm_mmu_memory_cache *cache,
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unsigned long addr)
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{
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p4d_t *p4d;
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pud_t *pud;
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pmd_t *pmd;
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pgd += pgd_index(addr);
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if (pgd_none(*pgd)) {
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/* Not used on MIPS yet */
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BUG();
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return NULL;
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}
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p4d = p4d_offset(pgd, addr);
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pud = pud_offset(p4d, addr);
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if (pud_none(*pud)) {
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pmd_t *new_pmd;
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if (!cache)
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return NULL;
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new_pmd = kvm_mmu_memory_cache_alloc(cache);
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pmd_init((unsigned long)new_pmd,
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(unsigned long)invalid_pte_table);
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pud_populate(NULL, pud, new_pmd);
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}
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pmd = pmd_offset(pud, addr);
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if (pmd_none(*pmd)) {
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pte_t *new_pte;
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if (!cache)
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return NULL;
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new_pte = kvm_mmu_memory_cache_alloc(cache);
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clear_page(new_pte);
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pmd_populate_kernel(NULL, pmd, new_pte);
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}
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return pte_offset_kernel(pmd, addr);
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}
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/* Caller must hold kvm->mm_lock */
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static pte_t *kvm_mips_pte_for_gpa(struct kvm *kvm,
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struct kvm_mmu_memory_cache *cache,
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unsigned long addr)
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{
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return kvm_mips_walk_pgd(kvm->arch.gpa_mm.pgd, cache, addr);
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}
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/*
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* kvm_mips_flush_gpa_{pte,pmd,pud,pgd,pt}.
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* Flush a range of guest physical address space from the VM's GPA page tables.
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*/
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static bool kvm_mips_flush_gpa_pte(pte_t *pte, unsigned long start_gpa,
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unsigned long end_gpa)
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{
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int i_min = pte_index(start_gpa);
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int i_max = pte_index(end_gpa);
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bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PTE - 1);
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int i;
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for (i = i_min; i <= i_max; ++i) {
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if (!pte_present(pte[i]))
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continue;
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set_pte(pte + i, __pte(0));
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}
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return safe_to_remove;
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}
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static bool kvm_mips_flush_gpa_pmd(pmd_t *pmd, unsigned long start_gpa,
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unsigned long end_gpa)
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{
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pte_t *pte;
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unsigned long end = ~0ul;
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int i_min = pmd_index(start_gpa);
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int i_max = pmd_index(end_gpa);
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bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PMD - 1);
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int i;
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for (i = i_min; i <= i_max; ++i, start_gpa = 0) {
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if (!pmd_present(pmd[i]))
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continue;
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pte = pte_offset_kernel(pmd + i, 0);
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if (i == i_max)
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end = end_gpa;
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if (kvm_mips_flush_gpa_pte(pte, start_gpa, end)) {
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pmd_clear(pmd + i);
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pte_free_kernel(NULL, pte);
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} else {
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safe_to_remove = false;
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}
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}
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return safe_to_remove;
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}
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static bool kvm_mips_flush_gpa_pud(pud_t *pud, unsigned long start_gpa,
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unsigned long end_gpa)
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{
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pmd_t *pmd;
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unsigned long end = ~0ul;
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int i_min = pud_index(start_gpa);
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int i_max = pud_index(end_gpa);
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bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PUD - 1);
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int i;
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for (i = i_min; i <= i_max; ++i, start_gpa = 0) {
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if (!pud_present(pud[i]))
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continue;
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pmd = pmd_offset(pud + i, 0);
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if (i == i_max)
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end = end_gpa;
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if (kvm_mips_flush_gpa_pmd(pmd, start_gpa, end)) {
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pud_clear(pud + i);
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pmd_free(NULL, pmd);
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} else {
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safe_to_remove = false;
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}
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}
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return safe_to_remove;
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}
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static bool kvm_mips_flush_gpa_pgd(pgd_t *pgd, unsigned long start_gpa,
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unsigned long end_gpa)
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{
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p4d_t *p4d;
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pud_t *pud;
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unsigned long end = ~0ul;
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int i_min = pgd_index(start_gpa);
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int i_max = pgd_index(end_gpa);
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bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PGD - 1);
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int i;
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for (i = i_min; i <= i_max; ++i, start_gpa = 0) {
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if (!pgd_present(pgd[i]))
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continue;
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p4d = p4d_offset(pgd, 0);
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pud = pud_offset(p4d + i, 0);
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if (i == i_max)
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end = end_gpa;
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if (kvm_mips_flush_gpa_pud(pud, start_gpa, end)) {
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pgd_clear(pgd + i);
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pud_free(NULL, pud);
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} else {
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safe_to_remove = false;
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}
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}
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return safe_to_remove;
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}
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/**
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* kvm_mips_flush_gpa_pt() - Flush a range of guest physical addresses.
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* @kvm: KVM pointer.
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* @start_gfn: Guest frame number of first page in GPA range to flush.
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* @end_gfn: Guest frame number of last page in GPA range to flush.
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*
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* Flushes a range of GPA mappings from the GPA page tables.
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*
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* The caller must hold the @kvm->mmu_lock spinlock.
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*
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* Returns: Whether its safe to remove the top level page directory because
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* all lower levels have been removed.
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*/
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bool kvm_mips_flush_gpa_pt(struct kvm *kvm, gfn_t start_gfn, gfn_t end_gfn)
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{
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return kvm_mips_flush_gpa_pgd(kvm->arch.gpa_mm.pgd,
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start_gfn << PAGE_SHIFT,
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end_gfn << PAGE_SHIFT);
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}
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#define BUILD_PTE_RANGE_OP(name, op) \
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static int kvm_mips_##name##_pte(pte_t *pte, unsigned long start, \
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unsigned long end) \
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{ \
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int ret = 0; \
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int i_min = pte_index(start); \
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int i_max = pte_index(end); \
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int i; \
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pte_t old, new; \
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\
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for (i = i_min; i <= i_max; ++i) { \
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if (!pte_present(pte[i])) \
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continue; \
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\
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old = pte[i]; \
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new = op(old); \
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if (pte_val(new) == pte_val(old)) \
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continue; \
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set_pte(pte + i, new); \
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ret = 1; \
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} \
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return ret; \
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} \
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\
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/* returns true if anything was done */ \
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static int kvm_mips_##name##_pmd(pmd_t *pmd, unsigned long start, \
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unsigned long end) \
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{ \
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int ret = 0; \
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pte_t *pte; \
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unsigned long cur_end = ~0ul; \
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int i_min = pmd_index(start); \
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int i_max = pmd_index(end); \
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int i; \
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\
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for (i = i_min; i <= i_max; ++i, start = 0) { \
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if (!pmd_present(pmd[i])) \
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continue; \
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\
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pte = pte_offset_kernel(pmd + i, 0); \
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if (i == i_max) \
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cur_end = end; \
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\
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ret |= kvm_mips_##name##_pte(pte, start, cur_end); \
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} \
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return ret; \
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} \
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\
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static int kvm_mips_##name##_pud(pud_t *pud, unsigned long start, \
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unsigned long end) \
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{ \
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int ret = 0; \
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pmd_t *pmd; \
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unsigned long cur_end = ~0ul; \
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int i_min = pud_index(start); \
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int i_max = pud_index(end); \
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int i; \
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\
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for (i = i_min; i <= i_max; ++i, start = 0) { \
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if (!pud_present(pud[i])) \
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continue; \
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\
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pmd = pmd_offset(pud + i, 0); \
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if (i == i_max) \
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cur_end = end; \
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\
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ret |= kvm_mips_##name##_pmd(pmd, start, cur_end); \
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} \
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return ret; \
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} \
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\
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static int kvm_mips_##name##_pgd(pgd_t *pgd, unsigned long start, \
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unsigned long end) \
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{ \
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int ret = 0; \
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p4d_t *p4d; \
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pud_t *pud; \
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unsigned long cur_end = ~0ul; \
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int i_min = pgd_index(start); \
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int i_max = pgd_index(end); \
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int i; \
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\
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for (i = i_min; i <= i_max; ++i, start = 0) { \
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if (!pgd_present(pgd[i])) \
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continue; \
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\
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p4d = p4d_offset(pgd, 0); \
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pud = pud_offset(p4d + i, 0); \
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if (i == i_max) \
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cur_end = end; \
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\
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ret |= kvm_mips_##name##_pud(pud, start, cur_end); \
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} \
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return ret; \
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}
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/*
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* kvm_mips_mkclean_gpa_pt.
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* Mark a range of guest physical address space clean (writes fault) in the VM's
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* GPA page table to allow dirty page tracking.
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*/
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BUILD_PTE_RANGE_OP(mkclean, pte_mkclean)
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/**
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* kvm_mips_mkclean_gpa_pt() - Make a range of guest physical addresses clean.
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* @kvm: KVM pointer.
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* @start_gfn: Guest frame number of first page in GPA range to flush.
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* @end_gfn: Guest frame number of last page in GPA range to flush.
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*
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* Make a range of GPA mappings clean so that guest writes will fault and
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* trigger dirty page logging.
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*
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* The caller must hold the @kvm->mmu_lock spinlock.
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*
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* Returns: Whether any GPA mappings were modified, which would require
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* derived mappings (GVA page tables & TLB enties) to be
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* invalidated.
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*/
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int kvm_mips_mkclean_gpa_pt(struct kvm *kvm, gfn_t start_gfn, gfn_t end_gfn)
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{
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return kvm_mips_mkclean_pgd(kvm->arch.gpa_mm.pgd,
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start_gfn << PAGE_SHIFT,
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end_gfn << PAGE_SHIFT);
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}
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/**
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* kvm_arch_mmu_enable_log_dirty_pt_masked() - write protect dirty pages
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* @kvm: The KVM pointer
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* @slot: The memory slot associated with mask
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* @gfn_offset: The gfn offset in memory slot
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* @mask: The mask of dirty pages at offset 'gfn_offset' in this memory
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* slot to be write protected
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*
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* Walks bits set in mask write protects the associated pte's. Caller must
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* acquire @kvm->mmu_lock.
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*/
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void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
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struct kvm_memory_slot *slot,
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gfn_t gfn_offset, unsigned long mask)
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{
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gfn_t base_gfn = slot->base_gfn + gfn_offset;
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gfn_t start = base_gfn + __ffs(mask);
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gfn_t end = base_gfn + __fls(mask);
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kvm_mips_mkclean_gpa_pt(kvm, start, end);
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}
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/*
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* kvm_mips_mkold_gpa_pt.
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* Mark a range of guest physical address space old (all accesses fault) in the
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* VM's GPA page table to allow detection of commonly used pages.
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*/
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BUILD_PTE_RANGE_OP(mkold, pte_mkold)
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static int kvm_mips_mkold_gpa_pt(struct kvm *kvm, gfn_t start_gfn,
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gfn_t end_gfn)
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{
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return kvm_mips_mkold_pgd(kvm->arch.gpa_mm.pgd,
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start_gfn << PAGE_SHIFT,
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end_gfn << PAGE_SHIFT);
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}
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bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range)
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{
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kvm_mips_flush_gpa_pt(kvm, range->start, range->end);
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return true;
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}
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bool kvm_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
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{
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gpa_t gpa = range->start << PAGE_SHIFT;
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pte_t hva_pte = range->pte;
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pte_t *gpa_pte = kvm_mips_pte_for_gpa(kvm, NULL, gpa);
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pte_t old_pte;
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if (!gpa_pte)
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return false;
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/* Mapping may need adjusting depending on memslot flags */
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old_pte = *gpa_pte;
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if (range->slot->flags & KVM_MEM_LOG_DIRTY_PAGES && !pte_dirty(old_pte))
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hva_pte = pte_mkclean(hva_pte);
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else if (range->slot->flags & KVM_MEM_READONLY)
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hva_pte = pte_wrprotect(hva_pte);
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set_pte(gpa_pte, hva_pte);
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/* Replacing an absent or old page doesn't need flushes */
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if (!pte_present(old_pte) || !pte_young(old_pte))
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return false;
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/* Pages swapped, aged, moved, or cleaned require flushes */
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return !pte_present(hva_pte) ||
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!pte_young(hva_pte) ||
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pte_pfn(old_pte) != pte_pfn(hva_pte) ||
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(pte_dirty(old_pte) && !pte_dirty(hva_pte));
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}
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bool kvm_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
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{
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return kvm_mips_mkold_gpa_pt(kvm, range->start, range->end);
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}
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|
|
bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
|
|
{
|
|
gpa_t gpa = range->start << PAGE_SHIFT;
|
|
pte_t *gpa_pte = kvm_mips_pte_for_gpa(kvm, NULL, gpa);
|
|
|
|
if (!gpa_pte)
|
|
return false;
|
|
return pte_young(*gpa_pte);
|
|
}
|
|
|
|
/**
|
|
* _kvm_mips_map_page_fast() - Fast path GPA fault handler.
|
|
* @vcpu: VCPU pointer.
|
|
* @gpa: Guest physical address of fault.
|
|
* @write_fault: Whether the fault was due to a write.
|
|
* @out_entry: New PTE for @gpa (written on success unless NULL).
|
|
* @out_buddy: New PTE for @gpa's buddy (written on success unless
|
|
* NULL).
|
|
*
|
|
* Perform fast path GPA fault handling, doing all that can be done without
|
|
* calling into KVM. This handles marking old pages young (for idle page
|
|
* tracking), and dirtying of clean pages (for dirty page logging).
|
|
*
|
|
* Returns: 0 on success, in which case we can update derived mappings and
|
|
* resume guest execution.
|
|
* -EFAULT on failure due to absent GPA mapping or write to
|
|
* read-only page, in which case KVM must be consulted.
|
|
*/
|
|
static int _kvm_mips_map_page_fast(struct kvm_vcpu *vcpu, unsigned long gpa,
|
|
bool write_fault,
|
|
pte_t *out_entry, pte_t *out_buddy)
|
|
{
|
|
struct kvm *kvm = vcpu->kvm;
|
|
gfn_t gfn = gpa >> PAGE_SHIFT;
|
|
pte_t *ptep;
|
|
kvm_pfn_t pfn = 0; /* silence bogus GCC warning */
|
|
bool pfn_valid = false;
|
|
int ret = 0;
|
|
|
|
spin_lock(&kvm->mmu_lock);
|
|
|
|
/* Fast path - just check GPA page table for an existing entry */
|
|
ptep = kvm_mips_pte_for_gpa(kvm, NULL, gpa);
|
|
if (!ptep || !pte_present(*ptep)) {
|
|
ret = -EFAULT;
|
|
goto out;
|
|
}
|
|
|
|
/* Track access to pages marked old */
|
|
if (!pte_young(*ptep)) {
|
|
set_pte(ptep, pte_mkyoung(*ptep));
|
|
pfn = pte_pfn(*ptep);
|
|
pfn_valid = true;
|
|
/* call kvm_set_pfn_accessed() after unlock */
|
|
}
|
|
if (write_fault && !pte_dirty(*ptep)) {
|
|
if (!pte_write(*ptep)) {
|
|
ret = -EFAULT;
|
|
goto out;
|
|
}
|
|
|
|
/* Track dirtying of writeable pages */
|
|
set_pte(ptep, pte_mkdirty(*ptep));
|
|
pfn = pte_pfn(*ptep);
|
|
mark_page_dirty(kvm, gfn);
|
|
kvm_set_pfn_dirty(pfn);
|
|
}
|
|
|
|
if (out_entry)
|
|
*out_entry = *ptep;
|
|
if (out_buddy)
|
|
*out_buddy = *ptep_buddy(ptep);
|
|
|
|
out:
|
|
spin_unlock(&kvm->mmu_lock);
|
|
if (pfn_valid)
|
|
kvm_set_pfn_accessed(pfn);
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* kvm_mips_map_page() - Map a guest physical page.
|
|
* @vcpu: VCPU pointer.
|
|
* @gpa: Guest physical address of fault.
|
|
* @write_fault: Whether the fault was due to a write.
|
|
* @out_entry: New PTE for @gpa (written on success unless NULL).
|
|
* @out_buddy: New PTE for @gpa's buddy (written on success unless
|
|
* NULL).
|
|
*
|
|
* Handle GPA faults by creating a new GPA mapping (or updating an existing
|
|
* one).
|
|
*
|
|
* This takes care of marking pages young or dirty (idle/dirty page tracking),
|
|
* asking KVM for the corresponding PFN, and creating a mapping in the GPA page
|
|
* tables. Derived mappings (GVA page tables and TLBs) must be handled by the
|
|
* caller.
|
|
*
|
|
* Returns: 0 on success, in which case the caller may use the @out_entry
|
|
* and @out_buddy PTEs to update derived mappings and resume guest
|
|
* execution.
|
|
* -EFAULT if there is no memory region at @gpa or a write was
|
|
* attempted to a read-only memory region. This is usually handled
|
|
* as an MMIO access.
|
|
*/
|
|
static int kvm_mips_map_page(struct kvm_vcpu *vcpu, unsigned long gpa,
|
|
bool write_fault,
|
|
pte_t *out_entry, pte_t *out_buddy)
|
|
{
|
|
struct kvm *kvm = vcpu->kvm;
|
|
struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
|
|
gfn_t gfn = gpa >> PAGE_SHIFT;
|
|
int srcu_idx, err;
|
|
kvm_pfn_t pfn;
|
|
pte_t *ptep, entry, old_pte;
|
|
bool writeable;
|
|
unsigned long prot_bits;
|
|
unsigned long mmu_seq;
|
|
|
|
/* Try the fast path to handle old / clean pages */
|
|
srcu_idx = srcu_read_lock(&kvm->srcu);
|
|
err = _kvm_mips_map_page_fast(vcpu, gpa, write_fault, out_entry,
|
|
out_buddy);
|
|
if (!err)
|
|
goto out;
|
|
|
|
/* We need a minimum of cached pages ready for page table creation */
|
|
err = kvm_mmu_topup_memory_cache(memcache, KVM_MMU_CACHE_MIN_PAGES);
|
|
if (err)
|
|
goto out;
|
|
|
|
retry:
|
|
/*
|
|
* Used to check for invalidations in progress, of the pfn that is
|
|
* returned by pfn_to_pfn_prot below.
|
|
*/
|
|
mmu_seq = kvm->mmu_notifier_seq;
|
|
/*
|
|
* Ensure the read of mmu_notifier_seq isn't reordered with PTE reads in
|
|
* gfn_to_pfn_prot() (which calls get_user_pages()), so that we don't
|
|
* risk the page we get a reference to getting unmapped before we have a
|
|
* chance to grab the mmu_lock without mmu_notifier_retry() noticing.
|
|
*
|
|
* This smp_rmb() pairs with the effective smp_wmb() of the combination
|
|
* of the pte_unmap_unlock() after the PTE is zapped, and the
|
|
* spin_lock() in kvm_mmu_notifier_invalidate_<page|range_end>() before
|
|
* mmu_notifier_seq is incremented.
|
|
*/
|
|
smp_rmb();
|
|
|
|
/* Slow path - ask KVM core whether we can access this GPA */
|
|
pfn = gfn_to_pfn_prot(kvm, gfn, write_fault, &writeable);
|
|
if (is_error_noslot_pfn(pfn)) {
|
|
err = -EFAULT;
|
|
goto out;
|
|
}
|
|
|
|
spin_lock(&kvm->mmu_lock);
|
|
/* Check if an invalidation has taken place since we got pfn */
|
|
if (mmu_notifier_retry(kvm, mmu_seq)) {
|
|
/*
|
|
* This can happen when mappings are changed asynchronously, but
|
|
* also synchronously if a COW is triggered by
|
|
* gfn_to_pfn_prot().
|
|
*/
|
|
spin_unlock(&kvm->mmu_lock);
|
|
kvm_release_pfn_clean(pfn);
|
|
goto retry;
|
|
}
|
|
|
|
/* Ensure page tables are allocated */
|
|
ptep = kvm_mips_pte_for_gpa(kvm, memcache, gpa);
|
|
|
|
/* Set up the PTE */
|
|
prot_bits = _PAGE_PRESENT | __READABLE | _page_cachable_default;
|
|
if (writeable) {
|
|
prot_bits |= _PAGE_WRITE;
|
|
if (write_fault) {
|
|
prot_bits |= __WRITEABLE;
|
|
mark_page_dirty(kvm, gfn);
|
|
kvm_set_pfn_dirty(pfn);
|
|
}
|
|
}
|
|
entry = pfn_pte(pfn, __pgprot(prot_bits));
|
|
|
|
/* Write the PTE */
|
|
old_pte = *ptep;
|
|
set_pte(ptep, entry);
|
|
|
|
err = 0;
|
|
if (out_entry)
|
|
*out_entry = *ptep;
|
|
if (out_buddy)
|
|
*out_buddy = *ptep_buddy(ptep);
|
|
|
|
spin_unlock(&kvm->mmu_lock);
|
|
kvm_release_pfn_clean(pfn);
|
|
kvm_set_pfn_accessed(pfn);
|
|
out:
|
|
srcu_read_unlock(&kvm->srcu, srcu_idx);
|
|
return err;
|
|
}
|
|
|
|
int kvm_mips_handle_vz_root_tlb_fault(unsigned long badvaddr,
|
|
struct kvm_vcpu *vcpu,
|
|
bool write_fault)
|
|
{
|
|
int ret;
|
|
|
|
ret = kvm_mips_map_page(vcpu, badvaddr, write_fault, NULL, NULL);
|
|
if (ret)
|
|
return ret;
|
|
|
|
/* Invalidate this entry in the TLB */
|
|
return kvm_vz_host_tlb_inv(vcpu, badvaddr);
|
|
}
|
|
|
|
/**
|
|
* kvm_mips_migrate_count() - Migrate timer.
|
|
* @vcpu: Virtual CPU.
|
|
*
|
|
* Migrate CP0_Count hrtimer to the current CPU by cancelling and restarting it
|
|
* if it was running prior to being cancelled.
|
|
*
|
|
* Must be called when the VCPU is migrated to a different CPU to ensure that
|
|
* timer expiry during guest execution interrupts the guest and causes the
|
|
* interrupt to be delivered in a timely manner.
|
|
*/
|
|
static void kvm_mips_migrate_count(struct kvm_vcpu *vcpu)
|
|
{
|
|
if (hrtimer_cancel(&vcpu->arch.comparecount_timer))
|
|
hrtimer_restart(&vcpu->arch.comparecount_timer);
|
|
}
|
|
|
|
/* Restore ASID once we are scheduled back after preemption */
|
|
void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
|
|
{
|
|
unsigned long flags;
|
|
|
|
kvm_debug("%s: vcpu %p, cpu: %d\n", __func__, vcpu, cpu);
|
|
|
|
local_irq_save(flags);
|
|
|
|
vcpu->cpu = cpu;
|
|
if (vcpu->arch.last_sched_cpu != cpu) {
|
|
kvm_debug("[%d->%d]KVM VCPU[%d] switch\n",
|
|
vcpu->arch.last_sched_cpu, cpu, vcpu->vcpu_id);
|
|
/*
|
|
* Migrate the timer interrupt to the current CPU so that it
|
|
* always interrupts the guest and synchronously triggers a
|
|
* guest timer interrupt.
|
|
*/
|
|
kvm_mips_migrate_count(vcpu);
|
|
}
|
|
|
|
/* restore guest state to registers */
|
|
kvm_mips_callbacks->vcpu_load(vcpu, cpu);
|
|
|
|
local_irq_restore(flags);
|
|
}
|
|
|
|
/* ASID can change if another task is scheduled during preemption */
|
|
void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
|
|
{
|
|
unsigned long flags;
|
|
int cpu;
|
|
|
|
local_irq_save(flags);
|
|
|
|
cpu = smp_processor_id();
|
|
vcpu->arch.last_sched_cpu = cpu;
|
|
vcpu->cpu = -1;
|
|
|
|
/* save guest state in registers */
|
|
kvm_mips_callbacks->vcpu_put(vcpu, cpu);
|
|
|
|
local_irq_restore(flags);
|
|
}
|