> -----原始邮件----- > 发件人: gregkh@xxxxxxxxxxxxxxxxxxx > 发送时间:2024-09-13 20:53:47 (星期五) > 收件人: chenhuacai@xxxxxxxxxxx, gregkh@xxxxxxxxxxxxxxxxxxx, helugang@xxxxxxxxxxxxx, maobibo@xxxxxxxxxxx, zhaotianrui@xxxxxxxxxxx > 抄送: stable-commits@xxxxxxxxxxxxxxx > 主题: Patch "LoongArch: KVM: Implement kvm mmu operations" has been added to the 6.6-stable tree > > > This is a note to let you know that I've just added the patch titled > > LoongArch: KVM: Implement kvm mmu operations > > to the 6.6-stable tree which can be found at: > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary > > The filename of the patch is: > loongarch-kvm-implement-kvm-mmu-operations.patch > and it can be found in the queue-6.6 subdirectory. > > If you, or anyone else, feels it should not be added to the stable tree, > please let <stable@xxxxxxxxxxxxxxx> know about it. Oh, no. This patch should not be added to 6.6, because 6.6 has no KVM at all. Huacai > > > From stable+bounces-75645-greg=kroah.com@xxxxxxxxxxxxxxx Tue Sep 10 15:12:27 2024 > From: He Lugang <helugang@xxxxxxxxxxxxx> > Date: Tue, 10 Sep 2024 21:11:18 +0800 > Subject: LoongArch: KVM: Implement kvm mmu operations > To: stable@xxxxxxxxxxxxxxx > Cc: Tianrui Zhao <zhaotianrui@xxxxxxxxxxx>, Bibo Mao <maobibo@xxxxxxxxxxx>, Huacai Chen <chenhuacai@xxxxxxxxxxx>, He Lugang <helugang@xxxxxxxxxxxxx> > Message-ID: <091CB73198EC428B+20240910131119.18625-1-helugang@xxxxxxxxxxxxx> > > From: Tianrui Zhao <zhaotianrui@xxxxxxxxxxx> > > commit 752e2cd7b4fb412f3e008493e0195e357bab9773 upstream > > Implement LoongArch kvm mmu, it is used to switch gpa to hpa when guest > exit because of address translation exception. > > This patch implement: allocating gpa page table, searching gpa from it, > and flushing guest gpa in the table. > > Reviewed-by: Bibo Mao <maobibo@xxxxxxxxxxx> > Tested-by: Huacai Chen <chenhuacai@xxxxxxxxxxx> > Signed-off-by: Tianrui Zhao <zhaotianrui@xxxxxxxxxxx> > Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx> > Signed-off-by: He Lugang <helugang@xxxxxxxxxxxxx> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > --- > arch/loongarch/include/asm/kvm_mmu.h | 139 +++++ > arch/loongarch/kvm/mmu.c | 914 +++++++++++++++++++++++++++++++++++ > 2 files changed, 1053 insertions(+) > create mode 100644 arch/loongarch/include/asm/kvm_mmu.h > create mode 100644 arch/loongarch/kvm/mmu.c > > --- /dev/null > +++ b/arch/loongarch/include/asm/kvm_mmu.h > @@ -0,0 +1,139 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * Copyright (C) 2020-2023 Loongson Technology Corporation Limited > + */ > + > +#ifndef __ASM_LOONGARCH_KVM_MMU_H__ > +#define __ASM_LOONGARCH_KVM_MMU_H__ > + > +#include <linux/kvm_host.h> > +#include <asm/pgalloc.h> > +#include <asm/tlb.h> > + > +/* > + * KVM_MMU_CACHE_MIN_PAGES is the number of GPA page table translation levels > + * for which pages need to be cached. > + */ > +#define KVM_MMU_CACHE_MIN_PAGES (CONFIG_PGTABLE_LEVELS - 1) > + > +#define _KVM_FLUSH_PGTABLE 0x1 > +#define _KVM_HAS_PGMASK 0x2 > +#define kvm_pfn_pte(pfn, prot) (((pfn) << PFN_PTE_SHIFT) | pgprot_val(prot)) > +#define kvm_pte_pfn(x) ((phys_addr_t)((x & _PFN_MASK) >> PFN_PTE_SHIFT)) > + > +typedef unsigned long kvm_pte_t; > +typedef struct kvm_ptw_ctx kvm_ptw_ctx; > +typedef int (*kvm_pte_ops)(kvm_pte_t *pte, phys_addr_t addr, kvm_ptw_ctx *ctx); > + > +struct kvm_ptw_ctx { > + kvm_pte_ops ops; > + unsigned long flag; > + > + /* for kvm_arch_mmu_enable_log_dirty_pt_masked use */ > + unsigned long mask; > + unsigned long gfn; > + > + /* page walk mmu info */ > + unsigned int level; > + unsigned long pgtable_shift; > + unsigned long invalid_entry; > + unsigned long *invalid_ptes; > + unsigned int *pte_shifts; > + void *opaque; > + > + /* free pte table page list */ > + struct list_head list; > +}; > + > +kvm_pte_t *kvm_pgd_alloc(void); > + > +static inline void kvm_set_pte(kvm_pte_t *ptep, kvm_pte_t val) > +{ > + WRITE_ONCE(*ptep, val); > +} > + > +static inline int kvm_pte_write(kvm_pte_t pte) { return pte & _PAGE_WRITE; } > +static inline int kvm_pte_dirty(kvm_pte_t pte) { return pte & _PAGE_DIRTY; } > +static inline int kvm_pte_young(kvm_pte_t pte) { return pte & _PAGE_ACCESSED; } > +static inline int kvm_pte_huge(kvm_pte_t pte) { return pte & _PAGE_HUGE; } > + > +static inline kvm_pte_t kvm_pte_mkyoung(kvm_pte_t pte) > +{ > + return pte | _PAGE_ACCESSED; > +} > + > +static inline kvm_pte_t kvm_pte_mkold(kvm_pte_t pte) > +{ > + return pte & ~_PAGE_ACCESSED; > +} > + > +static inline kvm_pte_t kvm_pte_mkdirty(kvm_pte_t pte) > +{ > + return pte | _PAGE_DIRTY; > +} > + > +static inline kvm_pte_t kvm_pte_mkclean(kvm_pte_t pte) > +{ > + return pte & ~_PAGE_DIRTY; > +} > + > +static inline kvm_pte_t kvm_pte_mkhuge(kvm_pte_t pte) > +{ > + return pte | _PAGE_HUGE; > +} > + > +static inline kvm_pte_t kvm_pte_mksmall(kvm_pte_t pte) > +{ > + return pte & ~_PAGE_HUGE; > +} > + > +static inline int kvm_need_flush(kvm_ptw_ctx *ctx) > +{ > + return ctx->flag & _KVM_FLUSH_PGTABLE; > +} > + > +static inline kvm_pte_t *kvm_pgtable_offset(kvm_ptw_ctx *ctx, kvm_pte_t *table, > + phys_addr_t addr) > +{ > + > + return table + ((addr >> ctx->pgtable_shift) & (PTRS_PER_PTE - 1)); > +} > + > +static inline phys_addr_t kvm_pgtable_addr_end(kvm_ptw_ctx *ctx, > + phys_addr_t addr, phys_addr_t end) > +{ > + phys_addr_t boundary, size; > + > + size = 0x1UL << ctx->pgtable_shift; > + boundary = (addr + size) & ~(size - 1); > + return (boundary - 1 < end - 1) ? boundary : end; > +} > + > +static inline int kvm_pte_present(kvm_ptw_ctx *ctx, kvm_pte_t *entry) > +{ > + if (!ctx || ctx->level == 0) > + return !!(*entry & _PAGE_PRESENT); > + > + return *entry != ctx->invalid_entry; > +} > + > +static inline int kvm_pte_none(kvm_ptw_ctx *ctx, kvm_pte_t *entry) > +{ > + return *entry == ctx->invalid_entry; > +} > + > +static inline void kvm_ptw_enter(kvm_ptw_ctx *ctx) > +{ > + ctx->level--; > + ctx->pgtable_shift = ctx->pte_shifts[ctx->level]; > + ctx->invalid_entry = ctx->invalid_ptes[ctx->level]; > +} > + > +static inline void kvm_ptw_exit(kvm_ptw_ctx *ctx) > +{ > + ctx->level++; > + ctx->pgtable_shift = ctx->pte_shifts[ctx->level]; > + ctx->invalid_entry = ctx->invalid_ptes[ctx->level]; > +} > + > +#endif /* __ASM_LOONGARCH_KVM_MMU_H__ */ > --- /dev/null > +++ b/arch/loongarch/kvm/mmu.c > @@ -0,0 +1,914 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (C) 2020-2023 Loongson Technology Corporation Limited > + */ > + > +#include <linux/highmem.h> > +#include <linux/hugetlb.h> > +#include <linux/kvm_host.h> > +#include <linux/page-flags.h> > +#include <linux/uaccess.h> > +#include <asm/mmu_context.h> > +#include <asm/pgalloc.h> > +#include <asm/tlb.h> > +#include <asm/kvm_mmu.h> > + > +static inline void kvm_ptw_prepare(struct kvm *kvm, kvm_ptw_ctx *ctx) > +{ > + ctx->level = kvm->arch.root_level; > + /* pte table */ > + ctx->invalid_ptes = kvm->arch.invalid_ptes; > + ctx->pte_shifts = kvm->arch.pte_shifts; > + ctx->pgtable_shift = ctx->pte_shifts[ctx->level]; > + ctx->invalid_entry = ctx->invalid_ptes[ctx->level]; > + ctx->opaque = kvm; > +} > + > +/* > + * Mark a range of guest physical address space old (all accesses fault) in the > + * VM's GPA page table to allow detection of commonly used pages. > + */ > +static int kvm_mkold_pte(kvm_pte_t *pte, phys_addr_t addr, kvm_ptw_ctx *ctx) > +{ > + if (kvm_pte_young(*pte)) { > + *pte = kvm_pte_mkold(*pte); > + return 1; > + } > + > + return 0; > +} > + > +/* > + * Mark a range of guest physical address space clean (writes fault) in the VM's > + * GPA page table to allow dirty page tracking. > + */ > +static int kvm_mkclean_pte(kvm_pte_t *pte, phys_addr_t addr, kvm_ptw_ctx *ctx) > +{ > + gfn_t offset; > + kvm_pte_t val; > + > + val = *pte; > + /* > + * For kvm_arch_mmu_enable_log_dirty_pt_masked with mask, start and end > + * may cross hugepage, for first huge page parameter addr is equal to > + * start, however for the second huge page addr is base address of > + * this huge page, rather than start or end address > + */ > + if ((ctx->flag & _KVM_HAS_PGMASK) && !kvm_pte_huge(val)) { > + offset = (addr >> PAGE_SHIFT) - ctx->gfn; > + if (!(BIT(offset) & ctx->mask)) > + return 0; > + } > + > + /* > + * Need not split huge page now, just set write-proect pte bit > + * Split huge page until next write fault > + */ > + if (kvm_pte_dirty(val)) { > + *pte = kvm_pte_mkclean(val); > + return 1; > + } > + > + return 0; > +} > + > +/* > + * Clear pte entry > + */ > +static int kvm_flush_pte(kvm_pte_t *pte, phys_addr_t addr, kvm_ptw_ctx *ctx) > +{ > + struct kvm *kvm; > + > + kvm = ctx->opaque; > + if (ctx->level) > + kvm->stat.hugepages--; > + else > + kvm->stat.pages--; > + > + *pte = ctx->invalid_entry; > + > + return 1; > +} > + > +/* > + * kvm_pgd_alloc() - Allocate and initialise a KVM GPA page directory. > + * > + * Allocate a blank KVM GPA page directory (PGD) for representing guest physical > + * to host physical page mappings. > + * > + * Returns: Pointer to new KVM GPA page directory. > + * NULL on allocation failure. > + */ > +kvm_pte_t *kvm_pgd_alloc(void) > +{ > + kvm_pte_t *pgd; > + > + pgd = (kvm_pte_t *)__get_free_pages(GFP_KERNEL, 0); > + if (pgd) > + pgd_init((void *)pgd); > + > + return pgd; > +} > + > +static void _kvm_pte_init(void *addr, unsigned long val) > +{ > + unsigned long *p, *end; > + > + p = (unsigned long *)addr; > + end = p + PTRS_PER_PTE; > + do { > + p[0] = val; > + p[1] = val; > + p[2] = val; > + p[3] = val; > + p[4] = val; > + p += 8; > + p[-3] = val; > + p[-2] = val; > + p[-1] = val; > + } while (p != end); > +} > + > +/* > + * Caller must hold kvm->mm_lock > + * > + * Walk the page tables of kvm to find the PTE corresponding to the > + * address @addr. If page tables don't exist for @addr, they will be created > + * from the MMU cache if @cache is not NULL. > + */ > +static kvm_pte_t *kvm_populate_gpa(struct kvm *kvm, > + struct kvm_mmu_memory_cache *cache, > + unsigned long addr, int level) > +{ > + kvm_ptw_ctx ctx; > + kvm_pte_t *entry, *child; > + > + kvm_ptw_prepare(kvm, &ctx); > + child = kvm->arch.pgd; > + while (ctx.level > level) { > + entry = kvm_pgtable_offset(&ctx, child, addr); > + if (kvm_pte_none(&ctx, entry)) { > + if (!cache) > + return NULL; > + > + child = kvm_mmu_memory_cache_alloc(cache); > + _kvm_pte_init(child, ctx.invalid_ptes[ctx.level - 1]); > + kvm_set_pte(entry, __pa(child)); > + } else if (kvm_pte_huge(*entry)) { > + return entry; > + } else > + child = (kvm_pte_t *)__va(PHYSADDR(*entry)); > + kvm_ptw_enter(&ctx); > + } > + > + entry = kvm_pgtable_offset(&ctx, child, addr); > + > + return entry; > +} > + > +/* > + * Page walker for VM shadow mmu at last level > + * The last level is small pte page or huge pmd page > + */ > +static int kvm_ptw_leaf(kvm_pte_t *dir, phys_addr_t addr, phys_addr_t end, kvm_ptw_ctx *ctx) > +{ > + int ret; > + phys_addr_t next, start, size; > + struct list_head *list; > + kvm_pte_t *entry, *child; > + > + ret = 0; > + start = addr; > + child = (kvm_pte_t *)__va(PHYSADDR(*dir)); > + entry = kvm_pgtable_offset(ctx, child, addr); > + do { > + next = addr + (0x1UL << ctx->pgtable_shift); > + if (!kvm_pte_present(ctx, entry)) > + continue; > + > + ret |= ctx->ops(entry, addr, ctx); > + } while (entry++, addr = next, addr < end); > + > + if (kvm_need_flush(ctx)) { > + size = 0x1UL << (ctx->pgtable_shift + PAGE_SHIFT - 3); > + if (start + size == end) { > + list = (struct list_head *)child; > + list_add_tail(list, &ctx->list); > + *dir = ctx->invalid_ptes[ctx->level + 1]; > + } > + } > + > + return ret; > +} > + > +/* > + * Page walker for VM shadow mmu at page table dir level > + */ > +static int kvm_ptw_dir(kvm_pte_t *dir, phys_addr_t addr, phys_addr_t end, kvm_ptw_ctx *ctx) > +{ > + int ret; > + phys_addr_t next, start, size; > + struct list_head *list; > + kvm_pte_t *entry, *child; > + > + ret = 0; > + start = addr; > + child = (kvm_pte_t *)__va(PHYSADDR(*dir)); > + entry = kvm_pgtable_offset(ctx, child, addr); > + do { > + next = kvm_pgtable_addr_end(ctx, addr, end); > + if (!kvm_pte_present(ctx, entry)) > + continue; > + > + if (kvm_pte_huge(*entry)) { > + ret |= ctx->ops(entry, addr, ctx); > + continue; > + } > + > + kvm_ptw_enter(ctx); > + if (ctx->level == 0) > + ret |= kvm_ptw_leaf(entry, addr, next, ctx); > + else > + ret |= kvm_ptw_dir(entry, addr, next, ctx); > + kvm_ptw_exit(ctx); > + } while (entry++, addr = next, addr < end); > + > + if (kvm_need_flush(ctx)) { > + size = 0x1UL << (ctx->pgtable_shift + PAGE_SHIFT - 3); > + if (start + size == end) { > + list = (struct list_head *)child; > + list_add_tail(list, &ctx->list); > + *dir = ctx->invalid_ptes[ctx->level + 1]; > + } > + } > + > + return ret; > +} > + > +/* > + * Page walker for VM shadow mmu at page root table > + */ > +static int kvm_ptw_top(kvm_pte_t *dir, phys_addr_t addr, phys_addr_t end, kvm_ptw_ctx *ctx) > +{ > + int ret; > + phys_addr_t next; > + kvm_pte_t *entry; > + > + ret = 0; > + entry = kvm_pgtable_offset(ctx, dir, addr); > + do { > + next = kvm_pgtable_addr_end(ctx, addr, end); > + if (!kvm_pte_present(ctx, entry)) > + continue; > + > + kvm_ptw_enter(ctx); > + ret |= kvm_ptw_dir(entry, addr, next, ctx); > + kvm_ptw_exit(ctx); > + } while (entry++, addr = next, addr < end); > + > + return ret; > +} > + > +/* > + * kvm_flush_range() - Flush a range of guest physical addresses. > + * @kvm: KVM pointer. > + * @start_gfn: Guest frame number of first page in GPA range to flush. > + * @end_gfn: Guest frame number of last page in GPA range to flush. > + * @lock: Whether to hold mmu_lock or not > + * > + * Flushes a range of GPA mappings from the GPA page tables. > + */ > +static void kvm_flush_range(struct kvm *kvm, gfn_t start_gfn, gfn_t end_gfn, int lock) > +{ > + int ret; > + kvm_ptw_ctx ctx; > + struct list_head *pos, *temp; > + > + ctx.ops = kvm_flush_pte; > + ctx.flag = _KVM_FLUSH_PGTABLE; > + kvm_ptw_prepare(kvm, &ctx); > + INIT_LIST_HEAD(&ctx.list); > + > + if (lock) { > + spin_lock(&kvm->mmu_lock); > + ret = kvm_ptw_top(kvm->arch.pgd, start_gfn << PAGE_SHIFT, > + end_gfn << PAGE_SHIFT, &ctx); > + spin_unlock(&kvm->mmu_lock); > + } else > + ret = kvm_ptw_top(kvm->arch.pgd, start_gfn << PAGE_SHIFT, > + end_gfn << PAGE_SHIFT, &ctx); > + > + /* Flush vpid for each vCPU individually */ > + if (ret) > + kvm_flush_remote_tlbs(kvm); > + > + /* > + * free pte table page after mmu_lock > + * the pte table page is linked together with ctx.list > + */ > + list_for_each_safe(pos, temp, &ctx.list) { > + list_del(pos); > + free_page((unsigned long)pos); > + } > +} > + > +/* > + * kvm_mkclean_gpa_pt() - Make a range of guest physical addresses clean. > + * @kvm: KVM pointer. > + * @start_gfn: Guest frame number of first page in GPA range to flush. > + * @end_gfn: Guest frame number of last page in GPA range to flush. > + * > + * Make a range of GPA mappings clean so that guest writes will fault and > + * trigger dirty page logging. > + * > + * The caller must hold the @kvm->mmu_lock spinlock. > + * > + * Returns: Whether any GPA mappings were modified, which would require > + * derived mappings (GVA page tables & TLB enties) to be > + * invalidated. > + */ > +static int kvm_mkclean_gpa_pt(struct kvm *kvm, gfn_t start_gfn, gfn_t end_gfn) > +{ > + kvm_ptw_ctx ctx; > + > + ctx.ops = kvm_mkclean_pte; > + ctx.flag = 0; > + kvm_ptw_prepare(kvm, &ctx); > + return kvm_ptw_top(kvm->arch.pgd, start_gfn << PAGE_SHIFT, end_gfn << PAGE_SHIFT, &ctx); > +} > + > +/* > + * kvm_arch_mmu_enable_log_dirty_pt_masked() - write protect dirty pages > + * @kvm: The KVM pointer > + * @slot: The memory slot associated with mask > + * @gfn_offset: The gfn offset in memory slot > + * @mask: The mask of dirty pages at offset 'gfn_offset' in this memory > + * slot to be write protected > + * > + * Walks bits set in mask write protects the associated pte's. Caller must > + * acquire @kvm->mmu_lock. > + */ > +void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm, > + struct kvm_memory_slot *slot, gfn_t gfn_offset, unsigned long mask) > +{ > + kvm_ptw_ctx ctx; > + gfn_t base_gfn = slot->base_gfn + gfn_offset; > + gfn_t start = base_gfn + __ffs(mask); > + gfn_t end = base_gfn + __fls(mask) + 1; > + > + ctx.ops = kvm_mkclean_pte; > + ctx.flag = _KVM_HAS_PGMASK; > + ctx.mask = mask; > + ctx.gfn = base_gfn; > + kvm_ptw_prepare(kvm, &ctx); > + > + kvm_ptw_top(kvm->arch.pgd, start << PAGE_SHIFT, end << PAGE_SHIFT, &ctx); > +} > + > +void kvm_arch_commit_memory_region(struct kvm *kvm, > + struct kvm_memory_slot *old, > + const struct kvm_memory_slot *new, > + enum kvm_mr_change change) > +{ > + int needs_flush; > + > + /* > + * If dirty page logging is enabled, write protect all pages in the slot > + * ready for dirty logging. > + * > + * There is no need to do this in any of the following cases: > + * CREATE: No dirty mappings will already exist. > + * MOVE/DELETE: The old mappings will already have been cleaned up by > + * kvm_arch_flush_shadow_memslot() > + */ > + if (change == KVM_MR_FLAGS_ONLY && > + (!(old->flags & KVM_MEM_LOG_DIRTY_PAGES) && > + new->flags & KVM_MEM_LOG_DIRTY_PAGES)) { > + spin_lock(&kvm->mmu_lock); > + /* Write protect GPA page table entries */ > + needs_flush = kvm_mkclean_gpa_pt(kvm, new->base_gfn, > + new->base_gfn + new->npages); > + spin_unlock(&kvm->mmu_lock); > + if (needs_flush) > + kvm_flush_remote_tlbs(kvm); > + } > +} > + > +void kvm_arch_flush_shadow_all(struct kvm *kvm) > +{ > + kvm_flush_range(kvm, 0, kvm->arch.gpa_size >> PAGE_SHIFT, 0); > +} > + > +void kvm_arch_flush_shadow_memslot(struct kvm *kvm, struct kvm_memory_slot *slot) > +{ > + /* > + * The slot has been made invalid (ready for moving or deletion), so we > + * need to ensure that it can no longer be accessed by any guest vCPUs. > + */ > + kvm_flush_range(kvm, slot->base_gfn, slot->base_gfn + slot->npages, 1); > +} > + > +bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range) > +{ > + kvm_ptw_ctx ctx; > + > + ctx.flag = 0; > + ctx.ops = kvm_flush_pte; > + kvm_ptw_prepare(kvm, &ctx); > + INIT_LIST_HEAD(&ctx.list); > + > + return kvm_ptw_top(kvm->arch.pgd, range->start << PAGE_SHIFT, > + range->end << PAGE_SHIFT, &ctx); > +} > + > +bool kvm_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range) > +{ > + unsigned long prot_bits; > + kvm_pte_t *ptep; > + kvm_pfn_t pfn = pte_pfn(range->arg.pte); > + gpa_t gpa = range->start << PAGE_SHIFT; > + > + ptep = kvm_populate_gpa(kvm, NULL, gpa, 0); > + if (!ptep) > + return false; > + > + /* Replacing an absent or old page doesn't need flushes */ > + if (!kvm_pte_present(NULL, ptep) || !kvm_pte_young(*ptep)) { > + kvm_set_pte(ptep, 0); > + return false; > + } > + > + /* Fill new pte if write protected or page migrated */ > + prot_bits = _PAGE_PRESENT | __READABLE; > + prot_bits |= _CACHE_MASK & pte_val(range->arg.pte); > + > + /* > + * Set _PAGE_WRITE or _PAGE_DIRTY iff old and new pte both support > + * _PAGE_WRITE for map_page_fast if next page write fault > + * _PAGE_DIRTY since gpa has already recorded as dirty page > + */ > + prot_bits |= __WRITEABLE & *ptep & pte_val(range->arg.pte); > + kvm_set_pte(ptep, kvm_pfn_pte(pfn, __pgprot(prot_bits))); > + > + return true; > +} > + > +bool kvm_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range) > +{ > + kvm_ptw_ctx ctx; > + > + ctx.flag = 0; > + ctx.ops = kvm_mkold_pte; > + kvm_ptw_prepare(kvm, &ctx); > + > + return kvm_ptw_top(kvm->arch.pgd, range->start << PAGE_SHIFT, > + range->end << PAGE_SHIFT, &ctx); > +} > + > +bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range) > +{ > + gpa_t gpa = range->start << PAGE_SHIFT; > + kvm_pte_t *ptep = kvm_populate_gpa(kvm, NULL, gpa, 0); > + > + if (ptep && kvm_pte_present(NULL, ptep) && kvm_pte_young(*ptep)) > + return true; > + > + return false; > +} > + > +/* > + * kvm_map_page_fast() - Fast path GPA fault handler. > + * @vcpu: vCPU pointer. > + * @gpa: Guest physical address of fault. > + * @write: Whether the fault was due to a write. > + * > + * 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_map_page_fast(struct kvm_vcpu *vcpu, unsigned long gpa, bool write) > +{ > + int ret = 0; > + kvm_pfn_t pfn = 0; > + kvm_pte_t *ptep, changed, new; > + gfn_t gfn = gpa >> PAGE_SHIFT; > + struct kvm *kvm = vcpu->kvm; > + struct kvm_memory_slot *slot; > + > + spin_lock(&kvm->mmu_lock); > + > + /* Fast path - just check GPA page table for an existing entry */ > + ptep = kvm_populate_gpa(kvm, NULL, gpa, 0); > + if (!ptep || !kvm_pte_present(NULL, ptep)) { > + ret = -EFAULT; > + goto out; > + } > + > + /* Track access to pages marked old */ > + new = *ptep; > + if (!kvm_pte_young(new)) > + new = kvm_pte_mkyoung(new); > + /* call kvm_set_pfn_accessed() after unlock */ > + > + if (write && !kvm_pte_dirty(new)) { > + if (!kvm_pte_write(new)) { > + ret = -EFAULT; > + goto out; > + } > + > + if (kvm_pte_huge(new)) { > + /* > + * Do not set write permission when dirty logging is > + * enabled for HugePages > + */ > + slot = gfn_to_memslot(kvm, gfn); > + if (kvm_slot_dirty_track_enabled(slot)) { > + ret = -EFAULT; > + goto out; > + } > + } > + > + /* Track dirtying of writeable pages */ > + new = kvm_pte_mkdirty(new); > + } > + > + changed = new ^ (*ptep); > + if (changed) { > + kvm_set_pte(ptep, new); > + pfn = kvm_pte_pfn(new); > + } > + spin_unlock(&kvm->mmu_lock); > + > + /* > + * Fixme: pfn may be freed after mmu_lock > + * kvm_try_get_pfn(pfn)/kvm_release_pfn pair to prevent this? > + */ > + if (kvm_pte_young(changed)) > + kvm_set_pfn_accessed(pfn); > + > + if (kvm_pte_dirty(changed)) { > + mark_page_dirty(kvm, gfn); > + kvm_set_pfn_dirty(pfn); > + } > + return ret; > +out: > + spin_unlock(&kvm->mmu_lock); > + return ret; > +} > + > +static bool fault_supports_huge_mapping(struct kvm_memory_slot *memslot, > + unsigned long hva, unsigned long map_size, bool write) > +{ > + size_t size; > + gpa_t gpa_start; > + hva_t uaddr_start, uaddr_end; > + > + /* Disable dirty logging on HugePages */ > + if (kvm_slot_dirty_track_enabled(memslot) && write) > + return false; > + > + size = memslot->npages * PAGE_SIZE; > + gpa_start = memslot->base_gfn << PAGE_SHIFT; > + uaddr_start = memslot->userspace_addr; > + uaddr_end = uaddr_start + size; > + > + /* > + * Pages belonging to memslots that don't have the same alignment > + * within a PMD for userspace and GPA cannot be mapped with stage-2 > + * PMD entries, because we'll end up mapping the wrong pages. > + * > + * Consider a layout like the following: > + * > + * memslot->userspace_addr: > + * +-----+--------------------+--------------------+---+ > + * |abcde|fgh Stage-1 block | Stage-1 block tv|xyz| > + * +-----+--------------------+--------------------+---+ > + * > + * memslot->base_gfn << PAGE_SIZE: > + * +---+--------------------+--------------------+-----+ > + * |abc|def Stage-2 block | Stage-2 block |tvxyz| > + * +---+--------------------+--------------------+-----+ > + * > + * If we create those stage-2 blocks, we'll end up with this incorrect > + * mapping: > + * d -> f > + * e -> g > + * f -> h > + */ > + if ((gpa_start & (map_size - 1)) != (uaddr_start & (map_size - 1))) > + return false; > + > + /* > + * Next, let's make sure we're not trying to map anything not covered > + * by the memslot. This means we have to prohibit block size mappings > + * for the beginning and end of a non-block aligned and non-block sized > + * memory slot (illustrated by the head and tail parts of the > + * userspace view above containing pages 'abcde' and 'xyz', > + * respectively). > + * > + * Note that it doesn't matter if we do the check using the > + * userspace_addr or the base_gfn, as both are equally aligned (per > + * the check above) and equally sized. > + */ > + return (hva & ~(map_size - 1)) >= uaddr_start && > + (hva & ~(map_size - 1)) + map_size <= uaddr_end; > +} > + > +/* > + * Lookup the mapping level for @gfn in the current mm. > + * > + * WARNING! Use of host_pfn_mapping_level() requires the caller and the end > + * consumer to be tied into KVM's handlers for MMU notifier events! > + * > + * There are several ways to safely use this helper: > + * > + * - Check mmu_invalidate_retry_hva() after grabbing the mapping level, before > + * consuming it. In this case, mmu_lock doesn't need to be held during the > + * lookup, but it does need to be held while checking the MMU notifier. > + * > + * - Hold mmu_lock AND ensure there is no in-progress MMU notifier invalidation > + * event for the hva. This can be done by explicit checking the MMU notifier > + * or by ensuring that KVM already has a valid mapping that covers the hva. > + * > + * - Do not use the result to install new mappings, e.g. use the host mapping > + * level only to decide whether or not to zap an entry. In this case, it's > + * not required to hold mmu_lock (though it's highly likely the caller will > + * want to hold mmu_lock anyways, e.g. to modify SPTEs). > + * > + * Note! The lookup can still race with modifications to host page tables, but > + * the above "rules" ensure KVM will not _consume_ the result of the walk if a > + * race with the primary MMU occurs. > + */ > +static int host_pfn_mapping_level(struct kvm *kvm, gfn_t gfn, > + const struct kvm_memory_slot *slot) > +{ > + int level = 0; > + unsigned long hva; > + unsigned long flags; > + pgd_t pgd; > + p4d_t p4d; > + pud_t pud; > + pmd_t pmd; > + > + /* > + * Note, using the already-retrieved memslot and __gfn_to_hva_memslot() > + * is not solely for performance, it's also necessary to avoid the > + * "writable" check in __gfn_to_hva_many(), which will always fail on > + * read-only memslots due to gfn_to_hva() assuming writes. Earlier > + * page fault steps have already verified the guest isn't writing a > + * read-only memslot. > + */ > + hva = __gfn_to_hva_memslot(slot, gfn); > + > + /* > + * Disable IRQs to prevent concurrent tear down of host page tables, > + * e.g. if the primary MMU promotes a P*D to a huge page and then frees > + * the original page table. > + */ > + local_irq_save(flags); > + > + /* > + * Read each entry once. As above, a non-leaf entry can be promoted to > + * a huge page _during_ this walk. Re-reading the entry could send the > + * walk into the weeks, e.g. p*d_large() returns false (sees the old > + * value) and then p*d_offset() walks into the target huge page instead > + * of the old page table (sees the new value). > + */ > + pgd = READ_ONCE(*pgd_offset(kvm->mm, hva)); > + if (pgd_none(pgd)) > + goto out; > + > + p4d = READ_ONCE(*p4d_offset(&pgd, hva)); > + if (p4d_none(p4d) || !p4d_present(p4d)) > + goto out; > + > + pud = READ_ONCE(*pud_offset(&p4d, hva)); > + if (pud_none(pud) || !pud_present(pud)) > + goto out; > + > + pmd = READ_ONCE(*pmd_offset(&pud, hva)); > + if (pmd_none(pmd) || !pmd_present(pmd)) > + goto out; > + > + if (kvm_pte_huge(pmd_val(pmd))) > + level = 1; > + > +out: > + local_irq_restore(flags); > + return level; > +} > + > +/* > + * Split huge page > + */ > +static kvm_pte_t *kvm_split_huge(struct kvm_vcpu *vcpu, kvm_pte_t *ptep, gfn_t gfn) > +{ > + int i; > + kvm_pte_t val, *child; > + struct kvm *kvm = vcpu->kvm; > + struct kvm_mmu_memory_cache *memcache; > + > + memcache = &vcpu->arch.mmu_page_cache; > + child = kvm_mmu_memory_cache_alloc(memcache); > + val = kvm_pte_mksmall(*ptep); > + for (i = 0; i < PTRS_PER_PTE; i++) { > + kvm_set_pte(child + i, val); > + val += PAGE_SIZE; > + } > + > + /* The later kvm_flush_tlb_gpa() will flush hugepage tlb */ > + kvm_set_pte(ptep, __pa(child)); > + > + kvm->stat.hugepages--; > + kvm->stat.pages += PTRS_PER_PTE; > + > + return child + (gfn & (PTRS_PER_PTE - 1)); > +} > + > +/* > + * kvm_map_page() - Map a guest physical page. > + * @vcpu: vCPU pointer. > + * @gpa: Guest physical address of fault. > + * @write: Whether the fault was due to a write. > + * > + * 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 > + * -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_map_page(struct kvm_vcpu *vcpu, unsigned long gpa, bool write) > +{ > + bool writeable; > + int srcu_idx, err, retry_no = 0, level; > + unsigned long hva, mmu_seq, prot_bits; > + kvm_pfn_t pfn; > + kvm_pte_t *ptep, new_pte; > + gfn_t gfn = gpa >> PAGE_SHIFT; > + struct kvm *kvm = vcpu->kvm; > + struct kvm_memory_slot *memslot; > + struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache; > + > + /* Try the fast path to handle old / clean pages */ > + srcu_idx = srcu_read_lock(&kvm->srcu); > + err = kvm_map_page_fast(vcpu, gpa, write); > + if (!err) > + goto out; > + > + memslot = gfn_to_memslot(kvm, gfn); > + hva = gfn_to_hva_memslot_prot(memslot, gfn, &writeable); > + if (kvm_is_error_hva(hva) || (write && !writeable)) { > + err = -EFAULT; > + 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_invalidate_seq; > + /* > + * Ensure the read of mmu_invalidate_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_invalidate_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_invalidate_invalidate_<page|range_end>() before > + * mmu_invalidate_seq is incremented. > + */ > + smp_rmb(); > + > + /* Slow path - ask KVM core whether we can access this GPA */ > + pfn = gfn_to_pfn_prot(kvm, gfn, write, &writeable); > + if (is_error_noslot_pfn(pfn)) { > + err = -EFAULT; > + goto out; > + } > + > + /* Check if an invalidation has taken place since we got pfn */ > + spin_lock(&kvm->mmu_lock); > + if (mmu_invalidate_retry_hva(kvm, mmu_seq, hva)) { > + /* > + * 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); > + if (retry_no > 100) { > + retry_no = 0; > + schedule(); > + } > + retry_no++; > + goto retry; > + } > + > + /* > + * For emulated devices such virtio device, actual cache attribute is > + * determined by physical machine. > + * For pass through physical device, it should be uncachable > + */ > + prot_bits = _PAGE_PRESENT | __READABLE; > + if (pfn_valid(pfn)) > + prot_bits |= _CACHE_CC; > + else > + prot_bits |= _CACHE_SUC; > + > + if (writeable) { > + prot_bits |= _PAGE_WRITE; > + if (write) > + prot_bits |= __WRITEABLE; > + } > + > + /* Disable dirty logging on HugePages */ > + level = 0; > + if (!fault_supports_huge_mapping(memslot, hva, PMD_SIZE, write)) { > + level = 0; > + } else { > + level = host_pfn_mapping_level(kvm, gfn, memslot); > + if (level == 1) { > + gfn = gfn & ~(PTRS_PER_PTE - 1); > + pfn = pfn & ~(PTRS_PER_PTE - 1); > + } > + } > + > + /* Ensure page tables are allocated */ > + ptep = kvm_populate_gpa(kvm, memcache, gpa, level); > + new_pte = kvm_pfn_pte(pfn, __pgprot(prot_bits)); > + if (level == 1) { > + new_pte = kvm_pte_mkhuge(new_pte); > + /* > + * previous pmd entry is invalid_pte_table > + * there is invalid tlb with small page > + * need flush these invalid tlbs for current vcpu > + */ > + kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu); > + ++kvm->stat.hugepages; > + } else if (kvm_pte_huge(*ptep) && write) > + ptep = kvm_split_huge(vcpu, ptep, gfn); > + else > + ++kvm->stat.pages; > + kvm_set_pte(ptep, new_pte); > + spin_unlock(&kvm->mmu_lock); > + > + if (prot_bits & _PAGE_DIRTY) { > + mark_page_dirty_in_slot(kvm, memslot, gfn); > + kvm_set_pfn_dirty(pfn); > + } > + > + kvm_set_pfn_accessed(pfn); > + kvm_release_pfn_clean(pfn); > +out: > + srcu_read_unlock(&kvm->srcu, srcu_idx); > + return err; > +} > + > +int kvm_handle_mm_fault(struct kvm_vcpu *vcpu, unsigned long gpa, bool write) > +{ > + int ret; > + > + ret = kvm_map_page(vcpu, gpa, write); > + if (ret) > + return ret; > + > + /* Invalidate this entry in the TLB */ > + kvm_flush_tlb_gpa(vcpu, gpa); > + > + return 0; > +} > + > +void kvm_arch_sync_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot) > +{ > +} > + > +int kvm_arch_prepare_memory_region(struct kvm *kvm, const struct kvm_memory_slot *old, > + struct kvm_memory_slot *new, enum kvm_mr_change change) > +{ > + return 0; > +} > + > +void kvm_arch_flush_remote_tlbs_memslot(struct kvm *kvm, > + const struct kvm_memory_slot *memslot) > +{ > + kvm_flush_remote_tlbs(kvm); > +} > > > Patches currently in stable-queue which might be from helugang@xxxxxxxxxxxxx are > > queue-6.6/loongarch-kvm-implement-kvm-mmu-operations.patch > queue-6.6/loongarch-use-accessors-to-page-table-entries-instead-of-direct-dereference.patch 本邮件及其附件含有龙芯中科的商业秘密信息，仅限于发送给上面地址中列出的个人或群组。禁止任何其他人以任何形式使用（包括但不限于全部或部分地泄露、复制或散发）本邮件及其附件中的信息。如果您错收本邮件，请您立即电话或邮件通知发件人并删除本邮件。 This email and its attachments contain confidential information from Loongson Technology , which is intended only for the person or entity whose address is listed above. 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