| Message ID | 20230206165851.3106338-4-ricarkol@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Implement Eager Page Splitting for ARM. | expand |
On Mon, Feb 6, 2023 at 8:58 AM Ricardo Koller <ricarkol@google.com> wrote: > > Add a stage2 helper, kvm_pgtable_stage2_create_unlinked(), for creating > unlinked tables (the opposite of kvm_pgtable_stage2_free_unlinked()). > Creating an unlinked table is useful for splitting block PTEs into > subtrees of 4K PTEs. For example, a 1G block PTE can be split into 4K > PTEs by first creating a fully populated tree, and then use it to > replace the 1G PTE in a single step. This will be used in a > subsequent commit for eager huge-page splitting (a dirty-logging > optimization). > > No functional change intended. This new function will be used in a > subsequent commit. > > Signed-off-by: Ricardo Koller <ricarkol@google.com> > --- > arch/arm64/include/asm/kvm_pgtable.h | 29 +++++++++++++++++ > arch/arm64/kvm/hyp/pgtable.c | 47 ++++++++++++++++++++++++++++ > 2 files changed, 76 insertions(+) > > diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h > index 7c45082e6c23..e94c92988745 100644 > --- a/arch/arm64/include/asm/kvm_pgtable.h > +++ b/arch/arm64/include/asm/kvm_pgtable.h > @@ -460,6 +460,35 @@ void kvm_pgtable_stage2_destroy(struct kvm_pgtable *pgt); > */ > void kvm_pgtable_stage2_free_unlinked(struct kvm_pgtable_mm_ops *mm_ops, void *pgtable, u32 level); > > +/** > + * kvm_pgtable_stage2_create_unlinked() - Create an unlinked stage-2 paging structure. > + * @pgt: Page-table structure initialised by kvm_pgtable_stage2_init*(). > + * @new: Unlinked stage-2 paging structure to be created. > + * @phys: Physical address of the memory to map. > + * @level: Level of the stage-2 paging structure to be created. > + * @prot: Permissions and attributes for the mapping. > + * @mc: Cache of pre-allocated and zeroed memory from which to allocate > + * page-table pages. > + * @force_pte: Force mappings to PAGE_SIZE granularity. > + * > + * Create an unlinked page-table tree under @new. If @force_pte is > + * true and @level is the PMD level, then the tree is mapped up to the typo: this should be: "if @force_pte is true OR @level is the PMD, then the tree is mapped up to the PAGE_SIZE leaf PTE" > + * PAGE_SIZE leaf PTE; the tree is mapped up one level otherwise. This > + * new page-table tree is not reachable (i.e., it is removed) from the > + * root pgd and it's therefore unreachableby the hardware page-table > + * walker. No TLB invalidation or CMOs are performed. > + * > + * If device attributes are not explicitly requested in @prot, then the > + * mapping will be normal, cacheable. > + * > + * Return: 0 only if a fully populated tree was created (all memory > + * under @level is mapped), negative error code on failure. > + */ > +int kvm_pgtable_stage2_create_unlinked(struct kvm_pgtable *pgt, > + kvm_pte_t *new, u64 phys, u32 level, > + enum kvm_pgtable_prot prot, void *mc, > + bool force_pte); > + > /** > * kvm_pgtable_stage2_map() - Install a mapping in a guest stage-2 page-table. > * @pgt: Page-table structure initialised by kvm_pgtable_stage2_init*(). > diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c > index 0a5ef9288371..fed314f2b320 100644 > --- a/arch/arm64/kvm/hyp/pgtable.c > +++ b/arch/arm64/kvm/hyp/pgtable.c > @@ -1181,6 +1181,53 @@ int kvm_pgtable_stage2_flush(struct kvm_pgtable *pgt, u64 addr, u64 size) > return kvm_pgtable_walk(pgt, addr, size, &walker); > } > > +int kvm_pgtable_stage2_create_unlinked(struct kvm_pgtable *pgt, > + kvm_pte_t *new, u64 phys, u32 level, > + enum kvm_pgtable_prot prot, void *mc, > + bool force_pte) > +{ > + struct stage2_map_data map_data = { > + .phys = phys, > + .mmu = pgt->mmu, > + .memcache = mc, > + .force_pte = force_pte, > + }; > + struct kvm_pgtable_walker walker = { > + .cb = stage2_map_walker, > + .flags = KVM_PGTABLE_WALK_LEAF | > + KVM_PGTABLE_WALK_SKIP_BBM | > + KVM_PGTABLE_WALK_SKIP_CMO, > + .arg = &map_data, > + }; > + /* .addr (the IPA) is irrelevant for a removed table */ > + struct kvm_pgtable_walk_data data = { > + .walker = &walker, > + .addr = 0, > + .end = kvm_granule_size(level), > + }; > + struct kvm_pgtable_mm_ops *mm_ops = pgt->mm_ops; > + kvm_pte_t *pgtable; > + int ret; > + > + ret = stage2_set_prot_attr(pgt, prot, &map_data.attr); > + if (ret) > + return ret; > + > + pgtable = mm_ops->zalloc_page(mc); > + if (!pgtable) > + return -ENOMEM; > + > + ret = __kvm_pgtable_walk(&data, mm_ops, (kvm_pteref_t)pgtable, > + level + 1); > + if (ret) { > + kvm_pgtable_stage2_free_unlinked(mm_ops, pgtable, level); > + mm_ops->put_page(pgtable); > + return ret; > + } > + > + *new = kvm_init_table_pte(pgtable, mm_ops); > + return 0; > +} > > int __kvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_s2_mmu *mmu, > struct kvm_pgtable_mm_ops *mm_ops, > -- > 2.39.1.519.gcb327c4b5f-goog >
diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h index 7c45082e6c23..e94c92988745 100644 --- a/arch/arm64/include/asm/kvm_pgtable.h +++ b/arch/arm64/include/asm/kvm_pgtable.h @@ -460,6 +460,35 @@ void kvm_pgtable_stage2_destroy(struct kvm_pgtable *pgt); */ void kvm_pgtable_stage2_free_unlinked(struct kvm_pgtable_mm_ops *mm_ops, void *pgtable, u32 level); +/** + * kvm_pgtable_stage2_create_unlinked() - Create an unlinked stage-2 paging structure. + * @pgt: Page-table structure initialised by kvm_pgtable_stage2_init*(). + * @new: Unlinked stage-2 paging structure to be created. + * @phys: Physical address of the memory to map. + * @level: Level of the stage-2 paging structure to be created. + * @prot: Permissions and attributes for the mapping. + * @mc: Cache of pre-allocated and zeroed memory from which to allocate + * page-table pages. + * @force_pte: Force mappings to PAGE_SIZE granularity. + * + * Create an unlinked page-table tree under @new. If @force_pte is + * true and @level is the PMD level, then the tree is mapped up to the + * PAGE_SIZE leaf PTE; the tree is mapped up one level otherwise. This + * new page-table tree is not reachable (i.e., it is removed) from the + * root pgd and it's therefore unreachableby the hardware page-table + * walker. No TLB invalidation or CMOs are performed. + * + * If device attributes are not explicitly requested in @prot, then the + * mapping will be normal, cacheable. + * + * Return: 0 only if a fully populated tree was created (all memory + * under @level is mapped), negative error code on failure. + */ +int kvm_pgtable_stage2_create_unlinked(struct kvm_pgtable *pgt, + kvm_pte_t *new, u64 phys, u32 level, + enum kvm_pgtable_prot prot, void *mc, + bool force_pte); + /** * kvm_pgtable_stage2_map() - Install a mapping in a guest stage-2 page-table. * @pgt: Page-table structure initialised by kvm_pgtable_stage2_init*(). diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c index 0a5ef9288371..fed314f2b320 100644 --- a/arch/arm64/kvm/hyp/pgtable.c +++ b/arch/arm64/kvm/hyp/pgtable.c @@ -1181,6 +1181,53 @@ int kvm_pgtable_stage2_flush(struct kvm_pgtable *pgt, u64 addr, u64 size) return kvm_pgtable_walk(pgt, addr, size, &walker); } +int kvm_pgtable_stage2_create_unlinked(struct kvm_pgtable *pgt, + kvm_pte_t *new, u64 phys, u32 level, + enum kvm_pgtable_prot prot, void *mc, + bool force_pte) +{ + struct stage2_map_data map_data = { + .phys = phys, + .mmu = pgt->mmu, + .memcache = mc, + .force_pte = force_pte, + }; + struct kvm_pgtable_walker walker = { + .cb = stage2_map_walker, + .flags = KVM_PGTABLE_WALK_LEAF | + KVM_PGTABLE_WALK_SKIP_BBM | + KVM_PGTABLE_WALK_SKIP_CMO, + .arg = &map_data, + }; + /* .addr (the IPA) is irrelevant for a removed table */ + struct kvm_pgtable_walk_data data = { + .walker = &walker, + .addr = 0, + .end = kvm_granule_size(level), + }; + struct kvm_pgtable_mm_ops *mm_ops = pgt->mm_ops; + kvm_pte_t *pgtable; + int ret; + + ret = stage2_set_prot_attr(pgt, prot, &map_data.attr); + if (ret) + return ret; + + pgtable = mm_ops->zalloc_page(mc); + if (!pgtable) + return -ENOMEM; + + ret = __kvm_pgtable_walk(&data, mm_ops, (kvm_pteref_t)pgtable, + level + 1); + if (ret) { + kvm_pgtable_stage2_free_unlinked(mm_ops, pgtable, level); + mm_ops->put_page(pgtable); + return ret; + } + + *new = kvm_init_table_pte(pgtable, mm_ops); + return 0; +} int __kvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_s2_mmu *mmu, struct kvm_pgtable_mm_ops *mm_ops,
Add a stage2 helper, kvm_pgtable_stage2_create_unlinked(), for creating unlinked tables (the opposite of kvm_pgtable_stage2_free_unlinked()). Creating an unlinked table is useful for splitting block PTEs into subtrees of 4K PTEs. For example, a 1G block PTE can be split into 4K PTEs by first creating a fully populated tree, and then use it to replace the 1G PTE in a single step. This will be used in a subsequent commit for eager huge-page splitting (a dirty-logging optimization). No functional change intended. This new function will be used in a subsequent commit. Signed-off-by: Ricardo Koller <ricarkol@google.com> --- arch/arm64/include/asm/kvm_pgtable.h | 29 +++++++++++++++++ arch/arm64/kvm/hyp/pgtable.c | 47 ++++++++++++++++++++++++++++ 2 files changed, 76 insertions(+)