| Message ID | 20221202061347.1070246-8-chao.p.peng@linux.intel.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | KVM: mm: fd-based approach for supporting KVM | expand |
On Fri, Dec 02, 2022 at 02:13:45PM +0800, Chao Peng <chao.p.peng@linux.intel.com> wrote: > A large page with mixed private/shared subpages can't be mapped as large > page since its sub private/shared pages are from different memory > backends and may also treated by architecture differently. When > private/shared memory are mixed in a large page, the current lpage_info > is not sufficient to decide whether the page can be mapped as large page > or not and additional private/shared mixed information is needed. > > Tracking this 'mixed' information with the current 'count' like > disallow_lpage is a bit challenge so reserve a bit in 'disallow_lpage' > to indicate a large page has mixed private/share subpages and update > this 'mixed' bit whenever the memory attribute is changed between > private and shared. > > Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com> > --- > arch/x86/include/asm/kvm_host.h | 8 ++ > arch/x86/kvm/mmu/mmu.c | 134 +++++++++++++++++++++++++++++++- > arch/x86/kvm/x86.c | 2 + > include/linux/kvm_host.h | 19 +++++ > virt/kvm/kvm_main.c | 9 ++- > 5 files changed, 169 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index 283cbb83d6ae..7772ab37ac89 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -38,6 +38,7 @@ > #include <asm/hyperv-tlfs.h> > > #define __KVM_HAVE_ARCH_VCPU_DEBUGFS > +#define __KVM_HAVE_ARCH_SET_MEMORY_ATTRIBUTES > > #define KVM_MAX_VCPUS 1024 > > @@ -1011,6 +1012,13 @@ struct kvm_vcpu_arch { > #endif > }; > > +/* > + * Use a bit in disallow_lpage to indicate private/shared pages mixed at the > + * level. The remaining bits are used as a reference count. > + */ > +#define KVM_LPAGE_PRIVATE_SHARED_MIXED (1U << 31) > +#define KVM_LPAGE_COUNT_MAX ((1U << 31) - 1) > + > struct kvm_lpage_info { > int disallow_lpage; > }; > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > index e2c70b5afa3e..2190fd8c95c0 100644 > --- a/arch/x86/kvm/mmu/mmu.c > +++ b/arch/x86/kvm/mmu/mmu.c > @@ -763,11 +763,16 @@ static void update_gfn_disallow_lpage_count(const struct kvm_memory_slot *slot, > { > struct kvm_lpage_info *linfo; > int i; > + int disallow_count; > > for (i = PG_LEVEL_2M; i <= KVM_MAX_HUGEPAGE_LEVEL; ++i) { > linfo = lpage_info_slot(gfn, slot, i); > + > + disallow_count = linfo->disallow_lpage & KVM_LPAGE_COUNT_MAX; > + WARN_ON(disallow_count + count < 0 || > + disallow_count > KVM_LPAGE_COUNT_MAX - count); > + > linfo->disallow_lpage += count; > - WARN_ON(linfo->disallow_lpage < 0); > } > } > > @@ -6986,3 +6991,130 @@ void kvm_mmu_pre_destroy_vm(struct kvm *kvm) > if (kvm->arch.nx_huge_page_recovery_thread) > kthread_stop(kvm->arch.nx_huge_page_recovery_thread); > } > + > +static bool linfo_is_mixed(struct kvm_lpage_info *linfo) > +{ > + return linfo->disallow_lpage & KVM_LPAGE_PRIVATE_SHARED_MIXED; > +} > + > +static void linfo_set_mixed(gfn_t gfn, struct kvm_memory_slot *slot, > + int level, bool mixed) > +{ > + struct kvm_lpage_info *linfo = lpage_info_slot(gfn, slot, level); > + > + if (mixed) > + linfo->disallow_lpage |= KVM_LPAGE_PRIVATE_SHARED_MIXED; > + else > + linfo->disallow_lpage &= ~KVM_LPAGE_PRIVATE_SHARED_MIXED; > +} > + > +static bool is_expected_attr_entry(void *entry, unsigned long expected_attrs) > +{ > + bool expect_private = expected_attrs & KVM_MEMORY_ATTRIBUTE_PRIVATE; > + > + if (xa_to_value(entry) & KVM_MEMORY_ATTRIBUTE_PRIVATE) { > + if (!expect_private) > + return false; > + } else if (expect_private) > + return false; > + > + return true; > +} > + > +static bool mem_attrs_mixed_2m(struct kvm *kvm, unsigned long attrs, > + gfn_t start, gfn_t end) > +{ > + XA_STATE(xas, &kvm->mem_attr_array, start); > + gfn_t gfn = start; > + void *entry; > + bool mixed = false; > + > + rcu_read_lock(); > + entry = xas_load(&xas); > + while (gfn < end) { > + if (xas_retry(&xas, entry)) > + continue; > + > + KVM_BUG_ON(gfn != xas.xa_index, kvm); > + > + if (!is_expected_attr_entry(entry, attrs)) { > + mixed = true; > + break; > + } > + > + entry = xas_next(&xas); > + gfn++; > + } > + > + rcu_read_unlock(); > + return mixed; > +} > + > +static bool mem_attrs_mixed(struct kvm *kvm, struct kvm_memory_slot *slot, > + int level, unsigned long attrs, > + gfn_t start, gfn_t end) > +{ > + unsigned long gfn; > + > + if (level == PG_LEVEL_2M) > + return mem_attrs_mixed_2m(kvm, attrs, start, end); > + > + for (gfn = start; gfn < end; gfn += KVM_PAGES_PER_HPAGE(level - 1)) > + if (linfo_is_mixed(lpage_info_slot(gfn, slot, level - 1)) || > + !is_expected_attr_entry(xa_load(&kvm->mem_attr_array, gfn), > + attrs)) > + return true; > + return false; > +} > + > +static void kvm_update_lpage_private_shared_mixed(struct kvm *kvm, > + struct kvm_memory_slot *slot, > + unsigned long attrs, > + gfn_t start, gfn_t end) > +{ > + unsigned long pages, mask; > + gfn_t gfn, gfn_end, first, last; > + int level; > + bool mixed; > + > + /* > + * The sequence matters here: we set the higher level basing on the > + * lower level's scanning result. > + */ > + for (level = PG_LEVEL_2M; level <= KVM_MAX_HUGEPAGE_LEVEL; level++) { > + pages = KVM_PAGES_PER_HPAGE(level); > + mask = ~(pages - 1); > + first = start & mask; > + last = (end - 1) & mask; > + > + /* > + * We only need to scan the head and tail page, for middle pages > + * we know they will not be mixed. > + */ > + gfn = max(first, slot->base_gfn); > + gfn_end = min(first + pages, slot->base_gfn + slot->npages); > + mixed = mem_attrs_mixed(kvm, slot, level, attrs, gfn, gfn_end); > + linfo_set_mixed(gfn, slot, level, mixed); > + > + if (first == last) > + return; continue. > + > + for (gfn = first + pages; gfn < last; gfn += pages) > + linfo_set_mixed(gfn, slot, level, false); > + > + gfn = last; > + gfn_end = min(last + pages, slot->base_gfn + slot->npages); if (gfn == gfn_end) continue. > + mixed = mem_attrs_mixed(kvm, slot, level, attrs, gfn, gfn_end); > + linfo_set_mixed(gfn, slot, level, mixed); > + } > +} > + > +void kvm_arch_set_memory_attributes(struct kvm *kvm, > + struct kvm_memory_slot *slot, > + unsigned long attrs, > + gfn_t start, gfn_t end) > +{ > + if (kvm_slot_can_be_private(slot)) > + kvm_update_lpage_private_shared_mixed(kvm, slot, attrs, > + start, end); > +} > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 9a07380f8d3c..5aefcff614d2 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -12362,6 +12362,8 @@ static int kvm_alloc_memslot_metadata(struct kvm *kvm, > if ((slot->base_gfn + npages) & (KVM_PAGES_PER_HPAGE(level) - 1)) > linfo[lpages - 1].disallow_lpage = 1; > ugfn = slot->userspace_addr >> PAGE_SHIFT; > + if (kvm_slot_can_be_private(slot)) > + ugfn |= slot->restricted_offset >> PAGE_SHIFT; Is there any alignment restriction? If no, It should be +=. In practice, alignment will hold though. Thanks, > /* > * If the gfn and userspace address are not aligned wrt each > * other, disable large page support for this slot. > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index 3331c0c92838..25099c94e770 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -592,6 +592,11 @@ struct kvm_memory_slot { > struct restrictedmem_notifier notifier; > }; > > +static inline bool kvm_slot_can_be_private(const struct kvm_memory_slot *slot) > +{ > + return slot && (slot->flags & KVM_MEM_PRIVATE); > +} > + > static inline bool kvm_slot_dirty_track_enabled(const struct kvm_memory_slot *slot) > { > return slot->flags & KVM_MEM_LOG_DIRTY_PAGES; > @@ -2316,4 +2321,18 @@ static inline void kvm_account_pgtable_pages(void *virt, int nr) > /* Max number of entries allowed for each kvm dirty ring */ > #define KVM_DIRTY_RING_MAX_ENTRIES 65536 > > +#ifdef __KVM_HAVE_ARCH_SET_MEMORY_ATTRIBUTES > +void kvm_arch_set_memory_attributes(struct kvm *kvm, > + struct kvm_memory_slot *slot, > + unsigned long attrs, > + gfn_t start, gfn_t end); > +#else > +static inline void kvm_arch_set_memory_attributes(struct kvm *kvm, > + struct kvm_memory_slot *slot, > + unsigned long attrs, > + gfn_t start, gfn_t end) > +{ > +} > +#endif /* __KVM_HAVE_ARCH_SET_MEMORY_ATTRIBUTES */ > + > #endif > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 4e1e1e113bf0..e107afea32f0 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -2354,7 +2354,8 @@ static u64 kvm_supported_mem_attributes(struct kvm *kvm) > return 0; > } > > -static void kvm_unmap_mem_range(struct kvm *kvm, gfn_t start, gfn_t end) > +static void kvm_unmap_mem_range(struct kvm *kvm, gfn_t start, gfn_t end, > + unsigned long attrs) > { > struct kvm_gfn_range gfn_range; > struct kvm_memory_slot *slot; > @@ -2378,6 +2379,10 @@ static void kvm_unmap_mem_range(struct kvm *kvm, gfn_t start, gfn_t end) > gfn_range.slot = slot; > > r |= kvm_unmap_gfn_range(kvm, &gfn_range); > + > + kvm_arch_set_memory_attributes(kvm, slot, attrs, > + gfn_range.start, > + gfn_range.end); > } > } > > @@ -2427,7 +2432,7 @@ static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm, > idx = srcu_read_lock(&kvm->srcu); > KVM_MMU_LOCK(kvm); > if (i > start) > - kvm_unmap_mem_range(kvm, start, i); > + kvm_unmap_mem_range(kvm, start, i, attrs->attributes); > kvm_mmu_invalidate_end(kvm); > KVM_MMU_UNLOCK(kvm); > srcu_read_unlock(&kvm->srcu, idx); > -- > 2.25.1 >
On Mon, Dec 05, 2022 at 02:49:59PM -0800, Isaku Yamahata wrote: > On Fri, Dec 02, 2022 at 02:13:45PM +0800, > Chao Peng <chao.p.peng@linux.intel.com> wrote: > > > A large page with mixed private/shared subpages can't be mapped as large > > page since its sub private/shared pages are from different memory > > backends and may also treated by architecture differently. When > > private/shared memory are mixed in a large page, the current lpage_info > > is not sufficient to decide whether the page can be mapped as large page > > or not and additional private/shared mixed information is needed. > > > > Tracking this 'mixed' information with the current 'count' like > > disallow_lpage is a bit challenge so reserve a bit in 'disallow_lpage' > > to indicate a large page has mixed private/share subpages and update > > this 'mixed' bit whenever the memory attribute is changed between > > private and shared. > > > > Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com> > > --- > > arch/x86/include/asm/kvm_host.h | 8 ++ > > arch/x86/kvm/mmu/mmu.c | 134 +++++++++++++++++++++++++++++++- > > arch/x86/kvm/x86.c | 2 + > > include/linux/kvm_host.h | 19 +++++ > > virt/kvm/kvm_main.c | 9 ++- > > 5 files changed, 169 insertions(+), 3 deletions(-) > > > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > > index 283cbb83d6ae..7772ab37ac89 100644 > > --- a/arch/x86/include/asm/kvm_host.h > > +++ b/arch/x86/include/asm/kvm_host.h > > @@ -38,6 +38,7 @@ > > #include <asm/hyperv-tlfs.h> > > > > #define __KVM_HAVE_ARCH_VCPU_DEBUGFS > > +#define __KVM_HAVE_ARCH_SET_MEMORY_ATTRIBUTES > > > > #define KVM_MAX_VCPUS 1024 > > > > @@ -1011,6 +1012,13 @@ struct kvm_vcpu_arch { > > #endif > > }; > > > > +/* > > + * Use a bit in disallow_lpage to indicate private/shared pages mixed at the > > + * level. The remaining bits are used as a reference count. > > + */ > > +#define KVM_LPAGE_PRIVATE_SHARED_MIXED (1U << 31) > > +#define KVM_LPAGE_COUNT_MAX ((1U << 31) - 1) > > + > > struct kvm_lpage_info { > > int disallow_lpage; > > }; > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > > index e2c70b5afa3e..2190fd8c95c0 100644 > > --- a/arch/x86/kvm/mmu/mmu.c > > +++ b/arch/x86/kvm/mmu/mmu.c > > @@ -763,11 +763,16 @@ static void update_gfn_disallow_lpage_count(const struct kvm_memory_slot *slot, > > { > > struct kvm_lpage_info *linfo; > > int i; > > + int disallow_count; > > > > for (i = PG_LEVEL_2M; i <= KVM_MAX_HUGEPAGE_LEVEL; ++i) { > > linfo = lpage_info_slot(gfn, slot, i); > > + > > + disallow_count = linfo->disallow_lpage & KVM_LPAGE_COUNT_MAX; > > + WARN_ON(disallow_count + count < 0 || > > + disallow_count > KVM_LPAGE_COUNT_MAX - count); > > + > > linfo->disallow_lpage += count; > > - WARN_ON(linfo->disallow_lpage < 0); > > } > > } > > > > @@ -6986,3 +6991,130 @@ void kvm_mmu_pre_destroy_vm(struct kvm *kvm) > > if (kvm->arch.nx_huge_page_recovery_thread) > > kthread_stop(kvm->arch.nx_huge_page_recovery_thread); > > } > > + > > +static bool linfo_is_mixed(struct kvm_lpage_info *linfo) > > +{ > > + return linfo->disallow_lpage & KVM_LPAGE_PRIVATE_SHARED_MIXED; > > +} > > + > > +static void linfo_set_mixed(gfn_t gfn, struct kvm_memory_slot *slot, > > + int level, bool mixed) > > +{ > > + struct kvm_lpage_info *linfo = lpage_info_slot(gfn, slot, level); > > + > > + if (mixed) > > + linfo->disallow_lpage |= KVM_LPAGE_PRIVATE_SHARED_MIXED; > > + else > > + linfo->disallow_lpage &= ~KVM_LPAGE_PRIVATE_SHARED_MIXED; > > +} > > + > > +static bool is_expected_attr_entry(void *entry, unsigned long expected_attrs) > > +{ > > + bool expect_private = expected_attrs & KVM_MEMORY_ATTRIBUTE_PRIVATE; > > + > > + if (xa_to_value(entry) & KVM_MEMORY_ATTRIBUTE_PRIVATE) { > > + if (!expect_private) > > + return false; > > + } else if (expect_private) > > + return false; > > + > > + return true; > > +} > > + > > +static bool mem_attrs_mixed_2m(struct kvm *kvm, unsigned long attrs, > > + gfn_t start, gfn_t end) > > +{ > > + XA_STATE(xas, &kvm->mem_attr_array, start); > > + gfn_t gfn = start; > > + void *entry; > > + bool mixed = false; > > + > > + rcu_read_lock(); > > + entry = xas_load(&xas); > > + while (gfn < end) { > > + if (xas_retry(&xas, entry)) > > + continue; > > + > > + KVM_BUG_ON(gfn != xas.xa_index, kvm); > > + > > + if (!is_expected_attr_entry(entry, attrs)) { > > + mixed = true; > > + break; > > + } > > + > > + entry = xas_next(&xas); > > + gfn++; > > + } > > + > > + rcu_read_unlock(); > > + return mixed; > > +} > > + > > +static bool mem_attrs_mixed(struct kvm *kvm, struct kvm_memory_slot *slot, > > + int level, unsigned long attrs, > > + gfn_t start, gfn_t end) > > +{ > > + unsigned long gfn; > > + > > + if (level == PG_LEVEL_2M) > > + return mem_attrs_mixed_2m(kvm, attrs, start, end); > > + > > + for (gfn = start; gfn < end; gfn += KVM_PAGES_PER_HPAGE(level - 1)) > > + if (linfo_is_mixed(lpage_info_slot(gfn, slot, level - 1)) || > > + !is_expected_attr_entry(xa_load(&kvm->mem_attr_array, gfn), > > + attrs)) > > + return true; > > + return false; > > +} > > + > > +static void kvm_update_lpage_private_shared_mixed(struct kvm *kvm, > > + struct kvm_memory_slot *slot, > > + unsigned long attrs, > > + gfn_t start, gfn_t end) > > +{ > > + unsigned long pages, mask; > > + gfn_t gfn, gfn_end, first, last; > > + int level; > > + bool mixed; > > + > > + /* > > + * The sequence matters here: we set the higher level basing on the > > + * lower level's scanning result. > > + */ > > + for (level = PG_LEVEL_2M; level <= KVM_MAX_HUGEPAGE_LEVEL; level++) { > > + pages = KVM_PAGES_PER_HPAGE(level); > > + mask = ~(pages - 1); > > + first = start & mask; > > + last = (end - 1) & mask; > > + > > + /* > > + * We only need to scan the head and tail page, for middle pages > > + * we know they will not be mixed. > > + */ > > + gfn = max(first, slot->base_gfn); > > + gfn_end = min(first + pages, slot->base_gfn + slot->npages); > > + mixed = mem_attrs_mixed(kvm, slot, level, attrs, gfn, gfn_end); > > + linfo_set_mixed(gfn, slot, level, mixed); > > + > > + if (first == last) > > + return; > > > continue. Ya! > > > + > > + for (gfn = first + pages; gfn < last; gfn += pages) > > + linfo_set_mixed(gfn, slot, level, false); > > + > > + gfn = last; > > + gfn_end = min(last + pages, slot->base_gfn + slot->npages); > > if (gfn == gfn_end) continue. Do you see a case where gfn can equal to gfn_end? Though it does not hurt to add a check. > > > > + mixed = mem_attrs_mixed(kvm, slot, level, attrs, gfn, gfn_end); > > + linfo_set_mixed(gfn, slot, level, mixed); > > + } > > +} > > + > > +void kvm_arch_set_memory_attributes(struct kvm *kvm, > > + struct kvm_memory_slot *slot, > > + unsigned long attrs, > > + gfn_t start, gfn_t end) > > +{ > > + if (kvm_slot_can_be_private(slot)) > > + kvm_update_lpage_private_shared_mixed(kvm, slot, attrs, > > + start, end); > > +} > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > > index 9a07380f8d3c..5aefcff614d2 100644 > > --- a/arch/x86/kvm/x86.c > > +++ b/arch/x86/kvm/x86.c > > @@ -12362,6 +12362,8 @@ static int kvm_alloc_memslot_metadata(struct kvm *kvm, > > if ((slot->base_gfn + npages) & (KVM_PAGES_PER_HPAGE(level) - 1)) > > linfo[lpages - 1].disallow_lpage = 1; > > ugfn = slot->userspace_addr >> PAGE_SHIFT; > > + if (kvm_slot_can_be_private(slot)) > > + ugfn |= slot->restricted_offset >> PAGE_SHIFT; > > Is there any alignment restriction? If no, It should be +=. > In practice, alignment will hold though. All we need here is checking whether both userspace_addr and restricted_offset are aligned to HPAGE_SIZE or not. '+=' actually can yield wrong value in cases when userspace_addr + restricted_offset is aligned to HPAGE_SIZE but individually they may not align to HPAGE_SIZE. Thanks, Chao > > Thanks, > > > /* > > * If the gfn and userspace address are not aligned wrt each > > * other, disable large page support for this slot. > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > > index 3331c0c92838..25099c94e770 100644 > > --- a/include/linux/kvm_host.h > > +++ b/include/linux/kvm_host.h > > @@ -592,6 +592,11 @@ struct kvm_memory_slot { > > struct restrictedmem_notifier notifier; > > }; > > > > +static inline bool kvm_slot_can_be_private(const struct kvm_memory_slot *slot) > > +{ > > + return slot && (slot->flags & KVM_MEM_PRIVATE); > > +} > > + > > static inline bool kvm_slot_dirty_track_enabled(const struct kvm_memory_slot *slot) > > { > > return slot->flags & KVM_MEM_LOG_DIRTY_PAGES; > > @@ -2316,4 +2321,18 @@ static inline void kvm_account_pgtable_pages(void *virt, int nr) > > /* Max number of entries allowed for each kvm dirty ring */ > > #define KVM_DIRTY_RING_MAX_ENTRIES 65536 > > > > +#ifdef __KVM_HAVE_ARCH_SET_MEMORY_ATTRIBUTES > > +void kvm_arch_set_memory_attributes(struct kvm *kvm, > > + struct kvm_memory_slot *slot, > > + unsigned long attrs, > > + gfn_t start, gfn_t end); > > +#else > > +static inline void kvm_arch_set_memory_attributes(struct kvm *kvm, > > + struct kvm_memory_slot *slot, > > + unsigned long attrs, > > + gfn_t start, gfn_t end) > > +{ > > +} > > +#endif /* __KVM_HAVE_ARCH_SET_MEMORY_ATTRIBUTES */ > > + > > #endif > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > > index 4e1e1e113bf0..e107afea32f0 100644 > > --- a/virt/kvm/kvm_main.c > > +++ b/virt/kvm/kvm_main.c > > @@ -2354,7 +2354,8 @@ static u64 kvm_supported_mem_attributes(struct kvm *kvm) > > return 0; > > } > > > > -static void kvm_unmap_mem_range(struct kvm *kvm, gfn_t start, gfn_t end) > > +static void kvm_unmap_mem_range(struct kvm *kvm, gfn_t start, gfn_t end, > > + unsigned long attrs) > > { > > struct kvm_gfn_range gfn_range; > > struct kvm_memory_slot *slot; > > @@ -2378,6 +2379,10 @@ static void kvm_unmap_mem_range(struct kvm *kvm, gfn_t start, gfn_t end) > > gfn_range.slot = slot; > > > > r |= kvm_unmap_gfn_range(kvm, &gfn_range); > > + > > + kvm_arch_set_memory_attributes(kvm, slot, attrs, > > + gfn_range.start, > > + gfn_range.end); > > } > > } > > > > @@ -2427,7 +2432,7 @@ static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm, > > idx = srcu_read_lock(&kvm->srcu); > > KVM_MMU_LOCK(kvm); > > if (i > start) > > - kvm_unmap_mem_range(kvm, start, i); > > + kvm_unmap_mem_range(kvm, start, i, attrs->attributes); > > kvm_mmu_invalidate_end(kvm); > > KVM_MMU_UNLOCK(kvm); > > srcu_read_unlock(&kvm->srcu, idx); > > -- > > 2.25.1 > > > > -- > Isaku Yamahata <isaku.yamahata@gmail.com>
On Tue, Dec 06, 2022 at 08:02:24PM +0800, Chao Peng <chao.p.peng@linux.intel.com> wrote: > On Mon, Dec 05, 2022 at 02:49:59PM -0800, Isaku Yamahata wrote: > > On Fri, Dec 02, 2022 at 02:13:45PM +0800, > > Chao Peng <chao.p.peng@linux.intel.com> wrote: > > > > > A large page with mixed private/shared subpages can't be mapped as large > > > page since its sub private/shared pages are from different memory > > > backends and may also treated by architecture differently. When > > > private/shared memory are mixed in a large page, the current lpage_info > > > is not sufficient to decide whether the page can be mapped as large page > > > or not and additional private/shared mixed information is needed. > > > > > > Tracking this 'mixed' information with the current 'count' like > > > disallow_lpage is a bit challenge so reserve a bit in 'disallow_lpage' > > > to indicate a large page has mixed private/share subpages and update > > > this 'mixed' bit whenever the memory attribute is changed between > > > private and shared. > > > > > > Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com> > > > --- > > > arch/x86/include/asm/kvm_host.h | 8 ++ > > > arch/x86/kvm/mmu/mmu.c | 134 +++++++++++++++++++++++++++++++- > > > arch/x86/kvm/x86.c | 2 + > > > include/linux/kvm_host.h | 19 +++++ > > > virt/kvm/kvm_main.c | 9 ++- > > > 5 files changed, 169 insertions(+), 3 deletions(-) > > > > > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > > > index 283cbb83d6ae..7772ab37ac89 100644 > > > --- a/arch/x86/include/asm/kvm_host.h > > > +++ b/arch/x86/include/asm/kvm_host.h > > > @@ -38,6 +38,7 @@ > > > #include <asm/hyperv-tlfs.h> > > > > > > #define __KVM_HAVE_ARCH_VCPU_DEBUGFS > > > +#define __KVM_HAVE_ARCH_SET_MEMORY_ATTRIBUTES > > > > > > #define KVM_MAX_VCPUS 1024 > > > > > > @@ -1011,6 +1012,13 @@ struct kvm_vcpu_arch { > > > #endif > > > }; > > > > > > +/* > > > + * Use a bit in disallow_lpage to indicate private/shared pages mixed at the > > > + * level. The remaining bits are used as a reference count. > > > + */ > > > +#define KVM_LPAGE_PRIVATE_SHARED_MIXED (1U << 31) > > > +#define KVM_LPAGE_COUNT_MAX ((1U << 31) - 1) > > > + > > > struct kvm_lpage_info { > > > int disallow_lpage; > > > }; > > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > > > index e2c70b5afa3e..2190fd8c95c0 100644 > > > --- a/arch/x86/kvm/mmu/mmu.c > > > +++ b/arch/x86/kvm/mmu/mmu.c > > > @@ -763,11 +763,16 @@ static void update_gfn_disallow_lpage_count(const struct kvm_memory_slot *slot, > > > { > > > struct kvm_lpage_info *linfo; > > > int i; > > > + int disallow_count; > > > > > > for (i = PG_LEVEL_2M; i <= KVM_MAX_HUGEPAGE_LEVEL; ++i) { > > > linfo = lpage_info_slot(gfn, slot, i); > > > + > > > + disallow_count = linfo->disallow_lpage & KVM_LPAGE_COUNT_MAX; > > > + WARN_ON(disallow_count + count < 0 || > > > + disallow_count > KVM_LPAGE_COUNT_MAX - count); > > > + > > > linfo->disallow_lpage += count; > > > - WARN_ON(linfo->disallow_lpage < 0); > > > } > > > } > > > > > > @@ -6986,3 +6991,130 @@ void kvm_mmu_pre_destroy_vm(struct kvm *kvm) > > > if (kvm->arch.nx_huge_page_recovery_thread) > > > kthread_stop(kvm->arch.nx_huge_page_recovery_thread); > > > } > > > + > > > +static bool linfo_is_mixed(struct kvm_lpage_info *linfo) > > > +{ > > > + return linfo->disallow_lpage & KVM_LPAGE_PRIVATE_SHARED_MIXED; > > > +} > > > + > > > +static void linfo_set_mixed(gfn_t gfn, struct kvm_memory_slot *slot, > > > + int level, bool mixed) > > > +{ > > > + struct kvm_lpage_info *linfo = lpage_info_slot(gfn, slot, level); > > > + > > > + if (mixed) > > > + linfo->disallow_lpage |= KVM_LPAGE_PRIVATE_SHARED_MIXED; > > > + else > > > + linfo->disallow_lpage &= ~KVM_LPAGE_PRIVATE_SHARED_MIXED; > > > +} > > > + > > > +static bool is_expected_attr_entry(void *entry, unsigned long expected_attrs) > > > +{ > > > + bool expect_private = expected_attrs & KVM_MEMORY_ATTRIBUTE_PRIVATE; > > > + > > > + if (xa_to_value(entry) & KVM_MEMORY_ATTRIBUTE_PRIVATE) { > > > + if (!expect_private) > > > + return false; > > > + } else if (expect_private) > > > + return false; > > > + > > > + return true; > > > +} > > > + > > > +static bool mem_attrs_mixed_2m(struct kvm *kvm, unsigned long attrs, > > > + gfn_t start, gfn_t end) > > > +{ > > > + XA_STATE(xas, &kvm->mem_attr_array, start); > > > + gfn_t gfn = start; > > > + void *entry; > > > + bool mixed = false; > > > + > > > + rcu_read_lock(); > > > + entry = xas_load(&xas); > > > + while (gfn < end) { > > > + if (xas_retry(&xas, entry)) > > > + continue; > > > + > > > + KVM_BUG_ON(gfn != xas.xa_index, kvm); > > > + > > > + if (!is_expected_attr_entry(entry, attrs)) { > > > + mixed = true; > > > + break; > > > + } > > > + > > > + entry = xas_next(&xas); > > > + gfn++; > > > + } > > > + > > > + rcu_read_unlock(); > > > + return mixed; > > > +} > > > + > > > +static bool mem_attrs_mixed(struct kvm *kvm, struct kvm_memory_slot *slot, > > > + int level, unsigned long attrs, > > > + gfn_t start, gfn_t end) > > > +{ > > > + unsigned long gfn; > > > + > > > + if (level == PG_LEVEL_2M) > > > + return mem_attrs_mixed_2m(kvm, attrs, start, end); > > > + > > > + for (gfn = start; gfn < end; gfn += KVM_PAGES_PER_HPAGE(level - 1)) > > > + if (linfo_is_mixed(lpage_info_slot(gfn, slot, level - 1)) || > > > + !is_expected_attr_entry(xa_load(&kvm->mem_attr_array, gfn), > > > + attrs)) > > > + return true; > > > + return false; > > > +} > > > + > > > +static void kvm_update_lpage_private_shared_mixed(struct kvm *kvm, > > > + struct kvm_memory_slot *slot, > > > + unsigned long attrs, > > > + gfn_t start, gfn_t end) > > > +{ > > > + unsigned long pages, mask; > > > + gfn_t gfn, gfn_end, first, last; > > > + int level; > > > + bool mixed; > > > + > > > + /* > > > + * The sequence matters here: we set the higher level basing on the > > > + * lower level's scanning result. > > > + */ > > > + for (level = PG_LEVEL_2M; level <= KVM_MAX_HUGEPAGE_LEVEL; level++) { > > > + pages = KVM_PAGES_PER_HPAGE(level); > > > + mask = ~(pages - 1); > > > + first = start & mask; > > > + last = (end - 1) & mask; > > > + > > > + /* > > > + * We only need to scan the head and tail page, for middle pages > > > + * we know they will not be mixed. > > > + */ > > > + gfn = max(first, slot->base_gfn); > > > + gfn_end = min(first + pages, slot->base_gfn + slot->npages); > > > + mixed = mem_attrs_mixed(kvm, slot, level, attrs, gfn, gfn_end); > > > + linfo_set_mixed(gfn, slot, level, mixed); > > > + > > > + if (first == last) > > > + return; > > > > > > continue. > > Ya! > > > > > > + > > > + for (gfn = first + pages; gfn < last; gfn += pages) > > > + linfo_set_mixed(gfn, slot, level, false); > > > + > > > + gfn = last; > > > + gfn_end = min(last + pages, slot->base_gfn + slot->npages); > > > > if (gfn == gfn_end) continue. > > Do you see a case where gfn can equal to gfn_end? Though it does not > hurt to add a check. If last == base_gfn + npages, gfn == gfn_end can occur. > > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > > > index 9a07380f8d3c..5aefcff614d2 100644 > > > --- a/arch/x86/kvm/x86.c > > > +++ b/arch/x86/kvm/x86.c > > > @@ -12362,6 +12362,8 @@ static int kvm_alloc_memslot_metadata(struct kvm *kvm, > > > if ((slot->base_gfn + npages) & (KVM_PAGES_PER_HPAGE(level) - 1)) > > > linfo[lpages - 1].disallow_lpage = 1; > > > ugfn = slot->userspace_addr >> PAGE_SHIFT; > > > + if (kvm_slot_can_be_private(slot)) > > > + ugfn |= slot->restricted_offset >> PAGE_SHIFT; > > > > Is there any alignment restriction? If no, It should be +=. > > In practice, alignment will hold though. > > All we need here is checking whether both userspace_addr and > restricted_offset are aligned to HPAGE_SIZE or not. '+=' actually can > yield wrong value in cases when userspace_addr + restricted_offset is > aligned to HPAGE_SIZE but individually they may not align to HPAGE_SIZE. Ah, got it. The blow comment explains it. > Thanks, > Chao > > > > Thanks, > > > > > /* > > > * If the gfn and userspace address are not aligned wrt each > > > * other, disable large page support for this slot.
On Tue, Dec 06, 2022 at 10:42:24PM -0800, Isaku Yamahata wrote: > On Tue, Dec 06, 2022 at 08:02:24PM +0800, > Chao Peng <chao.p.peng@linux.intel.com> wrote: > > > On Mon, Dec 05, 2022 at 02:49:59PM -0800, Isaku Yamahata wrote: > > > On Fri, Dec 02, 2022 at 02:13:45PM +0800, > > > Chao Peng <chao.p.peng@linux.intel.com> wrote: > > > > > > > A large page with mixed private/shared subpages can't be mapped as large > > > > page since its sub private/shared pages are from different memory > > > > backends and may also treated by architecture differently. When > > > > private/shared memory are mixed in a large page, the current lpage_info > > > > is not sufficient to decide whether the page can be mapped as large page > > > > or not and additional private/shared mixed information is needed. > > > > > > > > Tracking this 'mixed' information with the current 'count' like > > > > disallow_lpage is a bit challenge so reserve a bit in 'disallow_lpage' > > > > to indicate a large page has mixed private/share subpages and update > > > > this 'mixed' bit whenever the memory attribute is changed between > > > > private and shared. > > > > > > > > Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com> > > > > --- > > > > arch/x86/include/asm/kvm_host.h | 8 ++ > > > > arch/x86/kvm/mmu/mmu.c | 134 +++++++++++++++++++++++++++++++- > > > > arch/x86/kvm/x86.c | 2 + > > > > include/linux/kvm_host.h | 19 +++++ > > > > virt/kvm/kvm_main.c | 9 ++- > > > > 5 files changed, 169 insertions(+), 3 deletions(-) > > > > > > > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > > > > index 283cbb83d6ae..7772ab37ac89 100644 > > > > --- a/arch/x86/include/asm/kvm_host.h > > > > +++ b/arch/x86/include/asm/kvm_host.h > > > > @@ -38,6 +38,7 @@ > > > > #include <asm/hyperv-tlfs.h> > > > > > > > > #define __KVM_HAVE_ARCH_VCPU_DEBUGFS > > > > +#define __KVM_HAVE_ARCH_SET_MEMORY_ATTRIBUTES > > > > > > > > #define KVM_MAX_VCPUS 1024 > > > > > > > > @@ -1011,6 +1012,13 @@ struct kvm_vcpu_arch { > > > > #endif > > > > }; > > > > > > > > +/* > > > > + * Use a bit in disallow_lpage to indicate private/shared pages mixed at the > > > > + * level. The remaining bits are used as a reference count. > > > > + */ > > > > +#define KVM_LPAGE_PRIVATE_SHARED_MIXED (1U << 31) > > > > +#define KVM_LPAGE_COUNT_MAX ((1U << 31) - 1) > > > > + > > > > struct kvm_lpage_info { > > > > int disallow_lpage; > > > > }; > > > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > > > > index e2c70b5afa3e..2190fd8c95c0 100644 > > > > --- a/arch/x86/kvm/mmu/mmu.c > > > > +++ b/arch/x86/kvm/mmu/mmu.c > > > > @@ -763,11 +763,16 @@ static void update_gfn_disallow_lpage_count(const struct kvm_memory_slot *slot, > > > > { > > > > struct kvm_lpage_info *linfo; > > > > int i; > > > > + int disallow_count; > > > > > > > > for (i = PG_LEVEL_2M; i <= KVM_MAX_HUGEPAGE_LEVEL; ++i) { > > > > linfo = lpage_info_slot(gfn, slot, i); > > > > + > > > > + disallow_count = linfo->disallow_lpage & KVM_LPAGE_COUNT_MAX; > > > > + WARN_ON(disallow_count + count < 0 || > > > > + disallow_count > KVM_LPAGE_COUNT_MAX - count); > > > > + > > > > linfo->disallow_lpage += count; > > > > - WARN_ON(linfo->disallow_lpage < 0); > > > > } > > > > } > > > > > > > > @@ -6986,3 +6991,130 @@ void kvm_mmu_pre_destroy_vm(struct kvm *kvm) > > > > if (kvm->arch.nx_huge_page_recovery_thread) > > > > kthread_stop(kvm->arch.nx_huge_page_recovery_thread); > > > > } > > > > + > > > > +static bool linfo_is_mixed(struct kvm_lpage_info *linfo) > > > > +{ > > > > + return linfo->disallow_lpage & KVM_LPAGE_PRIVATE_SHARED_MIXED; > > > > +} > > > > + > > > > +static void linfo_set_mixed(gfn_t gfn, struct kvm_memory_slot *slot, > > > > + int level, bool mixed) > > > > +{ > > > > + struct kvm_lpage_info *linfo = lpage_info_slot(gfn, slot, level); > > > > + > > > > + if (mixed) > > > > + linfo->disallow_lpage |= KVM_LPAGE_PRIVATE_SHARED_MIXED; > > > > + else > > > > + linfo->disallow_lpage &= ~KVM_LPAGE_PRIVATE_SHARED_MIXED; > > > > +} > > > > + > > > > +static bool is_expected_attr_entry(void *entry, unsigned long expected_attrs) > > > > +{ > > > > + bool expect_private = expected_attrs & KVM_MEMORY_ATTRIBUTE_PRIVATE; > > > > + > > > > + if (xa_to_value(entry) & KVM_MEMORY_ATTRIBUTE_PRIVATE) { > > > > + if (!expect_private) > > > > + return false; > > > > + } else if (expect_private) > > > > + return false; > > > > + > > > > + return true; > > > > +} > > > > + > > > > +static bool mem_attrs_mixed_2m(struct kvm *kvm, unsigned long attrs, > > > > + gfn_t start, gfn_t end) > > > > +{ > > > > + XA_STATE(xas, &kvm->mem_attr_array, start); > > > > + gfn_t gfn = start; > > > > + void *entry; > > > > + bool mixed = false; > > > > + > > > > + rcu_read_lock(); > > > > + entry = xas_load(&xas); > > > > + while (gfn < end) { > > > > + if (xas_retry(&xas, entry)) > > > > + continue; > > > > + > > > > + KVM_BUG_ON(gfn != xas.xa_index, kvm); > > > > + > > > > + if (!is_expected_attr_entry(entry, attrs)) { > > > > + mixed = true; > > > > + break; > > > > + } > > > > + > > > > + entry = xas_next(&xas); > > > > + gfn++; > > > > + } > > > > + > > > > + rcu_read_unlock(); > > > > + return mixed; > > > > +} > > > > + > > > > +static bool mem_attrs_mixed(struct kvm *kvm, struct kvm_memory_slot *slot, > > > > + int level, unsigned long attrs, > > > > + gfn_t start, gfn_t end) > > > > +{ > > > > + unsigned long gfn; > > > > + > > > > + if (level == PG_LEVEL_2M) > > > > + return mem_attrs_mixed_2m(kvm, attrs, start, end); > > > > + > > > > + for (gfn = start; gfn < end; gfn += KVM_PAGES_PER_HPAGE(level - 1)) > > > > + if (linfo_is_mixed(lpage_info_slot(gfn, slot, level - 1)) || > > > > + !is_expected_attr_entry(xa_load(&kvm->mem_attr_array, gfn), > > > > + attrs)) > > > > + return true; > > > > + return false; > > > > +} > > > > + > > > > +static void kvm_update_lpage_private_shared_mixed(struct kvm *kvm, > > > > + struct kvm_memory_slot *slot, > > > > + unsigned long attrs, > > > > + gfn_t start, gfn_t end) > > > > +{ > > > > + unsigned long pages, mask; > > > > + gfn_t gfn, gfn_end, first, last; > > > > + int level; > > > > + bool mixed; > > > > + > > > > + /* > > > > + * The sequence matters here: we set the higher level basing on the > > > > + * lower level's scanning result. > > > > + */ > > > > + for (level = PG_LEVEL_2M; level <= KVM_MAX_HUGEPAGE_LEVEL; level++) { > > > > + pages = KVM_PAGES_PER_HPAGE(level); > > > > + mask = ~(pages - 1); > > > > + first = start & mask; > > > > + last = (end - 1) & mask; > > > > + > > > > + /* > > > > + * We only need to scan the head and tail page, for middle pages > > > > + * we know they will not be mixed. > > > > + */ > > > > + gfn = max(first, slot->base_gfn); > > > > + gfn_end = min(first + pages, slot->base_gfn + slot->npages); > > > > + mixed = mem_attrs_mixed(kvm, slot, level, attrs, gfn, gfn_end); > > > > + linfo_set_mixed(gfn, slot, level, mixed); > > > > + > > > > + if (first == last) > > > > + return; > > > > > > > > > continue. > > > > Ya! > > > > > > > > > + > > > > + for (gfn = first + pages; gfn < last; gfn += pages) > > > > + linfo_set_mixed(gfn, slot, level, false); > > > > + > > > > + gfn = last; > > > > + gfn_end = min(last + pages, slot->base_gfn + slot->npages); > > > > > > if (gfn == gfn_end) continue. > > > > Do you see a case where gfn can equal to gfn_end? Though it does not > > hurt to add a check. > > If last == base_gfn + npages, gfn == gfn_end can occur. 'end' is guaranteed <= base_gfn + npages in kvm_unmap_mem_range(): gfn_range.end = min(end, slot->base_gfn + slot->npages); And 'last' is defined as: last = (end - 1) & mask; Then the math is: last = (end - 1) & mask <= end - 1 <= base_gfn + npages - 1 < base_gfn + npages Thanks, Chao > > > > > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > > > > index 9a07380f8d3c..5aefcff614d2 100644 > > > > --- a/arch/x86/kvm/x86.c > > > > +++ b/arch/x86/kvm/x86.c > > > > @@ -12362,6 +12362,8 @@ static int kvm_alloc_memslot_metadata(struct kvm *kvm, > > > > if ((slot->base_gfn + npages) & (KVM_PAGES_PER_HPAGE(level) - 1)) > > > > linfo[lpages - 1].disallow_lpage = 1; > > > > ugfn = slot->userspace_addr >> PAGE_SHIFT; > > > > + if (kvm_slot_can_be_private(slot)) > > > > + ugfn |= slot->restricted_offset >> PAGE_SHIFT; > > > > > > Is there any alignment restriction? If no, It should be +=. > > > In practice, alignment will hold though. > > > > All we need here is checking whether both userspace_addr and > > restricted_offset are aligned to HPAGE_SIZE or not. '+=' actually can > > yield wrong value in cases when userspace_addr + restricted_offset is > > aligned to HPAGE_SIZE but individually they may not align to HPAGE_SIZE. > > Ah, got it. The blow comment explains it. > > > Thanks, > > Chao > > > > > > Thanks, > > > > > > > /* > > > > * If the gfn and userspace address are not aligned wrt each > > > > * other, disable large page support for this slot. > -- > Isaku Yamahata <isaku.yamahata@gmail.com>
On Fri, Dec 02, 2022, Chao Peng wrote: > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index 283cbb83d6ae..7772ab37ac89 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -38,6 +38,7 @@ > #include <asm/hyperv-tlfs.h> > > #define __KVM_HAVE_ARCH_VCPU_DEBUGFS > +#define __KVM_HAVE_ARCH_SET_MEMORY_ATTRIBUTES No need for this, I think we should just make it mandatory to implement the arch hook when CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES=y. If another arch gains support for mem attributes and doesn't need the hook, then we can simply add a weak helper (or maybe add a #define then if we feel that's the way to go). > #define KVM_MAX_VCPUS 1024 > > @@ -1011,6 +1012,13 @@ struct kvm_vcpu_arch { > #endif > }; > > +/* > + * Use a bit in disallow_lpage to indicate private/shared pages mixed at the > + * level. The remaining bits are used as a reference count. > + */ > +#define KVM_LPAGE_PRIVATE_SHARED_MIXED (1U << 31) Similar to the need to unmap, I think we should just say "mixed" and ignore the private vs. shared, i.e. make this a flag for all memory attributes. > +#define KVM_LPAGE_COUNT_MAX ((1U << 31) - 1) "MAX" is technically correct, but it's more of a mask. I think we can make it a moot point though. There's no need to mask the count, we just want to assert that adjusting the counting doesn't change the flag. I would also say throw these defines into mmu.c, at least pending the bug fix for kvm_alloc_memslot_metadata() (more on that below). > struct kvm_lpage_info { > int disallow_lpage; > }; > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > index e2c70b5afa3e..2190fd8c95c0 100644 > --- a/arch/x86/kvm/mmu/mmu.c > +++ b/arch/x86/kvm/mmu/mmu.c > @@ -763,11 +763,16 @@ static void update_gfn_disallow_lpage_count(const struct kvm_memory_slot *slot, > { > struct kvm_lpage_info *linfo; > int i; > + int disallow_count; > > for (i = PG_LEVEL_2M; i <= KVM_MAX_HUGEPAGE_LEVEL; ++i) { > linfo = lpage_info_slot(gfn, slot, i); > + > + disallow_count = linfo->disallow_lpage & KVM_LPAGE_COUNT_MAX; > + WARN_ON(disallow_count + count < 0 || > + disallow_count > KVM_LPAGE_COUNT_MAX - count); > + > linfo->disallow_lpage += count; > - WARN_ON(linfo->disallow_lpage < 0); It's been a long week so don't trust my math, but I believe this can simply be: old = linfo->disallow_lpage; linfo->disallow_lpage += count; WARN_ON_ONCE((old ^ linfo->disallow_lpage) & KVM_LPAGE_MIXED_FLAG); > } > } > > @@ -6986,3 +6991,130 @@ void kvm_mmu_pre_destroy_vm(struct kvm *kvm) > if (kvm->arch.nx_huge_page_recovery_thread) > kthread_stop(kvm->arch.nx_huge_page_recovery_thread); > } > + > +static bool linfo_is_mixed(struct kvm_lpage_info *linfo) > +{ > + return linfo->disallow_lpage & KVM_LPAGE_PRIVATE_SHARED_MIXED; > +} > + > +static void linfo_set_mixed(gfn_t gfn, struct kvm_memory_slot *slot, > + int level, bool mixed) > +{ > + struct kvm_lpage_info *linfo = lpage_info_slot(gfn, slot, level); > + > + if (mixed) > + linfo->disallow_lpage |= KVM_LPAGE_PRIVATE_SHARED_MIXED; > + else > + linfo->disallow_lpage &= ~KVM_LPAGE_PRIVATE_SHARED_MIXED; > +} > + > +static bool is_expected_attr_entry(void *entry, unsigned long expected_attrs) > +{ > + bool expect_private = expected_attrs & KVM_MEMORY_ATTRIBUTE_PRIVATE; > + > + if (xa_to_value(entry) & KVM_MEMORY_ATTRIBUTE_PRIVATE) { > + if (!expect_private) > + return false; > + } else if (expect_private) > + return false; This is messy. If we drop the private vs. shared specifity, this can go away if we add a helper to get attributes static inline unsigned long kvm_get_memory_attributes(struct kvm *kvm, gfn_t gfn) { return xa_to_value(xa_load(&kvm->mem_attr_array, gfn)); } and then we can do if (KVM_BUG_ON(gfn != xas.xa_index, kvm) || attrs != kvm_get_memory_attributes(kvm, gfn)) { mixed = true; break; } and if (linfo_is_mixed(lpage_info_slot(gfn, slot, level - 1)) || attrs != kvm_get_memory_attributes(kvm, gfn)) return true; > + > + return true; > +} > + > +static bool mem_attrs_mixed_2m(struct kvm *kvm, unsigned long attrs, > + gfn_t start, gfn_t end) > +{ > + XA_STATE(xas, &kvm->mem_attr_array, start); > + gfn_t gfn = start; > + void *entry; > + bool mixed = false; > + > + rcu_read_lock(); > + entry = xas_load(&xas); > + while (gfn < end) { > + if (xas_retry(&xas, entry)) > + continue; > + > + KVM_BUG_ON(gfn != xas.xa_index, kvm); As above, I think it's worth bailing immediately if there's a mismatch. > + > + if (!is_expected_attr_entry(entry, attrs)) { > + mixed = true; > + break; > + } > + > + entry = xas_next(&xas); > + gfn++; > + } > + > + rcu_read_unlock(); > + return mixed; > +} > + > +static bool mem_attrs_mixed(struct kvm *kvm, struct kvm_memory_slot *slot, s/mem_attrs_mixed/has_mixed_attrs to make it clear this is querying, not setting. And has_mixed_attrs_2m() above. > + int level, unsigned long attrs, > + gfn_t start, gfn_t end) > +{ > + unsigned long gfn; > + > + if (level == PG_LEVEL_2M) > + return mem_attrs_mixed_2m(kvm, attrs, start, end); > + > + for (gfn = start; gfn < end; gfn += KVM_PAGES_PER_HPAGE(level - 1)) Curly braces needed on the for-loop. > + if (linfo_is_mixed(lpage_info_slot(gfn, slot, level - 1)) || > + !is_expected_attr_entry(xa_load(&kvm->mem_attr_array, gfn), > + attrs)) > + return true; > + return false; > +} > + > +static void kvm_update_lpage_private_shared_mixed(struct kvm *kvm, > + struct kvm_memory_slot *slot, > + unsigned long attrs, > + gfn_t start, gfn_t end) > +{ > + unsigned long pages, mask; > + gfn_t gfn, gfn_end, first, last; > + int level; > + bool mixed; > + > + /* > + * The sequence matters here: we set the higher level basing on the > + * lower level's scanning result. > + */ > + for (level = PG_LEVEL_2M; level <= KVM_MAX_HUGEPAGE_LEVEL; level++) { > + pages = KVM_PAGES_PER_HPAGE(level); > + mask = ~(pages - 1); > + first = start & mask; > + last = (end - 1) & mask; > + > + /* > + * We only need to scan the head and tail page, for middle pages > + * we know they will not be mixed. > + */ > + gfn = max(first, slot->base_gfn); > + gfn_end = min(first + pages, slot->base_gfn + slot->npages); > + mixed = mem_attrs_mixed(kvm, slot, level, attrs, gfn, gfn_end); > + linfo_set_mixed(gfn, slot, level, mixed); > + > + if (first == last) > + return; > + > + for (gfn = first + pages; gfn < last; gfn += pages) > + linfo_set_mixed(gfn, slot, level, false); > + > + gfn = last; > + gfn_end = min(last + pages, slot->base_gfn + slot->npages); > + mixed = mem_attrs_mixed(kvm, slot, level, attrs, gfn, gfn_end); > + linfo_set_mixed(gfn, slot, level, mixed); > + } > +} > + > +void kvm_arch_set_memory_attributes(struct kvm *kvm, > + struct kvm_memory_slot *slot, > + unsigned long attrs, > + gfn_t start, gfn_t end) > +{ > + if (kvm_slot_can_be_private(slot)) Make this an early return optimization, with a comment explaining that KVM x86 doesn't yet support other attributes. /* * KVM x86 currently only supports KVM_MEMORY_ATTRIBUTE_PRIVATE, skip * the slot if the slot will never consume the PRIVATE attribute. */ if (!kvm_slot_can_be_private(slot)) return; > + kvm_update_lpage_private_shared_mixed(kvm, slot, attrs, > + start, end); > +} > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 9a07380f8d3c..5aefcff614d2 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -12362,6 +12362,8 @@ static int kvm_alloc_memslot_metadata(struct kvm *kvm, > if ((slot->base_gfn + npages) & (KVM_PAGES_PER_HPAGE(level) - 1)) > linfo[lpages - 1].disallow_lpage = 1; > ugfn = slot->userspace_addr >> PAGE_SHIFT; > + if (kvm_slot_can_be_private(slot)) > + ugfn |= slot->restricted_offset >> PAGE_SHIFT; I would rather reject memslot if the gfn has lesser alignment than the offset. I'm totally ok with this approach _if_ there's a use case. Until such a use case presents itself, I would rather be conservative from a uAPI perspective. > /* > * If the gfn and userspace address are not aligned wrt each > * other, disable large page support for this slot. > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index 3331c0c92838..25099c94e770 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -592,6 +592,11 @@ struct kvm_memory_slot { > struct restrictedmem_notifier notifier; > }; > > +static inline bool kvm_slot_can_be_private(const struct kvm_memory_slot *slot) > +{ > + return slot && (slot->flags & KVM_MEM_PRIVATE); KVM_MEM_PRIVATE should really be defined only when private memory is exposed to userspace. For this patch, even though it means we have untestable code, I think it makes sense to "return false". > +} > + > static inline bool kvm_slot_dirty_track_enabled(const struct kvm_memory_slot *slot) > { > return slot->flags & KVM_MEM_LOG_DIRTY_PAGES; > @@ -2316,4 +2321,18 @@ static inline void kvm_account_pgtable_pages(void *virt, int nr) > /* Max number of entries allowed for each kvm dirty ring */ > #define KVM_DIRTY_RING_MAX_ENTRIES 65536 > > +#ifdef __KVM_HAVE_ARCH_SET_MEMORY_ATTRIBUTES > +void kvm_arch_set_memory_attributes(struct kvm *kvm, > + struct kvm_memory_slot *slot, > + unsigned long attrs, > + gfn_t start, gfn_t end); > +#else > +static inline void kvm_arch_set_memory_attributes(struct kvm *kvm, > + struct kvm_memory_slot *slot, > + unsigned long attrs, > + gfn_t start, gfn_t end) > +{ > +} > +#endif /* __KVM_HAVE_ARCH_SET_MEMORY_ATTRIBUTES */ As above, no stub is necessary. > #endif > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 4e1e1e113bf0..e107afea32f0 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -2354,7 +2354,8 @@ static u64 kvm_supported_mem_attributes(struct kvm *kvm) > return 0; > } > > -static void kvm_unmap_mem_range(struct kvm *kvm, gfn_t start, gfn_t end) Feedback for an earlier patch (to avoid churn): this should be kvm_mem_attrs_changed() or so now that this does more than just unmap. > +static void kvm_unmap_mem_range(struct kvm *kvm, gfn_t start, gfn_t end, > + unsigned long attrs) Weird nit. I think we should keep the prototypes for kvm_mem_attrs_changed() and kvm_arch_set_memory_attributes() somewhat similar, i.e. squeeze in @attrs before @start. > { > struct kvm_gfn_range gfn_range; > struct kvm_memory_slot *slot; > @@ -2378,6 +2379,10 @@ static void kvm_unmap_mem_range(struct kvm *kvm, gfn_t start, gfn_t end) > gfn_range.slot = slot; > > r |= kvm_unmap_gfn_range(kvm, &gfn_range); > + > + kvm_arch_set_memory_attributes(kvm, slot, attrs, > + gfn_range.start, > + gfn_range.end); > } > } > > @@ -2427,7 +2432,7 @@ static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm, > idx = srcu_read_lock(&kvm->srcu); > KVM_MMU_LOCK(kvm); > if (i > start) > - kvm_unmap_mem_range(kvm, start, i); > + kvm_unmap_mem_range(kvm, start, i, attrs->attributes); > kvm_mmu_invalidate_end(kvm); > KVM_MMU_UNLOCK(kvm); > srcu_read_unlock(&kvm->srcu, idx); > -- > 2.25.1 >
On Fri, Dec 02, 2022, Chao Peng wrote: > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 9a07380f8d3c..5aefcff614d2 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -12362,6 +12362,8 @@ static int kvm_alloc_memslot_metadata(struct kvm *kvm, > if ((slot->base_gfn + npages) & (KVM_PAGES_PER_HPAGE(level) - 1)) > linfo[lpages - 1].disallow_lpage = 1; > ugfn = slot->userspace_addr >> PAGE_SHIFT; > + if (kvm_slot_can_be_private(slot)) > + ugfn |= slot->restricted_offset >> PAGE_SHIFT; > /* > * If the gfn and userspace address are not aligned wrt each > * other, disable large page support for this slot. Forgot to talk about the bug. This code needs to handle the scenario where a memslot is created with existing, non-uniform attributes. It might be a bit ugly (I didn't even try to write the code), but it's definitely possible, and since memslot updates are already slow I think it's best to handle things here. In the meantime, I added this so we don't forget to fix it before merging. #ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES pr_crit_once("FIXME: Walk the memory attributes of the slot and set the mixed status appropriately"); #endif
On Fri, Jan 13, 2023 at 11:16:27PM +0000, Sean Christopherson wrote: > On Fri, Dec 02, 2022, Chao Peng wrote: > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > > index 9a07380f8d3c..5aefcff614d2 100644 > > --- a/arch/x86/kvm/x86.c > > +++ b/arch/x86/kvm/x86.c > > @@ -12362,6 +12362,8 @@ static int kvm_alloc_memslot_metadata(struct kvm *kvm, > > if ((slot->base_gfn + npages) & (KVM_PAGES_PER_HPAGE(level) - 1)) > > linfo[lpages - 1].disallow_lpage = 1; > > ugfn = slot->userspace_addr >> PAGE_SHIFT; > > + if (kvm_slot_can_be_private(slot)) > > + ugfn |= slot->restricted_offset >> PAGE_SHIFT; > > /* > > * If the gfn and userspace address are not aligned wrt each > > * other, disable large page support for this slot. > > Forgot to talk about the bug. This code needs to handle the scenario where a > memslot is created with existing, non-uniform attributes. It might be a bit ugly > (I didn't even try to write the code), but it's definitely possible, and since > memslot updates are already slow I think it's best to handle things here. > > In the meantime, I added this so we don't forget to fix it before merging. > > #ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES > pr_crit_once("FIXME: Walk the memory attributes of the slot and set the mixed status appropriately"); > #endif Here is the code to fix (based on your latest github repo). diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index e552374f2357..609ff1cba9c5 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -2195,4 +2195,9 @@ int memslot_rmap_alloc(struct kvm_memory_slot *slot, unsigned long npages); KVM_X86_QUIRK_FIX_HYPERCALL_INSN | \ KVM_X86_QUIRK_MWAIT_NEVER_UD_FAULTS) +#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES +void kvm_memory_attributes_create_memslot(struct kvm *kvm, + struct kvm_memory_slot *slot); +#endif + #endif /* _ASM_X86_KVM_HOST_H */ diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index eda615f3951c..8833d7201e41 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -7201,10 +7201,11 @@ static bool has_mixed_attrs(struct kvm *kvm, struct kvm_memory_slot *slot, return false; } -void kvm_arch_set_memory_attributes(struct kvm *kvm, - struct kvm_memory_slot *slot, - unsigned long attrs, - gfn_t start, gfn_t end) +static void kvm_update_lpage_mixed_flag(struct kvm *kvm, + struct kvm_memory_slot *slot, + bool set_attrs, + unsigned long attrs, + gfn_t start, gfn_t end) { unsigned long pages, mask; gfn_t gfn, gfn_end, first, last; @@ -7231,25 +7232,53 @@ void kvm_arch_set_memory_attributes(struct kvm *kvm, first = start & mask; last = (end - 1) & mask; - /* - * We only need to scan the head and tail page, for middle pages - * we know they will not be mixed. - */ + /* head page */ gfn = max(first, slot->base_gfn); gfn_end = min(first + pages, slot->base_gfn + slot->npages); + if(!set_attrs) + attrs = kvm_get_memory_attributes(kvm, gfn); mixed = has_mixed_attrs(kvm, slot, level, attrs, gfn, gfn_end); linfo_update_mixed(gfn, slot, level, mixed); if (first == last) return; - for (gfn = first + pages; gfn < last; gfn += pages) - linfo_update_mixed(gfn, slot, level, false); + /* middle pages */ + for (gfn = first + pages; gfn < last; gfn += pages) { + if (set_attrs) { + mixed = false; + } else { + gfn_end = gfn + pages; + attrs = kvm_get_memory_attributes(kvm, gfn); + mixed = has_mixed_attrs(kvm, slot, level, attrs, + gfn, gfn_end); + } + linfo_update_mixed(gfn, slot, level, mixed); + } + /* tail page */ gfn = last; gfn_end = min(last + pages, slot->base_gfn + slot->npages); + if(!set_attrs) + attrs = kvm_get_memory_attributes(kvm, gfn); mixed = has_mixed_attrs(kvm, slot, level, attrs, gfn, gfn_end); linfo_update_mixed(gfn, slot, level, mixed); } } + +void kvm_arch_set_memory_attributes(struct kvm *kvm, + struct kvm_memory_slot *slot, + unsigned long attrs, + gfn_t start, gfn_t end) +{ + kvm_update_lpage_mixed_flag(kvm, slot, true, attrs, start, end); +} + +void kvm_memory_attributes_create_memslot(struct kvm *kvm, + struct kvm_memory_slot *slot) +{ + + kvm_update_lpage_mixed_flag(kvm, slot, false, 0, slot->base_gfn, + slot->base_gfn + slot->npages); +} #endif diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 268c3d16894d..c1074aecf2d0 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -12443,7 +12443,7 @@ static int kvm_alloc_memslot_metadata(struct kvm *kvm, } #ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES - pr_crit_once("FIXME: Walk the memory attributes of the slot and set the mixed status appropriately"); + kvm_memory_attributes_create_memslot(kvm, slot); #endif if (kvm_page_track_create_memslot(kvm, slot, npages))
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 283cbb83d6ae..7772ab37ac89 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -38,6 +38,7 @@ #include <asm/hyperv-tlfs.h> #define __KVM_HAVE_ARCH_VCPU_DEBUGFS +#define __KVM_HAVE_ARCH_SET_MEMORY_ATTRIBUTES #define KVM_MAX_VCPUS 1024 @@ -1011,6 +1012,13 @@ struct kvm_vcpu_arch { #endif }; +/* + * Use a bit in disallow_lpage to indicate private/shared pages mixed at the + * level. The remaining bits are used as a reference count. + */ +#define KVM_LPAGE_PRIVATE_SHARED_MIXED (1U << 31) +#define KVM_LPAGE_COUNT_MAX ((1U << 31) - 1) + struct kvm_lpage_info { int disallow_lpage; }; diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index e2c70b5afa3e..2190fd8c95c0 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -763,11 +763,16 @@ static void update_gfn_disallow_lpage_count(const struct kvm_memory_slot *slot, { struct kvm_lpage_info *linfo; int i; + int disallow_count; for (i = PG_LEVEL_2M; i <= KVM_MAX_HUGEPAGE_LEVEL; ++i) { linfo = lpage_info_slot(gfn, slot, i); + + disallow_count = linfo->disallow_lpage & KVM_LPAGE_COUNT_MAX; + WARN_ON(disallow_count + count < 0 || + disallow_count > KVM_LPAGE_COUNT_MAX - count); + linfo->disallow_lpage += count; - WARN_ON(linfo->disallow_lpage < 0); } } @@ -6986,3 +6991,130 @@ void kvm_mmu_pre_destroy_vm(struct kvm *kvm) if (kvm->arch.nx_huge_page_recovery_thread) kthread_stop(kvm->arch.nx_huge_page_recovery_thread); } + +static bool linfo_is_mixed(struct kvm_lpage_info *linfo) +{ + return linfo->disallow_lpage & KVM_LPAGE_PRIVATE_SHARED_MIXED; +} + +static void linfo_set_mixed(gfn_t gfn, struct kvm_memory_slot *slot, + int level, bool mixed) +{ + struct kvm_lpage_info *linfo = lpage_info_slot(gfn, slot, level); + + if (mixed) + linfo->disallow_lpage |= KVM_LPAGE_PRIVATE_SHARED_MIXED; + else + linfo->disallow_lpage &= ~KVM_LPAGE_PRIVATE_SHARED_MIXED; +} + +static bool is_expected_attr_entry(void *entry, unsigned long expected_attrs) +{ + bool expect_private = expected_attrs & KVM_MEMORY_ATTRIBUTE_PRIVATE; + + if (xa_to_value(entry) & KVM_MEMORY_ATTRIBUTE_PRIVATE) { + if (!expect_private) + return false; + } else if (expect_private) + return false; + + return true; +} + +static bool mem_attrs_mixed_2m(struct kvm *kvm, unsigned long attrs, + gfn_t start, gfn_t end) +{ + XA_STATE(xas, &kvm->mem_attr_array, start); + gfn_t gfn = start; + void *entry; + bool mixed = false; + + rcu_read_lock(); + entry = xas_load(&xas); + while (gfn < end) { + if (xas_retry(&xas, entry)) + continue; + + KVM_BUG_ON(gfn != xas.xa_index, kvm); + + if (!is_expected_attr_entry(entry, attrs)) { + mixed = true; + break; + } + + entry = xas_next(&xas); + gfn++; + } + + rcu_read_unlock(); + return mixed; +} + +static bool mem_attrs_mixed(struct kvm *kvm, struct kvm_memory_slot *slot, + int level, unsigned long attrs, + gfn_t start, gfn_t end) +{ + unsigned long gfn; + + if (level == PG_LEVEL_2M) + return mem_attrs_mixed_2m(kvm, attrs, start, end); + + for (gfn = start; gfn < end; gfn += KVM_PAGES_PER_HPAGE(level - 1)) + if (linfo_is_mixed(lpage_info_slot(gfn, slot, level - 1)) || + !is_expected_attr_entry(xa_load(&kvm->mem_attr_array, gfn), + attrs)) + return true; + return false; +} + +static void kvm_update_lpage_private_shared_mixed(struct kvm *kvm, + struct kvm_memory_slot *slot, + unsigned long attrs, + gfn_t start, gfn_t end) +{ + unsigned long pages, mask; + gfn_t gfn, gfn_end, first, last; + int level; + bool mixed; + + /* + * The sequence matters here: we set the higher level basing on the + * lower level's scanning result. + */ + for (level = PG_LEVEL_2M; level <= KVM_MAX_HUGEPAGE_LEVEL; level++) { + pages = KVM_PAGES_PER_HPAGE(level); + mask = ~(pages - 1); + first = start & mask; + last = (end - 1) & mask; + + /* + * We only need to scan the head and tail page, for middle pages + * we know they will not be mixed. + */ + gfn = max(first, slot->base_gfn); + gfn_end = min(first + pages, slot->base_gfn + slot->npages); + mixed = mem_attrs_mixed(kvm, slot, level, attrs, gfn, gfn_end); + linfo_set_mixed(gfn, slot, level, mixed); + + if (first == last) + return; + + for (gfn = first + pages; gfn < last; gfn += pages) + linfo_set_mixed(gfn, slot, level, false); + + gfn = last; + gfn_end = min(last + pages, slot->base_gfn + slot->npages); + mixed = mem_attrs_mixed(kvm, slot, level, attrs, gfn, gfn_end); + linfo_set_mixed(gfn, slot, level, mixed); + } +} + +void kvm_arch_set_memory_attributes(struct kvm *kvm, + struct kvm_memory_slot *slot, + unsigned long attrs, + gfn_t start, gfn_t end) +{ + if (kvm_slot_can_be_private(slot)) + kvm_update_lpage_private_shared_mixed(kvm, slot, attrs, + start, end); +} diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 9a07380f8d3c..5aefcff614d2 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -12362,6 +12362,8 @@ static int kvm_alloc_memslot_metadata(struct kvm *kvm, if ((slot->base_gfn + npages) & (KVM_PAGES_PER_HPAGE(level) - 1)) linfo[lpages - 1].disallow_lpage = 1; ugfn = slot->userspace_addr >> PAGE_SHIFT; + if (kvm_slot_can_be_private(slot)) + ugfn |= slot->restricted_offset >> PAGE_SHIFT; /* * If the gfn and userspace address are not aligned wrt each * other, disable large page support for this slot. diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 3331c0c92838..25099c94e770 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -592,6 +592,11 @@ struct kvm_memory_slot { struct restrictedmem_notifier notifier; }; +static inline bool kvm_slot_can_be_private(const struct kvm_memory_slot *slot) +{ + return slot && (slot->flags & KVM_MEM_PRIVATE); +} + static inline bool kvm_slot_dirty_track_enabled(const struct kvm_memory_slot *slot) { return slot->flags & KVM_MEM_LOG_DIRTY_PAGES; @@ -2316,4 +2321,18 @@ static inline void kvm_account_pgtable_pages(void *virt, int nr) /* Max number of entries allowed for each kvm dirty ring */ #define KVM_DIRTY_RING_MAX_ENTRIES 65536 +#ifdef __KVM_HAVE_ARCH_SET_MEMORY_ATTRIBUTES +void kvm_arch_set_memory_attributes(struct kvm *kvm, + struct kvm_memory_slot *slot, + unsigned long attrs, + gfn_t start, gfn_t end); +#else +static inline void kvm_arch_set_memory_attributes(struct kvm *kvm, + struct kvm_memory_slot *slot, + unsigned long attrs, + gfn_t start, gfn_t end) +{ +} +#endif /* __KVM_HAVE_ARCH_SET_MEMORY_ATTRIBUTES */ + #endif diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 4e1e1e113bf0..e107afea32f0 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2354,7 +2354,8 @@ static u64 kvm_supported_mem_attributes(struct kvm *kvm) return 0; } -static void kvm_unmap_mem_range(struct kvm *kvm, gfn_t start, gfn_t end) +static void kvm_unmap_mem_range(struct kvm *kvm, gfn_t start, gfn_t end, + unsigned long attrs) { struct kvm_gfn_range gfn_range; struct kvm_memory_slot *slot; @@ -2378,6 +2379,10 @@ static void kvm_unmap_mem_range(struct kvm *kvm, gfn_t start, gfn_t end) gfn_range.slot = slot; r |= kvm_unmap_gfn_range(kvm, &gfn_range); + + kvm_arch_set_memory_attributes(kvm, slot, attrs, + gfn_range.start, + gfn_range.end); } } @@ -2427,7 +2432,7 @@ static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm, idx = srcu_read_lock(&kvm->srcu); KVM_MMU_LOCK(kvm); if (i > start) - kvm_unmap_mem_range(kvm, start, i); + kvm_unmap_mem_range(kvm, start, i, attrs->attributes); kvm_mmu_invalidate_end(kvm); KVM_MMU_UNLOCK(kvm); srcu_read_unlock(&kvm->srcu, idx);
A large page with mixed private/shared subpages can't be mapped as large page since its sub private/shared pages are from different memory backends and may also treated by architecture differently. When private/shared memory are mixed in a large page, the current lpage_info is not sufficient to decide whether the page can be mapped as large page or not and additional private/shared mixed information is needed. Tracking this 'mixed' information with the current 'count' like disallow_lpage is a bit challenge so reserve a bit in 'disallow_lpage' to indicate a large page has mixed private/share subpages and update this 'mixed' bit whenever the memory attribute is changed between private and shared. Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com> --- arch/x86/include/asm/kvm_host.h | 8 ++ arch/x86/kvm/mmu/mmu.c | 134 +++++++++++++++++++++++++++++++- arch/x86/kvm/x86.c | 2 + include/linux/kvm_host.h | 19 +++++ virt/kvm/kvm_main.c | 9 ++- 5 files changed, 169 insertions(+), 3 deletions(-)