| Message ID | 20220915142913.2213336-7-chao.p.peng@linux.intel.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | KVM: mm: fd-based approach for supporting KVM | expand |
On Thu, Sep 15, 2022 at 10:29:11PM +0800, Chao Peng <chao.p.peng@linux.intel.com> wrote: > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > index 08abad4f3e6f..a0f198cede3d 100644 > --- a/arch/x86/kvm/mmu/mmu.c > +++ b/arch/x86/kvm/mmu/mmu.c ... > @@ -6894,3 +6899,115 @@ void kvm_mmu_pre_destroy_vm(struct kvm *kvm) > if (kvm->arch.nx_lpage_recovery_thread) > kthread_stop(kvm->arch.nx_lpage_recovery_thread); > } > + > +static bool mem_attr_is_mixed(struct kvm *kvm, unsigned int attr, > + gfn_t start, gfn_t end) > +{ > + XA_STATE(xas, &kvm->mem_attr_array, start); > + gfn_t gfn = start; > + void *entry; > + bool shared, private; > + bool mixed = false; > + > + if (attr == KVM_MEM_ATTR_SHARED) { > + shared = true; > + private = false; > + } else { > + shared = false; > + private = true; > + } We don't have to care the target is shared or private. We need to check only same or not. > + > + 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 (entry) > + private = true; > + else > + shared = true; > + > + if (private && shared) { > + mixed = true; > + goto out; > + } > + > + entry = xas_next(&xas); > + gfn++; > + } > +out: > + rcu_read_unlock(); > + return mixed; > +} > + > +static inline void update_mixed(struct kvm_lpage_info *linfo, bool mixed) > +{ > + if (mixed) > + linfo->disallow_lpage |= KVM_LPAGE_PRIVATE_SHARED_MIXED; > + else > + linfo->disallow_lpage &= ~KVM_LPAGE_PRIVATE_SHARED_MIXED; > +} > + > +static void update_mem_lpage_info(struct kvm *kvm, > + struct kvm_memory_slot *slot, > + unsigned int attr, > + gfn_t start, gfn_t end) > +{ > + unsigned long lpage_start, lpage_end; > + unsigned long gfn, pages, mask; > + int level; > + > + for (level = PG_LEVEL_2M; level <= KVM_MAX_HUGEPAGE_LEVEL; level++) { > + pages = KVM_PAGES_PER_HPAGE(level); > + mask = ~(pages - 1); > + lpage_start = start & mask; > + lpage_end = (end - 1) & mask; > + > + /* > + * We only need to scan the head and tail page, for middle pages > + * we know they are not mixed. > + */ > + update_mixed(lpage_info_slot(lpage_start, slot, level), > + mem_attr_is_mixed(kvm, attr, lpage_start, > + lpage_start + pages)); > + > + if (lpage_start == lpage_end) > + return; > + > + for (gfn = lpage_start + pages; gfn < lpage_end; gfn += pages) > + update_mixed(lpage_info_slot(gfn, slot, level), false); For >2M case, we don't have to check all entry. just check lower level case. > + > + update_mixed(lpage_info_slot(lpage_end, slot, level), > + mem_attr_is_mixed(kvm, attr, lpage_end, > + lpage_end + pages)); > + } > +} > + > +void kvm_arch_update_mem_attr(struct kvm *kvm, unsigned int attr, > + gfn_t start, gfn_t end) > +{ > + struct kvm_memory_slot *slot; > + struct kvm_memslots *slots; > + struct kvm_memslot_iter iter; > + int i; > + > + WARN_ONCE(!(attr & (KVM_MEM_ATTR_PRIVATE | KVM_MEM_ATTR_SHARED)), > + "Unsupported mem attribute.\n"); > + > + for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { > + slots = __kvm_memslots(kvm, i); > + > + kvm_for_each_memslot_in_gfn_range(&iter, slots, start, end) { > + slot = iter.slot; > + start = max(start, slot->base_gfn); > + end = min(end, slot->base_gfn + slot->npages); > + if (WARN_ON_ONCE(start >= end)) > + continue; > + > + update_mem_lpage_info(kvm, slot, attr, start, end); > + } > + } > +} Here is my updated version. bool kvm_mem_attr_is_mixed(struct kvm_memory_slot *slot, gfn_t gfn, int level) { gfn_t pages = KVM_PAGES_PER_HPAGE(level); gfn_t mask = ~(pages - 1); struct kvm_lpage_info *linfo = lpage_info_slot(gfn & mask, slot, level); WARN_ON_ONCE(level == PG_LEVEL_4K); return linfo->disallow_lpage & KVM_LPAGE_PRIVATE_SHARED_MIXED; } #ifdef CONFIG_HAVE_KVM_PRIVATE_MEM_ATTR static void update_mixed(struct kvm_lpage_info *linfo, bool mixed) { if (mixed) linfo->disallow_lpage |= KVM_LPAGE_PRIVATE_SHARED_MIXED; else linfo->disallow_lpage &= ~KVM_LPAGE_PRIVATE_SHARED_MIXED; } static bool __mem_attr_is_mixed(struct kvm *kvm, gfn_t start, gfn_t end) { XA_STATE(xas, &kvm->mem_attr_array, start); bool mixed = false; gfn_t gfn = start; void *s_entry; void *entry; rcu_read_lock(); s_entry = xas_load(&xas); entry = s_entry; while (gfn < end) { if (xas_retry(&xas, entry)) continue; KVM_BUG_ON(gfn != xas.xa_index, kvm); entry = xas_next(&xas); if (entry != s_entry) { mixed = true; break; } gfn++; } rcu_read_unlock(); return mixed; } static bool mem_attr_is_mixed(struct kvm *kvm, struct kvm_memory_slot *slot, int level, gfn_t start, gfn_t end) { struct kvm_lpage_info *child_linfo; unsigned long child_pages; bool mixed = false; unsigned long gfn; void *entry; if (WARN_ON_ONCE(level == PG_LEVEL_4K)) return false; if (level == PG_LEVEL_2M) return __mem_attr_is_mixed(kvm, start, end); /* This assumes that level - 1 is already updated. */ rcu_read_lock(); child_pages = KVM_PAGES_PER_HPAGE(level - 1); entry = xa_load(&kvm->mem_attr_array, start); for (gfn = start; gfn < end; gfn += child_pages) { child_linfo = lpage_info_slot(gfn, slot, level - 1); if (child_linfo->disallow_lpage & KVM_LPAGE_PRIVATE_SHARED_MIXED) { mixed = true; break; } if (xa_load(&kvm->mem_attr_array, gfn) != entry) { mixed = true; break; } } rcu_read_unlock(); return mixed; } static void update_mem_lpage_info(struct kvm *kvm, struct kvm_memory_slot *slot, unsigned int attr, gfn_t start, gfn_t end) { unsigned long lpage_start, lpage_end; unsigned long gfn, pages, mask; int level; for (level = PG_LEVEL_2M; level <= KVM_MAX_HUGEPAGE_LEVEL; level++) { pages = KVM_PAGES_PER_HPAGE(level); mask = ~(pages - 1); lpage_start = start & mask; lpage_end = (end - 1) & mask; /* * We only need to scan the head and tail page, for middle pages * we know they are not mixed. */ update_mixed(lpage_info_slot(lpage_start, slot, level), mem_attr_is_mixed(kvm, slot, level, lpage_start, lpage_start + pages)); if (lpage_start == lpage_end) return; for (gfn = lpage_start + pages; gfn < lpage_end; gfn += pages) update_mixed(lpage_info_slot(gfn, slot, level), false); update_mixed(lpage_info_slot(lpage_end, slot, level), mem_attr_is_mixed(kvm, slot, level, lpage_end, lpage_end + pages)); } } void kvm_arch_update_mem_attr(struct kvm *kvm, unsigned int attr, gfn_t start, gfn_t end) { struct kvm_memory_slot *slot; struct kvm_memslots *slots; struct kvm_memslot_iter iter; int idx; int i; WARN_ONCE(!(attr & (KVM_MEM_ATTR_PRIVATE | KVM_MEM_ATTR_SHARED)), "Unsupported mem attribute.\n"); idx = srcu_read_lock(&kvm->srcu); for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { slots = __kvm_memslots(kvm, i); kvm_for_each_memslot_in_gfn_range(&iter, slots, start, end) { slot = iter.slot; start = max(start, slot->base_gfn); end = min(end, slot->base_gfn + slot->npages); if (WARN_ON_ONCE(start >= end)) continue; update_mem_lpage_info(kvm, slot, attr, start, end); } } srcu_read_unlock(&kvm->srcu, idx); } #endif
On Thu, Sep 29, 2022 at 09:52:06AM -0700, Isaku Yamahata wrote: > On Thu, Sep 15, 2022 at 10:29:11PM +0800, > Chao Peng <chao.p.peng@linux.intel.com> wrote: > > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > > index 08abad4f3e6f..a0f198cede3d 100644 > > --- a/arch/x86/kvm/mmu/mmu.c > > +++ b/arch/x86/kvm/mmu/mmu.c > ... > > @@ -6894,3 +6899,115 @@ void kvm_mmu_pre_destroy_vm(struct kvm *kvm) > > if (kvm->arch.nx_lpage_recovery_thread) > > kthread_stop(kvm->arch.nx_lpage_recovery_thread); > > } > > + > > +static bool mem_attr_is_mixed(struct kvm *kvm, unsigned int attr, > > + gfn_t start, gfn_t end) > > +{ > > + XA_STATE(xas, &kvm->mem_attr_array, start); > > + gfn_t gfn = start; > > + void *entry; > > + bool shared, private; > > + bool mixed = false; > > + > > + if (attr == KVM_MEM_ATTR_SHARED) { > > + shared = true; > > + private = false; > > + } else { > > + shared = false; > > + private = true; > > + } > > We don't have to care the target is shared or private. We need to check > only same or not. There is optimization chance if we know what we are going to set. we can return 'mixed = true' earlier when we find the first reverse attr, e.g. it's unnecessarily to check all the child page attr in one largepage to give a conclusion. After a further look, the code can be refined as below: --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -7255,17 +7255,9 @@ static bool mem_attr_is_mixed(struct kvm *kvm, unsigned int attr, XA_STATE(xas, &kvm->mem_attr_array, start); gfn_t gfn = start; void *entry; - bool shared, private; + bool shared = attr == KVM_MEM_ATTR_SHARED; bool mixed = false; - if (attr == KVM_MEM_ATTR_SHARED) { - shared = true; - private = false; - } else { - shared = false; - private = true; - } - rcu_read_lock(); entry = xas_load(&xas); while (gfn < end) { @@ -7274,12 +7266,7 @@ static bool mem_attr_is_mixed(struct kvm *kvm, unsigned int attr, KVM_BUG_ON(gfn != xas.xa_index, kvm); - if (entry) - private = true; - else - shared = true; - - if (private && shared) { + if ((entry && !shared) || (!entry && shared)) { mixed = true; goto out; } @@ -7320,8 +7307,7 @@ static void update_mem_lpage_info(struct kvm *kvm, * we know they are not mixed. */ update_mixed(lpage_info_slot(lpage_start, slot, level), - mem_attr_is_mixed(kvm, attr, lpage_start, - lpage_start + pages)); + mem_attr_is_mixed(kvm, attr, lpage_start, start)); if (lpage_start == lpage_end) return; @@ -7330,7 +7316,7 @@ static void update_mem_lpage_info(struct kvm *kvm, update_mixed(lpage_info_slot(gfn, slot, level), false); update_mixed(lpage_info_slot(lpage_end, slot, level), - mem_attr_is_mixed(kvm, attr, lpage_end, + mem_attr_is_mixed(kvm, attr, end, lpage_end + pages)); } } > > > + > > + 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 (entry) > > + private = true; > > + else > > + shared = true; > > + > > + if (private && shared) { > > + mixed = true; > > + goto out; > > + } > > + > > + entry = xas_next(&xas); > > + gfn++; > > + } > > +out: > > + rcu_read_unlock(); > > + return mixed; > > +} > > + > > +static inline void update_mixed(struct kvm_lpage_info *linfo, bool mixed) > > +{ > > + if (mixed) > > + linfo->disallow_lpage |= KVM_LPAGE_PRIVATE_SHARED_MIXED; > > + else > > + linfo->disallow_lpage &= ~KVM_LPAGE_PRIVATE_SHARED_MIXED; > > +} > > + > > +static void update_mem_lpage_info(struct kvm *kvm, > > + struct kvm_memory_slot *slot, > > + unsigned int attr, > > + gfn_t start, gfn_t end) > > +{ > > + unsigned long lpage_start, lpage_end; > > + unsigned long gfn, pages, mask; > > + int level; > > + > > + for (level = PG_LEVEL_2M; level <= KVM_MAX_HUGEPAGE_LEVEL; level++) { > > + pages = KVM_PAGES_PER_HPAGE(level); > > + mask = ~(pages - 1); > > + lpage_start = start & mask; > > + lpage_end = (end - 1) & mask; > > + > > + /* > > + * We only need to scan the head and tail page, for middle pages > > + * we know they are not mixed. > > + */ > > + update_mixed(lpage_info_slot(lpage_start, slot, level), > > + mem_attr_is_mixed(kvm, attr, lpage_start, > > + lpage_start + pages)); > > + > > + if (lpage_start == lpage_end) > > + return; > > + > > + for (gfn = lpage_start + pages; gfn < lpage_end; gfn += pages) > > + update_mixed(lpage_info_slot(gfn, slot, level), false); > > > For >2M case, we don't have to check all entry. just check lower level case. Sounds good, we can reduce some scanning. Thanks, Chao > > > + > > + update_mixed(lpage_info_slot(lpage_end, slot, level), > > + mem_attr_is_mixed(kvm, attr, lpage_end, > > + lpage_end + pages)); > > + } > > +} > > + > > +void kvm_arch_update_mem_attr(struct kvm *kvm, unsigned int attr, > > + gfn_t start, gfn_t end) > > +{ > > + struct kvm_memory_slot *slot; > > + struct kvm_memslots *slots; > > + struct kvm_memslot_iter iter; > > + int i; > > + > > + WARN_ONCE(!(attr & (KVM_MEM_ATTR_PRIVATE | KVM_MEM_ATTR_SHARED)), > > + "Unsupported mem attribute.\n"); > > + > > + for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { > > + slots = __kvm_memslots(kvm, i); > > + > > + kvm_for_each_memslot_in_gfn_range(&iter, slots, start, end) { > > + slot = iter.slot; > > + start = max(start, slot->base_gfn); > > + end = min(end, slot->base_gfn + slot->npages); > > + if (WARN_ON_ONCE(start >= end)) > > + continue; > > + > > + update_mem_lpage_info(kvm, slot, attr, start, end); > > + } > > + } > > +} > > > Here is my updated version. > > bool kvm_mem_attr_is_mixed(struct kvm_memory_slot *slot, gfn_t gfn, int level) > { > gfn_t pages = KVM_PAGES_PER_HPAGE(level); > gfn_t mask = ~(pages - 1); > struct kvm_lpage_info *linfo = lpage_info_slot(gfn & mask, slot, level); > > WARN_ON_ONCE(level == PG_LEVEL_4K); > return linfo->disallow_lpage & KVM_LPAGE_PRIVATE_SHARED_MIXED; > } > > #ifdef CONFIG_HAVE_KVM_PRIVATE_MEM_ATTR > static void update_mixed(struct kvm_lpage_info *linfo, bool mixed) > { > if (mixed) > linfo->disallow_lpage |= KVM_LPAGE_PRIVATE_SHARED_MIXED; > else > linfo->disallow_lpage &= ~KVM_LPAGE_PRIVATE_SHARED_MIXED; > } > > static bool __mem_attr_is_mixed(struct kvm *kvm, gfn_t start, gfn_t end) > { > XA_STATE(xas, &kvm->mem_attr_array, start); > bool mixed = false; > gfn_t gfn = start; > void *s_entry; > void *entry; > > rcu_read_lock(); > s_entry = xas_load(&xas); > entry = s_entry; > while (gfn < end) { > if (xas_retry(&xas, entry)) > continue; > > KVM_BUG_ON(gfn != xas.xa_index, kvm); > > entry = xas_next(&xas); > if (entry != s_entry) { > mixed = true; > break; > } > gfn++; > } > rcu_read_unlock(); > return mixed; > } > > static bool mem_attr_is_mixed(struct kvm *kvm, > struct kvm_memory_slot *slot, int level, > gfn_t start, gfn_t end) > { > struct kvm_lpage_info *child_linfo; > unsigned long child_pages; > bool mixed = false; > unsigned long gfn; > void *entry; > > if (WARN_ON_ONCE(level == PG_LEVEL_4K)) > return false; > > if (level == PG_LEVEL_2M) > return __mem_attr_is_mixed(kvm, start, end); > > /* This assumes that level - 1 is already updated. */ > rcu_read_lock(); > child_pages = KVM_PAGES_PER_HPAGE(level - 1); > entry = xa_load(&kvm->mem_attr_array, start); > for (gfn = start; gfn < end; gfn += child_pages) { > child_linfo = lpage_info_slot(gfn, slot, level - 1); > if (child_linfo->disallow_lpage & KVM_LPAGE_PRIVATE_SHARED_MIXED) { > mixed = true; > break; > } > if (xa_load(&kvm->mem_attr_array, gfn) != entry) { > mixed = true; > break; > } > } > rcu_read_unlock(); > return mixed; > } > > static void update_mem_lpage_info(struct kvm *kvm, > struct kvm_memory_slot *slot, > unsigned int attr, > gfn_t start, gfn_t end) > { > unsigned long lpage_start, lpage_end; > unsigned long gfn, pages, mask; > int level; > > for (level = PG_LEVEL_2M; level <= KVM_MAX_HUGEPAGE_LEVEL; level++) { > pages = KVM_PAGES_PER_HPAGE(level); > mask = ~(pages - 1); > lpage_start = start & mask; > lpage_end = (end - 1) & mask; > > /* > * We only need to scan the head and tail page, for middle pages > * we know they are not mixed. > */ > update_mixed(lpage_info_slot(lpage_start, slot, level), > mem_attr_is_mixed(kvm, slot, level, > lpage_start, lpage_start + pages)); > > if (lpage_start == lpage_end) > return; > > for (gfn = lpage_start + pages; gfn < lpage_end; gfn += pages) > update_mixed(lpage_info_slot(gfn, slot, level), false); > > update_mixed(lpage_info_slot(lpage_end, slot, level), > mem_attr_is_mixed(kvm, slot, level, > lpage_end, lpage_end + pages)); > } > } > > void kvm_arch_update_mem_attr(struct kvm *kvm, unsigned int attr, > gfn_t start, gfn_t end) > { > struct kvm_memory_slot *slot; > struct kvm_memslots *slots; > struct kvm_memslot_iter iter; > int idx; > int i; > > WARN_ONCE(!(attr & (KVM_MEM_ATTR_PRIVATE | KVM_MEM_ATTR_SHARED)), > "Unsupported mem attribute.\n"); > > idx = srcu_read_lock(&kvm->srcu); > for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { > slots = __kvm_memslots(kvm, i); > > kvm_for_each_memslot_in_gfn_range(&iter, slots, start, end) { > slot = iter.slot; > start = max(start, slot->base_gfn); > end = min(end, slot->base_gfn + slot->npages); > if (WARN_ON_ONCE(start >= end)) > continue; > > update_mem_lpage_info(kvm, slot, attr, start, end); > } > } > srcu_read_unlock(&kvm->srcu, idx); > } > #endif > > > -- > Isaku Yamahata <isaku.yamahata@gmail.com>
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index cfad6ba1a70a..85119ed9527a 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -38,6 +38,7 @@ #define __KVM_HAVE_ARCH_VCPU_DEBUGFS #define __KVM_HAVE_ZAP_GFN_RANGE +#define __KVM_HAVE_ARCH_UPDATE_MEM_ATTR #define KVM_MAX_VCPUS 1024 @@ -945,6 +946,13 @@ struct kvm_vcpu_arch { #endif }; +/* + * Use a bit in disallow_lpage to indicate private/shared pages mixed at the + * level. The remaining bits will be used as a reference count for other users. + */ +#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 08abad4f3e6f..a0f198cede3d 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -762,11 +762,16 @@ 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); } } @@ -6894,3 +6899,115 @@ void kvm_mmu_pre_destroy_vm(struct kvm *kvm) if (kvm->arch.nx_lpage_recovery_thread) kthread_stop(kvm->arch.nx_lpage_recovery_thread); } + +static bool mem_attr_is_mixed(struct kvm *kvm, unsigned int attr, + gfn_t start, gfn_t end) +{ + XA_STATE(xas, &kvm->mem_attr_array, start); + gfn_t gfn = start; + void *entry; + bool shared, private; + bool mixed = false; + + if (attr == KVM_MEM_ATTR_SHARED) { + shared = true; + private = false; + } else { + shared = false; + private = true; + } + + 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 (entry) + private = true; + else + shared = true; + + if (private && shared) { + mixed = true; + goto out; + } + + entry = xas_next(&xas); + gfn++; + } +out: + rcu_read_unlock(); + return mixed; +} + +static inline void update_mixed(struct kvm_lpage_info *linfo, bool mixed) +{ + if (mixed) + linfo->disallow_lpage |= KVM_LPAGE_PRIVATE_SHARED_MIXED; + else + linfo->disallow_lpage &= ~KVM_LPAGE_PRIVATE_SHARED_MIXED; +} + +static void update_mem_lpage_info(struct kvm *kvm, + struct kvm_memory_slot *slot, + unsigned int attr, + gfn_t start, gfn_t end) +{ + unsigned long lpage_start, lpage_end; + unsigned long gfn, pages, mask; + int level; + + for (level = PG_LEVEL_2M; level <= KVM_MAX_HUGEPAGE_LEVEL; level++) { + pages = KVM_PAGES_PER_HPAGE(level); + mask = ~(pages - 1); + lpage_start = start & mask; + lpage_end = (end - 1) & mask; + + /* + * We only need to scan the head and tail page, for middle pages + * we know they are not mixed. + */ + update_mixed(lpage_info_slot(lpage_start, slot, level), + mem_attr_is_mixed(kvm, attr, lpage_start, + lpage_start + pages)); + + if (lpage_start == lpage_end) + return; + + for (gfn = lpage_start + pages; gfn < lpage_end; gfn += pages) + update_mixed(lpage_info_slot(gfn, slot, level), false); + + update_mixed(lpage_info_slot(lpage_end, slot, level), + mem_attr_is_mixed(kvm, attr, lpage_end, + lpage_end + pages)); + } +} + +void kvm_arch_update_mem_attr(struct kvm *kvm, unsigned int attr, + gfn_t start, gfn_t end) +{ + struct kvm_memory_slot *slot; + struct kvm_memslots *slots; + struct kvm_memslot_iter iter; + int i; + + WARN_ONCE(!(attr & (KVM_MEM_ATTR_PRIVATE | KVM_MEM_ATTR_SHARED)), + "Unsupported mem attribute.\n"); + + for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { + slots = __kvm_memslots(kvm, i); + + kvm_for_each_memslot_in_gfn_range(&iter, slots, start, end) { + slot = iter.slot; + start = max(start, slot->base_gfn); + end = min(end, slot->base_gfn + slot->npages); + if (WARN_ON_ONCE(start >= end)) + continue; + + update_mem_lpage_info(kvm, slot, attr, start, end); + } + } +} diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 081f62ccc9a1..ef11cda6f13f 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -12321,6 +12321,8 @@ 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->private_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 d65690cae80b..fd36ce6597ad 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -2277,4 +2277,21 @@ static inline void kvm_handle_signal_exit(struct kvm_vcpu *vcpu) /* Max number of entries allowed for each kvm dirty ring */ #define KVM_DIRTY_RING_MAX_ENTRIES 65536 +#ifdef CONFIG_HAVE_KVM_PRIVATE_MEM + +#define KVM_MEM_ATTR_SHARED 0x0001 +#define KVM_MEM_ATTR_PRIVATE 0x0002 + +#ifdef __KVM_HAVE_ARCH_UPDATE_MEM_ATTR +void kvm_arch_update_mem_attr(struct kvm *kvm, unsigned int attr, + gfn_t start, gfn_t end); +#else +static inline void kvm_arch_update_mem_attr(struct kvm *kvm, unsigned int attr, + gfn_t start, gfn_t end) +{ +} +#endif + +#endif /* CONFIG_HAVE_KVM_PRIVATE_MEM */ + #endif diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index de5cce8c82c7..97d893f7482c 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -938,13 +938,13 @@ static int kvm_init_mmu_notifier(struct kvm *kvm) #endif /* CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER */ #ifdef CONFIG_HAVE_KVM_PRIVATE_MEM -#define KVM_MEM_ATTR_SHARED 0x0001 static int kvm_vm_ioctl_set_mem_attr(struct kvm *kvm, gpa_t gpa, gpa_t size, bool is_private) { gfn_t start, end; unsigned long index; void *entry; + int attr; int r; if (size == 0 || gpa + size < gpa) @@ -959,7 +959,13 @@ static int kvm_vm_ioctl_set_mem_attr(struct kvm *kvm, gpa_t gpa, gpa_t size, * Guest memory defaults to private, kvm->mem_attr_array only stores * shared memory. */ - entry = is_private ? NULL : xa_mk_value(KVM_MEM_ATTR_SHARED); + if (is_private) { + attr = KVM_MEM_ATTR_PRIVATE; + entry = NULL; + } else { + attr = KVM_MEM_ATTR_SHARED; + entry = xa_mk_value(KVM_MEM_ATTR_SHARED); + } for (index = start; index < end; index++) { r = xa_err(xa_store(&kvm->mem_attr_array, index, entry, @@ -969,6 +975,7 @@ static int kvm_vm_ioctl_set_mem_attr(struct kvm *kvm, gpa_t gpa, gpa_t size, } kvm_zap_gfn_range(kvm, start, end); + kvm_arch_update_mem_attr(kvm, attr, start, end); return r; err:
When private/shared memory are mixed in a large page, the lpage_info may not be accurate and should be updated with this mixed info. A large page has mixed pages can't be really mapped as large page since its private/shared pages are from different physical memory. This patch updates lpage_info when private/shared memory attribute is changed. If both private and shared pages are within a large page region, it can't be mapped as large page. It's a bit challenge to track the mixed info in a 'count' like variable, this patch instead reserves a bit in disallow_lpage to indicate a large page include mixed private/share pages. 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 | 119 +++++++++++++++++++++++++++++++- arch/x86/kvm/x86.c | 2 + include/linux/kvm_host.h | 17 +++++ virt/kvm/kvm_main.c | 11 ++- 5 files changed, 154 insertions(+), 3 deletions(-)