* kvm_mmu_page_role tracks the properties of a shadow page (where shadow page
* also includes TDP pages) to determine whether or not a page can be used in
* the given MMU context. This is a subset of the overall kvm_cpu_role to
- * minimize the size of kvm_memory_slot.arch.gfn_track, i.e. allows allocating
- * 2 bytes per gfn instead of 4 bytes per gfn.
+ * minimize the size of kvm_memory_slot.arch.gfn_write_track, i.e. allows
+ * allocating 2 bytes per gfn instead of 4 bytes per gfn.
*
* Upper-level shadow pages having gptes are tracked for write-protection via
- * gfn_track. As above, gfn_track is a 16 bit counter, so KVM must not create
- * more than 2^16-1 upper-level shadow pages at a single gfn, otherwise
- * gfn_track will overflow and explosions will ensure.
+ * gfn_write_track. As above, gfn_write_track is a 16 bit counter, so KVM must
+ * not create more than 2^16-1 upper-level shadow pages at a single gfn,
+ * otherwise gfn_write_track will overflow and explosions will ensue.
*
* A unique shadow page (SP) for a gfn is created if and only if an existing SP
* cannot be reused. The ability to reuse a SP is tracked by its role, which
struct kvm_arch_memory_slot {
struct kvm_rmap_head *rmap[KVM_NR_PAGE_SIZES];
struct kvm_lpage_info *lpage_info[KVM_NR_PAGE_SIZES - 1];
- unsigned short *gfn_track[KVM_PAGE_TRACK_MAX];
+ unsigned short *gfn_write_track;
};
/*
/* the non-leaf shadow pages are keeping readonly. */
if (sp->role.level > PG_LEVEL_4K)
- return kvm_slot_page_track_add_page(kvm, slot, gfn,
- KVM_PAGE_TRACK_WRITE);
+ return kvm_slot_page_track_add_page(kvm, slot, gfn);
kvm_mmu_gfn_disallow_lpage(slot, gfn);
slots = kvm_memslots_for_spte_role(kvm, sp->role);
slot = __gfn_to_memslot(slots, gfn);
if (sp->role.level > PG_LEVEL_4K)
- return kvm_slot_page_track_remove_page(kvm, slot, gfn,
- KVM_PAGE_TRACK_WRITE);
+ return kvm_slot_page_track_remove_page(kvm, slot, gfn);
kvm_mmu_gfn_allow_lpage(slot, gfn);
}
* track machinery is used to write-protect upper-level shadow pages,
* i.e. this guards the role.level == 4K assertion below!
*/
- if (kvm_slot_page_track_is_active(kvm, slot, gfn, KVM_PAGE_TRACK_WRITE))
+ if (kvm_slot_page_track_is_active(kvm, slot, gfn))
return -EPERM;
/*
* guest is writing the page which is write tracked which can
* not be fixed by page fault handler.
*/
- if (kvm_slot_page_track_is_active(vcpu->kvm, fault->slot, fault->gfn, KVM_PAGE_TRACK_WRITE))
+ if (kvm_slot_page_track_is_active(vcpu->kvm, fault->slot, fault->gfn))
return true;
return false;
* physical address properties) in a single VM would require tracking
* all relevant CPUID information in kvm_mmu_page_role. That is very
* undesirable as it would increase the memory requirements for
- * gfn_track (see struct kvm_mmu_page_role comments). For now that
- * problem is swept under the rug; KVM's CPUID API is horrific and
+ * gfn_write_track (see struct kvm_mmu_page_role comments). For now
+ * that problem is swept under the rug; KVM's CPUID API is horrific and
* it's all but impossible to solve it without introducing a new API.
*/
vcpu->arch.root_mmu.root_role.word = 0;
void kvm_page_track_free_memslot(struct kvm_memory_slot *slot)
{
- int i;
-
- for (i = 0; i < KVM_PAGE_TRACK_MAX; i++) {
- kvfree(slot->arch.gfn_track[i]);
- slot->arch.gfn_track[i] = NULL;
- }
+ kvfree(slot->arch.gfn_write_track);
+ slot->arch.gfn_write_track = NULL;
}
-int kvm_page_track_create_memslot(struct kvm *kvm,
- struct kvm_memory_slot *slot,
- unsigned long npages)
+static int __kvm_page_track_write_tracking_alloc(struct kvm_memory_slot *slot,
+ unsigned long npages)
{
- int i;
-
- for (i = 0; i < KVM_PAGE_TRACK_MAX; i++) {
- if (i == KVM_PAGE_TRACK_WRITE &&
- !kvm_page_track_write_tracking_enabled(kvm))
- continue;
-
- slot->arch.gfn_track[i] =
- __vcalloc(npages, sizeof(*slot->arch.gfn_track[i]),
- GFP_KERNEL_ACCOUNT);
- if (!slot->arch.gfn_track[i])
- goto track_free;
- }
+ const size_t size = sizeof(*slot->arch.gfn_write_track);
- return 0;
+ if (!slot->arch.gfn_write_track)
+ slot->arch.gfn_write_track = __vcalloc(npages, size,
+ GFP_KERNEL_ACCOUNT);
-track_free:
- kvm_page_track_free_memslot(slot);
- return -ENOMEM;
+ return slot->arch.gfn_write_track ? 0 : -ENOMEM;
}
-static inline bool page_track_mode_is_valid(enum kvm_page_track_mode mode)
+int kvm_page_track_create_memslot(struct kvm *kvm,
+ struct kvm_memory_slot *slot,
+ unsigned long npages)
{
- if (mode < 0 || mode >= KVM_PAGE_TRACK_MAX)
- return false;
+ if (!kvm_page_track_write_tracking_enabled(kvm))
+ return 0;
- return true;
+ return __kvm_page_track_write_tracking_alloc(slot, npages);
}
int kvm_page_track_write_tracking_alloc(struct kvm_memory_slot *slot)
{
- unsigned short *gfn_track;
-
- if (slot->arch.gfn_track[KVM_PAGE_TRACK_WRITE])
- return 0;
-
- gfn_track = __vcalloc(slot->npages, sizeof(*gfn_track),
- GFP_KERNEL_ACCOUNT);
- if (gfn_track == NULL)
- return -ENOMEM;
-
- slot->arch.gfn_track[KVM_PAGE_TRACK_WRITE] = gfn_track;
- return 0;
+ return __kvm_page_track_write_tracking_alloc(slot, slot->npages);
}
-static void update_gfn_track(struct kvm_memory_slot *slot, gfn_t gfn,
- enum kvm_page_track_mode mode, short count)
+static void update_gfn_write_track(struct kvm_memory_slot *slot, gfn_t gfn,
+ short count)
{
int index, val;
index = gfn_to_index(gfn, slot->base_gfn, PG_LEVEL_4K);
- val = slot->arch.gfn_track[mode][index];
+ val = slot->arch.gfn_write_track[index];
if (WARN_ON_ONCE(val + count < 0 || val + count > USHRT_MAX))
return;
- slot->arch.gfn_track[mode][index] += count;
+ slot->arch.gfn_write_track[index] += count;
}
/*
* @kvm: the guest instance we are interested in.
* @slot: the @gfn belongs to.
* @gfn: the guest page.
- * @mode: tracking mode, currently only write track is supported.
*/
void kvm_slot_page_track_add_page(struct kvm *kvm,
- struct kvm_memory_slot *slot, gfn_t gfn,
- enum kvm_page_track_mode mode)
+ struct kvm_memory_slot *slot, gfn_t gfn)
{
-
- if (WARN_ON_ONCE(!page_track_mode_is_valid(mode)))
+ if (WARN_ON_ONCE(!kvm_page_track_write_tracking_enabled(kvm)))
return;
- if (WARN_ON_ONCE(mode == KVM_PAGE_TRACK_WRITE &&
- !kvm_page_track_write_tracking_enabled(kvm)))
- return;
-
- update_gfn_track(slot, gfn, mode, 1);
+ update_gfn_write_track(slot, gfn, 1);
/*
* new track stops large page mapping for the
*/
kvm_mmu_gfn_disallow_lpage(slot, gfn);
- if (mode == KVM_PAGE_TRACK_WRITE)
- if (kvm_mmu_slot_gfn_write_protect(kvm, slot, gfn, PG_LEVEL_4K))
- kvm_flush_remote_tlbs(kvm);
+ if (kvm_mmu_slot_gfn_write_protect(kvm, slot, gfn, PG_LEVEL_4K))
+ kvm_flush_remote_tlbs(kvm);
}
EXPORT_SYMBOL_GPL(kvm_slot_page_track_add_page);
* @kvm: the guest instance we are interested in.
* @slot: the @gfn belongs to.
* @gfn: the guest page.
- * @mode: tracking mode, currently only write track is supported.
*/
void kvm_slot_page_track_remove_page(struct kvm *kvm,
- struct kvm_memory_slot *slot, gfn_t gfn,
- enum kvm_page_track_mode mode)
+ struct kvm_memory_slot *slot, gfn_t gfn)
{
- if (WARN_ON_ONCE(!page_track_mode_is_valid(mode)))
- return;
-
- if (WARN_ON_ONCE(mode == KVM_PAGE_TRACK_WRITE &&
- !kvm_page_track_write_tracking_enabled(kvm)))
+ if (WARN_ON_ONCE(!kvm_page_track_write_tracking_enabled(kvm)))
return;
- update_gfn_track(slot, gfn, mode, -1);
+ update_gfn_write_track(slot, gfn, -1);
/*
* allow large page mapping for the tracked page
*/
bool kvm_slot_page_track_is_active(struct kvm *kvm,
const struct kvm_memory_slot *slot,
- gfn_t gfn, enum kvm_page_track_mode mode)
+ gfn_t gfn)
{
int index;
- if (WARN_ON_ONCE(!page_track_mode_is_valid(mode)))
- return false;
-
if (!slot)
return false;
- if (mode == KVM_PAGE_TRACK_WRITE &&
- !kvm_page_track_write_tracking_enabled(kvm))
+ if (!kvm_page_track_write_tracking_enabled(kvm))
return false;
index = gfn_to_index(gfn, slot->base_gfn, PG_LEVEL_4K);
- return !!READ_ONCE(slot->arch.gfn_track[mode][index]);
+ return !!READ_ONCE(slot->arch.gfn_write_track[index]);
}
#ifdef CONFIG_KVM_EXTERNAL_WRITE_TRACKING
projects / linux-2.6-block.git / commitdiff