forked from Minki/linux
KVM: Avoid checking huge page mappings in get_dirty_log()
Dropped such mappings when we enabled dirty logging and we will never create new ones until we stop the logging. For this we introduce a new function which can be used to write protect a range of PT level pages: although we do not need to care about a range of pages at this point, the following patch will need this feature to optimize the write protection of many pages. Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
parent
a0ed46073c
commit
5dc99b2380
@ -712,8 +712,9 @@ void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
|
||||
|
||||
int kvm_mmu_reset_context(struct kvm_vcpu *vcpu);
|
||||
void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot);
|
||||
int kvm_mmu_rmap_write_protect(struct kvm *kvm, u64 gfn,
|
||||
struct kvm_memory_slot *slot);
|
||||
void kvm_mmu_write_protect_pt_masked(struct kvm *kvm,
|
||||
struct kvm_memory_slot *slot,
|
||||
gfn_t gfn_offset, unsigned long mask);
|
||||
void kvm_mmu_zap_all(struct kvm *kvm);
|
||||
unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm);
|
||||
void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int kvm_nr_mmu_pages);
|
||||
|
@ -1037,11 +1037,39 @@ static int __rmap_write_protect(struct kvm *kvm, unsigned long *rmapp, int level
|
||||
return write_protected;
|
||||
}
|
||||
|
||||
int kvm_mmu_rmap_write_protect(struct kvm *kvm, u64 gfn,
|
||||
struct kvm_memory_slot *slot)
|
||||
/**
|
||||
* kvm_mmu_write_protect_pt_masked - write protect selected PT level pages
|
||||
* @kvm: kvm instance
|
||||
* @slot: slot to protect
|
||||
* @gfn_offset: start of the BITS_PER_LONG pages we care about
|
||||
* @mask: indicates which pages we should protect
|
||||
*
|
||||
* Used when we do not need to care about huge page mappings: e.g. during dirty
|
||||
* logging we do not have any such mappings.
|
||||
*/
|
||||
void kvm_mmu_write_protect_pt_masked(struct kvm *kvm,
|
||||
struct kvm_memory_slot *slot,
|
||||
gfn_t gfn_offset, unsigned long mask)
|
||||
{
|
||||
unsigned long *rmapp;
|
||||
int i, write_protected = 0;
|
||||
|
||||
while (mask) {
|
||||
rmapp = &slot->rmap[gfn_offset + __ffs(mask)];
|
||||
__rmap_write_protect(kvm, rmapp, PT_PAGE_TABLE_LEVEL);
|
||||
|
||||
/* clear the first set bit */
|
||||
mask &= mask - 1;
|
||||
}
|
||||
}
|
||||
|
||||
static int rmap_write_protect(struct kvm *kvm, u64 gfn)
|
||||
{
|
||||
struct kvm_memory_slot *slot;
|
||||
unsigned long *rmapp;
|
||||
int i;
|
||||
int write_protected = 0;
|
||||
|
||||
slot = gfn_to_memslot(kvm, gfn);
|
||||
|
||||
for (i = PT_PAGE_TABLE_LEVEL;
|
||||
i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
|
||||
@ -1052,14 +1080,6 @@ int kvm_mmu_rmap_write_protect(struct kvm *kvm, u64 gfn,
|
||||
return write_protected;
|
||||
}
|
||||
|
||||
static int rmap_write_protect(struct kvm *kvm, u64 gfn)
|
||||
{
|
||||
struct kvm_memory_slot *slot;
|
||||
|
||||
slot = gfn_to_memslot(kvm, gfn);
|
||||
return kvm_mmu_rmap_write_protect(kvm, gfn, slot);
|
||||
}
|
||||
|
||||
static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp,
|
||||
unsigned long data)
|
||||
{
|
||||
|
@ -3095,13 +3095,11 @@ static void write_protect_slot(struct kvm *kvm,
|
||||
|
||||
/* Not many dirty pages compared to # of shadow pages. */
|
||||
if (nr_dirty_pages < kvm->arch.n_used_mmu_pages) {
|
||||
unsigned long gfn_offset;
|
||||
gfn_t offset;
|
||||
|
||||
for_each_set_bit(gfn_offset, dirty_bitmap, memslot->npages) {
|
||||
unsigned long gfn = memslot->base_gfn + gfn_offset;
|
||||
for_each_set_bit(offset, dirty_bitmap, memslot->npages)
|
||||
kvm_mmu_write_protect_pt_masked(kvm, memslot, offset, 1);
|
||||
|
||||
kvm_mmu_rmap_write_protect(kvm, gfn, memslot);
|
||||
}
|
||||
kvm_flush_remote_tlbs(kvm);
|
||||
} else
|
||||
kvm_mmu_slot_remove_write_access(kvm, memslot->id);
|
||||
|
Loading…
Reference in New Issue
Block a user