Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 46971a2f authored by Xiao Guangrong's avatar Xiao Guangrong Committed by Radim Krčmář
Browse files

KVM: MMU: skip obsolete sp in for_each_gfn_*() 



The obsolete sp should not be used on current vCPUs and should not hurt
vCPU's running, so skip it from for_each_gfn_sp() and
for_each_gfn_indirect_valid_sp()

The side effort is we will double check role.invalid in kvm_mmu_get_page()
but i think it is okay as role is well cached

Signed-off-by: default avatarXiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent c54cdf14

arch/x86/kvm/mmu.c

+12 −16
Original line number Diff line number Diff line
@@ -1909,18 +1909,17 @@ static void kvm_mmu_commit_zap_page(struct kvm *kvm, 
 * since it has been deleted from active_mmu_pages but still can be found

 * at hast list.

 *

 * for_each_gfn_indirect_valid_sp has skipped that kind of page and

 * kvm_mmu_get_page(), the only user of for_each_gfn_sp(), has skipped

 * all the obsolete pages.

 * for_each_gfn_valid_sp() has skipped that kind of pages.

 */

#define for_each_gfn_sp(_kvm, _sp, _gfn)				\

#define for_each_gfn_valid_sp(_kvm, _sp, _gfn)				\

	hlist_for_each_entry(_sp,					\

	  &(_kvm)->arch.mmu_page_hash[kvm_page_table_hashfn(_gfn)], hash_link) \

		if ((_sp)->gfn != (_gfn)) {} else

		if ((_sp)->gfn != (_gfn) || is_obsolete_sp((_kvm), (_sp)) \

			|| (_sp)->role.invalid) {} else



#define for_each_gfn_indirect_valid_sp(_kvm, _sp, _gfn)			\

	for_each_gfn_sp(_kvm, _sp, _gfn)				\

		if ((_sp)->role.direct || (_sp)->role.invalid) {} else

	for_each_gfn_valid_sp(_kvm, _sp, _gfn)				\

		if ((_sp)->role.direct) {} else



/* @sp->gfn should be write-protected at the call site */

static bool __kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
@@ -1961,6 +1960,11 @@ static void kvm_mmu_audit(struct kvm_vcpu *vcpu, int point) { } 
static void mmu_audit_disable(void) { }

#endif



static bool is_obsolete_sp(struct kvm *kvm, struct kvm_mmu_page *sp)

{

	return unlikely(sp->mmu_valid_gen != kvm->arch.mmu_valid_gen);

}



static bool kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,

			 struct list_head *invalid_list)

{
@@ -2105,11 +2109,6 @@ static void clear_sp_write_flooding_count(u64 *spte) 
	__clear_sp_write_flooding_count(sp);

}



static bool is_obsolete_sp(struct kvm *kvm, struct kvm_mmu_page *sp)

{

	return unlikely(sp->mmu_valid_gen != kvm->arch.mmu_valid_gen);

}



static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,

					     gfn_t gfn,

					     gva_t gaddr,
@@ -2136,10 +2135,7 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, 
		quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1;

		role.quadrant = quadrant;

	}

	for_each_gfn_sp(vcpu->kvm, sp, gfn) {

		if (is_obsolete_sp(vcpu->kvm, sp))

			continue;



	for_each_gfn_valid_sp(vcpu->kvm, sp, gfn) {

		if (!need_sync && sp->unsync)

			need_sync = true;