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Commit 55514893 authored by Paul Mackerras's avatar Paul Mackerras Committed by Avi Kivity
Browse files

KVM: PPC: Book3S HV: Use the hardware referenced bit for kvm_age_hva 



This uses the host view of the hardware R (referenced) bit to speed
up kvm_age_hva() and kvm_test_age_hva().  Instead of removing all
the relevant HPTEs in kvm_age_hva(), we now just reset their R bits
if set.  Also, kvm_test_age_hva() now scans the relevant HPTEs to
see if any of them have R set.

Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent bad3b507

arch/powerpc/include/asm/kvm_book3s.h

+2 −0
Original line number Diff line number Diff line
@@ -147,6 +147,8 @@ extern void kvmppc_add_revmap_chain(struct kvm *kvm, struct revmap_entry *rev, 
			unsigned long *rmap, long pte_index, int realmode);

extern void kvmppc_invalidate_hpte(struct kvm *kvm, unsigned long *hptep,

			unsigned long pte_index);

void kvmppc_clear_ref_hpte(struct kvm *kvm, unsigned long *hptep,

			unsigned long pte_index);

extern void *kvmppc_pin_guest_page(struct kvm *kvm, unsigned long addr,

			unsigned long *nb_ret);

extern void kvmppc_unpin_guest_page(struct kvm *kvm, void *addr);

arch/powerpc/kvm/book3s_64_mmu_hv.c

+70 −11
Original line number Diff line number Diff line
@@ -772,16 +772,50 @@ int kvm_unmap_hva(struct kvm *kvm, unsigned long hva) 
static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,

			 unsigned long gfn)

{

	if (!kvm->arch.using_mmu_notifiers)

		return 0;

	if (!(*rmapp & KVMPPC_RMAP_REFERENCED))

		return 0;

	kvm_unmap_rmapp(kvm, rmapp, gfn);

	while (test_and_set_bit_lock(KVMPPC_RMAP_LOCK_BIT, rmapp))

		cpu_relax();

	struct revmap_entry *rev = kvm->arch.revmap;

	unsigned long head, i, j;

	unsigned long *hptep;

	int ret = 0;



 retry:

	lock_rmap(rmapp);

	if (*rmapp & KVMPPC_RMAP_REFERENCED) {

		*rmapp &= ~KVMPPC_RMAP_REFERENCED;

	__clear_bit_unlock(KVMPPC_RMAP_LOCK_BIT, rmapp);

	return 1;

		ret = 1;

	}

	if (!(*rmapp & KVMPPC_RMAP_PRESENT)) {

		unlock_rmap(rmapp);

		return ret;

	}



	i = head = *rmapp & KVMPPC_RMAP_INDEX;

	do {

		hptep = (unsigned long *) (kvm->arch.hpt_virt + (i << 4));

		j = rev[i].forw;



		/* If this HPTE isn't referenced, ignore it */

		if (!(hptep[1] & HPTE_R_R))

			continue;



		if (!try_lock_hpte(hptep, HPTE_V_HVLOCK)) {

			/* unlock rmap before spinning on the HPTE lock */

			unlock_rmap(rmapp);

			while (hptep[0] & HPTE_V_HVLOCK)

				cpu_relax();

			goto retry;

		}



		/* Now check and modify the HPTE */

		if ((hptep[0] & HPTE_V_VALID) && (hptep[1] & HPTE_R_R)) {

			kvmppc_clear_ref_hpte(kvm, hptep, i);

			rev[i].guest_rpte |= HPTE_R_R;

			ret = 1;

		}

		hptep[0] &= ~HPTE_V_HVLOCK;

	} while ((i = j) != head);



	unlock_rmap(rmapp);

	return ret;

}



int kvm_age_hva(struct kvm *kvm, unsigned long hva)
@@ -794,7 +828,32 @@ int kvm_age_hva(struct kvm *kvm, unsigned long hva) 
static int kvm_test_age_rmapp(struct kvm *kvm, unsigned long *rmapp,

			      unsigned long gfn)

{

	return !!(*rmapp & KVMPPC_RMAP_REFERENCED);

	struct revmap_entry *rev = kvm->arch.revmap;

	unsigned long head, i, j;

	unsigned long *hp;

	int ret = 1;



	if (*rmapp & KVMPPC_RMAP_REFERENCED)

		return 1;



	lock_rmap(rmapp);

	if (*rmapp & KVMPPC_RMAP_REFERENCED)

		goto out;



	if (*rmapp & KVMPPC_RMAP_PRESENT) {

		i = head = *rmapp & KVMPPC_RMAP_INDEX;

		do {

			hp = (unsigned long *)(kvm->arch.hpt_virt + (i << 4));

			j = rev[i].forw;

			if (hp[1] & HPTE_R_R)

				goto out;

		} while ((i = j) != head);

	}

	ret = 0;



 out:

	unlock_rmap(rmapp);

	return ret;

}



int kvm_test_age_hva(struct kvm *kvm, unsigned long hva)

arch/powerpc/kvm/book3s_hv_rm_mmu.c

+19 −0
Original line number Diff line number Diff line
@@ -641,6 +641,25 @@ void kvmppc_invalidate_hpte(struct kvm *kvm, unsigned long *hptep, 
}

EXPORT_SYMBOL_GPL(kvmppc_invalidate_hpte);



void kvmppc_clear_ref_hpte(struct kvm *kvm, unsigned long *hptep,

			   unsigned long pte_index)

{

	unsigned long rb;

	unsigned char rbyte;



	rb = compute_tlbie_rb(hptep[0], hptep[1], pte_index);

	rbyte = (hptep[1] & ~HPTE_R_R) >> 8;

	/* modify only the second-last byte, which contains the ref bit */

	*((char *)hptep + 14) = rbyte;

	while (!try_lock_tlbie(&kvm->arch.tlbie_lock))

		cpu_relax();

	asm volatile(PPC_TLBIE(%1,%0)"; eieio; tlbsync"

		     : : "r" (rb), "r" (kvm->arch.lpid));

	asm volatile("ptesync" : : : "memory");

	kvm->arch.tlbie_lock = 0;

}

EXPORT_SYMBOL_GPL(kvmppc_clear_ref_hpte);



static int slb_base_page_shift[4] = {

	24,	/* 16M */

	16,	/* 64k */