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Commit 639e4597 authored by David Gibson's avatar David Gibson Committed by Paul Mackerras
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KVM: PPC: Book3S HV: Create kvmppc_unmap_hpte_helper() 



The kvm_unmap_rmapp() function, called from certain MMU notifiers, is used
to force all guest mappings of a particular host page to be set ABSENT, and
removed from the reverse mappings.

For HPT resizing, we will have some cases where we want to set just a
single guest HPTE ABSENT and remove its reverse mappings.  To prepare with
this, we split out the logic from kvm_unmap_rmapp() to evict a single HPTE,
moving it to a new helper function.

Signed-off-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
parent f98a8bf9

arch/powerpc/kvm/book3s_64_mmu_hv.c

+44 −33
Original line number Diff line number Diff line
@@ -742,37 +742,15 @@ static int kvm_handle_hva(struct kvm *kvm, unsigned long hva, 
	return kvm_handle_hva_range(kvm, hva, hva + 1, handler);

}



static int kvm_unmap_rmapp(struct kvm *kvm, struct kvm_memory_slot *memslot,

			   unsigned long gfn)

/* Must be called with both HPTE and rmap locked */

static void kvmppc_unmap_hpte(struct kvm *kvm, unsigned long i,

			      unsigned long *rmapp, unsigned long gfn)

{

	__be64 *hptep = (__be64 *) (kvm->arch.hpt.virt + (i << 4));

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

	unsigned long h, i, j;

	__be64 *hptep;

	unsigned long j, h;

	unsigned long ptel, psize, rcbits;

	unsigned long *rmapp;



	rmapp = &memslot->arch.rmap[gfn - memslot->base_gfn];

	for (;;) {

		lock_rmap(rmapp);

		if (!(*rmapp & KVMPPC_RMAP_PRESENT)) {

			unlock_rmap(rmapp);

			break;

		}



		/*

		 * To avoid an ABBA deadlock with the HPTE lock bit,

		 * we can't spin on the HPTE lock while holding the

		 * rmap chain lock.

		 */

		i = *rmapp & KVMPPC_RMAP_INDEX;

		hptep = (__be64 *) (kvm->arch.hpt.virt + (i << 4));

		if (!try_lock_hpte(hptep, HPTE_V_HVLOCK)) {

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

			unlock_rmap(rmapp);

			while (be64_to_cpu(hptep[0]) & HPTE_V_HVLOCK)

				cpu_relax();

			continue;

		}

	j = rev[i].forw;

	if (j == i) {

		/* chain is now empty */
@@ -804,6 +782,39 @@ static int kvm_unmap_rmapp(struct kvm *kvm, struct kvm_memory_slot *memslot, 
			note_hpte_modification(kvm, &rev[i]);

		}

	}

}



static int kvm_unmap_rmapp(struct kvm *kvm, struct kvm_memory_slot *memslot,

			   unsigned long gfn)

{

	unsigned long i;

	__be64 *hptep;

	unsigned long *rmapp;



	rmapp = &memslot->arch.rmap[gfn - memslot->base_gfn];

	for (;;) {

		lock_rmap(rmapp);

		if (!(*rmapp & KVMPPC_RMAP_PRESENT)) {

			unlock_rmap(rmapp);

			break;

		}



		/*

		 * To avoid an ABBA deadlock with the HPTE lock bit,

		 * we can't spin on the HPTE lock while holding the

		 * rmap chain lock.

		 */

		i = *rmapp & KVMPPC_RMAP_INDEX;

		hptep = (__be64 *) (kvm->arch.hpt.virt + (i << 4));

		if (!try_lock_hpte(hptep, HPTE_V_HVLOCK)) {

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

			unlock_rmap(rmapp);

			while (be64_to_cpu(hptep[0]) & HPTE_V_HVLOCK)

				cpu_relax();

			continue;

		}



		kvmppc_unmap_hpte(kvm, i, rmapp, gfn);

		unlock_rmap(rmapp);

		__unlock_hpte(hptep, be64_to_cpu(hptep[0]));

	}