Commit ecba8297 authored Jan 10, 2018 by David Gibson Committed by Paul Mackerras Jan 10, 2018

KVM: PPC: Book3S HV: Always flush TLB in kvmppc_alloc_reset_hpt()



The KVM_PPC_ALLOCATE_HTAB ioctl(), implemented by kvmppc_alloc_reset_hpt()
is supposed to completely clear and reset a guest's Hashed Page Table (HPT)
allocating or re-allocating it if necessary.

In the case where an HPT of the right size already exists and it just
zeroes it, it forces a TLB flush on all guest CPUs, to remove any stale TLB
entries loaded from the old HPT.

However, that situation can arise when the HPT is resizing as well - or
even when switching from an RPT to HPT - so those cases need a TLB flush as
well.

So, move the TLB flush to trigger in all cases except for errors.

Cc: stable@vger.kernel.org # v4.10+
Fixes: f98a8bf9 ("KVM: PPC: Book3S HV: Allow KVM_PPC_ALLOCATE_HTAB ioctl() to change HPT size")
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

parent 6c7d47c3

arch/powerpc/kvm/book3s_64_mmu_hv.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -165,8 +165,6 @@ long kvmppc_alloc_reset_hpt(struct kvm *kvm, int order)
		* Reset all the reverse-mapping chains for all memslots
		*/
		kvmppc_rmap_reset(kvm);
		/* Ensure that each vcpu will flush its TLB on next entry. */
		cpumask_setall(&kvm->arch.need_tlb_flush);
		err = 0;
		goto out;
		}
		@@ -182,6 +180,10 @@ long kvmppc_alloc_reset_hpt(struct kvm *kvm, int order)
		kvmppc_set_hpt(kvm, &info);

		out:
		if (err == 0)
		/* Ensure that each vcpu will flush its TLB on next entry. */
		cpumask_setall(&kvm->arch.need_tlb_flush);

		mutex_unlock(&kvm->lock);
		return err;
		}