This is a note to let you know that I've just added the patch titled

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

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: kvm-ppc-book3s-hv-always-flush-tlb-in-kvmppc_alloc_reset_hpt.patch and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From ecba8297aafd50db6ae867e90844eead1611ef1c Mon Sep 17 00:00:00 2001

From: David Gibson david@gibson.dropbear.id.au Date: Wed, 10 Jan 2018 17:04:39 +1100 Subject: KVM: PPC: Book3S HV: Always flush TLB in kvmppc_alloc_reset_hpt()

From: David Gibson david@gibson.dropbear.id.au

commit ecba8297aafd50db6ae867e90844eead1611ef1c upstream.

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.

Fixes: f98a8bf9ee20 ("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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- arch/powerpc/kvm/book3s_64_mmu_hv.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c @@ -165,8 +165,6 @@ long kvmppc_alloc_reset_hpt(struct kvm * * 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 * 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; }

Patches currently in stable-queue which might be from david@gibson.dropbear.id.au are

queue-4.14/kvm-ppc-book3s-hv-always-flush-tlb-in-kvmppc_alloc_reset_hpt.patch queue-4.14/kvm-ppc-book3s-hv-drop-prepare_done-from-struct-kvm_resize_hpt.patch queue-4.14/kvm-ppc-book3s-hv-fix-use-after-free-in-case-of-multiple-resize-requests.patch