Subject: [PATCH 5/7] KVM: arm/arm64: Elide both CMOs and TBLIs on freeing the whole Stage-2

From: Marc Zyngier <[email-masked]>
Date: Fri, 13 Dec 2019 18:25:01 +0000

When freeing the whole of a VM's Stage-2 page tables, there is
little point in doing cache maintenance on each and every page
(the guest won't be running anymore, let alone having its MMU
off). As for TLBs, there is no point in invalidating individual
pages, as we can replace the whole thing with a VMALL operation,
which invalidates all the TLBs for this VM in one go.

Signed-off-by: Marc Zyngier <[email-masked]>
---
 virt/kvm/arm/mmu.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
index 4399866842dc..d7c710491d26 100644
--- a/virt/kvm/arm/mmu.c
+++ b/virt/kvm/arm/mmu.c
@@ -1016,10 +1016,13 @@ void kvm_free_stage2_pgd(struct kvm *kvm)
 
 	spin_lock(&kvm->mmu_lock);
 	if (kvm->arch.pgd) {
-		unmap_stage2_range(kvm, 0, kvm_phys_size(kvm), 0);
+		unmap_stage2_range(kvm, 0, kvm_phys_size(kvm),
+				   KVM_UNMAP_ELIDE_CMO | KVM_UNMAP_ELIDE_TBLI);
 		pgd = READ_ONCE(kvm->arch.pgd);
 		kvm->arch.pgd = NULL;
 		kvm->arch.pgd_phys = 0;
+
+		kvm_flush_remote_tlbs(kvm);
 	}
 	spin_unlock(&kvm->mmu_lock);
 
-- 
2.20.1

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