Commit 3a0b870e authored Dec 02, 2020 by Yanan Wang Committed by Marc Zyngier Dec 02, 2020

KVM: arm64: Fix handling of merging tables into a block entry



When dirty logging is enabled, we collapse block entries into tables
as necessary. If dirty logging gets canceled, we can end-up merging
tables back into block entries.

When this happens, we must not only free the non-huge page-table
pages but also invalidate all the TLB entries that can potentially
cover the block. Otherwise, we end-up with multiple possible translations
for the same physical page, which can legitimately result in a TLB
conflict.

To address this, replease the bogus invalidation by IPA with a full
VM invalidation. Although this is pretty heavy handed, it happens
very infrequently and saves a bunch of invalidations by IPA.

Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
[maz: fixup commit message]
Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201201201034.116760-3-wangyanan55@huawei.com

parent 5c646b7e

arch/arm64/kvm/hyp/pgtable.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -502,7 +502,13 @@ static int stage2_map_walk_table_pre(u64 addr, u64 end, u32 level,
		return 0;

		kvm_set_invalid_pte(ptep);
		kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, data->mmu, addr, 0);

		/*
		* Invalidate the whole stage-2, as we may have numerous leaf
		* entries below us which would otherwise need invalidating
		* individually.
		*/
		kvm_call_hyp(__kvm_tlb_flush_vmid, data->mmu);
		data->anchor = ptep;
		return 0;
		}

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