linux-kernel - [PATCH 4.14 020/122] kvm: arm/arm64: Fix stage2_flush

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Date:   Fri, 22 Nov 2019 11:27:53 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Christoffer Dall <cdall@...nel.org>,
        Marc Zyngier <marc.zyngier@....com>,
        Eric Auger <eric.auger@...hat.com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.14 020/122] kvm: arm/arm64: Fix stage2_flush_memslot for 4 level page table

From: Suzuki K Poulose <suzuki.poulose@....com>

[ Upstream commit d2db7773ba864df6b4e19643dfc54838550d8049 ]

So far we have only supported 3 level page table with fixed IPA of
40bits, where PUD is folded. With 4 level page tables, we need
to check if the PUD entry is valid or not. Fix stage2_flush_memslot()
to do this check, before walking down the table.

Acked-by: Christoffer Dall <cdall@...nel.org>
Acked-by: Marc Zyngier <marc.zyngier@....com>
Reviewed-by: Eric Auger <eric.auger@...hat.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@....com>
Signed-off-by: Marc Zyngier <marc.zyngier@....com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 virt/kvm/arm/mmu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
index 1f4cac53b9234..9f69202d8e49b 100644
--- a/virt/kvm/arm/mmu.c
+++ b/virt/kvm/arm/mmu.c
@@ -375,7 +375,8 @@ static void stage2_flush_memslot(struct kvm *kvm,
 	pgd = kvm->arch.pgd + stage2_pgd_index(addr);
 	do {
 		next = stage2_pgd_addr_end(addr, end);
-		stage2_flush_puds(kvm, pgd, addr, next);
+		if (!stage2_pgd_none(*pgd))
+			stage2_flush_puds(kvm, pgd, addr, next);
 	} while (pgd++, addr = next, addr != end);
 }
 
-- 
2.20.1