Re: [PATCH AUTOSEL 5.0 29/98] KVM: arm/arm64: Enforce PTE mappings at stage2 when needed

From: Sasha Levin
Date: Thu May 02 2019 - 08:57:11 EST


On Tue, Apr 23, 2019 at 10:27:26AM +0100, Suzuki K Poulose wrote:
Hi Sasha,

On 04/22/2019 08:40 PM, Sasha Levin wrote:
From: Suzuki K Poulose <suzuki.poulose@xxxxxxx>

[ Upstream commit a80868f398554842b14d07060012c06efb57c456 ]

commit 6794ad5443a2118 ("KVM: arm/arm64: Fix unintended stage 2 PMD mappings")
made the checks to skip huge mappings, stricter. However it introduced
a bug where we still use huge mappings, ignoring the flag to
use PTE mappings, by not reseting the vma_pagesize to PAGE_SIZE.

Also, the checks do not cover the PUD huge pages, that was
under review during the same period. This patch fixes both
the issues.

Fixes : 6794ad5443a2118 ("KVM: arm/arm64: Fix unintended stage 2 PMD mappings")
Reported-by: Zenghui Yu <yuzenghui@xxxxxxxxxx>
Cc: Zenghui Yu <yuzenghui@xxxxxxxxxx>
Cc: Christoffer Dall <christoffer.dall@xxxxxxx>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Sasha Levin (Microsoft) <sashal@xxxxxxxxxx>

Please be aware that we need a follow up fix for this patch to fix the
problem for THP backed memory.

http://lists.infradead.org/pipermail/linux-arm-kernel/2019-April/645324.html


It should appear upstream soon.

Since it's not upstream yet, I'll drop this patch for now and queue it
for a later release.

--
Thanks,
Sasha