KVM: arm64: add workaround for Cortex-A57 erratum #852523
authorWill Deacon <will.deacon@arm.com>
Mon, 14 Sep 2015 15:06:03 +0000 (16:06 +0100)
committerMarc Zyngier <marc.zyngier@arm.com>
Mon, 14 Sep 2015 15:46:39 +0000 (16:46 +0100)
commit43297dda0a51e4ffed0888ce727c218cfb7474b6
treed86ed5b183570877d837c6f2ec5a869c7afc62c5
parent0c0672922dcc70ffba11d96385e98e42fb3ae08d
KVM: arm64: add workaround for Cortex-A57 erratum #852523

When restoring the system register state for an AArch32 guest at EL2,
writes to DACR32_EL2 may not be correctly synchronised by Cortex-A57,
which can lead to the guest effectively running with junk in the DACR
and running into unexpected domain faults.

This patch works around the issue by re-ordering our restoration of the
AArch32 register aliases so that they happen before the AArch64 system
registers. Ensuring that the registers are restored in this order
guarantees that they will be correctly synchronised by the core.

Cc: <stable@vger.kernel.org>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
arch/arm64/kvm/hyp.S