From 6a077e4ab9cbfbf279fb955bae05b03781c97013 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Fri, 21 Jun 2013 13:08:46 +0100 Subject: ARM: KVM: perform save/restore of PAR Not saving PAR is an unfortunate oversight. If the guest performs an AT* operation and gets scheduled out before reading the result of the translation from PAR, it could become corrupted by another guest or the host. Saving this register is made slightly more complicated as KVM also uses it on the permission fault handling path, leading to an ugly "stash and restore" sequence. Fortunately, this is already a slow path so we don't really care. Also, Linux doesn't do any AT* operation, so Linux guests are not impacted by this bug. [ Slightly tweaked to use an even register as first operand to ldrd and strd operations in interrupts_head.S - Christoffer ] Signed-off-by: Marc Zyngier Signed-off-by: Christoffer Dall --- arch/arm/kvm/coproc.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch/arm/kvm/coproc.c') diff --git a/arch/arm/kvm/coproc.c b/arch/arm/kvm/coproc.c index 8eea97b..4a51990 100644 --- a/arch/arm/kvm/coproc.c +++ b/arch/arm/kvm/coproc.c @@ -180,6 +180,10 @@ static const struct coproc_reg cp15_regs[] = { NULL, reset_unknown, c6_DFAR }, { CRn( 6), CRm( 0), Op1( 0), Op2( 2), is32, NULL, reset_unknown, c6_IFAR }, + + /* PAR swapped by interrupt.S */ + { CRn( 7), Op1( 0), is64, NULL, reset_unknown64, c7_PAR }, + /* * DC{C,I,CI}SW operations: */ -- cgit v1.1