diff options
| author | Marc Zyngier <marc.zyngier@arm.com> | 2013-06-21 13:08:46 +0100 |
|---|---|---|
| committer | Christoffer Dall <christoffer.dall@linaro.org> | 2013-06-26 10:50:04 -0700 |
| commit | 6a077e4ab9cbfbf279fb955bae05b03781c97013 (patch) | |
| tree | 78f18407f328888685939a1f183beebd349e6cc3 /arch/arm/kvm/interrupts_head.S | |
| parent | 4db845c3d8e2f8a219e8ac48834dd4fe085e5d63 (diff) | |
| download | linux-6a077e4ab9cbfbf279fb955bae05b03781c97013.tar.bz2 | |
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 <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Diffstat (limited to 'arch/arm/kvm/interrupts_head.S')
| -rw-r--r-- | arch/arm/kvm/interrupts_head.S | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/arch/arm/kvm/interrupts_head.S b/arch/arm/kvm/interrupts_head.S index 3c8f2f0b4c5e..2b44b95a86dd 100644 --- a/arch/arm/kvm/interrupts_head.S +++ b/arch/arm/kvm/interrupts_head.S @@ -302,11 +302,14 @@ vcpu .req r0 @ vcpu pointer always in r0 .endif mrc p15, 0, r2, c14, c1, 0 @ CNTKCTL + mrrc p15, 0, r4, r5, c7 @ PAR .if \store_to_vcpu == 0 - push {r2} + push {r2,r4-r5} .else str r2, [vcpu, #CP15_OFFSET(c14_CNTKCTL)] + add r12, vcpu, #CP15_OFFSET(c7_PAR) + strd r4, r5, [r12] .endif .endm @@ -319,12 +322,15 @@ vcpu .req r0 @ vcpu pointer always in r0 */ .macro write_cp15_state read_from_vcpu .if \read_from_vcpu == 0 - pop {r2} + pop {r2,r4-r5} .else ldr r2, [vcpu, #CP15_OFFSET(c14_CNTKCTL)] + add r12, vcpu, #CP15_OFFSET(c7_PAR) + ldrd r4, r5, [r12] .endif mcr p15, 0, r2, c14, c1, 0 @ CNTKCTL + mcrr p15, 0, r4, r5, c7 @ PAR .if \read_from_vcpu == 0 pop {r2-r12} |