[PATCH v3 17/19] arm64: KVM: move hcr_el2 setting into vgic-v2-switch.S
marc.zyngier at arm.com
Wed May 14 07:33:17 PDT 2014
On Fri, May 09 2014 at 3:07:23 pm BST, Christoffer Dall <christoffer.dall at linaro.org> wrote:
> On Wed, Apr 16, 2014 at 02:39:49PM +0100, Marc Zyngier wrote:
>> GICv3 requires the hcr_el2 switch to be tightly coupled with some
>> of the interrupt controller's register switch.
> can you be more specific, this feels a bit odd, enabling Stage-2
> translation and configuring all traps from within the vgic code...
The IMO and FMO bits must be set before restoring the various system
registers in GICv3. But I agreee that this looks pretty horrible.
The alternative is to split the bits we set in HCR_EL2 into two sets (VM
and trap control on one side, interrupt control on the other). This
would translate into two accesses to HCR_EL2, but it would look
nicer. I'll have a look.
>> In order to have similar code paths, start moving the hcr_el2
>> manipulation code to the GICv2 switch code.
>> Acked-by: Catalin Marinas <catalin.marinas at arm.com>
>> Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
>> arch/arm64/kvm/hyp.S | 7 -------
>> arch/arm64/kvm/vgic-v2-switch.S | 8 ++++++++
>> 2 files changed, 8 insertions(+), 7 deletions(-)
>> diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
>> index aed72d0..92b9120 100644
>> --- a/arch/arm64/kvm/hyp.S
>> +++ b/arch/arm64/kvm/hyp.S
>> @@ -335,11 +335,6 @@
>> .macro activate_traps
>> - ldr x2, [x0, #VCPU_IRQ_LINES]
>> - ldr x1, [x0, #VCPU_HCR_EL2]
>> - orr x2, x2, x1
>> - msr hcr_el2, x2
>> ldr x2, =(CPTR_EL2_TTA)
>> msr cptr_el2, x2
>> @@ -353,8 +348,6 @@
>> .macro deactivate_traps
>> - mov x2, #HCR_RW
>> - msr hcr_el2, x2
>> msr cptr_el2, xzr
>> msr hstr_el2, xzr
>> diff --git a/arch/arm64/kvm/vgic-v2-switch.S b/arch/arm64/kvm/vgic-v2-switch.S
>> index c5dc777..d36cd7a 100644
>> --- a/arch/arm64/kvm/vgic-v2-switch.S
>> +++ b/arch/arm64/kvm/vgic-v2-switch.S
>> @@ -85,6 +85,9 @@ CPU_BE( rev w5, w5 )
>> sub w4, w4, #1
>> cbnz w4, 1b
>> + mov x2, #HCR_RW
>> + msr hcr_el2, x2
>> + isb
>> @@ -92,6 +95,11 @@ CPU_BE( rev w5, w5 )
>> * x0: Register pointing to VCPU struct
>> .macro restore_vgic_v2_state
>> + ldr x2, [x0, #VCPU_IRQ_LINES]
> will this ever have any values on aarch64? Don't we mandate vgic
> support and bail out during hyp init if we cannot init a vgic?
Yes. But that doesn't mean we don't support the feature either. The case
is fairly slim, I agree, but it has been there since Day-1...
Jazz is not dead. It just smells funny.
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