Re: [PATCH v2 12/25] KVM: arm64: Enable GICv3 Group-1 sysreg trapping via command-line

Marc Zyngier
2017-06-06T13:59:34Z

On 06/06/17 13:06, Christoffer Dall wrote:
> On Thu, Jun 01, 2017 at 11:21:04AM +0100, Marc Zyngier wrote:
>> Now that we're able to safely handle Group-1 sysreg access, let's
>> give the user the opportunity to enable it by passing a specific
>> command-line option (vgic_v3.group1_trap).
>>
>> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
>> ---
>> virt/kvm/arm/hyp/vgic-v3-sr.c | 6 +++++-
>> virt/kvm/arm/vgic/vgic-v3.c | 11 +++++++++++
>> 2 files changed, 16 insertions(+), 1 deletion(-)
>>
>> diff --git a/virt/kvm/arm/hyp/vgic-v3-sr.c b/virt/kvm/arm/hyp/vgic-v3-sr.c
>> index 8973bad35748..42ac9ee7650a 100644
>> --- a/virt/kvm/arm/hyp/vgic-v3-sr.c
>> +++ b/virt/kvm/arm/hyp/vgic-v3-sr.c
>> @@ -334,7 +334,11 @@ void __hyp_text __vgic_v3_restore_state(struct kvm_vcpu *vcpu)
>> for (i = 0; i < used_lrs; i++)
>> __gic_v3_set_lr(cpu_if->vgic_lr[i], i);
>> } else {
>> - /* Always write ICH_HCR_EL2 to enable trapping */
>> + /*
>> + * If we don't have any interrupt to inject, but that
>> + * trapping is enabled, write the ICH_HCR_EL2 config
>> + * anyway.
>> + */
>
> nit: Whitespace and grammar issues, and maybe this hunk was supposed to
> be in the last patch?

Indeed, on both counts.

>
>> if (static_branch_unlikely(&vgic_v3_cpuif_trap))
>> write_gicreg(cpu_if->vgic_hcr, ICH_HCR_EL2);
>> }
>> diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
>> index fbd678bc046d..a16769276efd 100644
>> --- a/virt/kvm/arm/vgic/vgic-v3.c
>> +++ b/virt/kvm/arm/vgic/vgic-v3.c
>> @@ -416,6 +416,12 @@ int vgic_v3_map_resources(struct kvm *kvm)
>>
>> DEFINE_STATIC_KEY_FALSE(vgic_v3_cpuif_trap);
>>
>> +static int __init early_group1_trap_cfg(char *buf)
>> +{
>> + return strtobool(buf, &group1_trap);
>> +}
>> +early_param("vgic_v3.group1_trap", early_group1_trap_cfg);
>> +
>
> this shouldn't be named something with KVM (we're not going to trap
> anything on the host somehow are we?)?

Good point. kvm_vgic_v3.whatever?

Thanks,

M.
--
Jazz is not dead. It just smells funny...