On Fri, Jun 09, 2017 at 12:49:53PM +0100, Marc Zyngier wrote:
> Now that we're able to safely handle common sysreg access, let's
> give the user the opportunity to enable it by passing a specific
> command-line option (vgic_v3.common_trap).
>
> Tested-by: Alexander Graf <agraf@xxxxxxx>
> Acked-by: David Daney <david.daney@xxxxxxxxxx>
> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Acked-by: Christoffer Dall <cdall@xxxxxxxxxx>
> ---
> Documentation/admin-guide/kernel-parameters.txt | 4 ++++
> include/linux/irqchip/arm-gic-v3.h | 1 +
> virt/kvm/arm/vgic/vgic-v3.c | 11 ++++++++++-
> 3 files changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 88bdc421351f..aa8341e73b35 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -1837,6 +1837,10 @@
> [KVM,ARM] Trap guest accesses to GICv3 group-1
> system registers
>
> + kvm-arm.vgic_v3_common_trap=
> + [KVM,ARM] Trap guest accesses to GICv3 common
> + system registers
> +
> kvm-intel.ept= [KVM,Intel] Disable extended page tables
> (virtualized MMU) support on capable Intel chips.
> Default is 1 (enabled)
> diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
> index 46a1e0943cf8..f0cebb6e57d0 100644
> --- a/include/linux/irqchip/arm-gic-v3.h
> +++ b/include/linux/irqchip/arm-gic-v3.h
> @@ -417,6 +417,7 @@
>
> #define ICH_HCR_EN (1 << 0)
> #define ICH_HCR_UIE (1 << 1)
> +#define ICH_HCR_TC (1 << 10)
> #define ICH_HCR_TALL0 (1 << 11)
> #define ICH_HCR_TALL1 (1 << 12)
> #define ICH_HCR_EOIcount_SHIFT 27
> diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
> index ffc581b70c4e..3960e89c05ad 100644
> --- a/virt/kvm/arm/vgic/vgic-v3.c
> +++ b/virt/kvm/arm/vgic/vgic-v3.c
> @@ -23,6 +23,7 @@
>
> static bool group0_trap;
> static bool group1_trap;
> +static bool common_trap;
>
> void vgic_v3_set_underflow(struct kvm_vcpu *vcpu)
> {
> @@ -246,6 +247,8 @@ void vgic_v3_enable(struct kvm_vcpu *vcpu)
> vgic_v3->vgic_hcr |= ICH_HCR_TALL0;
> if (group1_trap)
> vgic_v3->vgic_hcr |= ICH_HCR_TALL1;
> + if (common_trap)
> + vgic_v3->vgic_hcr |= ICH_HCR_TC;
> }
>
> int vgic_v3_lpi_sync_pending_status(struct kvm *kvm, struct vgic_irq *irq)
> @@ -431,6 +434,12 @@ static int __init early_group1_trap_cfg(char *buf)
> }
> early_param("kvm-arm.vgic_v3_group1_trap", early_group1_trap_cfg);
>
> +static int __init early_common_trap_cfg(char *buf)
> +{
> + return strtobool(buf, &common_trap);
> +}
> +early_param("kvm-arm.vgic_v3_common_trap", early_common_trap_cfg);
> +
> /**
> * vgic_v3_probe - probe for a GICv3 compatible interrupt controller in DT
> * @node: pointer to the DT node
> @@ -489,7 +498,7 @@ int vgic_v3_probe(const struct gic_kvm_info *info)
> }
> #endif
>
> - if (group0_trap || group1_trap) {
> + if (group0_trap || group1_trap || common_trap) {
> kvm_info("GICv3 sysreg trapping enabled (reduced performance)\n");
> static_branch_enable(&vgic_v3_cpuif_trap);
> }
> --
> 2.11.0
>
