From 5a7a8426b2ac004b064e4106911769e0a55e7c4b Mon Sep 17 00:00:00 2001 From: Vladimir Murzin Date: Mon, 12 Sep 2016 15:49:15 +0100 Subject: [PATCH] arm64: KVM: Use static keys for selecting the GIC backend Currently GIC backend is selected via alternative framework and this is fine. We are going to introduce vgic-v3 to 32-bit world and there we don't have patching framework in hand, so we can either check support for GICv3 every time we need to choose which backend to use or try to optimise it by using static keys. The later looks quite promising because we can share logic involved in selecting GIC backend between architectures if both uses static keys. This patch moves arm64 from alternative to static keys framework for selecting GIC backend. For that we embed static key into vgic_global and enable the key during vgic initialisation based on what has already been exposed by the host GIC driver. Acked-by: Marc Zyngier Signed-off-by: Vladimir Murzin Signed-off-by: Christoffer Dall --- arch/arm64/kvm/hyp/switch.c | 21 +++++++++++---------- include/kvm/arm_vgic.h | 4 ++++ virt/kvm/arm/vgic/vgic-init.c | 4 ++++ virt/kvm/arm/vgic/vgic.c | 2 +- 4 files changed, 20 insertions(+), 11 deletions(-) diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c index 731519cfee8e..83037cd62d01 100644 --- a/arch/arm64/kvm/hyp/switch.c +++ b/arch/arm64/kvm/hyp/switch.c @@ -16,6 +16,8 @@ */ #include +#include + #include #include #include @@ -136,17 +138,13 @@ static void __hyp_text __deactivate_vm(struct kvm_vcpu *vcpu) write_sysreg(0, vttbr_el2); } -static hyp_alternate_select(__vgic_call_save_state, - __vgic_v2_save_state, __vgic_v3_save_state, - ARM64_HAS_SYSREG_GIC_CPUIF); - -static hyp_alternate_select(__vgic_call_restore_state, - __vgic_v2_restore_state, __vgic_v3_restore_state, - ARM64_HAS_SYSREG_GIC_CPUIF); - static void __hyp_text __vgic_save_state(struct kvm_vcpu *vcpu) { - __vgic_call_save_state()(vcpu); + if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif)) + __vgic_v3_save_state(vcpu); + else + __vgic_v2_save_state(vcpu); + write_sysreg(read_sysreg(hcr_el2) & ~HCR_INT_OVERRIDE, hcr_el2); } @@ -159,7 +157,10 @@ static void __hyp_text __vgic_restore_state(struct kvm_vcpu *vcpu) val |= vcpu->arch.irq_lines; write_sysreg(val, hcr_el2); - __vgic_call_restore_state()(vcpu); + if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif)) + __vgic_v3_restore_state(vcpu); + else + __vgic_v2_restore_state(vcpu); } static bool __hyp_text __true_value(void) diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h index bb46c03eb3c7..8d22adcfe522 100644 --- a/include/kvm/arm_vgic.h +++ b/include/kvm/arm_vgic.h @@ -24,6 +24,7 @@ #include #include #include +#include #define VGIC_V3_MAX_CPUS 255 #define VGIC_V2_MAX_CPUS 8 @@ -67,6 +68,9 @@ struct vgic_global { /* Only needed for the legacy KVM_CREATE_IRQCHIP */ bool can_emulate_gicv2; + + /* GIC system register CPU interface */ + struct static_key_false gicv3_cpuif; }; extern struct vgic_global kvm_vgic_global_state; diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c index 83777c1cbae0..8cebfbc19e90 100644 --- a/virt/kvm/arm/vgic/vgic-init.c +++ b/virt/kvm/arm/vgic/vgic-init.c @@ -405,6 +405,10 @@ int kvm_vgic_hyp_init(void) break; case GIC_V3: ret = vgic_v3_probe(gic_kvm_info); + if (!ret) { + static_branch_enable(&kvm_vgic_global_state.gicv3_cpuif); + kvm_info("GIC system register CPU interface enabled\n"); + } break; default: ret = -ENODEV; diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c index e83b7fe4baae..8a529a732941 100644 --- a/virt/kvm/arm/vgic/vgic.c +++ b/virt/kvm/arm/vgic/vgic.c @@ -29,7 +29,7 @@ #define DEBUG_SPINLOCK_BUG_ON(p) #endif -struct vgic_global __section(.hyp.text) kvm_vgic_global_state; +struct vgic_global __section(.hyp.text) kvm_vgic_global_state = {.gicv3_cpuif = STATIC_KEY_FALSE_INIT,}; /* * Locking order is always: