Platforms running hypervisor nowadays are normally powerful servers
which at least support GICv3, so it should be better to switch
kvm_vgic_global_state.gicv3_cpuif to static likely branch, which can
reduce two "b" instructions to a single "nop" for GICv3 branches.
We don't update arm32 specific code for they may still only have
GICv2.
Signed-off-by: Heyi Guo <guoheyi@xxxxxxxxxx>
Cc: Marc Zyngier <maz@xxxxxxxxxx>
Cc: James Morse <james.morse@xxxxxxx>
Cc: Julien Thierry <julien.thierry.kdev@xxxxxxxxx>
Cc: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
---
arch/arm64/kvm/hyp/switch.c | 4 ++--
include/kvm/arm_vgic.h | 2 +-
virt/kvm/arm/vgic/vgic-init.c | 9 +++++----
virt/kvm/arm/vgic/vgic.c | 9 +++++----
4 files changed, 13 insertions(+), 11 deletions(-)
diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
index 799e84a40335..57e7d314211a 100644
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c
@@ -219,7 +219,7 @@ static void __hyp_text __deactivate_vm(struct kvm_vcpu *vcpu)
/* Save VGICv3 state on non-VHE systems */
static void __hyp_text __hyp_vgic_save_state(struct kvm_vcpu *vcpu)
{
- if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif)) {
+ if (static_branch_likely(&kvm_vgic_global_state.gicv3_cpuif)) {
__vgic_v3_save_state(vcpu);
__vgic_v3_deactivate_traps(vcpu);
}
@@ -228,7 +228,7 @@ static void __hyp_text __hyp_vgic_save_state(struct kvm_vcpu *vcpu)
/* Restore VGICv3 state on non_VEH systems */
static void __hyp_text __hyp_vgic_restore_state(struct kvm_vcpu *vcpu)
{
- if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif)) {
+ if (static_branch_likely(&kvm_vgic_global_state.gicv3_cpuif)) {
__vgic_v3_activate_traps(vcpu);
__vgic_v3_restore_state(vcpu);
}
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index af4f09c02bf1..474e73dd3112 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -72,7 +72,7 @@ struct vgic_global {
bool has_gicv4;
/* GIC system register CPU interface */
- struct static_key_false gicv3_cpuif;
+ struct static_key_true gicv3_cpuif;
u32 ich_vtr_el2;
};
diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c
index 6f50c429196d..b03e5c8e1731 100644
--- a/virt/kvm/arm/vgic/vgic-init.c
+++ b/virt/kvm/arm/vgic/vgic-init.c
@@ -509,13 +509,14 @@ int kvm_vgic_hyp_init(void)
switch (gic_kvm_info->type) {
case GIC_V2:
ret = vgic_v2_probe(gic_kvm_info);
+ if (!ret) {
+ static_branch_disable(
+ &kvm_vgic_global_state.gicv3_cpuif);
+ kvm_info("GIC system register CPU interface disabled\n");
+ }
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 45a870cb63f5..9dafeeb1457b 100644
--- a/virt/kvm/arm/vgic/vgic.c
+++ b/virt/kvm/arm/vgic/vgic.c
@@ -18,7 +18,7 @@
#include "trace.h"
struct vgic_global kvm_vgic_global_state __ro_after_init = {
- .gicv3_cpuif = STATIC_KEY_FALSE_INIT,
+ .gicv3_cpuif = STATIC_KEY_TRUE_INIT,
};
/*
@@ -841,12 +841,13 @@ static inline bool can_access_vgic_from_kernel(void)
* memory-mapped, and VHE systems can access GICv3 EL2 system
* registers.
*/
- return !static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif) || has_vhe();
+ return !static_branch_likely(&kvm_vgic_global_state.gicv3_cpuif) ||
+ has_vhe();
}
static inline void vgic_save_state(struct kvm_vcpu *vcpu)
{
- if (!static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif))
+ if (!static_branch_likely(&kvm_vgic_global_state.gicv3_cpuif))
vgic_v2_save_state(vcpu);
else
__vgic_v3_save_state(vcpu);
@@ -873,7 +874,7 @@ void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
static inline void vgic_restore_state(struct kvm_vcpu *vcpu)
{
- if (!static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif))
+ if (!static_branch_likely(&kvm_vgic_global_state.gicv3_cpuif))
vgic_v2_restore_state(vcpu);
else
__vgic_v3_restore_state(vcpu);
--
2.19.1
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