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authorChristoffer Dall <christoffer.dall@linaro.org>2017-10-05 17:19:19 +0200
committerMarc Zyngier <marc.zyngier@arm.com>2018-03-19 10:53:21 +0000
commit2d0e63e030babe19c94b4453ef4b272c0aacd75a (patch)
treec73409c2a22592b03f50bbe5d7e825fe028ab16a /arch/arm
parent923a2e30e5745a8f94f953f7aacaafd3d551e12d (diff)
KVM: arm/arm64: Avoid VGICv3 save/restore on VHE with no IRQs
We can finally get completely rid of any calls to the VGICv3 save/restore functions when the AP lists are empty on VHE systems. This requires carefully factoring out trap configuration from saving and restoring state, and carefully choosing what to do on the VHE and non-VHE path. One of the challenges is that we cannot save/restore the VMCR lazily because we can only write the VMCR when ICC_SRE_EL1.SRE is cleared when emulating a GICv2-on-GICv3, since otherwise all Group-0 interrupts end up being delivered as FIQ. To solve this problem, and still provide fast performance in the fast path of exiting a VM when no interrupts are pending (which also optimized the latency for actually delivering virtual interrupts coming from physical interrupts), we orchestrate a dance of only doing the activate/deactivate traps in vgic load/put for VHE systems (which can have ICC_SRE_EL1.SRE cleared when running in the host), and doing the configuration on every round-trip on non-VHE systems. Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'arch/arm')
-rw-r--r--arch/arm/include/asm/kvm_hyp.h2
-rw-r--r--arch/arm/kvm/hyp/switch.c8
2 files changed, 8 insertions, 2 deletions
diff --git a/arch/arm/include/asm/kvm_hyp.h b/arch/arm/include/asm/kvm_hyp.h
index 530a3c1cfe6f..e93a0cac9add 100644
--- a/arch/arm/include/asm/kvm_hyp.h
+++ b/arch/arm/include/asm/kvm_hyp.h
@@ -110,6 +110,8 @@ void __sysreg_restore_state(struct kvm_cpu_context *ctxt);
void __vgic_v3_save_state(struct kvm_vcpu *vcpu);
void __vgic_v3_restore_state(struct kvm_vcpu *vcpu);
+void __vgic_v3_activate_traps(struct kvm_vcpu *vcpu);
+void __vgic_v3_deactivate_traps(struct kvm_vcpu *vcpu);
void __vgic_v3_save_aprs(struct kvm_vcpu *vcpu);
void __vgic_v3_restore_aprs(struct kvm_vcpu *vcpu);
diff --git a/arch/arm/kvm/hyp/switch.c b/arch/arm/kvm/hyp/switch.c
index 882b9b9e0077..acf1c37fa49c 100644
--- a/arch/arm/kvm/hyp/switch.c
+++ b/arch/arm/kvm/hyp/switch.c
@@ -90,14 +90,18 @@ static void __hyp_text __deactivate_vm(struct kvm_vcpu *vcpu)
static void __hyp_text __vgic_save_state(struct kvm_vcpu *vcpu)
{
- if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif))
+ if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif)) {
__vgic_v3_save_state(vcpu);
+ __vgic_v3_deactivate_traps(vcpu);
+ }
}
static void __hyp_text __vgic_restore_state(struct kvm_vcpu *vcpu)
{
- if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif))
+ if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif)) {
+ __vgic_v3_activate_traps(vcpu);
__vgic_v3_restore_state(vcpu);
+ }
}
static bool __hyp_text __populate_fault_info(struct kvm_vcpu *vcpu)