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| author |   Christoffer Dall <christoffer.dall@linaro.org> | 2017-10-05 17:19:19 +0200 |
|---|---|---|
| committer |   Marc Zyngier <marc.zyngier@arm.com> | 2018-03-19 10:53:21 +0000 |
| commit | 2d0e63e030babe19c94b4453ef4b272c0aacd75a (patch) | |
| tree | c73409c2a22592b03f50bbe5d7e825fe028ab16a /arch/arm64/kvm | |
| parent | KVM: arm/arm64: Move VGIC APR save/restore to vgic put/load (diff) | |
| download | linux-dev-2d0e63e030babe19c94b4453ef4b272c0aacd75a.tar.xz linux-dev-2d0e63e030babe19c94b4453ef4b272c0aacd75a.zip | |
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/arm64/kvm')
| -rw-r--r-- | arch/arm64/kvm/hyp/switch.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c index 86abbee40d3f..07b572173265 100644 --- a/arch/arm64/kvm/hyp/switch.c +++ b/arch/arm64/kvm/hyp/switch.c @@ -195,15 +195,19 @@ 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_unlikely(&kvm_vgic_global_state.gicv3_cpuif)) { __vgic_v3_save_state(vcpu); + __vgic_v3_deactivate_traps(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_unlikely(&kvm_vgic_global_state.gicv3_cpuif)) { + __vgic_v3_activate_traps(vcpu); __vgic_v3_restore_state(vcpu); + } } static bool __hyp_text __true_value(void) |