Hi Marc, On 2020/4/25 17:44, Marc Zyngier wrote:
KVM now expects to be able to use HW-accelerated delivery of vSGIs as soon as the guest has enabled thm. Unfortunately, we only
them
initialize the GICv4 context if we have a virtual ITS exposed to the guest. Fix it by always initializing the GICv4.1 context if it is available on the host. Fixes: 2291ff2f2a56 ("KVM: arm64: GICv4.1: Plumb SGI implementation selection in the distributor") Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx> --- virt/kvm/arm/vgic/vgic-init.c | 9 ++++++++- virt/kvm/arm/vgic/vgic-mmio-v3.c | 3 ++- 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c index a963b9d766b73..8e6f350c3bcd1 100644 --- a/virt/kvm/arm/vgic/vgic-init.c +++ b/virt/kvm/arm/vgic/vgic-init.c @@ -294,8 +294,15 @@ int vgic_init(struct kvm *kvm) } }- if (vgic_has_its(kvm)) {+ if (vgic_has_its(kvm)) vgic_lpi_translation_cache_init(kvm); + + /* + * If we have GICv4.1 enabled, unconditionnaly request enable the + * v4 support so that we get HW-accelerated vSGIs. Otherwise, only + * enable it if we present a virtual ITS to the guest. + */ + if (vgic_supports_direct_msis(kvm)) { ret = vgic_v4_init(kvm); if (ret) goto out; diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c index e72dcc4542475..26b11dcd45524 100644 --- a/virt/kvm/arm/vgic/vgic-mmio-v3.c +++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c @@ -50,7 +50,8 @@ bool vgic_has_its(struct kvm *kvm)bool vgic_supports_direct_msis(struct kvm *kvm){ - return kvm_vgic_global_state.has_gicv4 && vgic_has_its(kvm); + return (kvm_vgic_global_state.has_gicv4_1 || + (kvm_vgic_global_state.has_gicv4 && vgic_has_its(kvm))); }
Not related to this patch, but I think that the function name can be improved a bit after this change. It now indicates whether the vGIC supports direct MSIs injection *or* direct SGIs injection, not just MSIs. And if vgic_has_its() is false, we don't even support MSIs. The fix itself looks correct to me, Reviewed-by: Zenghui Yu <yuzenghui@xxxxxxxxxx> Thanks.
