Hi Zenghui,
On 2020-04-30 12:24, Zenghui Yu wrote:
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.
Yes, I noticed that too. But in the spirit of keeping the change minimal
and avoid later conflicts with potential fixes, I decided against
changing
it right now.
The fix itself looks correct to me,
Reviewed-by: Zenghui Yu <yuzenghui@xxxxxxxxxx>
Thanks,
M.
--
Jazz is not dead. It just smells funny...
