Hi Marc,
On 2023/9/7 18:09, Marc Zyngier wrote:
As we're about to change the way SGIs are sent, start by splitting
out some of the basic functionnality: instead of intermingling
functionality
the broadcast and non-broadcast cases with the actual SGI generation,
perform the following cleanups:
- move the SGI queuing into its own helper
- split the broadcast code from the affinity-driven code
- replace the mask/shift combinations with FIELD_GET()
The result is much more readable, and paves the way for further
optimisations.
Indeed!
@@ -1070,19 +1102,30 @@ void vgic_v3_dispatch_sgi(struct kvm_vcpu *vcpu, u64 reg, bool allow_group1)
{
struct kvm *kvm = vcpu->kvm;
struct kvm_vcpu *c_vcpu;
- u16 target_cpus;
+ unsigned long target_cpus;
u64 mpidr;
- int sgi;
- int vcpu_id = vcpu->vcpu_id;
- bool broadcast;
- unsigned long c, flags;
-
- sgi = (reg & ICC_SGI1R_SGI_ID_MASK) >> ICC_SGI1R_SGI_ID_SHIFT;
- broadcast = reg & BIT_ULL(ICC_SGI1R_IRQ_ROUTING_MODE_BIT);
- target_cpus = (reg & ICC_SGI1R_TARGET_LIST_MASK) >> ICC_SGI1R_TARGET_LIST_SHIFT;
+ u32 sgi;
+ unsigned long c;
+
+ sgi = FIELD_GET(ICC_SGI1R_SGI_ID_MASK, reg);
+
+ /* Broadcast */
+ if (unlikely(reg & BIT_ULL(ICC_SGI1R_IRQ_ROUTING_MODE_BIT))) {
+ kvm_for_each_vcpu(c, c_vcpu, kvm) {
+ /* Don't signal the calling VCPU */
+ if (c_vcpu == vcpu)
+ continue;
+
+ vgic_v3_queue_sgi(c_vcpu, sgi, allow_group1);
+ }
+
+ return;
+ }
+
mpidr = SGI_AFFINITY_LEVEL(reg, 3);
mpidr |= SGI_AFFINITY_LEVEL(reg, 2);
mpidr |= SGI_AFFINITY_LEVEL(reg, 1);
+ target_cpus = FIELD_GET(ICC_SGI1R_TARGET_LIST_MASK, reg);
/*
* We iterate over all VCPUs to find the MPIDRs matching the request.
@@ -1091,54 +1134,19 @@ void vgic_v3_dispatch_sgi(struct kvm_vcpu *vcpu, u64 reg, bool allow_group1)
* VCPUs when most of the times we just signal a single VCPU.
*/
kvm_for_each_vcpu(c, c_vcpu, kvm) {
- struct vgic_irq *irq;
+ int level0;
/* Exit early if we have dealt with all requested CPUs */
- if (!broadcast && target_cpus == 0)
+ if (target_cpus == 0)
break;
-
- /* Don't signal the calling VCPU */
- if (broadcast && c == vcpu_id)
Unrelated to this patch, but it looks that we were comparing the value
of *vcpu_idx* and vcpu_id to skip the calling VCPU. Is there a rule in
KVM that userspace should invoke KVM_CREATE_VCPU with sequential
"vcpu id"s, starting at 0, so that the user-provided vcpu_id always
equals to the KVM-internal vcpu_idx for a given VCPU?
I asked because it seems that in kvm/arm64 we always use
kvm_get_vcpu(kvm, i) to obtain the kvm_vcpu pointer, even if *i* is
sometimes essentially provided by userspace..
Besides, the refactor itself looks good to me.
Thanks,
Zenghui
