| Message ID | 20240229065313.1871095-2-foxywang@tencent.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: irqchip: synchronize srcu only if needed | expand |
On 2/28/24 22:53, Yi Wang wrote: > From: Yi Wang <foxywang@tencent.com> > > Add a new function to setup empty irq routing in kvm path, which > can be invoded in non-architecture-specific functions. The difference :s/invoded/invoked/ Dongli Zhang
On Thu, Feb 29, 2024 at 6:15 PM Dongli Zhang <dongli.zhang@oracle.com> wrote: > > > > On 2/28/24 22:53, Yi Wang wrote: > > From: Yi Wang <foxywang@tencent.com> > > > > Add a new function to setup empty irq routing in kvm path, which > > can be invoded in non-architecture-specific functions. The difference > > :s/invoded/invoked/ Thanks for pointing this out. Sean, Oliver, Christian, Do you have any other thoughts? Any suggestions are appreciated. > > Dongli Zhang
On 2/29/2024 2:53 PM, Yi Wang wrote: > From: Yi Wang <foxywang@tencent.com> > > Add a new function to setup empty irq routing in kvm path, which > can be invoded in non-architecture-specific functions. The difference > compared to the kvm_setup_empty_irq_routing() is this function just > alloc the empty irq routing and does not need synchronize srcu, as > we will call it in kvm_create_vm(). > > Using the new adding function, we can setup empty irq routing when > kvm_create_vm(), so that x86 and s390 no longer need to set > empty/dummy irq routing when creating an IRQCHIP 'cause it avoid > an synchronize_srcu. > > Signed-off-by: Yi Wang <foxywang@tencent.com> > --- > include/linux/kvm_host.h | 1 + > virt/kvm/irqchip.c | 19 +++++++++++++++++++ > virt/kvm/kvm_main.c | 4 ++++ > 3 files changed, 24 insertions(+) > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index 4944136efaa2..e91525c0a4ea 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -2000,6 +2000,7 @@ int kvm_set_irq_routing(struct kvm *kvm, > const struct kvm_irq_routing_entry *entries, > unsigned nr, > unsigned flags); > +int kvm_setup_empty_irq_routing_lockless(struct kvm *kvm); > int kvm_set_routing_entry(struct kvm *kvm, > struct kvm_kernel_irq_routing_entry *e, > const struct kvm_irq_routing_entry *ue); > diff --git a/virt/kvm/irqchip.c b/virt/kvm/irqchip.c > index 1e567d1f6d3d..90fc43bd0fe4 100644 > --- a/virt/kvm/irqchip.c > +++ b/virt/kvm/irqchip.c > @@ -237,3 +237,22 @@ int kvm_set_irq_routing(struct kvm *kvm, > > return r; > } > + > +int kvm_setup_empty_irq_routing_lockless(struct kvm *kvm) > +{ > + struct kvm_irq_routing_table *new; > + u32 i, j; > + > + new = kzalloc(struct_size(new, map, 1), GFP_KERNEL_ACCOUNT); > + if (!new) > + return -ENOMEM; > + > + new->nr_rt_entries = 1; > + for (i = 0; i < KVM_NR_IRQCHIPS; i++) > + for (j = 0; j < KVM_IRQCHIP_NUM_PINS; j++) > + new->chip[i][j] = -1; Maybe it looks nicer by: size = sizeof(int) * KVM_NR_IRQCHIPS *KVM_IRQCHIP_NUM_PINS; memset(new->chip, -1, size); > + > + RCU_INIT_POINTER(kvm->irq_routing, new); > + > + return 0; > +} > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 7db96875ac46..db1b13fc0502 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -1242,6 +1242,10 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname) > if (r) > goto out_err; > > + r = kvm_setup_empty_irq_routing_lockless(kvm); > + if (r) > + goto out_err; > + > mutex_lock(&kvm_lock); > list_add(&kvm->vm_list, &vm_list); > mutex_unlock(&kvm_lock);
On Fri, Mar 8, 2024 at 12:06 PM Yang, Weijiang <weijiang.yang@intel.com> wrote: > > On 2/29/2024 2:53 PM, Yi Wang wrote: > > From: Yi Wang <foxywang@tencent.com> > > + > > +int kvm_setup_empty_irq_routing_lockless(struct kvm *kvm) > > +{ > > + struct kvm_irq_routing_table *new; > > + u32 i, j; > > + > > + new = kzalloc(struct_size(new, map, 1), GFP_KERNEL_ACCOUNT); > > + if (!new) > > + return -ENOMEM; > > + > > + new->nr_rt_entries = 1; > > + for (i = 0; i < KVM_NR_IRQCHIPS; i++) > > + for (j = 0; j < KVM_IRQCHIP_NUM_PINS; j++) > > + new->chip[i][j] = -1; > > Maybe it looks nicer by: > size = sizeof(int) * KVM_NR_IRQCHIPS *KVM_IRQCHIP_NUM_PINS; > memset(new->chip, -1, size); > It seems better, I'll update this patch. Thx a lot! > > + > > + RCU_INIT_POINTER(kvm->irq_routing, new); > > + > > + return 0; > --- Best wishes Yi Wang
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 4944136efaa2..e91525c0a4ea 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -2000,6 +2000,7 @@ int kvm_set_irq_routing(struct kvm *kvm, const struct kvm_irq_routing_entry *entries, unsigned nr, unsigned flags); +int kvm_setup_empty_irq_routing_lockless(struct kvm *kvm); int kvm_set_routing_entry(struct kvm *kvm, struct kvm_kernel_irq_routing_entry *e, const struct kvm_irq_routing_entry *ue); diff --git a/virt/kvm/irqchip.c b/virt/kvm/irqchip.c index 1e567d1f6d3d..90fc43bd0fe4 100644 --- a/virt/kvm/irqchip.c +++ b/virt/kvm/irqchip.c @@ -237,3 +237,22 @@ int kvm_set_irq_routing(struct kvm *kvm, return r; } + +int kvm_setup_empty_irq_routing_lockless(struct kvm *kvm) +{ + struct kvm_irq_routing_table *new; + u32 i, j; + + new = kzalloc(struct_size(new, map, 1), GFP_KERNEL_ACCOUNT); + if (!new) + return -ENOMEM; + + new->nr_rt_entries = 1; + for (i = 0; i < KVM_NR_IRQCHIPS; i++) + for (j = 0; j < KVM_IRQCHIP_NUM_PINS; j++) + new->chip[i][j] = -1; + + RCU_INIT_POINTER(kvm->irq_routing, new); + + return 0; +} diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 7db96875ac46..db1b13fc0502 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1242,6 +1242,10 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname) if (r) goto out_err; + r = kvm_setup_empty_irq_routing_lockless(kvm); + if (r) + goto out_err; + mutex_lock(&kvm_lock); list_add(&kvm->vm_list, &vm_list); mutex_unlock(&kvm_lock);