| Message ID | 20240506101751.3145407-2-foxywang@tencent.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: irqchip: synchronize srcu only if needed | expand |
Am 06.05.24 um 12:17 schrieb Yi Wang: > 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> Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com> > --- > include/linux/kvm_host.h | 2 ++ > virt/kvm/irqchip.c | 23 +++++++++++++++++++++++ > virt/kvm/kvm_main.c | 9 ++++++++- > 3 files changed, 33 insertions(+), 1 deletion(-) > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index 48f31dcd318a..a5f12b667ca5 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -2100,6 +2100,7 @@ int kvm_set_irq_routing(struct kvm *kvm, > const struct kvm_irq_routing_entry *entries, > unsigned nr, > unsigned flags); > +int kvm_init_irq_routing(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); > @@ -2108,6 +2109,7 @@ void kvm_free_irq_routing(struct kvm *kvm); > #else > > static inline void kvm_free_irq_routing(struct kvm *kvm) {} > +int kvm_init_irq_routing(struct kvm *kvm) {} > > #endif > > diff --git a/virt/kvm/irqchip.c b/virt/kvm/irqchip.c > index 1e567d1f6d3d..ec1fda7fffea 100644 > --- a/virt/kvm/irqchip.c > +++ b/virt/kvm/irqchip.c > @@ -237,3 +237,26 @@ int kvm_set_irq_routing(struct kvm *kvm, > > return r; > } > + > +/* > + * Alloc empty irq routing. > + * Called only during vm creation, because we don't synchronize_srcu here. > + */ > +int kvm_init_irq_routing(struct kvm *kvm) > +{ > + struct kvm_irq_routing_table *new; > + int chip_size; > + > + new = kzalloc(struct_size(new, map, 1), GFP_KERNEL_ACCOUNT); > + if (!new) > + return -ENOMEM; > + > + new->nr_rt_entries = 1; > + > + chip_size = sizeof(int) * KVM_NR_IRQCHIPS * KVM_IRQCHIP_NUM_PINS; > + memset(new->chip, -1, chip_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 ff0a20565f90..4100ebdd14fe 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -1233,6 +1233,11 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname) > goto out_err_no_irq_srcu; > > refcount_set(&kvm->users_count, 1); > + > + r = kvm_init_irq_routing(kvm); > + if (r) > + goto out_err_no_irq_routing; > + > for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) { > for (j = 0; j < 2; j++) { > slots = &kvm->__memslots[i][j]; > @@ -1308,9 +1313,11 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname) > out_err_no_disable: > kvm_arch_destroy_vm(kvm); > out_err_no_arch_destroy_vm: > - WARN_ON_ONCE(!refcount_dec_and_test(&kvm->users_count)); > for (i = 0; i < KVM_NR_BUSES; i++) > kfree(kvm_get_bus(kvm, i)); > + kvm_free_irq_routing(kvm); > +out_err_no_irq_routing: > + WARN_ON_ONCE(!refcount_dec_and_test(&kvm->users_count)); > cleanup_srcu_struct(&kvm->irq_srcu); > out_err_no_irq_srcu: > cleanup_srcu_struct(&kvm->srcu);
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 48f31dcd318a..a5f12b667ca5 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -2100,6 +2100,7 @@ int kvm_set_irq_routing(struct kvm *kvm, const struct kvm_irq_routing_entry *entries, unsigned nr, unsigned flags); +int kvm_init_irq_routing(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); @@ -2108,6 +2109,7 @@ void kvm_free_irq_routing(struct kvm *kvm); #else static inline void kvm_free_irq_routing(struct kvm *kvm) {} +int kvm_init_irq_routing(struct kvm *kvm) {} #endif diff --git a/virt/kvm/irqchip.c b/virt/kvm/irqchip.c index 1e567d1f6d3d..ec1fda7fffea 100644 --- a/virt/kvm/irqchip.c +++ b/virt/kvm/irqchip.c @@ -237,3 +237,26 @@ int kvm_set_irq_routing(struct kvm *kvm, return r; } + +/* + * Alloc empty irq routing. + * Called only during vm creation, because we don't synchronize_srcu here. + */ +int kvm_init_irq_routing(struct kvm *kvm) +{ + struct kvm_irq_routing_table *new; + int chip_size; + + new = kzalloc(struct_size(new, map, 1), GFP_KERNEL_ACCOUNT); + if (!new) + return -ENOMEM; + + new->nr_rt_entries = 1; + + chip_size = sizeof(int) * KVM_NR_IRQCHIPS * KVM_IRQCHIP_NUM_PINS; + memset(new->chip, -1, chip_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 ff0a20565f90..4100ebdd14fe 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1233,6 +1233,11 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname) goto out_err_no_irq_srcu; refcount_set(&kvm->users_count, 1); + + r = kvm_init_irq_routing(kvm); + if (r) + goto out_err_no_irq_routing; + for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) { for (j = 0; j < 2; j++) { slots = &kvm->__memslots[i][j]; @@ -1308,9 +1313,11 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname) out_err_no_disable: kvm_arch_destroy_vm(kvm); out_err_no_arch_destroy_vm: - WARN_ON_ONCE(!refcount_dec_and_test(&kvm->users_count)); for (i = 0; i < KVM_NR_BUSES; i++) kfree(kvm_get_bus(kvm, i)); + kvm_free_irq_routing(kvm); +out_err_no_irq_routing: + WARN_ON_ONCE(!refcount_dec_and_test(&kvm->users_count)); cleanup_srcu_struct(&kvm->irq_srcu); out_err_no_irq_srcu: cleanup_srcu_struct(&kvm->srcu);