Re: [PATCH 6/8] KVM: arm/arm64: Register iodevs when setting redist base and creating VCPUs

Christoffer Dall
2017-05-08T17:20:17Z

On Mon, May 08, 2017 at 07:09:07PM +0200, Auger Eric wrote:
> Hi Christoffer,
>
> On 08/05/2017 13:54, Christoffer Dall wrote:
> > Instead of waiting with registering KVM iodevs until the very last VCPU
> > is created,
> aren't they registered on the 1st VCPU run?

yeah, that's what i meant

>> we can actually create the iodevs when the redist base
> > address is set. The only downside is that we must now also check if we
> > need to do this for VCPUs which are created after creating the VGIC,
> > because there is no enforced ordering between creating the VGIC
> (and setting its base addresses)

ok

>> and the
> > VCPUs.
> >
> > Signed-off-by: Christoffer Dall <cdall@linaro.org>
> > ---
> > include/kvm/arm_vgic.h | 1 +
> > virt/kvm/arm/arm.c | 6 +++++-
> > virt/kvm/arm/vgic/vgic-init.c | 21 ++++++++++++++++++
> > virt/kvm/arm/vgic/vgic-kvm-device.c | 7 +++++-
> > virt/kvm/arm/vgic/vgic-mmio-v3.c | 43 +++++++++++++++++++++++++++++++++++--
> > virt/kvm/arm/vgic/vgic-v3.c | 6 ------
> > virt/kvm/arm/vgic/vgic.h | 3 ++-
> > 7 files changed, 76 insertions(+), 11 deletions(-)
> >
> > diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
> > index fabcc64..4ff65ef 100644
> > --- a/include/kvm/arm_vgic.h
> > +++ b/include/kvm/arm_vgic.h
> > @@ -286,6 +286,7 @@ extern struct static_key_false vgic_v2_cpuif_trap;
> >
> > int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write);
> > void kvm_vgic_early_init(struct kvm *kvm);
> > +int kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu);
> > int kvm_vgic_create(struct kvm *kvm, u32 type);
> > void kvm_vgic_destroy(struct kvm *kvm);
> > void kvm_vgic_vcpu_early_init(struct kvm_vcpu *vcpu);
> > diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
> > index 7941699..dd74d39 100644
> > --- a/virt/kvm/arm/arm.c
> > +++ b/virt/kvm/arm/arm.c
> > @@ -326,6 +326,8 @@ void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu)
> >
> > int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
> > {
> > + int ret = 0;
> > +
> > /* Force users to call KVM_ARM_VCPU_INIT */
> > vcpu->arch.target = -1;
> > bitmap_zero(vcpu->arch.features, KVM_VCPU_MAX_FEATURES);
> > @@ -335,7 +337,9 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
> >
> > kvm_arm_reset_debug_ptr(vcpu);
> >
> > - return 0;
> > + ret = kvm_vgic_vcpu_init(vcpu);
> > +
> > + return ret;
> nit: ret can be removed
> > }
> >
> > void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
> > diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c
> > index 0ea64a1..962bb57 100644
> > --- a/virt/kvm/arm/vgic/vgic-init.c
> > +++ b/virt/kvm/arm/vgic/vgic-init.c
> > @@ -226,6 +226,27 @@ static int kvm_vgic_dist_init(struct kvm *kvm, unsigned int nr_spis)
> > return 0;
> > }
> >
> > +/**
> > + * kvm_vgic_vcpu_init() - Register VCPU-specific KVM iodevs
> > + * @vcpu: pointer to the VCPU being created and initialized
> > + */
> > +int kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu)
> > +{
> > + int ret = 0;
> > + struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
> > +
> > + if (!irqchip_in_kernel(vcpu->kvm))
> > + return 0;
> > +
> > + /*
> > + * If we are creating a VCPU with a GICv3 we must also register the
> > + * KVM io device for the redistributor that belongs to this VCPU.
> > + */
> > + if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3)
> > + ret = vgic_register_redist_iodev(vcpu);
> > + return ret;
> > +}
> > +
> > static void kvm_vgic_vcpu_enable(struct kvm_vcpu *vcpu)
> > {
> > if (kvm_vgic_global_state.type == VGIC_V2)
> > diff --git a/virt/kvm/arm/vgic/vgic-kvm-device.c b/virt/kvm/arm/vgic/vgic-kvm-device.c
> > index 69ccfd5..10ae6f3 100644
> > --- a/virt/kvm/arm/vgic/vgic-kvm-device.c
> > +++ b/virt/kvm/arm/vgic/vgic-kvm-device.c
> > @@ -86,8 +86,13 @@ int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write)
> > break;
> > case KVM_VGIC_V3_ADDR_TYPE_REDIST:
> > r = vgic_check_type(kvm, KVM_DEV_TYPE_ARM_VGIC_V3);
> > + if (r)
> > + break;
> > + if (write) {
> > + r = vgic_v3_set_redist_base(kvm, *addr);
> > + goto out;
> > + }
> > addr_ptr = &vgic->vgic_redist_base;
> > - alignment = SZ_64K;
> > break;
> > default:
> > r = -ENODEV;
> > diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c
> > index 1828ac7..297557b 100644
> > --- a/virt/kvm/arm/vgic/vgic-mmio-v3.c
> > +++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c
> > @@ -565,7 +565,7 @@ unsigned int vgic_v3_init_dist_iodev(struct vgic_io_device *dev)
> > *
> > * Return 0 on success, -ERRNO otherwise.
> > */
> > -static int vgic_register_redist_iodev(struct kvm_vcpu *vcpu)
> > +int vgic_register_redist_iodev(struct kvm_vcpu *vcpu)
> > {
> > struct kvm *kvm = vcpu->kvm;
> > struct vgic_dist *vgic = &kvm->arch.vgic;
> > @@ -574,6 +574,18 @@ static int vgic_register_redist_iodev(struct kvm_vcpu *vcpu)
> > gpa_t rd_base, sgi_base;
> > int ret;
> >
> > + /*
> > + * We may be creating VCPUs before having set the base address for the
> > + * redistributor region, in which case we will come back to this
> > + * function for all VCPUs when the base address is set. Just return
> > + * without doing any work for now.
> > + */
> > + if (IS_VGIC_ADDR_UNDEF(vgic->vgic_redist_base))
> > + return 0;
> > +
> > + if (!vgic_v3_check_base(kvm))
> > + return -EINVAL;
> > +
> > rd_base = vgic->vgic_redist_base + vcpu->vcpu_id * SZ_64K * 2;
> > sgi_base = rd_base + SZ_64K;
> >
> > @@ -619,7 +631,7 @@ static void vgic_unregister_redist_iodev(struct kvm_vcpu *vcpu)
> > kvm_io_bus_unregister_dev(vcpu->kvm, KVM_MMIO_BUS, &sgi_dev->dev);
> > }
> >
> > -int vgic_register_redist_iodevs(struct kvm *kvm)
> > +static int vgic_register_all_redist_iodevs(struct kvm *kvm)
> > {
> > struct kvm_vcpu *vcpu;
> > int c, ret = 0;
> > @@ -641,6 +653,33 @@ int vgic_register_redist_iodevs(struct kvm *kvm)
> > return ret;
> > }
> >
> > +int vgic_v3_set_redist_base(struct kvm *kvm, u64 addr)
> > +{
> > + struct vgic_dist *vgic = &kvm->arch.vgic;
> > + int ret;
> > +
> > + /* vgic_check_ioaddr makes sure we don't do this twice */
> > + ret = vgic_check_ioaddr(kvm, &vgic->vgic_redist_base, addr, SZ_64K);
> > + if (ret)
> > + return ret;
> > +
> > + vgic->vgic_redist_base = addr;
> > + if (!vgic_v3_check_base(kvm)) {
> So we must make sure this check takes into account the case dist base
> address is not set yet.

It should already.

>
> Otherwise looks good to me.
>
> Reviewed-by: Eric Auger <eric.auger@redhat.com>
>

Thanks,
-Christoffer

> > + vgic->vgic_redist_base = VGIC_ADDR_UNDEF;
> > + return -EINVAL;
> > + }
> > +
> > + /*
> > + * Register iodevs for each existing VCPU. Adding more VCPUs
> > + * afterwards will register the iodevs when needed.
> > + */
> > + ret = vgic_register_all_redist_iodevs(kvm);
> > + if (ret)
> > + return ret;
> > +
> > + return 0;
> > +}
> > +
> > int vgic_v3_has_attr_regs(struct kvm_device *dev, struct kvm_device_attr *attr)
> > {
> > const struct vgic_register_region *region;
> > diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
> > index b934e78..4d51d1f 100644
> > --- a/virt/kvm/arm/vgic/vgic-v3.c
> > +++ b/virt/kvm/arm/vgic/vgic-v3.c
> > @@ -396,12 +396,6 @@ int vgic_v3_map_resources(struct kvm *kvm)
> > goto out;
> > }
> >
> > - ret = vgic_register_redist_iodevs(kvm);
> > - if (ret) {
> > - kvm_err("Unable to register VGICv3 redist MMIO regions\n");
> > - goto out;
> > - }
> > -
> > if (vgic_has_its(kvm)) {
> > ret = vgic_register_its_iodevs(kvm);
> > if (ret) {
> > diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
> > index 89eb935..5f17eac 100644
> > --- a/virt/kvm/arm/vgic/vgic.h
> > +++ b/virt/kvm/arm/vgic/vgic.h
> > @@ -174,7 +174,8 @@ int vgic_v3_probe(const struct gic_kvm_info *info);
> > int vgic_v3_map_resources(struct kvm *kvm);
> > int vgic_v3_lpi_sync_pending_status(struct kvm *kvm, struct vgic_irq *irq);
> > int vgic_v3_save_pending_tables(struct kvm *kvm);
> > -int vgic_register_redist_iodevs(struct kvm *kvm);
> > +int vgic_v3_set_redist_base(struct kvm *kvm, u64 addr);
> > +int vgic_register_redist_iodev(struct kvm_vcpu *vcpu);
> > bool vgic_v3_check_base(struct kvm *kvm);
> >
> > void vgic_v3_load(struct kvm_vcpu *vcpu);
> >