Re: [RFC PATCH 16/45] KVM: arm/arm64: vgic-new: Add PENDING registers handlers

Christoffer Dall
2016-03-31T09:34:49Z

On Fri, Mar 25, 2016 at 02:04:39AM +0000, Andre Przywara wrote:
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> ---
> virt/kvm/arm/vgic/vgic_mmio.c | 87 ++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 85 insertions(+), 2 deletions(-)
>
> diff --git a/virt/kvm/arm/vgic/vgic_mmio.c b/virt/kvm/arm/vgic/vgic_mmio.c
> index 0688a69..8514f92 100644
> --- a/virt/kvm/arm/vgic/vgic_mmio.c
> +++ b/virt/kvm/arm/vgic/vgic_mmio.c
> @@ -206,6 +206,89 @@ static int vgic_mmio_write_cenable(struct kvm_vcpu *vcpu,
> return 0;
> }
>
> +static int vgic_mmio_read_pending(struct kvm_vcpu *vcpu,
> + struct kvm_io_device *this,
> + gpa_t addr, int len, void *val)
> +{
> + struct vgic_io_device *iodev = container_of(this,
> + struct vgic_io_device, dev);
> + u32 intid = (addr - iodev->base_addr) * 8;
> + u32 value = 0;
> + int i;
> +
> + if (iodev->redist_vcpu)
> + vcpu = iodev->redist_vcpu;
> +
> + /* Loop over all IRQs affected by this read */
> + for (i = 0; i < len * 8; i++) {
> + struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
> +
> + spin_lock(&irq->irq_lock);
> + if (irq->pending)
> + value |= (1U << i);
> + spin_unlock(&irq->irq_lock);

here there clearly is no need to take the lock (because a bool read is
atomic), but that should be explained in a one-line comment.

> + }
> +
> + write_mask32(value, addr & 3, len, val);
> + return 0;
> +}
> +
> +static int vgic_mmio_write_spending(struct kvm_vcpu *vcpu,
> + struct kvm_io_device *this,
> + gpa_t addr, int len, const void *val)
> +{
> + struct vgic_io_device *iodev = container_of(this,
> + struct vgic_io_device, dev);
> + u32 intid = (addr - iodev->base_addr) * 8;
> + int i;
> +
> + if (iodev->redist_vcpu)
> + vcpu = iodev->redist_vcpu;
> +
> + for_each_set_bit(i, val, len * 8) {
> + struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
> +
> + spin_lock(&irq->irq_lock);
> + irq->pending = true;
> + if (irq->config == VGIC_CONFIG_LEVEL)
> + irq->soft_pending = true;
> +
> + vgic_queue_irq(vcpu->kvm, irq);
> + }
> +
> + return 0;
> +}
> +
> +static int vgic_mmio_write_cpending(struct kvm_vcpu *vcpu,
> + struct kvm_io_device *this,
> + gpa_t addr, int len, const void *val)
> +{
> + struct vgic_io_device *iodev = container_of(this,
> + struct vgic_io_device, dev);
> + u32 intid = (addr - iodev->base_addr) * 8;
> + int i;
> +
> + if (iodev->redist_vcpu)
> + vcpu = iodev->redist_vcpu;
> +
> + for_each_set_bit(i, val, len * 8) {
> + struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
> +
> + spin_lock(&irq->irq_lock);
> +
> + if (irq->config == VGIC_CONFIG_LEVEL) {
> + irq->soft_pending = false;
> + irq->pending = irq->line_level;
> + } else {
> + irq->pending = false;
> + }
> + /* TODO: Does the exit/entry code take care of "unqueuing"? */

see previous patch comment

> +
> + spin_unlock(&irq->irq_lock);
> + }
> + return 0;
> +}
> +
> struct vgic_register_region vgic_v2_dist_registers[] = {
> REGISTER_DESC_WITH_LENGTH(GIC_DIST_CTRL,
> vgic_mmio_read_v2_misc, vgic_mmio_write_v2_misc, 12),
> @@ -216,9 +299,9 @@ struct vgic_register_region vgic_v2_dist_registers[] = {
> REGISTER_DESC_WITH_BITS_PER_IRQ(GIC_DIST_ENABLE_CLEAR,
> vgic_mmio_read_enable, vgic_mmio_write_cenable, 1),
> REGISTER_DESC_WITH_BITS_PER_IRQ(GIC_DIST_PENDING_SET,
> - vgic_mmio_read_nyi, vgic_mmio_write_nyi, 1),
> + vgic_mmio_read_pending, vgic_mmio_write_spending, 1),
> REGISTER_DESC_WITH_BITS_PER_IRQ(GIC_DIST_PENDING_CLEAR,
> - vgic_mmio_read_nyi, vgic_mmio_write_nyi, 1),
> + vgic_mmio_read_pending, vgic_mmio_write_cpending, 1),
> REGISTER_DESC_WITH_BITS_PER_IRQ(GIC_DIST_ACTIVE_SET,
> vgic_mmio_read_nyi, vgic_mmio_write_nyi, 1),
> REGISTER_DESC_WITH_BITS_PER_IRQ(GIC_DIST_ACTIVE_CLEAR,
> --
> 2.7.3
>