Re: [PATCH v5 18/23] KVM: arm64: GICv4.1: Add direct injection capability to SGI registers

Auger Eric
2020-03-20T08:11:52Z

Hi Marc,
On 3/4/20 9:33 PM, Marc Zyngier wrote:
> Most of the GICv3 emulation code that deals with SGIs now has to be
> aware of the v4.1 capabilities in order to benefit from it.
>
> Add such support, keyed on the interrupt having the hw flag set and
> being a SGI.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
> virt/kvm/arm/vgic/vgic-mmio-v3.c | 15 +++++-
> virt/kvm/arm/vgic/vgic-mmio.c | 88 ++++++++++++++++++++++++++++++--
> 2 files changed, 96 insertions(+), 7 deletions(-)
>
> diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c
> index ebc218840fc2..de89da76a379 100644
> --- a/virt/kvm/arm/vgic/vgic-mmio-v3.c
> +++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c
> @@ -6,6 +6,7 @@
> #include <linux/irqchip/arm-gic-v3.h>
> #include <linux/kvm.h>
> #include <linux/kvm_host.h>
> +#include <linux/interrupt.h>
> #include <kvm/iodev.h>
> #include <kvm/arm_vgic.h>
>
> @@ -942,8 +943,18 @@ void vgic_v3_dispatch_sgi(struct kvm_vcpu *vcpu, u64 reg, bool allow_group1)
> * generate interrupts of either group.
> */
> if (!irq->group || allow_group1) {
> - irq->pending_latch = true;
> - vgic_queue_irq_unlock(vcpu->kvm, irq, flags);
> + if (!irq->hw) {
> + irq->pending_latch = true;
> + vgic_queue_irq_unlock(vcpu->kvm, irq, flags);
> + } else {
> + /* HW SGI? Ask the GIC to inject it */
> + int err;
nit: add line
> + err = irq_set_irqchip_state(irq->host_irq,
> + IRQCHIP_STATE_PENDING,
> + true);
> + WARN_RATELIMIT(err, "IRQ %d", irq->host_irq);
> + raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
> + }
> } else {
> raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
> }
> diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c
> index 97fb2a40e6ba..2199302597fa 100644
> --- a/virt/kvm/arm/vgic/vgic-mmio.c
> +++ b/virt/kvm/arm/vgic/vgic-mmio.c
> @@ -5,6 +5,8 @@
>
> #include <linux/bitops.h>
> #include <linux/bsearch.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
> #include <linux/kvm.h>
> #include <linux/kvm_host.h>
> #include <kvm/iodev.h>
> @@ -59,6 +61,11 @@ unsigned long vgic_mmio_read_group(struct kvm_vcpu *vcpu,
> return value;
> }
>
> +static void vgic_update_vsgi(struct vgic_irq *irq)
> +{
> + WARN_ON(its_prop_update_vsgi(irq->host_irq, irq->priority, irq->group));
> +}
> +
> void vgic_mmio_write_group(struct kvm_vcpu *vcpu, gpa_t addr,
> unsigned int len, unsigned long val)
> {
> @@ -71,7 +78,12 @@ void vgic_mmio_write_group(struct kvm_vcpu *vcpu, gpa_t addr,
>
> raw_spin_lock_irqsave(&irq->irq_lock, flags);
> irq->group = !!(val & BIT(i));
> - vgic_queue_irq_unlock(vcpu->kvm, irq, flags);
> + if (irq->hw && vgic_irq_is_sgi(irq->intid)) {
> + vgic_update_vsgi(irq);
> + raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
> + } else {
> + vgic_queue_irq_unlock(vcpu->kvm, irq, flags);
> + }
>
> vgic_put_irq(vcpu->kvm, irq);
> }
> @@ -113,7 +125,21 @@ void vgic_mmio_write_senable(struct kvm_vcpu *vcpu,
> struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
>
> raw_spin_lock_irqsave(&irq->irq_lock, flags);
> - if (vgic_irq_is_mapped_level(irq)) {
> + if (irq->hw && vgic_irq_is_sgi(irq->intid)) {
> + if (!irq->enabled) {
> + struct irq_data *data;
> +
> + irq->enabled = true;
> + data = &irq_to_desc(irq->host_irq)->irq_data;
> + while (irqd_irq_disabled(data))
> + enable_irq(irq->host_irq);
could you explain me why the while() is requested?
> + }
> +
> + raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
> + vgic_put_irq(vcpu->kvm, irq);
> +
> + continue;
> + } else if (vgic_irq_is_mapped_level(irq)) {
> bool was_high = irq->line_level;
>
> /*
> @@ -148,6 +174,8 @@ void vgic_mmio_write_cenable(struct kvm_vcpu *vcpu,
> struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
>
> raw_spin_lock_irqsave(&irq->irq_lock, flags);
> + if (irq->hw && vgic_irq_is_sgi(irq->intid) && irq->enabled)
> + disable_irq_nosync(irq->host_irq);
>
> irq->enabled = false;
>
> @@ -167,10 +195,22 @@ unsigned long vgic_mmio_read_pending(struct kvm_vcpu *vcpu,
> for (i = 0; i < len * 8; i++) {
> struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
> unsigned long flags;
> + bool val;
>
> raw_spin_lock_irqsave(&irq->irq_lock, flags);
> - if (irq_is_pending(irq))
> - value |= (1U << i);
> + if (irq->hw && vgic_irq_is_sgi(irq->intid)) {
> + int err;
> +
> + val = false;
> + err = irq_get_irqchip_state(irq->host_irq,
> + IRQCHIP_STATE_PENDING,
> + &val);
> + WARN_RATELIMIT(err, "IRQ %d", irq->host_irq);
> + } else {
> + val = irq_is_pending(irq);
> + }
> +
> + value |= ((u32)val << i);
> raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
>
> vgic_put_irq(vcpu->kvm, irq);
> @@ -215,6 +255,21 @@ void vgic_mmio_write_spending(struct kvm_vcpu *vcpu,
> }
>
> raw_spin_lock_irqsave(&irq->irq_lock, flags);
> +
> + if (irq->hw && vgic_irq_is_sgi(irq->intid)) {
> + /* HW SGI? Ask the GIC to inject it */
> + int err;
nit: extra line
> + err = irq_set_irqchip_state(irq->host_irq,
> + IRQCHIP_STATE_PENDING,
> + true);
> + WARN_RATELIMIT(err, "IRQ %d", irq->host_irq);
> +
> + raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
> + vgic_put_irq(vcpu->kvm, irq);
> +
> + continue;
> + }
> +
> if (irq->hw)
> vgic_hw_irq_spending(vcpu, irq, is_uaccess);
> else
> @@ -269,6 +324,20 @@ void vgic_mmio_write_cpending(struct kvm_vcpu *vcpu,
>
> raw_spin_lock_irqsave(&irq->irq_lock, flags);
>
> + if (irq->hw && vgic_irq_is_sgi(irq->intid)) {
> + /* HW SGI? Ask the GIC to clear its pending bit */
> + int err;
> + err = irq_set_irqchip_state(irq->host_irq,
> + IRQCHIP_STATE_PENDING,
> + false);
> + WARN_RATELIMIT(err, "IRQ %d", irq->host_irq);
> +
> + raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
> + vgic_put_irq(vcpu->kvm, irq);
> +
> + continue;
> + }
> +
> if (irq->hw)
> vgic_hw_irq_cpending(vcpu, irq, is_uaccess);
> else
> @@ -318,8 +387,15 @@ static void vgic_mmio_change_active(struct kvm_vcpu *vcpu, struct vgic_irq *irq,
>
> raw_spin_lock_irqsave(&irq->irq_lock, flags);
>
> - if (irq->hw) {
> + if (irq->hw && !vgic_irq_is_sgi(irq->intid)) {
> vgic_hw_irq_change_active(vcpu, irq, active, !requester_vcpu);
> + } else if (irq->hw && vgic_irq_is_sgi(irq->intid)) {
> + /*
> + * GICv4.1 VSGI feature doesn't track an active state,
> + * so let's not kid ourselves, there is nothing we can
> + * do here.
> + */
> + irq->active = false;
> } else {
> u32 model = vcpu->kvm->arch.vgic.vgic_model;
> u8 active_source;
> @@ -493,6 +569,8 @@ void vgic_mmio_write_priority(struct kvm_vcpu *vcpu,
> raw_spin_lock_irqsave(&irq->irq_lock, flags);
> /* Narrow the priority range to what we actually support */
> irq->priority = (val >> (i * 8)) & GENMASK(7, 8 - VGIC_PRI_BITS);
> + if (irq->hw && vgic_irq_is_sgi(irq->intid))
> + vgic_update_vsgi(irq);
> raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
>
> vgic_put_irq(vcpu->kvm, irq);
>
Reviewed-by: Eric Auger <eric.auger@redhat.com>

Thanks

Eric