[PATCH v3 06/19] KVM: ARM: vgic: introduce vgic_ops and LR manipulation primitives
Christoffer Dall
christoffer.dall at linaro.org
Fri May 9 07:05:54 PDT 2014
On Wed, Apr 16, 2014 at 02:39:38PM +0100, Marc Zyngier wrote:
> In order to split the various register manipulation from the main vgic
> code, introduce a vgic_ops structure, and start by abstracting the
> LR manipulation code with a couple of accessors.
>
> Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
> ---
> include/kvm/arm_vgic.h | 18 ++++++
> virt/kvm/arm/vgic.c | 170 +++++++++++++++++++++++++++++++++----------------
> 2 files changed, 132 insertions(+), 56 deletions(-)
>
> diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
> index f738e5a..17bbe51 100644
> --- a/include/kvm/arm_vgic.h
> +++ b/include/kvm/arm_vgic.h
> @@ -68,6 +68,24 @@ struct vgic_bytemap {
> u32 shared[VGIC_NR_SHARED_IRQS / 4];
> };
>
> +struct kvm_vcpu;
> +
> +#define LR_STATE_PENDING (1 << 0)
> +#define LR_STATE_ACTIVE (1 << 1)
> +#define LR_STATE_MASK (3 << 0)
> +#define LR_EOI_INT (1 << 2)
> +
> +struct vgic_lr {
> + u16 irq;
> + u8 source;
> + u8 state;
> +};
> +
> +struct vgic_ops {
> + struct vgic_lr (*get_lr)(const struct kvm_vcpu *, int);
> + void (*set_lr)(struct kvm_vcpu *, int, struct vgic_lr);
> +};
> +
> struct vgic_dist {
> #ifdef CONFIG_KVM_ARM_VGIC
> spinlock_t lock;
> diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
> index 6bc6c7a..bac37b8 100644
> --- a/virt/kvm/arm/vgic.c
> +++ b/virt/kvm/arm/vgic.c
> @@ -94,9 +94,12 @@ static struct device_node *vgic_node;
> #define ACCESS_WRITE_MASK(x) ((x) & (3 << 1))
>
> static void vgic_retire_disabled_irqs(struct kvm_vcpu *vcpu);
> +static void vgic_retire_lr(int lr_nr, int irq, struct kvm_vcpu *vcpu);
> static void vgic_update_state(struct kvm *kvm);
> static void vgic_kick_vcpus(struct kvm *kvm);
> static void vgic_dispatch_sgi(struct kvm_vcpu *vcpu, u32 reg);
> +static struct vgic_lr vgic_get_lr(const struct kvm_vcpu *vcpu, int lr);
> +static void vgic_set_lr(struct kvm_vcpu *vcpu, int lr, struct vgic_lr lr_desc);
> static u32 vgic_nr_lr;
>
> static unsigned int vgic_maint_irq;
> @@ -594,18 +597,6 @@ static bool handle_mmio_sgi_reg(struct kvm_vcpu *vcpu,
> return false;
> }
>
> -#define LR_CPUID(lr) \
> - (((lr) & GICH_LR_PHYSID_CPUID) >> GICH_LR_PHYSID_CPUID_SHIFT)
> -#define LR_IRQID(lr) \
> - ((lr) & GICH_LR_VIRTUALID)
> -
> -static void vgic_retire_lr(int lr_nr, int irq, struct vgic_cpu *vgic_cpu)
> -{
> - clear_bit(lr_nr, vgic_cpu->lr_used);
> - vgic_cpu->vgic_v2.vgic_lr[lr_nr] &= ~GICH_LR_STATE;
> - vgic_cpu->vgic_irq_lr_map[irq] = LR_EMPTY;
> -}
> -
> /**
> * vgic_unqueue_irqs - move pending IRQs from LRs to the distributor
> * @vgic_cpu: Pointer to the vgic_cpu struct holding the LRs
> @@ -623,13 +614,10 @@ static void vgic_unqueue_irqs(struct kvm_vcpu *vcpu)
> struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
> struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
> int vcpu_id = vcpu->vcpu_id;
> - int i, irq, source_cpu;
> - u32 *lr;
> + int i;
>
> for_each_set_bit(i, vgic_cpu->lr_used, vgic_cpu->nr_lr) {
> - lr = &vgic_cpu->vgic_v2.vgic_lr[i];
> - irq = LR_IRQID(*lr);
> - source_cpu = LR_CPUID(*lr);
> + struct vgic_lr lr = vgic_get_lr(vcpu, i);
>
> /*
> * There are three options for the state bits:
> @@ -641,7 +629,7 @@ static void vgic_unqueue_irqs(struct kvm_vcpu *vcpu)
> * If the LR holds only an active interrupt (not pending) then
> * just leave it alone.
> */
> - if ((*lr & GICH_LR_STATE) == GICH_LR_ACTIVE_BIT)
> + if ((lr.state & LR_STATE_MASK) == LR_STATE_ACTIVE)
> continue;
>
> /*
> @@ -650,18 +638,19 @@ static void vgic_unqueue_irqs(struct kvm_vcpu *vcpu)
> * is fine, then we are only setting a few bits that were
> * already set.
> */
> - vgic_dist_irq_set(vcpu, irq);
> - if (irq < VGIC_NR_SGIS)
> - dist->irq_sgi_sources[vcpu_id][irq] |= 1 << source_cpu;
> - *lr &= ~GICH_LR_PENDING_BIT;
> + vgic_dist_irq_set(vcpu, lr.irq);
> + if (lr.irq < VGIC_NR_SGIS)
> + dist->irq_sgi_sources[vcpu_id][lr.irq] |= 1 << lr.source;
> + lr.state &= ~LR_STATE_PENDING;
> + vgic_set_lr(vcpu, i, lr);
>
> /*
> * If there's no state left on the LR (it could still be
> * active), then the LR does not hold any useful info and can
> * be marked as free for other use.
> */
> - if (!(*lr & GICH_LR_STATE))
> - vgic_retire_lr(i, irq, vgic_cpu);
> + if (!(lr.state & LR_STATE_MASK))
> + vgic_retire_lr(i, lr.irq, vcpu);
>
> /* Finally update the VGIC state. */
> vgic_update_state(vcpu->kvm);
> @@ -989,9 +978,77 @@ static void vgic_update_state(struct kvm *kvm)
> }
> }
>
> +static struct vgic_lr vgic_v2_get_lr(const struct kvm_vcpu *vcpu, int lr)
> +{
> + struct vgic_lr lr_desc;
> + u32 val = vcpu->arch.vgic_cpu.vgic_v2.vgic_lr[lr];
> +
> + lr_desc.irq = val & GICH_LR_VIRTUALID;
> + lr_desc.source = (val >> GICH_LR_PHYSID_CPUID_SHIFT) & 0xff;
shouldn't the mask here be 0xf according to the GICv2 spec?
> + lr_desc.state = 0;
> +
> + if (val & GICH_LR_PENDING_BIT)
> + lr_desc.state |= LR_STATE_PENDING;
> + if (val & GICH_LR_ACTIVE_BIT)
> + lr_desc.state |= LR_STATE_ACTIVE;
> + if (val & GICH_LR_EOI)
> + lr_desc.state |= LR_EOI_INT;
> +
> + return lr_desc;
> +}
> +
> #define MK_LR_PEND(src, irq) \
> (GICH_LR_PENDING_BIT | ((src) << GICH_LR_PHYSID_CPUID_SHIFT) | (irq))
>
> +static void vgic_v2_set_lr(struct kvm_vcpu *vcpu, int lr,
> + struct vgic_lr lr_desc)
> +{
> + u32 lr_val = MK_LR_PEND(lr_desc.source, lr_desc.irq);
this looks a bit weird, the check just below suggests that you can
convert a struct vgic_lr into an lr register for, for example, an lr
which is just active and not pending.
> +
> + if (lr_desc.state & LR_STATE_PENDING)
> + lr_val |= GICH_LR_PENDING_BIT;
> + if (lr_desc.state & LR_STATE_ACTIVE)
> + lr_val |= GICH_LR_ACTIVE_BIT;
> + if (lr_desc.state & LR_EOI_INT)
> + lr_val |= GICH_LR_EOI;
> +
> + vcpu->arch.vgic_cpu.vgic_v2.vgic_lr[lr] = lr_val;
> +
> + /*
> + * Despite being EOIed, the LR may not have been marked as
> + * empty.
> + */
> + if (!(lr_val & GICH_LR_STATE))
> + set_bit(lr, (unsigned long *)vcpu->arch.vgic_cpu.vgic_v2.vgic_elrsr);
This feels weird in vgic_v2_set_lr, the name/style suggests that these
get/set functions are just converters from a struct vgic_lr (that
presumably common code can deal with) and architecture-specific LR
register formats.
If these functions have richer semantics than that (like maintaining the
elrsr register), please comment that on the function.
> +}
> +
> +static const struct vgic_ops vgic_ops = {
> + .get_lr = vgic_v2_get_lr,
> + .set_lr = vgic_v2_set_lr,
> +};
> +
> +static inline struct vgic_lr vgic_get_lr(const struct kvm_vcpu *vcpu, int lr)
> +{
> + return vgic_ops.get_lr(vcpu, lr);
> +}
> +
> +static inline void vgic_set_lr(struct kvm_vcpu *vcpu, int lr,
> + struct vgic_lr vlr)
> +{
> + vgic_ops.set_lr(vcpu, lr, vlr);
> +}
inline statics in a C file? Surely the compiler is smart enough to
inline this without any hints.
> +
> +static void vgic_retire_lr(int lr_nr, int irq, struct kvm_vcpu *vcpu)
> +{
> + struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
> + struct vgic_lr vlr = vgic_get_lr(vcpu, lr_nr);
seems like we're doing a lot of copying back and forward between the
struct vgic_lr and the LRs on the vgic_cpu struct, I wonder if it makes
more sense to only deal with it during the sync/flush functions, or
maybe we end up messing with more state than necessary then?
> +
> + vlr.state = 0;
> + vgic_set_lr(vcpu, lr_nr, vlr);
> + clear_bit(lr_nr, vgic_cpu->lr_used);
> + vgic_cpu->vgic_irq_lr_map[irq] = LR_EMPTY;
> +}
> +
> /*
> * An interrupt may have been disabled after being made pending on the
> * CPU interface (the classic case is a timer running while we're
> @@ -1007,12 +1064,12 @@ static void vgic_retire_disabled_irqs(struct kvm_vcpu *vcpu)
> int lr;
>
> for_each_set_bit(lr, vgic_cpu->lr_used, vgic_cpu->nr_lr) {
> - int irq = vgic_cpu->vgic_v2.vgic_lr[lr] & GICH_LR_VIRTUALID;
> + struct vgic_lr vlr = vgic_get_lr(vcpu, lr);
>
> - if (!vgic_irq_is_enabled(vcpu, irq)) {
> - vgic_retire_lr(lr, irq, vgic_cpu);
> - if (vgic_irq_is_active(vcpu, irq))
> - vgic_irq_clear_active(vcpu, irq);
> + if (!vgic_irq_is_enabled(vcpu, vlr.irq)) {
> + vgic_retire_lr(lr, vlr.irq, vcpu);
> + if (vgic_irq_is_active(vcpu, vlr.irq))
> + vgic_irq_clear_active(vcpu, vlr.irq);
> }
> }
> }
> @@ -1024,6 +1081,7 @@ static void vgic_retire_disabled_irqs(struct kvm_vcpu *vcpu)
> static bool vgic_queue_irq(struct kvm_vcpu *vcpu, u8 sgi_source_id, int irq)
> {
> struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
> + struct vgic_lr vlr;
> int lr;
>
> /* Sanitize the input... */
> @@ -1036,13 +1094,15 @@ static bool vgic_queue_irq(struct kvm_vcpu *vcpu, u8 sgi_source_id, int irq)
> lr = vgic_cpu->vgic_irq_lr_map[irq];
>
> /* Do we have an active interrupt for the same CPUID? */
> - if (lr != LR_EMPTY &&
> - (LR_CPUID(vgic_cpu->vgic_v2.vgic_lr[lr]) == sgi_source_id)) {
> - kvm_debug("LR%d piggyback for IRQ%d %x\n",
> - lr, irq, vgic_cpu->vgic_v2.vgic_lr[lr]);
> - BUG_ON(!test_bit(lr, vgic_cpu->lr_used));
> - vgic_cpu->vgic_v2.vgic_lr[lr] |= GICH_LR_PENDING_BIT;
> - return true;
> + if (lr != LR_EMPTY) {
> + vlr = vgic_get_lr(vcpu, lr);
> + if (vlr.source == sgi_source_id) {
> + kvm_debug("LR%d piggyback for IRQ%d\n", lr, vlr.irq);
> + BUG_ON(!test_bit(lr, vgic_cpu->lr_used));
> + vlr.state |= LR_STATE_PENDING;
> + vgic_set_lr(vcpu, lr, vlr);
> + return true;
> + }
> }
>
> /* Try to use another LR for this interrupt */
> @@ -1052,12 +1112,16 @@ static bool vgic_queue_irq(struct kvm_vcpu *vcpu, u8 sgi_source_id, int irq)
> return false;
>
> kvm_debug("LR%d allocated for IRQ%d %x\n", lr, irq, sgi_source_id);
> - vgic_cpu->vgic_v2.vgic_lr[lr] = MK_LR_PEND(sgi_source_id, irq);
> vgic_cpu->vgic_irq_lr_map[irq] = lr;
> set_bit(lr, vgic_cpu->lr_used);
>
> + vlr.irq = irq;
> + vlr.source = sgi_source_id;
> + vlr.state = LR_STATE_PENDING;
> if (!vgic_irq_is_edge(vcpu, irq))
> - vgic_cpu->vgic_v2.vgic_lr[lr] |= GICH_LR_EOI;
> + vlr.state |= LR_EOI_INT;
> +
> + vgic_set_lr(vcpu, lr, vlr);
>
> return true;
> }
> @@ -1180,29 +1244,23 @@ static bool vgic_process_maintenance(struct kvm_vcpu *vcpu)
> * Some level interrupts have been EOIed. Clear their
> * active bit.
> */
> - int lr, irq;
> + int lr;
>
> for_each_set_bit(lr, (unsigned long *)vgic_cpu->vgic_v2.vgic_eisr,
> vgic_cpu->nr_lr) {
> - irq = vgic_cpu->vgic_v2.vgic_lr[lr] & GICH_LR_VIRTUALID;
> + struct vgic_lr vlr = vgic_get_lr(vcpu, lr);
>
> - vgic_irq_clear_active(vcpu, irq);
> - vgic_cpu->vgic_v2.vgic_lr[lr] &= ~GICH_LR_EOI;
> + vgic_irq_clear_active(vcpu, vlr.irq);
> + vlr.state = 0;
slight change of semantics here. It is still correct, but only because
we never set the pending bit on an already active level interrupt, but I
guess this could technically be closer to real hardware by allowing
world-switching VMs that are processing active interrupts to pick up an
additional pending state, in which case just setting state = 0 would be
incorrect here, and you should instead lower the EOI mask like you did
before.
That being said, it is a pseudo-theoretical point, and you can make me
more happy by adding:
BUG_ON(vlr.state & LR_STATE_MASK);
before clearing the state completely.
> + vgic_set_lr(vcpu, lr, vlr);
>
> /* Any additional pending interrupt? */
> - if (vgic_dist_irq_is_pending(vcpu, irq)) {
> - vgic_cpu_irq_set(vcpu, irq);
> + if (vgic_dist_irq_is_pending(vcpu, vlr.irq)) {
> + vgic_cpu_irq_set(vcpu, vlr.irq);
> level_pending = true;
> } else {
> - vgic_cpu_irq_clear(vcpu, irq);
> + vgic_cpu_irq_clear(vcpu, vlr.irq);
> }
> -
> - /*
> - * Despite being EOIed, the LR may not have
> - * been marked as empty.
> - */
> - set_bit(lr, (unsigned long *)vgic_cpu->vgic_v2.vgic_elrsr);
> - vgic_cpu->vgic_v2.vgic_lr[lr] &= ~GICH_LR_ACTIVE_BIT;
> }
> }
>
> @@ -1228,15 +1286,15 @@ static void __kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
> /* Clear mappings for empty LRs */
> for_each_set_bit(lr, (unsigned long *)vgic_cpu->vgic_v2.vgic_elrsr,
> vgic_cpu->nr_lr) {
> - int irq;
> + struct vgic_lr vlr;
>
> if (!test_and_clear_bit(lr, vgic_cpu->lr_used))
> continue;
>
> - irq = vgic_cpu->vgic_v2.vgic_lr[lr] & GICH_LR_VIRTUALID;
> + vlr = vgic_get_lr(vcpu, lr);
>
> - BUG_ON(irq >= VGIC_NR_IRQS);
> - vgic_cpu->vgic_irq_lr_map[irq] = LR_EMPTY;
> + BUG_ON(vlr.irq >= VGIC_NR_IRQS);
> + vgic_cpu->vgic_irq_lr_map[vlr.irq] = LR_EMPTY;
> }
>
> /* Check if we still have something up our sleeve... */
> --
> 1.8.3.4
>
-Christoffer
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