Re: [PATCH v3 05/20] KVM: arm/arm64: Support calling vgic_update_irq_pending from irq context

Marc Zyngier
2017-10-09T16:37:43Z

On 23/09/17 01:41, Christoffer Dall wrote:
> We are about to optimize our timer handling logic which involves
> injecting irqs to the vgic directly from the irq handler.
>
> Unfortunately, the injection path can take any AP list lock and irq lock
> and we must therefore make sure to use spin_lock_irqsave where ever
> interrupts are enabled and we are taking any of those locks, to avoid
> deadlocking between process context and the ISR.
>
> This changes a lot of the VGIC code, but The good news are that the
> changes are mostly mechanical.
>
> Signed-off-by: Christoffer Dall <cdall@linaro.org>
> ---
> virt/kvm/arm/vgic/vgic-its.c | 17 +++++++-----
> virt/kvm/arm/vgic/vgic-mmio-v2.c | 22 +++++++++------
> virt/kvm/arm/vgic/vgic-mmio-v3.c | 17 +++++++-----
> virt/kvm/arm/vgic/vgic-mmio.c | 44 +++++++++++++++++------------
> virt/kvm/arm/vgic/vgic-v2.c | 5 ++--
> virt/kvm/arm/vgic/vgic-v3.c | 12 ++++----
> virt/kvm/arm/vgic/vgic.c | 60 +++++++++++++++++++++++++---------------
> virt/kvm/arm/vgic/vgic.h | 3 +-
> 8 files changed, 108 insertions(+), 72 deletions(-)
>
> diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
> index f51c1e1..9f5e347 100644
> --- a/virt/kvm/arm/vgic/vgic-its.c
> +++ b/virt/kvm/arm/vgic/vgic-its.c
> @@ -278,6 +278,7 @@ static int update_lpi_config(struct kvm *kvm, struct vgic_irq *irq,
> u64 propbase = GICR_PROPBASER_ADDRESS(kvm->arch.vgic.propbaser);
> u8 prop;
> int ret;
> + unsigned long flags;
>
> ret = kvm_read_guest(kvm, propbase + irq->intid - GIC_LPI_OFFSET,
> &prop, 1);
> @@ -285,15 +286,15 @@ static int update_lpi_config(struct kvm *kvm, struct vgic_irq *irq,
> if (ret)
> return ret;
>
> - spin_lock(&irq->irq_lock);
> + spin_lock_irqsave(&irq->irq_lock, flags);
>
> if (!filter_vcpu || filter_vcpu == irq->target_vcpu) {
> irq->priority = LPI_PROP_PRIORITY(prop);
> irq->enabled = LPI_PROP_ENABLE_BIT(prop);
>
> - vgic_queue_irq_unlock(kvm, irq);
> + vgic_queue_irq_unlock(kvm, irq, flags);
> } else {
> - spin_unlock(&irq->irq_lock);
> + spin_unlock_irqrestore(&irq->irq_lock, flags);
> }
>
> return 0;
> @@ -393,6 +394,7 @@ static int its_sync_lpi_pending_table(struct kvm_vcpu *vcpu)
> int ret = 0;
> u32 *intids;
> int nr_irqs, i;
> + unsigned long flags;
>
> nr_irqs = vgic_copy_lpi_list(vcpu, &intids);
> if (nr_irqs < 0)
> @@ -420,9 +422,9 @@ static int its_sync_lpi_pending_table(struct kvm_vcpu *vcpu)
> }
>
> irq = vgic_get_irq(vcpu->kvm, NULL, intids[i]);
> - spin_lock(&irq->irq_lock);
> + spin_lock_irqsave(&irq->irq_lock, flags);
> irq->pending_latch = pendmask & (1U << bit_nr);
> - vgic_queue_irq_unlock(vcpu->kvm, irq);
> + vgic_queue_irq_unlock(vcpu->kvm, irq, flags);
> vgic_put_irq(vcpu->kvm, irq);
> }
>
> @@ -515,6 +517,7 @@ static int vgic_its_trigger_msi(struct kvm *kvm, struct vgic_its *its,
> {
> struct kvm_vcpu *vcpu;
> struct its_ite *ite;
> + unsigned long flags;
>
> if (!its->enabled)
> return -EBUSY;
> @@ -530,9 +533,9 @@ static int vgic_its_trigger_msi(struct kvm *kvm, struct vgic_its *its,
> if (!vcpu->arch.vgic_cpu.lpis_enabled)
> return -EBUSY;
>
> - spin_lock(&ite->irq->irq_lock);
> + spin_lock_irqsave(&ite->irq->irq_lock, flags);
> ite->irq->pending_latch = true;
> - vgic_queue_irq_unlock(kvm, ite->irq);
> + vgic_queue_irq_unlock(kvm, ite->irq, flags);
>
> return 0;
> }
> diff --git a/virt/kvm/arm/vgic/vgic-mmio-v2.c b/virt/kvm/arm/vgic/vgic-mmio-v2.c
> index b3d4a10..e21e2f4 100644
> --- a/virt/kvm/arm/vgic/vgic-mmio-v2.c
> +++ b/virt/kvm/arm/vgic/vgic-mmio-v2.c
> @@ -74,6 +74,7 @@ static void vgic_mmio_write_sgir(struct kvm_vcpu *source_vcpu,
> int mode = (val >> 24) & 0x03;
> int c;
> struct kvm_vcpu *vcpu;
> + unsigned long flags;
>
> switch (mode) {
> case 0x0: /* as specified by targets */
> @@ -97,11 +98,11 @@ static void vgic_mmio_write_sgir(struct kvm_vcpu *source_vcpu,
>
> irq = vgic_get_irq(source_vcpu->kvm, vcpu, intid);
>
> - spin_lock(&irq->irq_lock);
> + spin_lock_irqsave(&irq->irq_lock, flags);
> irq->pending_latch = true;
> irq->source |= 1U << source_vcpu->vcpu_id;
>
> - vgic_queue_irq_unlock(source_vcpu->kvm, irq);
> + vgic_queue_irq_unlock(source_vcpu->kvm, irq, flags);
> vgic_put_irq(source_vcpu->kvm, irq);
> }
> }
> @@ -131,6 +132,7 @@ static void vgic_mmio_write_target(struct kvm_vcpu *vcpu,
> u32 intid = VGIC_ADDR_TO_INTID(addr, 8);
> u8 cpu_mask = GENMASK(atomic_read(&vcpu->kvm->online_vcpus) - 1, 0);
> int i;
> + unsigned long flags;
>
> /* GICD_ITARGETSR[0-7] are read-only */
> if (intid < VGIC_NR_PRIVATE_IRQS)
> @@ -140,13 +142,13 @@ static void vgic_mmio_write_target(struct kvm_vcpu *vcpu,
> struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, NULL, intid + i);
> int target;
>
> - spin_lock(&irq->irq_lock);
> + spin_lock_irqsave(&irq->irq_lock, flags);
>
> irq->targets = (val >> (i * 8)) & cpu_mask;
> target = irq->targets ? __ffs(irq->targets) : 0;
> irq->target_vcpu = kvm_get_vcpu(vcpu->kvm, target);
>
> - spin_unlock(&irq->irq_lock);
> + spin_unlock_irqrestore(&irq->irq_lock, flags);
> vgic_put_irq(vcpu->kvm, irq);
> }
> }
> @@ -174,17 +176,18 @@ static void vgic_mmio_write_sgipendc(struct kvm_vcpu *vcpu,
> {
> u32 intid = addr & 0x0f;
> int i;
> + unsigned long flags;
>
> for (i = 0; i < len; i++) {
> struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
>
> - spin_lock(&irq->irq_lock);
> + spin_lock_irqsave(&irq->irq_lock, flags);
>
> irq->source &= ~((val >> (i * 8)) & 0xff);
> if (!irq->source)
> irq->pending_latch = false;
>
> - spin_unlock(&irq->irq_lock);
> + spin_unlock_irqrestore(&irq->irq_lock, flags);
> vgic_put_irq(vcpu->kvm, irq);
> }
> }
> @@ -195,19 +198,20 @@ static void vgic_mmio_write_sgipends(struct kvm_vcpu *vcpu,
> {
> u32 intid = addr & 0x0f;
> int i;
> + unsigned long flags;
>
> for (i = 0; i < len; i++) {
> struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
>
> - spin_lock(&irq->irq_lock);
> + spin_lock_irqsave(&irq->irq_lock, flags);
>
> irq->source |= (val >> (i * 8)) & 0xff;
>
> if (irq->source) {
> irq->pending_latch = true;
> - vgic_queue_irq_unlock(vcpu->kvm, irq);
> + vgic_queue_irq_unlock(vcpu->kvm, irq, flags);
> } else {
> - spin_unlock(&irq->irq_lock);
> + spin_unlock_irqrestore(&irq->irq_lock, flags);
> }
> vgic_put_irq(vcpu->kvm, irq);
> }
> diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c
> index 408ef06..8378610 100644
> --- a/virt/kvm/arm/vgic/vgic-mmio-v3.c
> +++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c
> @@ -129,6 +129,7 @@ static void vgic_mmio_write_irouter(struct kvm_vcpu *vcpu,
> {
> int intid = VGIC_ADDR_TO_INTID(addr, 64);
> struct vgic_irq *irq;
> + unsigned long flags;
>
> /* The upper word is WI for us since we don't implement Aff3. */
> if (addr & 4)
> @@ -139,13 +140,13 @@ static void vgic_mmio_write_irouter(struct kvm_vcpu *vcpu,
> if (!irq)
> return;
>
> - spin_lock(&irq->irq_lock);
> + spin_lock_irqsave(&irq->irq_lock, flags);
>
> /* We only care about and preserve Aff0, Aff1 and Aff2. */
> irq->mpidr = val & GENMASK(23, 0);
> irq->target_vcpu = kvm_mpidr_to_vcpu(vcpu->kvm, irq->mpidr);
>
> - spin_unlock(&irq->irq_lock);
> + spin_unlock_irqrestore(&irq->irq_lock, flags);
> vgic_put_irq(vcpu->kvm, irq);
> }
>
> @@ -241,11 +242,12 @@ static void vgic_v3_uaccess_write_pending(struct kvm_vcpu *vcpu,
> {
> u32 intid = VGIC_ADDR_TO_INTID(addr, 1);
> int i;
> + unsigned long flags;
>
> for (i = 0; i < len * 8; i++) {
> struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
>
> - spin_lock(&irq->irq_lock);
> + spin_lock_irqsave(&irq->irq_lock, flags);
> if (test_bit(i, &val)) {
> /*
> * pending_latch is set irrespective of irq type
> @@ -253,10 +255,10 @@ static void vgic_v3_uaccess_write_pending(struct kvm_vcpu *vcpu,
> * restore irq config before pending info.
> */
> irq->pending_latch = true;
> - vgic_queue_irq_unlock(vcpu->kvm, irq);
> + vgic_queue_irq_unlock(vcpu->kvm, irq, flags);
> } else {
> irq->pending_latch = false;
> - spin_unlock(&irq->irq_lock);
> + spin_unlock_irqrestore(&irq->irq_lock, flags);
> }
>
> vgic_put_irq(vcpu->kvm, irq);
> @@ -799,6 +801,7 @@ void vgic_v3_dispatch_sgi(struct kvm_vcpu *vcpu, u64 reg)
> int sgi, c;
> int vcpu_id = vcpu->vcpu_id;
> bool broadcast;
> + unsigned long flags;
>
> sgi = (reg & ICC_SGI1R_SGI_ID_MASK) >> ICC_SGI1R_SGI_ID_SHIFT;
> broadcast = reg & BIT_ULL(ICC_SGI1R_IRQ_ROUTING_MODE_BIT);
> @@ -837,10 +840,10 @@ void vgic_v3_dispatch_sgi(struct kvm_vcpu *vcpu, u64 reg)
>
> irq = vgic_get_irq(vcpu->kvm, c_vcpu, sgi);
>
> - spin_lock(&irq->irq_lock);
> + spin_lock_irqsave(&irq->irq_lock, flags);
> irq->pending_latch = true;
>
> - vgic_queue_irq_unlock(vcpu->kvm, irq);
> + vgic_queue_irq_unlock(vcpu->kvm, irq, flags);
> vgic_put_irq(vcpu->kvm, irq);
> }
> }
> diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c
> index c1e4bdd..deb51ee 100644
> --- a/virt/kvm/arm/vgic/vgic-mmio.c
> +++ b/virt/kvm/arm/vgic/vgic-mmio.c
> @@ -69,13 +69,14 @@ void vgic_mmio_write_senable(struct kvm_vcpu *vcpu,
> {
> u32 intid = VGIC_ADDR_TO_INTID(addr, 1);
> int i;
> + unsigned long flags;
>
> 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);
> + spin_lock_irqsave(&irq->irq_lock, flags);
> irq->enabled = true;
> - vgic_queue_irq_unlock(vcpu->kvm, irq);
> + vgic_queue_irq_unlock(vcpu->kvm, irq, flags);
>
> vgic_put_irq(vcpu->kvm, irq);
> }
> @@ -87,15 +88,16 @@ void vgic_mmio_write_cenable(struct kvm_vcpu *vcpu,
> {
> u32 intid = VGIC_ADDR_TO_INTID(addr, 1);
> int i;
> + unsigned long flags;
>
> 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);
> + spin_lock_irqsave(&irq->irq_lock, flags);
>
> irq->enabled = false;
>
> - spin_unlock(&irq->irq_lock);
> + spin_unlock_irqrestore(&irq->irq_lock, flags);
> vgic_put_irq(vcpu->kvm, irq);
> }
> }
> @@ -126,14 +128,15 @@ void vgic_mmio_write_spending(struct kvm_vcpu *vcpu,
> {
> u32 intid = VGIC_ADDR_TO_INTID(addr, 1);
> int i;
> + unsigned long flags;
>
> 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);
> + spin_lock_irqsave(&irq->irq_lock, flags);
> irq->pending_latch = true;
>
> - vgic_queue_irq_unlock(vcpu->kvm, irq);
> + vgic_queue_irq_unlock(vcpu->kvm, irq, flags);
> vgic_put_irq(vcpu->kvm, irq);
> }
> }
> @@ -144,15 +147,16 @@ void vgic_mmio_write_cpending(struct kvm_vcpu *vcpu,
> {
> u32 intid = VGIC_ADDR_TO_INTID(addr, 1);
> int i;
> + unsigned long flags;
>
> 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);
> + spin_lock_irqsave(&irq->irq_lock, flags);
>
> irq->pending_latch = false;
>
> - spin_unlock(&irq->irq_lock);
> + spin_unlock_irqrestore(&irq->irq_lock, flags);
> vgic_put_irq(vcpu->kvm, irq);
> }
> }
> @@ -181,7 +185,8 @@ static void vgic_mmio_change_active(struct kvm_vcpu *vcpu, struct vgic_irq *irq,
> bool new_active_state)
> {
> struct kvm_vcpu *requester_vcpu;
> - spin_lock(&irq->irq_lock);
> + unsigned long flags;
> + spin_lock_irqsave(&irq->irq_lock, flags);
>
> /*
> * The vcpu parameter here can mean multiple things depending on how
> @@ -216,9 +221,9 @@ static void vgic_mmio_change_active(struct kvm_vcpu *vcpu, struct vgic_irq *irq,
>
> irq->active = new_active_state;
> if (new_active_state)
> - vgic_queue_irq_unlock(vcpu->kvm, irq);
> + vgic_queue_irq_unlock(vcpu->kvm, irq, flags);
> else
> - spin_unlock(&irq->irq_lock);
> + spin_unlock_irqrestore(&irq->irq_lock, flags);
> }
>
> /*
> @@ -352,14 +357,15 @@ void vgic_mmio_write_priority(struct kvm_vcpu *vcpu,
> {
> u32 intid = VGIC_ADDR_TO_INTID(addr, 8);
> int i;
> + unsigned long flags;
>
> for (i = 0; i < len; i++) {
> struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
>
> - spin_lock(&irq->irq_lock);
> + 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);
> - spin_unlock(&irq->irq_lock);
> + spin_unlock_irqrestore(&irq->irq_lock, flags);
>
> vgic_put_irq(vcpu->kvm, irq);
> }
> @@ -390,6 +396,7 @@ void vgic_mmio_write_config(struct kvm_vcpu *vcpu,
> {
> u32 intid = VGIC_ADDR_TO_INTID(addr, 2);
> int i;
> + unsigned long flags;
>
> for (i = 0; i < len * 4; i++) {
> struct vgic_irq *irq;
> @@ -404,14 +411,14 @@ void vgic_mmio_write_config(struct kvm_vcpu *vcpu,
> continue;
>
> irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
> - spin_lock(&irq->irq_lock);
> + spin_lock_irqsave(&irq->irq_lock, flags);
>
> if (test_bit(i * 2 + 1, &val))
> irq->config = VGIC_CONFIG_EDGE;
> else
> irq->config = VGIC_CONFIG_LEVEL;
>
> - spin_unlock(&irq->irq_lock);
> + spin_unlock_irqrestore(&irq->irq_lock, flags);
> vgic_put_irq(vcpu->kvm, irq);
> }
> }
> @@ -443,6 +450,7 @@ void vgic_write_irq_line_level_info(struct kvm_vcpu *vcpu, u32 intid,
> {
> int i;
> int nr_irqs = vcpu->kvm->arch.vgic.nr_spis + VGIC_NR_PRIVATE_IRQS;
> + unsigned long flags;
>
> for (i = 0; i < 32; i++) {
> struct vgic_irq *irq;
> @@ -459,12 +467,12 @@ void vgic_write_irq_line_level_info(struct kvm_vcpu *vcpu, u32 intid,
> * restore irq config before line level.
> */
> new_level = !!(val & (1U << i));
> - spin_lock(&irq->irq_lock);
> + spin_lock_irqsave(&irq->irq_lock, flags);
> irq->line_level = new_level;
> if (new_level)
> - vgic_queue_irq_unlock(vcpu->kvm, irq);
> + vgic_queue_irq_unlock(vcpu->kvm, irq, flags);
> else
> - spin_unlock(&irq->irq_lock);
> + spin_unlock_irqrestore(&irq->irq_lock, flags);
>
> vgic_put_irq(vcpu->kvm, irq);
> }
> diff --git a/virt/kvm/arm/vgic/vgic-v2.c b/virt/kvm/arm/vgic/vgic-v2.c
> index e4187e5..8089710 100644
> --- a/virt/kvm/arm/vgic/vgic-v2.c
> +++ b/virt/kvm/arm/vgic/vgic-v2.c
> @@ -62,6 +62,7 @@ void vgic_v2_fold_lr_state(struct kvm_vcpu *vcpu)
> struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
> struct vgic_v2_cpu_if *cpuif = &vgic_cpu->vgic_v2;
> int lr;
> + unsigned long flags;
>
> cpuif->vgic_hcr &= ~GICH_HCR_UIE;
>
> @@ -77,7 +78,7 @@ void vgic_v2_fold_lr_state(struct kvm_vcpu *vcpu)
>
> irq = vgic_get_irq(vcpu->kvm, vcpu, intid);
>
> - spin_lock(&irq->irq_lock);
> + spin_lock_irqsave(&irq->irq_lock, flags);
>
> /* Always preserve the active bit */
> irq->active = !!(val & GICH_LR_ACTIVE_BIT);
> @@ -104,7 +105,7 @@ void vgic_v2_fold_lr_state(struct kvm_vcpu *vcpu)
> irq->pending_latch = false;
> }
>
> - spin_unlock(&irq->irq_lock);
> + spin_unlock_irqrestore(&irq->irq_lock, flags);
> vgic_put_irq(vcpu->kvm, irq);
> }
>
> diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
> index 96ea597..863351c 100644
> --- a/virt/kvm/arm/vgic/vgic-v3.c
> +++ b/virt/kvm/arm/vgic/vgic-v3.c
> @@ -44,6 +44,7 @@ void vgic_v3_fold_lr_state(struct kvm_vcpu *vcpu)
> struct vgic_v3_cpu_if *cpuif = &vgic_cpu->vgic_v3;
> u32 model = vcpu->kvm->arch.vgic.vgic_model;
> int lr;
> + unsigned long flags;
>
> cpuif->vgic_hcr &= ~ICH_HCR_UIE;
>
> @@ -66,7 +67,7 @@ void vgic_v3_fold_lr_state(struct kvm_vcpu *vcpu)
> if (!irq) /* An LPI could have been unmapped. */
> continue;
>
> - spin_lock(&irq->irq_lock);
> + spin_lock_irqsave(&irq->irq_lock, flags);
>
> /* Always preserve the active bit */
> irq->active = !!(val & ICH_LR_ACTIVE_BIT);
> @@ -94,7 +95,7 @@ void vgic_v3_fold_lr_state(struct kvm_vcpu *vcpu)
> irq->pending_latch = false;
> }
>
> - spin_unlock(&irq->irq_lock);
> + spin_unlock_irqrestore(&irq->irq_lock, flags);
> vgic_put_irq(vcpu->kvm, irq);
> }
>
> @@ -278,6 +279,7 @@ int vgic_v3_lpi_sync_pending_status(struct kvm *kvm, struct vgic_irq *irq)
> bool status;
> u8 val;
> int ret;
> + unsigned long flags;
>
> retry:
> vcpu = irq->target_vcpu;
> @@ -296,13 +298,13 @@ int vgic_v3_lpi_sync_pending_status(struct kvm *kvm, struct vgic_irq *irq)
>
> status = val & (1 << bit_nr);
>
> - spin_lock(&irq->irq_lock);
> + spin_lock_irqsave(&irq->irq_lock, flags);
> if (irq->target_vcpu != vcpu) {
> - spin_unlock(&irq->irq_lock);
> + spin_unlock_irqrestore(&irq->irq_lock, flags);
> goto retry;
> }
> irq->pending_latch = status;
> - vgic_queue_irq_unlock(vcpu->kvm, irq);
> + vgic_queue_irq_unlock(vcpu->kvm, irq, flags);
>
> if (status) {
> /* clear consumed data */
> diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c
> index e1f7dbc..b1bd238 100644
> --- a/virt/kvm/arm/vgic/vgic.c
> +++ b/virt/kvm/arm/vgic/vgic.c
> @@ -53,6 +53,10 @@ struct vgic_global kvm_vgic_global_state __ro_after_init = {
> * vcpuX->vcpu_id < vcpuY->vcpu_id:
> * spin_lock(vcpuX->arch.vgic_cpu.ap_list_lock);
> * spin_lock(vcpuY->arch.vgic_cpu.ap_list_lock);
> + *
> + * Since the VGIC must support injecting virtual interrupts from ISRs, we have
> + * to use the spin_lock_irqsave/spin_unlock_irqrestore versions of outer
> + * spinlocks for any lock that may be taken while injecting an interrupt.
> */
>
> /*
> @@ -261,7 +265,8 @@ static bool vgic_validate_injection(struct vgic_irq *irq, bool level, void *owne
> * Needs to be entered with the IRQ lock already held, but will return
> * with all locks dropped.
> */
> -bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq)
> +bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq,
> + unsigned long flags)
> {
> struct kvm_vcpu *vcpu;
>
> @@ -279,7 +284,7 @@ bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq)
> * not need to be inserted into an ap_list and there is also
> * no more work for us to do.
> */
> - spin_unlock(&irq->irq_lock);
> + spin_unlock_irqrestore(&irq->irq_lock, flags);
>
> /*
> * We have to kick the VCPU here, because we could be
> @@ -301,11 +306,11 @@ bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq)
> * We must unlock the irq lock to take the ap_list_lock where
> * we are going to insert this new pending interrupt.
> */
> - spin_unlock(&irq->irq_lock);
> + spin_unlock_irqrestore(&irq->irq_lock, flags);
>
> /* someone can do stuff here, which we re-check below */
>
> - spin_lock(&vcpu->arch.vgic_cpu.ap_list_lock);
> + spin_lock_irqsave(&vcpu->arch.vgic_cpu.ap_list_lock, flags);
> spin_lock(&irq->irq_lock);
>
> /*
> @@ -322,9 +327,9 @@ bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq)
>
> if (unlikely(irq->vcpu || vcpu != vgic_target_oracle(irq))) {
> spin_unlock(&irq->irq_lock);
> - spin_unlock(&vcpu->arch.vgic_cpu.ap_list_lock);
> + spin_unlock_irqrestore(&vcpu->arch.vgic_cpu.ap_list_lock, flags);
>
> - spin_lock(&irq->irq_lock);
> + spin_lock_irqsave(&irq->irq_lock, flags);
> goto retry;
> }
>
> @@ -337,7 +342,7 @@ bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq)
> irq->vcpu = vcpu;
>
> spin_unlock(&irq->irq_lock);
> - spin_unlock(&vcpu->arch.vgic_cpu.ap_list_lock);
> + spin_unlock_irqrestore(&vcpu->arch.vgic_cpu.ap_list_lock, flags);
>
> kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
> kvm_vcpu_kick(vcpu);
> @@ -367,6 +372,7 @@ int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid,
> {
> struct kvm_vcpu *vcpu;
> struct vgic_irq *irq;
> + unsigned long flags;
> int ret;
>
> trace_vgic_update_irq_pending(cpuid, intid, level);
> @@ -383,11 +389,11 @@ int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid,
> if (!irq)
> return -EINVAL;
>
> - spin_lock(&irq->irq_lock);
> + spin_lock_irqsave(&irq->irq_lock, flags);
>
> if (!vgic_validate_injection(irq, level, owner)) {
> /* Nothing to see here, move along... */
> - spin_unlock(&irq->irq_lock);
> + spin_unlock_irqrestore(&irq->irq_lock, flags);
> vgic_put_irq(kvm, irq);
> return 0;
> }
> @@ -397,7 +403,7 @@ int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid,
> else
> irq->pending_latch = true;
>
> - vgic_queue_irq_unlock(kvm, irq);
> + vgic_queue_irq_unlock(kvm, irq, flags);
> vgic_put_irq(kvm, irq);
>
> return 0;
> @@ -406,15 +412,16 @@ int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid,
> int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, u32 virt_irq, u32 phys_irq)
> {
> struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, virt_irq);
> + unsigned long flags;
>
> BUG_ON(!irq);
>
> - spin_lock(&irq->irq_lock);
> + spin_lock_irqsave(&irq->irq_lock, flags);
>
> irq->hw = true;
> irq->hwintid = phys_irq;
>
> - spin_unlock(&irq->irq_lock);
> + spin_unlock_irqrestore(&irq->irq_lock, flags);
> vgic_put_irq(vcpu->kvm, irq);
>
> return 0;
> @@ -423,6 +430,7 @@ int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, u32 virt_irq, u32 phys_irq)
> int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int virt_irq)
> {
> struct vgic_irq *irq;
> + unsigned long flags;
>
> if (!vgic_initialized(vcpu->kvm))
> return -EAGAIN;
> @@ -430,12 +438,12 @@ int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int virt_irq)
> irq = vgic_get_irq(vcpu->kvm, vcpu, virt_irq);
> BUG_ON(!irq);
>
> - spin_lock(&irq->irq_lock);
> + spin_lock_irqsave(&irq->irq_lock, flags);
>
> irq->hw = false;
> irq->hwintid = 0;
>
> - spin_unlock(&irq->irq_lock);
> + spin_unlock_irqrestore(&irq->irq_lock, flags);
> vgic_put_irq(vcpu->kvm, irq);
>
> return 0;
> @@ -486,9 +494,10 @@ static void vgic_prune_ap_list(struct kvm_vcpu *vcpu)
> {
> struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
> struct vgic_irq *irq, *tmp;
> + unsigned long flags;
>
> retry:
> - spin_lock(&vgic_cpu->ap_list_lock);
> + spin_lock_irqsave(&vgic_cpu->ap_list_lock, flags);
>
> list_for_each_entry_safe(irq, tmp, &vgic_cpu->ap_list_head, ap_list) {
> struct kvm_vcpu *target_vcpu, *vcpuA, *vcpuB;
> @@ -528,7 +537,7 @@ static void vgic_prune_ap_list(struct kvm_vcpu *vcpu)
> /* This interrupt looks like it has to be migrated. */
>
> spin_unlock(&irq->irq_lock);
> - spin_unlock(&vgic_cpu->ap_list_lock);
> + spin_unlock_irqrestore(&vgic_cpu->ap_list_lock, flags);
>
> /*
> * Ensure locking order by always locking the smallest
> @@ -542,7 +551,7 @@ static void vgic_prune_ap_list(struct kvm_vcpu *vcpu)
> vcpuB = vcpu;
> }
>
> - spin_lock(&vcpuA->arch.vgic_cpu.ap_list_lock);
> + spin_lock_irqsave(&vcpuA->arch.vgic_cpu.ap_list_lock, flags);
> spin_lock_nested(&vcpuB->arch.vgic_cpu.ap_list_lock,
> SINGLE_DEPTH_NESTING);
> spin_lock(&irq->irq_lock);
> @@ -566,11 +575,11 @@ static void vgic_prune_ap_list(struct kvm_vcpu *vcpu)
>
> spin_unlock(&irq->irq_lock);
> spin_unlock(&vcpuB->arch.vgic_cpu.ap_list_lock);
> - spin_unlock(&vcpuA->arch.vgic_cpu.ap_list_lock);
> + spin_unlock_irqrestore(&vcpuA->arch.vgic_cpu.ap_list_lock, flags);
> goto retry;
> }
>
> - spin_unlock(&vgic_cpu->ap_list_lock);
> + spin_unlock_irqrestore(&vgic_cpu->ap_list_lock, flags);
> }
>
> static inline void vgic_fold_lr_state(struct kvm_vcpu *vcpu)
> @@ -703,6 +712,8 @@ void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu)
> if (list_empty(&vcpu->arch.vgic_cpu.ap_list_head))
> return;
>
> + DEBUG_SPINLOCK_BUG_ON(!irqs_disabled());
> +
> spin_lock(&vcpu->arch.vgic_cpu.ap_list_lock);
> vgic_flush_lr_state(vcpu);
> spin_unlock(&vcpu->arch.vgic_cpu.ap_list_lock);
> @@ -735,11 +746,12 @@ int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu)
> struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
> struct vgic_irq *irq;
> bool pending = false;
> + unsigned long flags;
>
> if (!vcpu->kvm->arch.vgic.enabled)
> return false;
>
> - spin_lock(&vgic_cpu->ap_list_lock);
> + spin_lock_irqsave(&vgic_cpu->ap_list_lock, flags);
>
> list_for_each_entry(irq, &vgic_cpu->ap_list_head, ap_list) {
> spin_lock(&irq->irq_lock);
> @@ -750,7 +762,7 @@ int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu)
> break;
> }
>
> - spin_unlock(&vgic_cpu->ap_list_lock);
> + spin_unlock_irqrestore(&vgic_cpu->ap_list_lock, flags);
>
> return pending;
> }
> @@ -776,13 +788,15 @@ bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, unsigned int virt_irq)
> {
> struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, virt_irq);
> bool map_is_active;
> + unsigned long flags;
>
> if (!vgic_initialized(vcpu->kvm))
> return false;
> + DEBUG_SPINLOCK_BUG_ON(!irqs_disabled());
>
> - spin_lock(&irq->irq_lock);
> + spin_lock_irqsave(&irq->irq_lock, flags);

I'm a bit puzzled by this sequence: Either interrupts are disabled and
we don't need the irqsave version, or they aren't and the BUG_ON will
fire. kvm_vgic_map_is_active is called (indirectly) from
kvm_timer_flush_hwstate. And at this stage of the patches, we definitely
call this function with interrupts enabled.

Is it just a patch splitting snafu? Or something more serious? Same goes
for the DEBUG_SPINLOCK_BUG_ON in kvm_vgic_flush_hwstate.

> map_is_active = irq->hw && irq->active;
> - spin_unlock(&irq->irq_lock);
> + spin_unlock_irqrestore(&irq->irq_lock, flags);
> vgic_put_irq(vcpu->kvm, irq);
>
> return map_is_active;
> diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
> index bf9ceab..4f8aecb 100644
> --- a/virt/kvm/arm/vgic/vgic.h
> +++ b/virt/kvm/arm/vgic/vgic.h
> @@ -140,7 +140,8 @@ vgic_get_mmio_region(struct kvm_vcpu *vcpu, struct vgic_io_device *iodev,
> struct vgic_irq *vgic_get_irq(struct kvm *kvm, struct kvm_vcpu *vcpu,
> u32 intid);
> void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq);
> -bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq);
> +bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq,
> + unsigned long flags);
> void vgic_kick_vcpus(struct kvm *kvm);
>
> int vgic_check_ioaddr(struct kvm *kvm, phys_addr_t *ioaddr,
>

Otherwise looks good to me.

M.
--
Jazz is not dead. It just smells funny...