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Message-ID: <4a8fd699-7690-9056-d0b0-3e4c30778e69@arm.com>
Date: Fri, 23 Mar 2018 19:32:41 +0000
From: Marc Zyngier <marc.zyngier@....com>
To: Peng Hao <peng.hao2@....com.cn>, cdall@...nel.org
Cc: linux-kernel@...r.kernel.org, kvmarm@...ts.cs.columbia.edu,
linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v3] KVM: arm/arm64 : add lpi info in vgic-debug
On 24/03/18 00:42, Peng Hao wrote:
> Add lpi debug info to vgic-stat.
> The printed info like this:
> SPI 287 0 000001 0 0 0 160 -1
> LPI 8192 2 000100 0 0 0 160 -1
>
> Signed-off-by: Peng Hao <peng.hao2@....com.cn>
> ---
> virt/kvm/arm/vgic/vgic-debug.c | 59 ++++++++++++++++++++++++++++++++++++++----
> virt/kvm/arm/vgic/vgic-its.c | 16 ++++++------
> virt/kvm/arm/vgic/vgic.h | 1 +
> 3 files changed, 63 insertions(+), 13 deletions(-)
>
> diff --git a/virt/kvm/arm/vgic/vgic-debug.c b/virt/kvm/arm/vgic/vgic-debug.c
> index 10b3817..ddac6bd 100644
> --- a/virt/kvm/arm/vgic/vgic-debug.c
> +++ b/virt/kvm/arm/vgic/vgic-debug.c
> @@ -36,9 +36,12 @@
> struct vgic_state_iter {
> int nr_cpus;
> int nr_spis;
> + int nr_lpis;
> int dist_id;
> int vcpu_id;
> int intid;
> + int lpi_print_count;
> + struct vgic_irq **lpi_irqs;
> };
>
> static void iter_next(struct vgic_state_iter *iter)
> @@ -52,6 +55,39 @@ static void iter_next(struct vgic_state_iter *iter)
> if (iter->intid == VGIC_NR_PRIVATE_IRQS &&
> ++iter->vcpu_id < iter->nr_cpus)
> iter->intid = 0;
> +
> + if (iter->intid >= VGIC_NR_PRIVATE_IRQS + iter->nr_spis) {
> + if (iter->lpi_print_count < iter->nr_lpis)
> + iter->intid = iter->lpi_irqs[iter->lpi_print_count]->intid;
> + iter->lpi_print_count++;
> + }
> +}
> +
> +static void vgic_debug_get_lpis(struct kvm *kvm, struct vgic_state_iter *iter)
> +{
> + u32 *intids;
> + int i, irq_count;
> + struct vgic_irq *irq = NULL, **lpi_irqs;
> +
> + iter->nr_lpis = 0;
> + irq_count = vgic_copy_lpi_list(kvm, NULL, &intids);
> + if (irq_count < 0)
> + return;
> +
> + lpi_irqs = kmalloc_array(irq_count, sizeof(irq), GFP_KERNEL);
> + if (!lpi_irqs) {
> + kfree(intids);
> + return;
> + }
> +
> + for (i = 0; i < irq_count; i++) {
> + irq = vgic_get_irq(kvm, NULL, intids[i]);
> + if (!irq)
> + continue;
> + lpi_irqs[iter->nr_lpis++] = irq;
> + }
> + iter->lpi_irqs = lpi_irqs;
> + kfree(intids);
You are still completely missing the point. Why are you allocating this
array of pointers while you have a perfectly sensible array of intids,
allowing you do treat all the irqs uniformly?
> }
>
> static void iter_init(struct kvm *kvm, struct vgic_state_iter *iter,
> @@ -64,6 +100,8 @@ static void iter_init(struct kvm *kvm, struct vgic_state_iter *iter,
> iter->nr_cpus = nr_cpus;
> iter->nr_spis = kvm->arch.vgic.nr_spis;
>
> + if (vgic_supports_direct_msis(kvm) && !pos)
> + vgic_debug_get_lpis(kvm, iter);
Again: What is the point of this?
> /* Fast forward to the right position if needed */
> while (pos--)
> iter_next(iter);
> @@ -73,7 +111,9 @@ static bool end_of_vgic(struct vgic_state_iter *iter)
> {
> return iter->dist_id > 0 &&
> iter->vcpu_id == iter->nr_cpus &&
> - (iter->intid - VGIC_NR_PRIVATE_IRQS) == iter->nr_spis;
> + (iter->intid - VGIC_NR_PRIVATE_IRQS) >= iter->nr_spis &&
> + ((iter->nr_lpis == 0) ||
> + (iter->lpi_print_count == iter->nr_lpis + 1));
> }
>
> static void *vgic_debug_start(struct seq_file *s, loff_t *pos)
> @@ -130,6 +170,7 @@ static void vgic_debug_stop(struct seq_file *s, void *v)
>
> mutex_lock(&kvm->lock);
> iter = kvm->arch.vgic.iter;
> + kfree(iter->lpi_irqs);
> kfree(iter);
> kvm->arch.vgic.iter = NULL;
> mutex_unlock(&kvm->lock);
> @@ -154,7 +195,7 @@ static void print_header(struct seq_file *s, struct vgic_irq *irq,
> struct kvm_vcpu *vcpu)
> {
> int id = 0;
> - char *hdr = "SPI ";
> + char *hdr = "Global";
>
> if (vcpu) {
> hdr = "VCPU";
> @@ -162,7 +203,10 @@ static void print_header(struct seq_file *s, struct vgic_irq *irq,
> }
>
> seq_printf(s, "\n");
> - seq_printf(s, "%s%2d TYP ID TGT_ID PLAEHC HWID TARGET SRC PRI VCPU_ID\n", hdr, id);
> + if (vcpu)
> + seq_printf(s, "%s%2d TYP ID TGT_ID PLAEHC HWID TARGET SRC PRI VCPU_ID\n", hdr, id);
> + else
> + seq_printf(s, "%s TYP ID TGT_ID PLAEHC HWID TARGET SRC PRI VCPU_ID\n", hdr);
> seq_printf(s, "---------------------------------------------------------------\n");
> }
>
> @@ -174,8 +218,10 @@ static void print_irq_state(struct seq_file *s, struct vgic_irq *irq,
> type = "SGI";
> else if (irq->intid < VGIC_NR_PRIVATE_IRQS)
> type = "PPI";
> - else
> + else if (irq->intid < VGIC_MAX_SPI)
> type = "SPI";
> + else if (irq->intid >= VGIC_MIN_LPI)
> + type = "LPI";
>
> if (irq->intid ==0 || irq->intid == VGIC_NR_PRIVATE_IRQS)
> print_header(s, irq, vcpu);
> @@ -220,7 +266,9 @@ static int vgic_debug_show(struct seq_file *s, void *v)
> if (!kvm->arch.vgic.initialized)
> return 0;
>
> - if (iter->vcpu_id < iter->nr_cpus) {
> + if (iter->intid >= VGIC_MIN_LPI)
> + irq = iter->lpi_irqs[iter->lpi_print_count - 1];
> + else if (iter->vcpu_id < iter->nr_cpus) {
> vcpu = kvm_get_vcpu(kvm, iter->vcpu_id);
> irq = &vcpu->arch.vgic_cpu.private_irqs[iter->intid];
> } else {
> @@ -230,6 +278,7 @@ static int vgic_debug_show(struct seq_file *s, void *v)
> spin_lock(&irq->irq_lock);
> print_irq_state(s, irq, vcpu);
> spin_unlock(&irq->irq_lock);
> + vgic_put_irq(kvm, irq);
Doesn't it shock you that you're doing a "put" on something you haven't
done a "get" on?
[...]
Here's what I mean[1]. No double allocation, uniform access to the irq
pointer, no imbalance in reference management.
M.
[1]
https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git/commit/?h=kvm-arm64/vgic-debug&id=7ab86b67167698d30a93b9f5079eb9f48f885bf6
--
Jazz is not dead. It just smells funny...
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