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KVM: arm64: vgic-debug: Exit the iterator properly w/o LPI

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In case the guest doesn't have any LPI, we previously relied on the
iterator setting

	'intid = nr_spis + VGIC_NR_PRIVATE_IRQS' && 'lpi_idx = 1'

to exit the iterator. But it was broken with commit 85d3ccc8b7 ("KVM:
arm64: vgic-debug: Use an xarray mark for debug iterator") -- the intid
remains at 'nr_spis + VGIC_NR_PRIVATE_IRQS - 1', and we end up endlessly
printing the last SPI's state.

Consider that it's meaningless to search the LPI xarray and populate
lpi_idx when there is no LPI, let's just skip the process for that case.

The result is that

* If there's no LPI, we focus on the intid and exit the iterator when it
  runs out of the valid SPI range.
* Otherwise we keep the current logic and let the xarray drive the
  iterator.

Fixes: 85d3ccc8b7 ("KVM: arm64: vgic-debug: Use an xarray mark for debug iterator")
Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240807052024.2084-1-yuzenghui@huawei.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
This commit is contained in:
Zenghui Yu
2024-08-07 13:20:24 +08:00
committed by Oliver Upton
parent 10f2ad032d
commit 01ab08cafe
1 changed files with 3 additions and 2 deletions
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arch/arm64/kvm/vgic/vgic-debug.c
+3 -2
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@@ -45,7 +45,8 @@ static void iter_next(struct kvm *kvm, struct vgic_state_iter *iter)
* Let the xarray drive the iterator after the last SPI, as the iterator
* has exhausted the sequentially-allocated INTID space.
*/
if (iter->intid >= (iter->nr_spis + VGIC_NR_PRIVATE_IRQS - 1)) {
if (iter->intid >= (iter->nr_spis + VGIC_NR_PRIVATE_IRQS - 1) &&
iter->nr_lpis) {
if (iter->lpi_idx < iter->nr_lpis)
xa_find_after(&dist->lpi_xa, &iter->intid,
VGIC_LPI_MAX_INTID,
@@ -112,7 +113,7 @@ static bool end_of_vgic(struct vgic_state_iter *iter)
return iter->dist_id > 0 &&
iter->vcpu_id == iter->nr_cpus &&
iter->intid >= (iter->nr_spis + VGIC_NR_PRIVATE_IRQS) &&
iter->lpi_idx > iter->nr_lpis;
(!iter->nr_lpis || iter->lpi_idx > iter->nr_lpis);
}
static void *vgic_debug_start(struct seq_file *s, loff_t *pos)