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irqchip/riscv-imsic: Adjust the number of available guest irq files

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Currently, KVM assumes the minimum of implemented HGEIE bits and
"BIT(gc->guest_index_bits) - 1" as the number of guest files available
across all CPUs. This will not work when CPUs have different number
of guest files because KVM may incorrectly allocate a guest file on a
CPU with fewer guest files.

To address above, during initialization, calculate the number of
available guest interrupt files according to MMIO resources and
constrain the number of guest interrupt files that can be allocated
by KVM.

Signed-off-by: Xu Lu <luxu.kernel@bytedance.com>
Reviewed-by: Nutty Liu <nutty.liu@hotmail.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Acked-by: Thomas Gleixner <tglx@kernel.org>
Link: https://lore.kernel.org/r/20260104133457.57742-1-luxu.kernel@bytedance.com
Signed-off-by: Anup Patel <anup@brainfault.org>
This commit is contained in:
Xu Lu
2026-01-04 21:34:57 +08:00
committed by Anup Patel
parent ed7ae7a34b
commit 376e2f8cca
3 changed files with 15 additions and 2 deletions
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12
drivers/irqchip/irq-riscv-imsic-state.c
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@@ -784,7 +784,7 @@ static int __init imsic_parse_fwnode(struct fwnode_handle *fwnode,
int __init imsic_setup_state(struct fwnode_handle *fwnode, void *opaque)
{
u32 i, j, index, nr_parent_irqs, nr_mmios, nr_handlers = 0;
u32 i, j, index, nr_parent_irqs, nr_mmios, nr_guest_files, nr_handlers = 0;
struct imsic_global_config *global;
struct imsic_local_config *local;
void __iomem **mmios_va = NULL;
@@ -878,6 +878,7 @@ int __init imsic_setup_state(struct fwnode_handle *fwnode, void *opaque)
}
/* Configure handlers for target CPUs */
global->nr_guest_files = BIT(global->guest_index_bits) - 1;
for (i = 0; i < nr_parent_irqs; i++) {
rc = imsic_get_parent_hartid(fwnode, i, &hartid);
if (rc) {
@@ -918,6 +919,15 @@ int __init imsic_setup_state(struct fwnode_handle *fwnode, void *opaque)
local->msi_pa = mmios[index].start + reloff;
local->msi_va = mmios_va[index] + reloff;
/*
* KVM uses global->nr_guest_files to determine the available guest
* interrupt files on each CPU. Take the minimum number of guest
* interrupt files across all CPUs to avoid KVM incorrectly allocating
* an unexisted or unmapped guest interrupt file on some CPUs.
*/
nr_guest_files = (resource_size(&mmios[index]) - reloff) / IMSIC_MMIO_PAGE_SZ - 1;
global->nr_guest_files = min(global->nr_guest_files, nr_guest_files);
nr_handlers++;
}