[PATCH V2 3/4] irqchip/riscv-imsic: Move nr_guest_files to per-HART local config

guoren
2026-04-25T00:59:55Z

With the recent KVM AIA per-HART HGEI conversion, the global
nr_guest_files is no longer appropriate. Different HARTs in
heterogeneous SoCs may have different numbers of guest interrupt
files.

Move `nr_guest_files` from `struct imsic_global_config` to
`struct imsic_local_config`, and compute it per-CPU in
imsic_setup_state() based on the actual MMIO guest file region size.

Update the related comment to reflect that KVM now uses the
per-HART value.

This eliminates the last global assumption about guest files and
completes the per-HART conversion series for RISC-V AIA/IMSIC.

Signed-off-by: Guo Ren (Alibaba DAMO Academy) <guoren@kernel.org>
---
drivers/irqchip/irq-riscv-imsic-state.c | 10 ++++++----
include/linux/irqchip/riscv-imsic.h | 6 +++---
2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/irqchip/irq-riscv-imsic-state.c b/drivers/irqchip/irq-riscv-imsic-state.c
index e3ed874d89e7..f01525362cf7 100644
--- a/drivers/irqchip/irq-riscv-imsic-state.c
+++ b/drivers/irqchip/irq-riscv-imsic-state.c
@@ -878,7 +878,6 @@ 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) {
@@ -910,23 +909,26 @@ int __init imsic_setup_state(struct fwnode_handle *fwnode, void *opaque)
reloff -= ALIGN(resource_size(&mmios[j]),
BIT(global->guest_index_bits) * IMSIC_MMIO_PAGE_SZ);
}
+
+ local = per_cpu_ptr(global->local, cpu);
+ local->nr_guest_files = BIT(global->guest_index_bits) - 1;
+
if (index >= nr_mmios) {
pr_warn("%pfwP: MMIO not found for parent irq%d\n", fwnode, i);
continue;
}

- local = per_cpu_ptr(global->local, cpu);
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
+ * KVM uses local->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);
+ local->nr_guest_files = min(local->nr_guest_files, nr_guest_files);

nr_handlers++;
}
diff --git a/include/linux/irqchip/riscv-imsic.h b/include/linux/irqchip/riscv-imsic.h
index 4b348836de7a..13e8bd7ff4b4 100644
--- a/include/linux/irqchip/riscv-imsic.h
+++ b/include/linux/irqchip/riscv-imsic.h
@@ -40,6 +40,9 @@
struct imsic_local_config {
phys_addr_t msi_pa;
void __iomem *msi_va;
+
+ /* Number of guest interrupt files per core */
+ u32 nr_guest_files;
};

struct imsic_global_config {
@@ -68,9 +71,6 @@ struct imsic_global_config {
/* Number of guest interrupt identities */
u32 nr_guest_ids;

- /* Number of guest interrupt files per core */
- u32 nr_guest_files;
-
/* Per-CPU IMSIC addresses */
struct imsic_local_config __percpu *local;
};
--
2.43.0