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

[guoren@kernel.org]

From: "Guo Ren (Alibaba DAMO Academy)" <guoren@kernel.org>

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