[PATCH v3 1/2] irqchip/riscv-imsic: Add nr_guest_files in per-HART local config

[Anup Patel]

From: "Guo Ren (Alibaba DAMO Academy)" <guoren@xxxxxxxxxx>

Add nr_guest_files in per-HART local config to represent the number of
guest files available on a particular HART whereas the nr_guest_files
in the global config represents the number of guest files available
across all HARTs.

This allows KVM RISC-V to use nr_guest_files from per-HART local
config for asymmetric big.Little systems.

Signed-off-by: Guo Ren (Alibaba DAMO Academy) <guoren@xxxxxxxxxx>
Acked-by: Thomas Gleixner <tglx@xxxxxxxxxx>
Signed-off-by: Anup Patel <anup.patel@xxxxxxxxxxxxxxxx>
---
 drivers/irqchip/irq-riscv-imsic-state.c | 9 ++++-----
 include/linux/irqchip/riscv-imsic.h     | 5 ++++-
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/irqchip/irq-riscv-imsic-state.c b/drivers/irqchip/irq-riscv-imsic-state.c
index e3ed874d89e7..b8d1bbbf42f7 100644
--- a/drivers/irqchip/irq-riscv-imsic-state.c
+++ b/drivers/irqchip/irq-riscv-imsic-state.c
@@ -920,13 +920,12 @@ int __init imsic_setup_state(struct fwnode_handle *fwnode, void *opaque)
 		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.
+		 * KVM uses both local->nr_guest_files and global->nr_guest_files
+		 * to determine the available guest interrupt files on each CPU.
 		 */
 		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((BIT(global->guest_index_bits) - 1), nr_guest_files);
+		global->nr_guest_files = min(global->nr_guest_files, local->nr_guest_files);
 
 		nr_handlers++;
 	}
diff --git a/include/linux/irqchip/riscv-imsic.h b/include/linux/irqchip/riscv-imsic.h
index 4b348836de7a..61af3a5bea09 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-HART */
+	u32					nr_guest_files;
 };
 
 struct imsic_global_config {
@@ -68,7 +71,7 @@ struct imsic_global_config {
 	/* Number of guest interrupt identities */
 	u32					nr_guest_ids;
 
-	/* Number of guest interrupt files per core */
+	/* Number of guest interrupt files across all HARTs */
 	u32					nr_guest_files;
 
 	/* Per-CPU IMSIC addresses */
-- 
2.43.0