[PATCH 6.6 215/254] irqchip/gic-v3-its: Avoid truncating memory addresses

Greg Kroah-Hartman
2026-01-28T15:40:07Z

From: Arnd Bergmann <arnd@arndb.de>

commit 8d76a7d89c12d08382b66e2f21f20d0627d14859 upstream.

On 32-bit machines with CONFIG_ARM_LPAE, it is possible for lowmem
allocations to be backed by addresses physical memory above the 32-bit
address limit, as found while experimenting with larger VMSPLIT
configurations.

This caused the qemu virt model to crash in the GICv3 driver, which
allocates the 'itt' object using GFP_KERNEL. Since all memory below
the 4GB physical address limit is in ZONE_DMA in this configuration,
kmalloc() defaults to higher addresses for ZONE_NORMAL, and the
ITS driver stores the physical address in a 32-bit 'unsigned long'
variable.

Change the itt_addr variable to the correct phys_addr_t type instead,
along with all other variables in this driver that hold a physical
address.

The gicv5 driver correctly uses u64 variables, while all other irqchip
drivers don't call virt_to_phys or similar interfaces. It's expected that
other device drivers have similar issues, but fixing this one is
sufficient for booting a virtio based guest.

Fixes: cc2d3216f53c ("irqchip: GICv3: ITS command queue")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260119201603.2713066-1-arnd@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/irqchip/irq-gic-v3-its.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -616,7 +616,7 @@ static struct its_collection *its_build_
struct its_cmd_block *cmd,
struct its_cmd_desc *desc)
{
- unsigned long itt_addr;
+ phys_addr_t itt_addr;
u8 size = ilog2(desc->its_mapd_cmd.dev->nr_ites);

itt_addr = virt_to_phys(desc->its_mapd_cmd.dev->itt);
@@ -787,7 +787,7 @@ static struct its_vpe *its_build_vmapp_c
struct its_cmd_desc *desc)
{
struct its_vpe *vpe = valid_vpe(its, desc->its_vmapp_cmd.vpe);
- unsigned long vpt_addr, vconf_addr;
+ phys_addr_t vpt_addr, vconf_addr;
u64 target;
bool alloc;

@@ -2404,10 +2404,10 @@ retry_baser:
baser->psz = psz;
tmp = indirect ? GITS_LVL1_ENTRY_SIZE : esz;

- pr_info("ITS@%pa: allocated %d %s @%lx (%s, esz %d, psz %dK, shr %d)\n",
+ pr_info("ITS@%pa: allocated %d %s @%llx (%s, esz %d, psz %dK, shr %d)\n",
&its->phys_base, (int)(PAGE_ORDER_TO_SIZE(order) / (int)tmp),
its_base_type_string[type],
- (unsigned long)virt_to_phys(base),
+ (u64)virt_to_phys(base),
indirect ? "indirect" : "flat", (int)esz,
psz / SZ_1K, (int)shr >> GITS_BASER_SHAREABILITY_SHIFT);