its_create_device() over-allocated by ITS_ITT_ALIGN - 1 bytes to ensure
that an aligned area was available within the allocation. The new
genpool allocator has its min_alloc_order set to
get_order(ITS_ITT_ALIGN) so all allocations from it should be
appropriately aligned.

Remove the over-allocation from its_create_device() and alignment from
its_build_mapd_cmd().

Tested-by: Will Deacon <will@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Steven Price <steven.price@arm.com>
---
 drivers/irqchip/irq-gic-v3-its.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 7a62fd3a8673..1d2a952e342d 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -712,7 +712,6 @@ static struct its_collection *its_build_mapd_cmd(struct its_node *its,
 	u8 size = ilog2(desc->its_mapd_cmd.dev->nr_ites);
 
 	itt_addr = virt_to_phys(desc->its_mapd_cmd.dev->itt);
-	itt_addr = ALIGN(itt_addr, ITS_ITT_ALIGN);
 
 	its_encode_cmd(cmd, GITS_CMD_MAPD);
 	its_encode_devid(cmd, desc->its_mapd_cmd.dev->device_id);
@@ -3501,7 +3500,7 @@ static struct its_device *its_create_device(struct its_node *its, u32 dev_id,
 	 */
 	nr_ites = max(2, nvecs);
 	sz = nr_ites * (FIELD_GET(GITS_TYPER_ITT_ENTRY_SIZE, its->typer) + 1);
-	sz = max(sz, ITS_ITT_ALIGN) + ITS_ITT_ALIGN - 1;
+	sz = max(sz, ITS_ITT_ALIGN);
 
 	itt = itt_alloc_pool(its->numa_node, sz);
 
-- 
2.34.1

On Wed, Oct 02, 2024 at 03:16:30PM +0100, Steven Price wrote:
> its_create_device() over-allocated by ITS_ITT_ALIGN - 1 bytes to ensure
> that an aligned area was available within the allocation. The new
> genpool allocator has its min_alloc_order set to
> get_order(ITS_ITT_ALIGN) so all allocations from it should be
> appropriately aligned.
> 
> Remove the over-allocation from its_create_device() and alignment from
> its_build_mapd_cmd().
> 
> Tested-by: Will Deacon <will@kernel.org>
> Reviewed-by: Marc Zyngier <maz@kernel.org>
> Signed-off-by: Steven Price <steven.price@arm.com>

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>

The following commit has been merged into the irq/core branch of tip:

Commit-ID:     e36d4165f0796536b338521ef714551be0feb706
Gitweb:        https://git.kernel.org/tip/e36d4165f0796536b338521ef714551be0feb706
Author:        Steven Price <steven.price@arm.com>
AuthorDate:    Wed, 02 Oct 2024 15:16:30 +01:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Wed, 02 Oct 2024 18:00:41 +02:00

irqchip/gic-v3-its: Rely on genpool alignment

its_create_device() over-allocated by ITS_ITT_ALIGN - 1 bytes to ensure
that an aligned area was available within the allocation. The new genpool
allocator has its min_alloc_order set to get_order(ITS_ITT_ALIGN) so all
allocations from it should be appropriately aligned.

Remove the over-allocation from its_create_device() and alignment from
its_build_mapd_cmd().

Signed-off-by: Steven Price <steven.price@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Will Deacon <will@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/all/20241002141630.433502-3-steven.price@arm.com

---
 drivers/irqchip/irq-gic-v3-its.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 6c1581b..be77f92 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -706,7 +706,6 @@ static struct its_collection *its_build_mapd_cmd(struct its_node *its,
 	u8 size = ilog2(desc->its_mapd_cmd.dev->nr_ites);
 
 	itt_addr = virt_to_phys(desc->its_mapd_cmd.dev->itt);
-	itt_addr = ALIGN(itt_addr, ITS_ITT_ALIGN);
 
 	its_encode_cmd(cmd, GITS_CMD_MAPD);
 	its_encode_devid(cmd, desc->its_mapd_cmd.dev->device_id);
@@ -3488,7 +3487,7 @@ static struct its_device *its_create_device(struct its_node *its, u32 dev_id,
 	 */
 	nr_ites = max(2, nvecs);
 	sz = nr_ites * (FIELD_GET(GITS_TYPER_ITT_ENTRY_SIZE, its->typer) + 1);
-	sz = max(sz, ITS_ITT_ALIGN) + ITS_ITT_ALIGN - 1;
+	sz = max(sz, ITS_ITT_ALIGN);
 
 	itt = itt_alloc_pool(its->numa_node, sz);