Commit b1fe7f2c authored by Peter Zijlstra's avatar Peter Zijlstra
Browse files

x86,intel_iommu: Replace cmpxchg_double() 



Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarLu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: default avatarArnd Bergmann <arnd@arndb.de>
Reviewed-by: default avatarMark Rutland <mark.rutland@arm.com>
Tested-by: default avatarMark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20230531132323.855976804@infradead.org
parent 0a0a6800

drivers/iommu/intel/irq_remapping.c

+2 −6
Original line number Diff line number Diff line
@@ -175,18 +175,14 @@ static int modify_irte(struct irq_2_iommu *irq_iommu, 
	irte = &iommu->ir_table->base[index];



	if ((irte->pst == 1) || (irte_modified->pst == 1)) {

		bool ret;



		ret = cmpxchg_double(&irte->low, &irte->high,

				     irte->low, irte->high,

				     irte_modified->low, irte_modified->high);

		/*

		 * We use cmpxchg16 to atomically update the 128-bit IRTE,

		 * and it cannot be updated by the hardware or other processors

		 * behind us, so the return value of cmpxchg16 should be the

		 * same as the old value.

		 */

		WARN_ON(!ret);

		u128 old = irte->irte;

		WARN_ON(!try_cmpxchg128(&irte->irte, &old, irte_modified->irte));

	} else {

		WRITE_ONCE(irte->low, irte_modified->low);

		WRITE_ONCE(irte->high, irte_modified->high);

include/linux/dmar.h

+66 −59
Original line number Diff line number Diff line
@@ -201,6 +201,8 @@ static inline void detect_intel_iommu(void) 
#endif /* CONFIG_DMAR_TABLE */



struct irte {

	union {

		struct {

			union {

				/* Shared between remapped and posted mode*/

				struct {
@@ -265,6 +267,11 @@ struct irte { 
				__u64 high;

			};

		};

#ifdef CONFIG_IRQ_REMAP

		__u128 irte;

#endif

	};

};



static inline void dmar_copy_shared_irte(struct irte *dst, struct irte *src)

{