Commit 0a0a6800 authored by Peter Zijlstra's avatar Peter Zijlstra
Browse files

x86,amd_iommu: Replace cmpxchg_double() 



Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarArnd Bergmann <arnd@arndb.de>
Reviewed-by: default avatarMark Rutland <mark.rutland@arm.com>
Tested-by: default avatarVasant Hegde <vasant.hegde@amd.com>
Tested-by: default avatarMark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20230531132323.788955257@infradead.org
parent 8664645a

drivers/iommu/amd/amd_iommu_types.h

+7 −2
Original line number Diff line number Diff line
@@ -986,9 +986,14 @@ union irte_ga_hi { 
};



struct irte_ga {

	union {

		struct {

			union irte_ga_lo lo;

			union irte_ga_hi hi;

		};

		u128 irte;

	};

};



struct irq_2_irte {

	u16 devid; /* Device ID for IRTE table */

drivers/iommu/amd/iommu.c

+4 −6
Original line number Diff line number Diff line
@@ -3003,10 +3003,10 @@ static int alloc_irq_index(struct amd_iommu *iommu, u16 devid, int count, 
static int modify_irte_ga(struct amd_iommu *iommu, u16 devid, int index,

			  struct irte_ga *irte, struct amd_ir_data *data)

{

	bool ret;

	struct irq_remap_table *table;

	unsigned long flags;

	struct irte_ga *entry;

	unsigned long flags;

	u128 old;



	table = get_irq_table(iommu, devid);

	if (!table)
@@ -3017,16 +3017,14 @@ static int modify_irte_ga(struct amd_iommu *iommu, u16 devid, int index, 
	entry = (struct irte_ga *)table->table;

	entry = &entry[index];



	ret = cmpxchg_double(&entry->lo.val, &entry->hi.val,

			     entry->lo.val, entry->hi.val,

			     irte->lo.val, irte->hi.val);

	/*

	 * 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);

	old = entry->irte;

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



	if (data)

		data->ref = entry;