x86,intel_iommu: Replace cmpxchg_double()

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20230531132323.855976804@infradead.org

diff --git a/drivers/iommu/intel/irq_remapping.c b/drivers/iommu/intel/irq_remapping.c
index a1b9873..08f5632 100644 (file)
--- a/drivers/iommu/intel/irq_remapping.c
+++ b/drivers/iommu/intel/irq_remapping.c
@@ -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);

diff --git a/include/linux/dmar.h b/include/linux/dmar.h
index 725d5e6..27dbd4c 100644 (file)
--- a/include/linux/dmar.h
+++ b/include/linux/dmar.h
@@ -202,67 +202,74 @@ static inline void detect_intel_iommu(void)
 
 struct irte {
        union {
-               /* Shared between remapped and posted mode*/
                struct {
-                       __u64   present         : 1,  /*  0      */
-                               fpd             : 1,  /*  1      */
-                               __res0          : 6,  /*  2 -  6 */
-                               avail           : 4,  /*  8 - 11 */
-                               __res1          : 3,  /* 12 - 14 */
-                               pst             : 1,  /* 15      */
-                               vector          : 8,  /* 16 - 23 */
-                               __res2          : 40; /* 24 - 63 */
+                       union {
+                               /* Shared between remapped and posted mode*/
+                               struct {
+                                       __u64   present         : 1,  /*  0      */
+                                               fpd             : 1,  /*  1      */
+                                               __res0          : 6,  /*  2 -  6 */
+                                               avail           : 4,  /*  8 - 11 */
+                                               __res1          : 3,  /* 12 - 14 */
+                                               pst             : 1,  /* 15      */
+                                               vector          : 8,  /* 16 - 23 */
+                                               __res2          : 40; /* 24 - 63 */
+                               };
+
+                               /* Remapped mode */
+                               struct {
+                                       __u64   r_present       : 1,  /*  0      */
+                                               r_fpd           : 1,  /*  1      */
+                                               dst_mode        : 1,  /*  2      */
+                                               redir_hint      : 1,  /*  3      */
+                                               trigger_mode    : 1,  /*  4      */
+                                               dlvry_mode      : 3,  /*  5 -  7 */
+                                               r_avail         : 4,  /*  8 - 11 */
+                                               r_res0          : 4,  /* 12 - 15 */
+                                               r_vector        : 8,  /* 16 - 23 */
+                                               r_res1          : 8,  /* 24 - 31 */
+                                               dest_id         : 32; /* 32 - 63 */
+                               };
+
+                               /* Posted mode */
+                               struct {
+                                       __u64   p_present       : 1,  /*  0      */
+                                               p_fpd           : 1,  /*  1      */
+                                               p_res0          : 6,  /*  2 -  7 */
+                                               p_avail         : 4,  /*  8 - 11 */
+                                               p_res1          : 2,  /* 12 - 13 */
+                                               p_urgent        : 1,  /* 14      */
+                                               p_pst           : 1,  /* 15      */
+                                               p_vector        : 8,  /* 16 - 23 */
+                                               p_res2          : 14, /* 24 - 37 */
+                                               pda_l           : 26; /* 38 - 63 */
+                               };
+                               __u64 low;
+                       };
+
+                       union {
+                               /* Shared between remapped and posted mode*/
+                               struct {
+                                       __u64   sid             : 16,  /* 64 - 79  */
+                                               sq              : 2,   /* 80 - 81  */
+                                               svt             : 2,   /* 82 - 83  */
+                                               __res3          : 44;  /* 84 - 127 */
+                               };
+
+                               /* Posted mode*/
+                               struct {
+                                       __u64   p_sid           : 16,  /* 64 - 79  */
+                                               p_sq            : 2,   /* 80 - 81  */
+                                               p_svt           : 2,   /* 82 - 83  */
+                                               p_res3          : 12,  /* 84 - 95  */
+                                               pda_h           : 32;  /* 96 - 127 */
+                               };
+                               __u64 high;
+                       };
                };
-
-               /* Remapped mode */
-               struct {
-                       __u64   r_present       : 1,  /*  0      */
-                               r_fpd           : 1,  /*  1      */
-                               dst_mode        : 1,  /*  2      */
-                               redir_hint      : 1,  /*  3      */
-                               trigger_mode    : 1,  /*  4      */
-                               dlvry_mode      : 3,  /*  5 -  7 */
-                               r_avail         : 4,  /*  8 - 11 */
-                               r_res0          : 4,  /* 12 - 15 */
-                               r_vector        : 8,  /* 16 - 23 */
-                               r_res1          : 8,  /* 24 - 31 */
-                               dest_id         : 32; /* 32 - 63 */
-               };
-
-               /* Posted mode */
-               struct {
-                       __u64   p_present       : 1,  /*  0      */
-                               p_fpd           : 1,  /*  1      */
-                               p_res0          : 6,  /*  2 -  7 */
-                               p_avail         : 4,  /*  8 - 11 */
-                               p_res1          : 2,  /* 12 - 13 */
-                               p_urgent        : 1,  /* 14      */
-                               p_pst           : 1,  /* 15      */
-                               p_vector        : 8,  /* 16 - 23 */
-                               p_res2          : 14, /* 24 - 37 */
-                               pda_l           : 26; /* 38 - 63 */
-               };
-               __u64 low;
-       };
-
-       union {
-               /* Shared between remapped and posted mode*/
-               struct {
-                       __u64   sid             : 16,  /* 64 - 79  */
-                               sq              : 2,   /* 80 - 81  */
-                               svt             : 2,   /* 82 - 83  */
-                               __res3          : 44;  /* 84 - 127 */
-               };
-
-               /* Posted mode*/
-               struct {
-                       __u64   p_sid           : 16,  /* 64 - 79  */
-                               p_sq            : 2,   /* 80 - 81  */
-                               p_svt           : 2,   /* 82 - 83  */
-                               p_res3          : 12,  /* 84 - 95  */
-                               pda_h           : 32;  /* 96 - 127 */
-               };
-               __u64 high;
+#ifdef CONFIG_IRQ_REMAP
+               __u128 irte;
+#endif
        };
 };