To allow nested stage support, we need to store both
stage 1 and stage 2 configurations (and remove the former
union).

A nested setup is characterized by both s1_cfg and s2_cfg
set.

We introduce a new ste.abort field that will be set upon
guest stage1 configuration passing. If s1_cfg is NULL and
ste.abort is set, traffic can't pass. If ste.abort is not set,
S1 is bypassed.

arm_smmu_write_strtab_ent() is modified to write both stage
fields in the STE and deal with the abort field.

In nested mode, only stage 2 is "finalized" as the host does
not own/configure the stage 1 context descriptor, guest does.

Signed-off-by: Eric Auger <eric.au...@redhat.com>

---

v4 -> v5:
- reset ste.abort on detach

v3 -> v4:
- s1_cfg.nested_abort and nested_bypass removed.
- s/ste.nested/ste.abort
- arm_smmu_write_strtab_ent modifications with introduction
  of local abort, bypass and translate local variables
- comment updated

v1 -> v2:
- invalidate the STE before moving from a live STE config to another
- add the nested_abort and nested_bypass fields
---
 drivers/iommu/arm-smmu-v3.c | 35 ++++++++++++++++++++---------------
 1 file changed, 20 insertions(+), 15 deletions(-)

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index 21d027695181..e22e944ffc05 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -211,6 +211,7 @@
 #define STRTAB_STE_0_CFG_BYPASS                4
 #define STRTAB_STE_0_CFG_S1_TRANS      5
 #define STRTAB_STE_0_CFG_S2_TRANS      6
+#define STRTAB_STE_0_CFG_NESTED                7
 
 #define STRTAB_STE_0_S1FMT             GENMASK_ULL(5, 4)
 #define STRTAB_STE_0_S1FMT_LINEAR      0
@@ -514,6 +515,7 @@ struct arm_smmu_strtab_ent {
         * configured according to the domain type.
         */
        bool                            assigned;
+       bool                            abort;
        struct arm_smmu_s1_cfg          *s1_cfg;
        struct arm_smmu_s2_cfg          *s2_cfg;
 };
@@ -628,10 +630,8 @@ struct arm_smmu_domain {
        bool                            non_strict;
 
        enum arm_smmu_domain_stage      stage;
-       union {
-               struct arm_smmu_s1_cfg  s1_cfg;
-               struct arm_smmu_s2_cfg  s2_cfg;
-       };
+       struct arm_smmu_s1_cfg  s1_cfg;
+       struct arm_smmu_s2_cfg  s2_cfg;
 
        struct iommu_domain             domain;
 
@@ -1108,12 +1108,13 @@ static void arm_smmu_write_strtab_ent(struct 
arm_smmu_device *smmu, u32 sid,
                                      __le64 *dst, struct arm_smmu_strtab_ent 
*ste)
 {
        /*
-        * This is hideously complicated, but we only really care about
-        * three cases at the moment:
+        * We care about the following transitions:
         *
         * 1. Invalid (all zero) -> bypass/fault (init)
-        * 2. Bypass/fault -> translation/bypass (attach)
-        * 3. Translation/bypass -> bypass/fault (detach)
+        * 2. Bypass/fault -> single stage translation/bypass (attach)
+        * 3. single stage Translation/bypass -> bypass/fault (detach)
+        * 4. S2 -> S1 + S2 (attach_pasid_table)
+        * 5. S1 + S2 -> S2 (detach_pasid_table)
         *
         * Given that we can't update the STE atomically and the SMMU
         * doesn't read the thing in a defined order, that leaves us
@@ -1124,7 +1125,7 @@ static void arm_smmu_write_strtab_ent(struct 
arm_smmu_device *smmu, u32 sid,
         * 3. Update Config, sync
         */
        u64 val = le64_to_cpu(dst[0]);
-       bool ste_live = false;
+       bool abort, bypass, translate, ste_live = false;
        struct arm_smmu_cmdq_ent prefetch_cmd = {
                .opcode         = CMDQ_OP_PREFETCH_CFG,
                .prefetch       = {
@@ -1138,11 +1139,11 @@ static void arm_smmu_write_strtab_ent(struct 
arm_smmu_device *smmu, u32 sid,
                        break;
                case STRTAB_STE_0_CFG_S1_TRANS:
                case STRTAB_STE_0_CFG_S2_TRANS:
+               case STRTAB_STE_0_CFG_NESTED:
                        ste_live = true;
                        break;
                case STRTAB_STE_0_CFG_ABORT:
-                       if (disable_bypass)
-                               break;
+                       break;
                default:
                        BUG(); /* STE corruption */
                }
@@ -1152,8 +1153,13 @@ static void arm_smmu_write_strtab_ent(struct 
arm_smmu_device *smmu, u32 sid,
        val = STRTAB_STE_0_V;
 
        /* Bypass/fault */
-       if (!ste->assigned || !(ste->s1_cfg || ste->s2_cfg)) {
-               if (!ste->assigned && disable_bypass)
+
+       abort = (!ste->assigned && disable_bypass) || ste->abort;
+       translate = ste->s1_cfg || ste->s2_cfg;
+       bypass = !abort && !translate;
+
+       if (abort || bypass) {
+               if (abort)
                        val |= FIELD_PREP(STRTAB_STE_0_CFG, 
STRTAB_STE_0_CFG_ABORT);
                else
                        val |= FIELD_PREP(STRTAB_STE_0_CFG, 
STRTAB_STE_0_CFG_BYPASS);
@@ -1172,7 +1178,6 @@ static void arm_smmu_write_strtab_ent(struct 
arm_smmu_device *smmu, u32 sid,
        }
 
        if (ste->s1_cfg) {
-               BUG_ON(ste_live);
                dst[1] = cpu_to_le64(
                         FIELD_PREP(STRTAB_STE_1_S1CIR, 
STRTAB_STE_1_S1C_CACHE_WBRA) |
                         FIELD_PREP(STRTAB_STE_1_S1COR, 
STRTAB_STE_1_S1C_CACHE_WBRA) |
@@ -1191,7 +1196,6 @@ static void arm_smmu_write_strtab_ent(struct 
arm_smmu_device *smmu, u32 sid,
        }
 
        if (ste->s2_cfg) {
-               BUG_ON(ste_live);
                dst[2] = cpu_to_le64(
                         FIELD_PREP(STRTAB_STE_2_S2VMID, ste->s2_cfg->vmid) |
                         FIELD_PREP(STRTAB_STE_2_VTCR, ste->s2_cfg->vtcr) |
@@ -1773,6 +1777,7 @@ static void arm_smmu_detach_dev(struct device *dev)
        }
 
        master->ste.assigned = false;
+       master->ste.abort = false;
        arm_smmu_install_ste_for_dev(fwspec);
 }
 
-- 
2.20.1

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