Re: [RFC v3 09/21] iommu/smmuv3: Get prepared for nested stage support
From: Robin Murphy
Date: Fri Jan 25 2019 - 14:27:56 EST
On 08/01/2019 10:26, Eric Auger wrote:
To allow nested stage support, we need to store both
stage 1 and stage 2 configurations (and remove the former
union).
arm_smmu_write_strtab_ent() is modified to write both stage
fields in the STE.
We add a nested_bypass field to the S1 configuration as the first
stage can be bypassed. Also the guest may force the STE to abort:
this information gets stored into the nested_abort field.
Only S2 stage is "finalized" as the host does not configure
S1 CD, guest does.
Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
---
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 | 43 ++++++++++++++++++++++++++++---------
1 file changed, 33 insertions(+), 10 deletions(-)
diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index 9af68266bbb1..9716a301d9ae 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -212,6 +212,7 @@
#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
@@ -491,6 +492,10 @@ struct arm_smmu_strtab_l1_desc {
struct arm_smmu_s1_cfg {
__le64 *cdptr;
dma_addr_t cdptr_dma;
+ /* in nested mode, tells s1 must be bypassed */
+ bool nested_bypass;
Couldn't that be inferred from "s1_cfg == NULL"?
+ /* in nested mode, abort is forced by guest */
+ bool nested_abort;
Couldn't that be inferred from "s1_cfg == NULL && s2_cfg == NULL &&
smmu_domain->stage == ARM_SMMU_DOMAIN_NESTED"?
struct arm_smmu_ctx_desc {
u16 asid;
@@ -515,6 +520,7 @@ struct arm_smmu_strtab_ent {
* configured according to the domain type.
*/
bool assigned;
+ bool nested;
AFAICS, "nested" really only serves a differentiator between the
assigned-as-bypass and assigned-as-fault cases. The latter isn't
actually unique to nested though, I'd say it's more just that nobody's
found reason to do anything with IOMMU_DOMAIN_BLOCKED yet. There's some
argument for upgrading "assigned" into a tristate enum, but I think it
might have a few drawbacks elsewhere, so an extra flag here seems
reasonable, but I think it should just be named "abort". If we have both
s1_cfg and s2_cfg set, we can see it's nested; if we only have s2_cfg, I
don't think we really care whether the host or guest asked for stage 1
bypass; and if in future we care about the difference between host- vs.
guest-requested abort, leaving s2_cfg set for the latter would probably
suffice.
struct arm_smmu_s1_cfg *s1_cfg;
struct arm_smmu_s2_cfg *s2_cfg;
};
@@ -629,10 +635,8 @@ 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;
@@ -1139,10 +1143,11 @@ 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)
+ if (disable_bypass || ste->nested)
break;
default:
BUG(); /* STE corruption */
@@ -1154,7 +1159,8 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_device *smmu, u32 sid,
/* Bypass/fault */
if (!ste->assigned || !(ste->s1_cfg || ste->s2_cfg)) {
- if (!ste->assigned && disable_bypass)
+ if ((!ste->assigned && disable_bypass) ||
+ (ste->s1_cfg && ste->s1_cfg->nested_abort))
Yikes, these conditions were hard enough to follow before...
I think what I've proposed above might allow the logic here to be a bit
less convoluted, but even then it may be time to hoist all these checks
out and have a temporary decision variable for the bypass/abort/valid
config outcome.
Robin.
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);
@@ -1172,8 +1178,17 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_device *smmu, u32 sid,
return;
}
+ if (ste->nested && ste_live) {
+ /*
+ * When enabling nested, the STE may be transitionning from
+ * s2 to nested and back. Invalidate the STE before changing it.
+ */
+ dst[0] = cpu_to_le64(0);
+ arm_smmu_sync_ste_for_sid(smmu, sid);
+ val = STRTAB_STE_0_V;
+ }
+
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) |
@@ -1187,12 +1202,12 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_device *smmu, u32 sid,
!(smmu->features & ARM_SMMU_FEAT_STALL_FORCE))
dst[1] |= cpu_to_le64(STRTAB_STE_1_S1STALLD);
- val |= (ste->s1_cfg->cdptr_dma & STRTAB_STE_0_S1CTXPTR_MASK) |
- FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_S1_TRANS);
+ if (!ste->s1_cfg->nested_bypass)
+ val |= (ste->s1_cfg->cdptr_dma & STRTAB_STE_0_S1CTXPTR_MASK) |
+ FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_S1_TRANS);
}
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) |
@@ -1454,6 +1469,10 @@ static void arm_smmu_tlb_inv_context(void *cookie)
cmd.opcode = CMDQ_OP_TLBI_NH_ASID;
cmd.tlbi.asid = smmu_domain->s1_cfg.cd.asid;
cmd.tlbi.vmid = 0;
+ } else if (smmu_domain->stage == ARM_SMMU_DOMAIN_NESTED) {
+ cmd.opcode = CMDQ_OP_TLBI_NH_ASID;
+ cmd.tlbi.asid = smmu_domain->s1_cfg.cd.asid;
+ cmd.tlbi.vmid = smmu_domain->s2_cfg.vmid;
} else {
cmd.opcode = CMDQ_OP_TLBI_S12_VMALL;
cmd.tlbi.vmid = smmu_domain->s2_cfg.vmid;
@@ -1484,6 +1503,10 @@ static void arm_smmu_tlb_inv_range_nosync(unsigned long iova, size_t size,
if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
cmd.opcode = CMDQ_OP_TLBI_NH_VA;
cmd.tlbi.asid = smmu_domain->s1_cfg.cd.asid;
+ } else if (smmu_domain->stage == ARM_SMMU_DOMAIN_NESTED) {
+ cmd.opcode = CMDQ_OP_TLBI_NH_VA;
+ cmd.tlbi.asid = smmu_domain->s1_cfg.cd.asid;
+ cmd.tlbi.vmid = smmu_domain->s2_cfg.vmid;
} else {
cmd.opcode = CMDQ_OP_TLBI_S2_IPA;
cmd.tlbi.vmid = smmu_domain->s2_cfg.vmid;