[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH v2 02/23] xen/arm: smmuv3: Add support for stage-1 and nested stage translation
Hi Milan,
On 24/03/2026 07:51, Milan Djokic wrote:
From: Rahul Singh <rahul.singh@xxxxxxx>
Xen SMMUv3 driver only supports stage-2 translation. Add support for
Stage-1 translation that is required to support nested stage
translation.
In true nested mode, both s1_cfg and s2_cfg will coexist.
Let's remove the union. When nested stage translation is setup, both
s1_cfg and s2_cfg are valid.
We introduce a new smmu_domain abort field that will be set
upon guest stage-1 configuration passing. If no guest stage-1
config has been attached, it is ignored when writing the STE.
arm_smmu_write_strtab_ent() is modified to write both stage
fields in the STE and deal with the abort field.
Signed-off-by: Rahul Singh <rahul.singh@xxxxxxx>
Signed-off-by: Milan Djokic <milan_djokic@xxxxxxxx>
---
xen/drivers/passthrough/arm/smmu-v3.c | 93 +++++++++++++++++++++++----
xen/drivers/passthrough/arm/smmu-v3.h | 9 +++
2 files changed, 91 insertions(+), 11 deletions(-)
diff --git a/xen/drivers/passthrough/arm/smmu-v3.c
b/xen/drivers/passthrough/arm/smmu-v3.c
index 73cc4ef08f..f9c6837919 100644
--- a/xen/drivers/passthrough/arm/smmu-v3.c
+++ b/xen/drivers/passthrough/arm/smmu-v3.c
@@ -683,8 +683,10 @@ static void arm_smmu_write_strtab_ent(struct
arm_smmu_master *master, u32 sid,
* 3. Update Config, sync
*/
u64 val = le64_to_cpu(dst[0]);
- bool ste_live = false;
+ bool s1_live = false, s2_live = false, ste_live = false;
+ bool abort, translate = false;
struct arm_smmu_device *smmu = NULL;
+ struct arm_smmu_s1_cfg *s1_cfg = NULL;
struct arm_smmu_s2_cfg *s2_cfg = NULL;
struct arm_smmu_domain *smmu_domain = NULL;
struct arm_smmu_cmdq_ent prefetch_cmd = {
@@ -699,30 +701,54 @@ static void arm_smmu_write_strtab_ent(struct
arm_smmu_master *master, u32 sid,
smmu = master->smmu;
}
- if (smmu_domain)
- s2_cfg = &smmu_domain->s2_cfg;
+ if (smmu_domain) {
+ switch (smmu_domain->stage) {
+ case ARM_SMMU_DOMAIN_NESTED:
+ s1_cfg = &smmu_domain->s1_cfg;
+ fallthrough;
+ case ARM_SMMU_DOMAIN_S2:
+ s2_cfg = &smmu_domain->s2_cfg;
+ break;
+ default:
+ break;
+ }
+ translate = !!s1_cfg || !!s2_cfg;
NIT: translate is a bool. So do you actually need the !!?
+ }
if (val & STRTAB_STE_0_V) {
switch (FIELD_GET(STRTAB_STE_0_CFG, val)) {
case STRTAB_STE_0_CFG_BYPASS:
break;
+ case STRTAB_STE_0_CFG_S1_TRANS:
+ s1_live = true;
+ break;
case STRTAB_STE_0_CFG_S2_TRANS:
- ste_live = true;
+ s2_live = true;
+ break;
+ case STRTAB_STE_0_CFG_NESTED:
+ s1_live = true;
+ s2_live = true;
break;
case STRTAB_STE_0_CFG_ABORT:
- BUG_ON(!disable_bypass);
I am not sure I understand why this was removed. Can you clarify?
break;
default:
BUG(); /* STE corruption */
}
}
+ ste_live = s1_live || s2_live;
+
/* Nuke the existing STE_0 value, as we're going to rewrite it */
val = STRTAB_STE_0_V;
/* Bypass/fault */
- if (!smmu_domain || !(s2_cfg)) {
- if (!smmu_domain && disable_bypass)
+ if (!smmu_domain)
+ abort = disable_bypass;
+ else
+ abort = smmu_domain->abort;
+
+ if (abort || !translate) {
+ 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);
@@ -740,7 +766,33 @@ static void arm_smmu_write_strtab_ent(struct
arm_smmu_master *master, u32 sid,
return;
}
+ if (ste_live) {
+ /* First invalidate the live STE */
+ dst[0] = cpu_to_le64(STRTAB_STE_0_CFG_ABORT);
+ arm_smmu_sync_ste_for_sid(smmu, sid);
+ }
+
+ if (s1_cfg) {
+ BUG_ON(s1_live);
+ dst[1] = cpu_to_le64(
+ FIELD_PREP(STRTAB_STE_1_S1DSS,
STRTAB_STE_1_S1DSS_SSID0) |
+ FIELD_PREP(STRTAB_STE_1_S1CIR,
STRTAB_STE_1_S1C_CACHE_WBRA) |
+ FIELD_PREP(STRTAB_STE_1_S1COR,
STRTAB_STE_1_S1C_CACHE_WBRA) |
+ FIELD_PREP(STRTAB_STE_1_S1CSH, ARM_SMMU_SH_ISH) |
+ FIELD_PREP(STRTAB_STE_1_STRW,
STRTAB_STE_1_STRW_NSEL1));
+
+ if (smmu->features & ARM_SMMU_FEAT_STALLS &&
+ !(smmu->features & ARM_SMMU_FEAT_STALL_FORCE))
+ dst[1] |= cpu_to_le64(STRTAB_STE_1_S1STALLD);
+
+ val |= (s1_cfg->s1ctxptr & STRTAB_STE_0_S1CTXPTR_MASK) |
+ FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_S1_TRANS)
|
+ FIELD_PREP(STRTAB_STE_0_S1CDMAX, s1_cfg->s1cdmax) |
+ FIELD_PREP(STRTAB_STE_0_S1FMT, s1_cfg->s1fmt);
+ }
+
if (s2_cfg) {
+ u64 vttbr = s2_cfg->vttbr & STRTAB_STE_3_S2TTB_MASK;
u64 strtab =
FIELD_PREP(STRTAB_STE_2_S2VMID, s2_cfg->vmid) |
FIELD_PREP(STRTAB_STE_2_VTCR, s2_cfg->vtcr) |
@@ -750,12 +802,19 @@ static void arm_smmu_write_strtab_ent(struct
arm_smmu_master *master, u32 sid,
STRTAB_STE_2_S2PTW | STRTAB_STE_2_S2AA64 |
STRTAB_STE_2_S2R;
- BUG_ON(ste_live);
+ if (s2_live) {
+ u64 s2ttb = le64_to_cpu(dst[3]) &
STRTAB_STE_3_S2TTB_MASK;
+ BUG_ON(s2ttb != vttbr);
+ }
+
dst[2] = cpu_to_le64(strtab);
- dst[3] = cpu_to_le64(s2_cfg->vttbr & STRTAB_STE_3_S2TTB_MASK);
+ dst[3] = cpu_to_le64(vttbr);
val |= FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_S2_TRANS);
+ } else {
+ dst[2] = 0;
+ dst[3] = 0;
}
if (master->ats_enabled)
@@ -1254,6 +1313,15 @@ static int arm_smmu_domain_finalise(struct iommu_domain
*domain,
{
int ret;
struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
+ struct arm_smmu_device *smmu = smmu_domain->smmu;
+
+ if (smmu_domain->stage == ARM_SMMU_DOMAIN_NESTED &&
+ (!(smmu->features & ARM_SMMU_FEAT_TRANS_S1) ||
+ !(smmu->features & ARM_SMMU_FEAT_TRANS_S2))) {
+ dev_info(smmu_domain->smmu->dev,
+ "does not implement two stages\n");
+ return -EINVAL;
+ }
/* Restrict the stage to what we can actually support */
smmu_domain->stage = ARM_SMMU_DOMAIN_S2;
@@ -2353,11 +2421,14 @@ static int arm_smmu_device_hw_probe(struct
arm_smmu_device *smmu)
break;
}
+ if (reg & IDR0_S1P)
+ smmu->features |= ARM_SMMU_FEAT_TRANS_S1;
+
if (reg & IDR0_S2P)
smmu->features |= ARM_SMMU_FEAT_TRANS_S2;
- if (!(reg & IDR0_S2P)) {
- dev_err(smmu->dev, "no stage-2 translation support!\n");
+ if (!(reg & (IDR0_S1P | IDR0_S2P))) {
I believe the behavior is now slightly different. This would not print
anything if the SMMU support stage-1 but not stage-2. However, Xen at
least need the latter.
+ dev_err(smmu->dev, "no translation support!\n");
return -ENXIO;
}
diff --git a/xen/drivers/passthrough/arm/smmu-v3.h b/xen/drivers/passthrough/arm/smmu-v3.h
index ab1f29f6c7..3fb13b7e21 100644
--- a/xen/drivers/passthrough/arm/smmu-v3.h
+++ b/xen/drivers/passthrough/arm/smmu-v3.h
@@ -197,6 +197,7 @@
#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
@@ -549,6 +550,12 @@ struct arm_smmu_strtab_l1_desc {
dma_addr_t l2ptr_dma;
};
+struct arm_smmu_s1_cfg {
+ u64 s1ctxptr;
+ u8 s1fmt;
+ u8 s1cdmax;
+};
+
struct arm_smmu_s2_cfg {
u16 vmid;
u64 vttbr;
@@ -669,7 +676,9 @@ struct arm_smmu_domain {
atomic_t nr_ats_masters;
enum arm_smmu_domain_stage stage;
+ struct arm_smmu_s1_cfg s1_cfg;
struct arm_smmu_s2_cfg s2_cfg;
+ bool abort;
I think there might be some padding before s1_cfg. So I wonder whether
this would be better be moved before to reduce the size of the structure.
/* Xen domain associated with this SMMU domain */
struct domain *d;
Cheers,
--
Julien Grall
|
