[RFC PATCH v1 3/8] iommu/arm-smmu-v3-sva: Allocate new ASID from installed_smmus

Michael Shavit
2023-08-17T18:23:35Z

Pick an ASID that is within the supported range of all SMMUs that the
domain is installed to.

Signed-off-by: Michael Shavit <mshavit@google.com>
---

.../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c | 23 +++++++++++++++----
1 file changed, 19 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
index 58def59c36004..ab941e394cae5 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
@@ -82,6 +82,20 @@ static int arm_smmu_write_ctx_desc_devices(struct arm_smmu_domain *smmu_domain,
return ret;
}

+static u32 arm_smmu_domain_max_asid_bits(struct arm_smmu_domain *smmu_domain)
+{
+ struct arm_smmu_installed_smmu *installed_smmu;
+ unsigned long flags;
+ u32 asid_bits = 16;
+
+ spin_lock_irqsave(&smmu_domain->installed_smmus_lock, flags);
+ list_for_each_entry(installed_smmu, &smmu_domain->installed_smmus,
+ list)
+ asid_bits = min(asid_bits, installed_smmu->smmu->asid_bits);
+ spin_unlock_irqrestore(&smmu_domain->installed_smmus_lock, flags);
+ return asid_bits;
+}
+
/*
* Check if the CPU ASID is available on the SMMU side. If a private context
* descriptor is using it, try to replace it.
@@ -92,7 +106,6 @@ arm_smmu_share_asid(struct mm_struct *mm, u16 asid)
int ret;
u32 new_asid;
struct arm_smmu_ctx_desc *cd;
- struct arm_smmu_device *smmu;
struct arm_smmu_domain *smmu_domain;

cd = xa_load(&arm_smmu_asid_xa, asid);
@@ -108,10 +121,12 @@ arm_smmu_share_asid(struct mm_struct *mm, u16 asid)
}

smmu_domain = container_of(cd, struct arm_smmu_domain, cd);
- smmu = smmu_domain->smmu;

- ret = xa_alloc(&arm_smmu_asid_xa, &new_asid, cd,
- XA_LIMIT(1, (1 << smmu->asid_bits) - 1), GFP_KERNEL);
+ ret = xa_alloc(
+ &arm_smmu_asid_xa, &new_asid, cd,
+ XA_LIMIT(1,
+ (1 << arm_smmu_domain_max_asid_bits(smmu_domain)) - 1),
+ GFP_KERNEL);
if (ret)
return ERR_PTR(-ENOSPC);
/*
--
2.42.0.rc1.204.g551eb34607-goog