diff options
| author | Nicolin Chen <nicolinc@nvidia.com> | 2026-01-14 17:12:43 -0800 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2026-01-23 13:58:38 +0000 |
| commit | a45dd34663025c75652b27e384e91c9c05ba1d80 (patch) | |
| tree | 97f2996050e3da0b9d2933bd3436e2d0ba2c863a | |
| parent | a4f976edcb87a9daf5384f3e5e13f80e0e180aa6 (diff) | |
iommu/arm-smmu-v3: Do not set disable_ats unless vSTE is Translate
A vSTE may have three configuration types: Abort, Bypass, and Translate.
An Abort vSTE wouldn't enable ATS, but the other two might.
It makes sense for a Transalte vSTE to rely on the guest vSTE.EATS field.
For a Bypass vSTE, it would end up with an S2-only physical STE, similar
to an attachment to a regular S2 domain. However, the nested case always
disables ATS following the Bypass vSTE, while the regular S2 case always
enables ATS so long as arm_smmu_ats_supported(master) == true.
Note that ATS is needed for certain VM centric workloads and historically
non-vSMMU cases have relied on this automatic enablement. So, having the
nested case behave differently causes problems.
To fix that, add a condition to disable_ats, so that it might enable ATS
for a Bypass vSTE, aligning with the regular S2 case.
Fixes: f27298a82ba0 ("iommu/arm-smmu-v3: Allow ATS for IOMMU_DOMAIN_NESTED")
Cc: stable@vger.kernel.org
Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-by: Pranjal Shrivastava <praan@google.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Will Deacon <will@kernel.org>
| -rw-r--r-- | drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c index 93fdadd07431..823461a26659 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c @@ -177,7 +177,9 @@ static int arm_smmu_attach_dev_nested(struct iommu_domain *domain, * config bit here base this off the EATS value in the STE. If the EATS * is set then the VM must generate ATC flushes. */ - state.disable_ats = !nested_domain->enable_ats; + if (FIELD_GET(STRTAB_STE_0_CFG, le64_to_cpu(nested_domain->ste[0])) == + STRTAB_STE_0_CFG_S1_TRANS) + state.disable_ats = !nested_domain->enable_ats; ret = arm_smmu_attach_prepare(&state, domain); if (ret) { mutex_unlock(&arm_smmu_asid_lock); |