[PATCH 1/5] iommu: Add capability IOMMU_CAP_BYPASS
From: robin.murphy@arm.com (Robin Murphy)
Date: 2017-07-19 10:58:09
Also in:
kvm, linux-iommu, lkml
On 19/07/17 10:33, Anup Patel wrote:
Some of the IOMMUs (such as ARM SMMU) are capable of bypassing transactions for which no IOMMU domain is configured. This patch adds IOMMU_CAP_BYPASS which can be used by IOMMU drivers to advertise transation bypass capability of an IOMMU.
Whatever the intended semantics of this are, I can't help thinking it would be better served by allowing callers to explicitly allocate their own IOMMU_DOMAIN_IDENTITY domains. That would also be useful for the problem we have with legacy virtio devices behind real IOMMUs. Robin.
quoted hunk ↗ jump to hunk
Signed-off-by: Anup Patel <redacted> --- include/linux/iommu.h | 4 ++++ 1 file changed, 4 insertions(+)diff --git a/include/linux/iommu.h b/include/linux/iommu.h index 2cb54ad..6bbb4cc 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h@@ -101,6 +101,10 @@ enum iommu_cap { transactions */ IOMMU_CAP_INTR_REMAP, /* IOMMU supports interrupt isolation */ IOMMU_CAP_NOEXEC, /* IOMMU_NOEXEC flag */ + IOMMU_CAP_BYPASS, /* + * IOMMU can bypass transactions for + * which domain is not configured + */ }; /*