| Message ID | 2b5dc62a6325075cb5bd1ceec31ebad1833acf83.1649089693.git.robin.murphy@arm.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | d0be55fbeb6ac694d15af5d1aad19cdec8cd64e5 |
| Headers | show |
| Series | thunderbolt: Make iommu_dma_protection more accurate | expand |
On 2022/4/5 18:41, Robin Murphy wrote: > VT-d's dmar_platform_optin() actually represents a combination of > properties fairly well standardised by Microsoft as "Pre-boot DMA > Protection" and "Kernel DMA Protection"[1]. As such, we can provide > interested consumers with an abstracted capability rather than > driver-specific interfaces that won't scale. We name it for the former > aspect since that's what external callers are most likely to be > interested in; the latter is for the IOMMU layer to handle itself. > > [1] https://docs.microsoft.com/en-us/windows-hardware/design/device-experiences/oem-kernel-dma-protection > > Suggested-by: Christoph Hellwig <hch@lst.de> > Reviewed-by: Christoph Hellwig <hch@lst.de> > Signed-off-by: Robin Murphy <robin.murphy@arm.com> Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Best regards, baolu > --- > drivers/iommu/intel/iommu.c | 2 ++ > include/linux/iommu.h | 2 ++ > 2 files changed, 4 insertions(+) > > diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c > index 255304eb3b1f..49d552a96098 100644 > --- a/drivers/iommu/intel/iommu.c > +++ b/drivers/iommu/intel/iommu.c > @@ -4550,6 +4550,8 @@ static bool intel_iommu_capable(struct device *dev, enum iommu_cap cap) > return domain_update_iommu_snooping(NULL); > if (cap == IOMMU_CAP_INTR_REMAP) > return irq_remapping_enabled == 1; > + if (cap == IOMMU_CAP_PRE_BOOT_PROTECTION) > + return dmar_platform_optin(); > > return false; > } > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index 1fa927e6f1c6..64c02f472f7b 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -107,6 +107,8 @@ enum iommu_cap { > transactions */ > IOMMU_CAP_INTR_REMAP, /* IOMMU supports interrupt isolation */ > IOMMU_CAP_NOEXEC, /* IOMMU_NOEXEC flag */ > + IOMMU_CAP_PRE_BOOT_PROTECTION, /* Firmware says it used the IOMMU for > + DMA protection and we should too */ > }; > > /* These are the possible reserved region types */
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 255304eb3b1f..49d552a96098 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -4550,6 +4550,8 @@ static bool intel_iommu_capable(struct device *dev, enum iommu_cap cap) return domain_update_iommu_snooping(NULL); if (cap == IOMMU_CAP_INTR_REMAP) return irq_remapping_enabled == 1; + if (cap == IOMMU_CAP_PRE_BOOT_PROTECTION) + return dmar_platform_optin(); return false; } diff --git a/include/linux/iommu.h b/include/linux/iommu.h index 1fa927e6f1c6..64c02f472f7b 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -107,6 +107,8 @@ enum iommu_cap { transactions */ IOMMU_CAP_INTR_REMAP, /* IOMMU supports interrupt isolation */ IOMMU_CAP_NOEXEC, /* IOMMU_NOEXEC flag */ + IOMMU_CAP_PRE_BOOT_PROTECTION, /* Firmware says it used the IOMMU for + DMA protection and we should too */ }; /* These are the possible reserved region types */