BMC/Intel-BMC/linux.git/drivers/iommu/intel-iommu.c, branch dev

iommu/vt-d: Fix VM domain ID leak

2015-07-23T12:17:39+00:00

This continues the attempt to fix commit fb170fb4c548 ("iommu/vt-d: Introduce helper functions to make code symmetric for readability"). The previous attempt in commit 71684406905f ("iommu/vt-d: Detach domain *only* from attached iommus") overlooked the fact that dmar_domain.iommu_bmp gets cleared for VM domains when devices are detached: intel_iommu_detach_device domain_remove_one_dev_info domain_detach_iommu The domain is detached from the iommu, but the iommu is still attached to the domain, for whatever reason. Thus when we get to domain_exit(), we can't rely on iommu_bmp for VM domains to find the active iommus, we must check them all. Without that, the corresponding bit in intel_iommu.domain_ids doesn't get cleared and repeated VM domain creation and destruction will run out of domain IDs. Meanwhile we still can't call iommu_detach_domain() on arbitrary non-VM domains or we risk clearing in-use domain IDs, as 71684406905f attempted to address. It's tempting to modify iommu_detach_domain() to test the domain iommu_bmp, but the call ordering from domain_remove_one_dev_info() prevents it being able to work as fb170fb4c548 seems to have intended. Caching of unused VM domains on the iommu object seems to be the root of the problem, but this code is far too fragile for that kind of rework to be proposed for stable, so we simply revert this chunk to its state prior to fb170fb4c548. Fixes: fb170fb4c548 ("iommu/vt-d: Introduce helper functions to make code symmetric for readability") Fixes: 71684406905f ("iommu/vt-d: Detach domain *only* from attached iommus") Signed-off-by: Alex Williamson Cc: Jiang Liu Cc: stable@vger.kernel.org # v3.17+ Signed-off-by: Joerg Roedel

iommu/vt-d: Enable Translation only if it was previously disabled

2015-06-16T08:59:35+00:00

Do not touch the TE bit unless we know translation is disabled. Tested-by: ZhenHua Li Tested-by: Baoquan He Signed-off-by: Joerg Roedel

iommu/vt-d: Don't disable translation prior to OS handover

2015-06-16T08:59:35+00:00

For all the copy-translation code to run, we have to keep translation enabled in intel_iommu_init(). So remove the code disabling it. Tested-by: ZhenHua Li Tested-by: Baoquan He Signed-off-by: Joerg Roedel

iommu/vt-d: Don't copy translation tables if RTT bit needs to be changed

2015-06-16T08:59:35+00:00

We can't change the RTT bit when translation is enabled, so don't copy translation tables when we would change the bit with our new root entry. Tested-by: ZhenHua Li Tested-by: Baoquan He Signed-off-by: Joerg Roedel

iommu/vt-d: Don't do early domain assignment if kdump kernel

2015-06-16T08:59:35+00:00

When we copied over context tables from an old kernel, we need to defer assignment of devices to domains until the device driver takes over. So skip this part of initialization when we copied over translation tables from the old kernel. Tested-by: ZhenHua Li Tested-by: Baoquan He Signed-off-by: Joerg Roedel

iommu/vt-d: Allocate si_domain in init_dmars()

2015-06-16T08:59:34+00:00

This seperates the allocation of the si_domain from its assignment to devices. It makes sure that the iommu=pt case still works in the kdump kernel, when we have to defer the assignment of devices to domains to device driver initialization time. Tested-by: ZhenHua Li Tested-by: Baoquan He Signed-off-by: Joerg Roedel

iommu/vt-d: Mark copied context entries

2015-06-16T08:59:34+00:00

Mark the context entries we copied over from the old kernel, so that we don't detect them as present in other code paths. This makes sure we safely overwrite old context entries when a new domain is assigned. Tested-by: ZhenHua Li Tested-by: Baoquan He Signed-off-by: Joerg Roedel

iommu/vt-d: Do not re-use domain-ids from the old kernel

2015-06-16T08:59:34+00:00

Mark all domain-ids we find as reserved, so that there could be no collision between domains from the previous kernel and our domains in the IOMMU TLB. Tested-by: ZhenHua Li Tested-by: Baoquan He Signed-off-by: Joerg Roedel

iommu/vt-d: Copy translation tables from old kernel

2015-06-16T08:59:34+00:00

If we are in a kdump kernel and find translation enabled in the iommu, try to copy the translation tables from the old kernel to preserve the mappings until the device driver takes over. This supports old and the extended root-entry and context-table formats. Tested-by: ZhenHua Li Tested-by: Baoquan He Signed-off-by: Joerg Roedel

iommu/vt-d: Detect pre enabled translation

2015-06-16T08:59:34+00:00

Add code to detect whether translation is already enabled in the IOMMU. Save this state in a flags field added to struct intel_iommu. Tested-by: ZhenHua Li Tested-by: Baoquan He Signed-off-by: Joerg Roedel