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| author | Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> | 2023-05-30 10:11:35 -0400 |
|---|---|---|
| committer | Joerg Roedel <jroedel@suse.de> | 2023-06-09 14:47:09 +0200 |
| commit | 66419036f68a838c00cbccacd6cb2e99da6e5710 (patch) | |
| tree | 33546e4d8e48d6e2214ffc9dfb98607a716530db /drivers/iommu/amd/amd_iommu_types.h | |
| parent | 74a37817bd1567330fb372eb01223e31b45b1cc0 (diff) | |
iommu/amd: Introduce Disable IRTE Caching Support
An Interrupt Remapping Table (IRT) stores interrupt remapping configuration
for each device. In a normal operation, the AMD IOMMU caches the table
to optimize subsequent data accesses. This requires the IOMMU driver to
invalidate IRT whenever it updates the table. The invalidation process
includes issuing an INVALIDATE_INTERRUPT_TABLE command following by
a COMPLETION_WAIT command.
However, there are cases in which the IRT is updated at a high rate.
For example, for IOMMU AVIC, the IRTE[IsRun] bit is updated on every
vcpu scheduling (i.e. amd_iommu_update_ga()). On system with large
amount of vcpus and VFIO PCI pass-through devices, the invalidation
process could potentially become a performance bottleneck.
Introducing a new kernel boot option:
amd_iommu=irtcachedis
which disables IRTE caching by setting the IRTCachedis bit in each IOMMU
Control register, and bypass the IRT invalidation process.
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Co-developed-by: Alejandro Jimenez <alejandro.j.jimenez@oracle.com>
Signed-off-by: Alejandro Jimenez <alejandro.j.jimenez@oracle.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Link: https://lore.kernel.org/r/20230530141137.14376-4-suravee.suthikulpanit@amd.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Diffstat (limited to 'drivers/iommu/amd/amd_iommu_types.h')
| -rw-r--r-- | drivers/iommu/amd/amd_iommu_types.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/iommu/amd/amd_iommu_types.h b/drivers/iommu/amd/amd_iommu_types.h index 8c072be68875..8eeea1f25e69 100644 --- a/drivers/iommu/amd/amd_iommu_types.h +++ b/drivers/iommu/amd/amd_iommu_types.h @@ -174,6 +174,7 @@ #define CONTROL_GAINT_EN 29 #define CONTROL_XT_EN 50 #define CONTROL_INTCAPXT_EN 51 +#define CONTROL_IRTCACHEDIS 59 #define CONTROL_SNPAVIC_EN 61 #define CTRL_INV_TO_MASK (7 << CONTROL_INV_TIMEOUT) @@ -716,6 +717,9 @@ struct amd_iommu { /* if one, we need to send a completion wait command */ bool need_sync; + /* true if disable irte caching */ + bool irtcachedis_enabled; + /* Handle for IOMMU core code */ struct iommu_device iommu; |