From 7d8b06ecc45bd679dec58d2cc2bd86223d4e076d Mon Sep 17 00:00:00 2001 From: Suravee Suthikulpanit Date: Thu, 15 Jan 2026 06:08:02 +0000 Subject: [PATCH] iommu/amd: Add support for hw_info for iommu capability query AMD IOMMU Extended Feature (EFR) and Extended Feature 2 (EFR2) registers specify features supported by each IOMMU hardware instance. The IOMMU driver checks each feature-specific bits before enabling each feature at run time. For IOMMUFD, the hypervisor passes the raw value of amd_iommu_efr and amd_iommu_efr2 to VMM via iommufd IOMMU_DEVICE_GET_HW_INFO ioctl. Reviewed-by: Nicolin Chen Reviewed-by: Vasant Hegde Reviewed-by: Jason Gunthorpe Signed-off-by: Suravee Suthikulpanit Signed-off-by: Joerg Roedel --- drivers/iommu/amd/Kconfig | 10 ++++++++++ drivers/iommu/amd/Makefile | 1 + drivers/iommu/amd/iommu.c | 2 ++ drivers/iommu/amd/iommufd.c | 31 +++++++++++++++++++++++++++++++ drivers/iommu/amd/iommufd.h | 15 +++++++++++++++ include/uapi/linux/iommufd.h | 28 ++++++++++++++++++++++++++++ 6 files changed, 87 insertions(+) create mode 100644 drivers/iommu/amd/iommufd.c create mode 100644 drivers/iommu/amd/iommufd.h diff --git a/drivers/iommu/amd/Kconfig b/drivers/iommu/amd/Kconfig index f2acf471cb5d..588355ff7eb7 100644 --- a/drivers/iommu/amd/Kconfig +++ b/drivers/iommu/amd/Kconfig @@ -30,6 +30,16 @@ config AMD_IOMMU your BIOS for an option to enable it or if you have an IVRS ACPI table. +config AMD_IOMMU_IOMMUFD + bool "Enable IOMMUFD features for AMD IOMMU (EXPERIMENTAL)" + depends on IOMMUFD + depends on AMD_IOMMU + help + Support for IOMMUFD features intended to support virtual machines + with accelerated virtual IOMMUs. + + Say Y here if you are doing development and testing on this feature. + config AMD_IOMMU_DEBUGFS bool "Enable AMD IOMMU internals in DebugFS" depends on AMD_IOMMU && IOMMU_DEBUGFS diff --git a/drivers/iommu/amd/Makefile b/drivers/iommu/amd/Makefile index 5412a563c697..41f053b49dce 100644 --- a/drivers/iommu/amd/Makefile +++ b/drivers/iommu/amd/Makefile @@ -1,3 +1,4 @@ # SPDX-License-Identifier: GPL-2.0-only obj-y += iommu.o init.o quirks.o ppr.o pasid.o +obj-$(CONFIG_AMD_IOMMU_IOMMUFD) += iommufd.o obj-$(CONFIG_AMD_IOMMU_DEBUGFS) += debugfs.o diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c index d7f457338de7..d550a7e431ac 100644 --- a/drivers/iommu/amd/iommu.c +++ b/drivers/iommu/amd/iommu.c @@ -43,6 +43,7 @@ #include #include "amd_iommu.h" +#include "iommufd.h" #include "../irq_remapping.h" #include "../iommu-pages.h" @@ -3083,6 +3084,7 @@ static bool amd_iommu_enforce_cache_coherency(struct iommu_domain *domain) const struct iommu_ops amd_iommu_ops = { .capable = amd_iommu_capable, + .hw_info = amd_iommufd_hw_info, .blocked_domain = &blocked_domain, .release_domain = &blocked_domain, .identity_domain = &identity_domain.domain, diff --git a/drivers/iommu/amd/iommufd.c b/drivers/iommu/amd/iommufd.c new file mode 100644 index 000000000000..72eaaa923d04 --- /dev/null +++ b/drivers/iommu/amd/iommufd.c @@ -0,0 +1,31 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2025 Advanced Micro Devices, Inc. + */ + +#include + +#include "iommufd.h" +#include "amd_iommu.h" +#include "amd_iommu_types.h" + +void *amd_iommufd_hw_info(struct device *dev, u32 *length, u32 *type) +{ + struct iommu_hw_info_amd *hwinfo; + + if (*type != IOMMU_HW_INFO_TYPE_DEFAULT && + *type != IOMMU_HW_INFO_TYPE_AMD) + return ERR_PTR(-EOPNOTSUPP); + + hwinfo = kzalloc(sizeof(*hwinfo), GFP_KERNEL); + if (!hwinfo) + return ERR_PTR(-ENOMEM); + + *length = sizeof(*hwinfo); + *type = IOMMU_HW_INFO_TYPE_AMD; + + hwinfo->efr = amd_iommu_efr; + hwinfo->efr2 = amd_iommu_efr2; + + return hwinfo; +} diff --git a/drivers/iommu/amd/iommufd.h b/drivers/iommu/amd/iommufd.h new file mode 100644 index 000000000000..f880be80a30d --- /dev/null +++ b/drivers/iommu/amd/iommufd.h @@ -0,0 +1,15 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2025 Advanced Micro Devices, Inc. + */ + +#ifndef AMD_IOMMUFD_H +#define AMD_IOMMUFD_H + +#if IS_ENABLED(CONFIG_AMD_IOMMU_IOMMUFD) +void *amd_iommufd_hw_info(struct device *dev, u32 *length, u32 *type); +#else +#define amd_iommufd_hw_info NULL +#endif /* CONFIG_AMD_IOMMU_IOMMUFD */ + +#endif /* AMD_IOMMUFD_H */ diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h index 2c41920b641d..3db37f6042a0 100644 --- a/include/uapi/linux/iommufd.h +++ b/include/uapi/linux/iommufd.h @@ -623,6 +623,32 @@ struct iommu_hw_info_tegra241_cmdqv { __u8 __reserved; }; +/** + * struct iommu_hw_info_amd - AMD IOMMU device info + * + * @efr : Value of AMD IOMMU Extended Feature Register (EFR) + * @efr2: Value of AMD IOMMU Extended Feature 2 Register (EFR2) + * + * Please See description of these registers in the following sections of + * the AMD I/O Virtualization Technology (IOMMU) Specification. + * (https://docs.amd.com/v/u/en-US/48882_3.10_PUB) + * + * - MMIO Offset 0030h IOMMU Extended Feature Register + * - MMIO Offset 01A0h IOMMU Extended Feature 2 Register + * + * Note: The EFR and EFR2 are raw values reported by hardware. + * VMM is responsible to determine the appropriate flags to be exposed to + * the VM since cetertain features are not currently supported by the kernel + * for HW-vIOMMU. + * + * Current VMM-allowed list of feature flags are: + * - EFR[GTSup, GASup, GioSup, PPRSup, EPHSup, GATS, GLX, PASmax] + */ +struct iommu_hw_info_amd { + __aligned_u64 efr; + __aligned_u64 efr2; +}; + /** * enum iommu_hw_info_type - IOMMU Hardware Info Types * @IOMMU_HW_INFO_TYPE_NONE: Output by the drivers that do not report hardware @@ -632,6 +658,7 @@ struct iommu_hw_info_tegra241_cmdqv { * @IOMMU_HW_INFO_TYPE_ARM_SMMUV3: ARM SMMUv3 iommu info type * @IOMMU_HW_INFO_TYPE_TEGRA241_CMDQV: NVIDIA Tegra241 CMDQV (extension for ARM * SMMUv3) info type + * @IOMMU_HW_INFO_TYPE_AMD: AMD IOMMU info type */ enum iommu_hw_info_type { IOMMU_HW_INFO_TYPE_NONE = 0, @@ -639,6 +666,7 @@ enum iommu_hw_info_type { IOMMU_HW_INFO_TYPE_INTEL_VTD = 1, IOMMU_HW_INFO_TYPE_ARM_SMMUV3 = 2, IOMMU_HW_INFO_TYPE_TEGRA241_CMDQV = 3, + IOMMU_HW_INFO_TYPE_AMD = 4, }; /**