[PATCH v2] iommu/amd: Add support to indicate whether DMA remap support is enabled

[PATCH v2] iommu/amd: Add support to indicate whether DMA remap support is enabled

[Mario Limonciello]

Bit 1 of the IVFS IVInfo field indicates that IOMMU has been used for
pre-boot DMA protection.

Export this capability to allow other places in the kernel to be able to
check for it on AMD systems.

Cc: Robin Murphy <robin.murphy@arm.com>
Link: https://www.amd.com/system/files/TechDocs/48882_IOMMU.pdf
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
changes from v1->v2:
 * Rebase on top of Robin Murphy's patch series to add generic interface
   https://lore.kernel.org/linux-usb/cover.1647624084.git.robin.murphy@arm.com/T/#t
 * Drop changes to Thunderbolt driver

Robin,
If your patch series revs again, and this looks good suggest to just roll it into
your series as a 3rd patch.

 drivers/iommu/amd/amd_iommu_types.h | 4 ++++
 drivers/iommu/amd/init.c            | 3 +++
 drivers/iommu/amd/iommu.c           | 2 ++
 3 files changed, 9 insertions(+)

diff --git a/drivers/iommu/amd/amd_iommu_types.h b/drivers/iommu/amd/amd_iommu_types.h
index 47108ed44fbb..72d0f5e2f651 100644
--- a/drivers/iommu/amd/amd_iommu_types.h
+++ b/drivers/iommu/amd/amd_iommu_types.h
@@ -407,6 +407,7 @@
 /* IOMMU IVINFO */
 #define IOMMU_IVINFO_OFFSET     36
 #define IOMMU_IVINFO_EFRSUP     BIT(0)
+#define IOMMU_IVINFO_DMA_REMAP  BIT(1)
 
 /* IOMMU Feature Reporting Field (for IVHD type 10h */
 #define IOMMU_FEAT_GASUP_SHIFT	6
@@ -449,6 +450,9 @@ extern struct irq_remap_table **irq_lookup_table;
 /* Interrupt remapping feature used? */
 extern bool amd_iommu_irq_remap;
 
+/* IVRS indicates that pre-boot remapping was enabled */
+extern bool amdr_ivrs_remap_support;
+
 /* kmem_cache to get tables with 128 byte alignement */
 extern struct kmem_cache *amd_iommu_irq_cache;
 
diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index 7bfe37e52e21..fc12ead49a03 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -182,6 +182,7 @@ u32 amd_iommu_max_pasid __read_mostly = ~0;
 
 bool amd_iommu_v2_present __read_mostly;
 static bool amd_iommu_pc_present __read_mostly;
+bool amdr_ivrs_remap_support __read_mostly;
 
 bool amd_iommu_force_isolation __read_mostly;
 
@@ -326,6 +327,8 @@ static void __init early_iommu_features_init(struct amd_iommu *iommu,
 {
 	if (amd_iommu_ivinfo & IOMMU_IVINFO_EFRSUP)
 		iommu->features = h->efr_reg;
+	if (amd_iommu_ivinfo & IOMMU_IVINFO_DMA_REMAP)
+		amdr_ivrs_remap_support = true;
 }
 
 /* Access to l1 and l2 indexed register spaces */
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index a18b549951bb..e4b4dad027f7 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -2162,6 +2162,8 @@ static bool amd_iommu_capable(enum iommu_cap cap)
 		return (irq_remapping_enabled == 1);
 	case IOMMU_CAP_NOEXEC:
 		return false;
+	case IOMMU_CAP_PRE_BOOT_PROTECTION:
+		return amdr_ivrs_remap_support;
 	default:
 		break;
 	}
-- 
2.34.1

Re: [PATCH v2] iommu/amd: Add support to indicate whether DMA remap support is enabled

[kernel test robot]

Hi Mario,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on joro-iommu/next]
[also build test ERROR on v5.17 next-20220318]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Mario-Limonciello/iommu-amd-Add-support-to-indicate-whether-DMA-remap-support-is-enabled/20220319-063131
base:   https://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git next
config: x86_64-defconfig (https://download.01.org/0day-ci/archive/20220321/202203211032.FSaAOkQt-lkp@intel.com/config)
compiler: gcc-9 (Ubuntu 9.4.0-1ubuntu1~20.04) 9.4.0
reproduce (this is a W=1 build):
        # https://github.com/0day-ci/linux/commit/105690537e561d997e376617aa6a7d6d7b74a6a6
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Mario-Limonciello/iommu-amd-Add-support-to-indicate-whether-DMA-remap-support-is-enabled/20220319-063131
        git checkout 105690537e561d997e376617aa6a7d6d7b74a6a6
        # save the config file to linux build tree
        mkdir build_dir
        make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   drivers/iommu/amd/iommu.c: In function 'amd_iommu_capable':
>> drivers/iommu/amd/iommu.c:2165:7: error: 'IOMMU_CAP_PRE_BOOT_PROTECTION' undeclared (first use in this function)
    2165 |  case IOMMU_CAP_PRE_BOOT_PROTECTION:
         |       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/iommu/amd/iommu.c:2165:7: note: each undeclared identifier is reported only once for each function it appears in


vim +/IOMMU_CAP_PRE_BOOT_PROTECTION +2165 drivers/iommu/amd/iommu.c

  2155	
  2156	static bool amd_iommu_capable(enum iommu_cap cap)
  2157	{
  2158		switch (cap) {
  2159		case IOMMU_CAP_CACHE_COHERENCY:
  2160			return true;
  2161		case IOMMU_CAP_INTR_REMAP:
  2162			return (irq_remapping_enabled == 1);
  2163		case IOMMU_CAP_NOEXEC:
  2164			return false;
> 2165		case IOMMU_CAP_PRE_BOOT_PROTECTION:
  2166			return amdr_ivrs_remap_support;
  2167		default:
  2168			break;
  2169		}
  2170	
  2171		return false;
  2172	}
  2173	

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp

Re: [PATCH v2] iommu/amd: Add support to indicate whether DMA remap support is enabled

[kernel test robot]

Hi Mario,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on joro-iommu/next]
[also build test ERROR on v5.17 next-20220318]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Mario-Limonciello/iommu-amd-Add-support-to-indicate-whether-DMA-remap-support-is-enabled/20220319-063131
base:   https://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git next
config: x86_64-buildonly-randconfig-r004-20220321 (https://download.01.org/0day-ci/archive/20220321/202203211052.WEPydSQ9-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 85e9b2687a13d1908aa86d1b89c5ce398a06cd39)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/105690537e561d997e376617aa6a7d6d7b74a6a6
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Mario-Limonciello/iommu-amd-Add-support-to-indicate-whether-DMA-remap-support-is-enabled/20220319-063131
        git checkout 105690537e561d997e376617aa6a7d6d7b74a6a6
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash drivers/iommu/amd/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> drivers/iommu/amd/iommu.c:2165:7: error: use of undeclared identifier 'IOMMU_CAP_PRE_BOOT_PROTECTION'
           case IOMMU_CAP_PRE_BOOT_PROTECTION:
                ^
   1 error generated.


vim +/IOMMU_CAP_PRE_BOOT_PROTECTION +2165 drivers/iommu/amd/iommu.c

  2155	
  2156	static bool amd_iommu_capable(enum iommu_cap cap)
  2157	{
  2158		switch (cap) {
  2159		case IOMMU_CAP_CACHE_COHERENCY:
  2160			return true;
  2161		case IOMMU_CAP_INTR_REMAP:
  2162			return (irq_remapping_enabled == 1);
  2163		case IOMMU_CAP_NOEXEC:
  2164			return false;
> 2165		case IOMMU_CAP_PRE_BOOT_PROTECTION:
  2166			return amdr_ivrs_remap_support;
  2167		default:
  2168			break;
  2169		}
  2170	
  2171		return false;
  2172	}
  2173	

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp