diff options
Diffstat (limited to 'SOURCES/0001-iommu-arm-smmu-workaround-DMA-mode-issues.patch')
| -rw-r--r-- | SOURCES/0001-iommu-arm-smmu-workaround-DMA-mode-issues.patch | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/SOURCES/0001-iommu-arm-smmu-workaround-DMA-mode-issues.patch b/SOURCES/0001-iommu-arm-smmu-workaround-DMA-mode-issues.patch new file mode 100644 index 0000000..e6eef22 --- /dev/null +++ b/SOURCES/0001-iommu-arm-smmu-workaround-DMA-mode-issues.patch @@ -0,0 +1,98 @@ +From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 +From: Laura Abbott <labbott@redhat.com> +Date: Mon, 20 May 2019 22:21:02 -0400 +Subject: [PATCH] iommu/arm-smmu: workaround DMA mode issues + +Message-id: <20190520222102.19488-1-labbott@redhat.com> +Patchwork-id: 259215 +O-Subject: [ARK INTERNAL PATCH] iommu/arm-smmu: workaround DMA mode issues +Bugzilla: +RH-Acked-by: Mark Langsdorf <mlangsdo@redhat.com> +RH-Acked-by: Mark Salter <msalter@redhat.com> + +From: Mark Salter <msalter@redhat.com> + +Rebased for v5.2-rc1 + + Bugzilla: 1652259 + Brew: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=19244562 + Upstream status: RHEL only. + + rhel8 commit 65feb1ed0ec9a088a63a90d46c0f7563ac96ad0f + Author: Mark Salter <msalter@redhat.com> + Date: Wed Nov 21 17:15:59 2018 +0100 + + [iommu] iommu/arm-smmu: workaround DMA mode issues + + Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1624077 + Brew: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=18112820 + Testing: Verified iommu.passthrough=1 no longer needed on gigabyte platforms. + Upstream Status: RHEL-only + + In RHEL_ALT 7.5 we carried a RHEL-only patch which forced the arm smmuv2 + into bypass mode due to performance issues on CN88xx. This was intended + to be a temporary hack until the issues were resolved. Another vendor + had issues with the iommu in bypass mode so we reverted the RHEL-only + patch so that iommu is in DMA mode by default (upstream default). + + It turns on that there are remaining SMMU DMA mode issues on Gigabyte + platformws with CN88xx cpus. The problem manifests itself by pcie + card drivers failing to initialize the cards when SMMU is in DMA mode. + The root cause has not been determined yet, but looks likely to be + a hw or firmware issue. This patch forces bypass mode for Gigabyte + platforms. CN88xx isn't officially supported in RHEL but we have a + lot of them being used internally for testing, so I think we want + this to support that use case in RHEL8. + + Signed-off-by: Mark Salter <msalter@redhat.com> + Signed-off-by: Herton R. Krzesinski <herton@redhat.com> + + Acked-by: Mark Salter <msalter@redhat.com> + Acked-by: Donald Dutile <ddutile@redhat.com> + +Upstream Status: RHEL only +Signed-off-by: Laura Abbott <labbott@redhat.com> +--- + drivers/iommu/iommu.c | 22 ++++++++++++++++++++++ + 1 file changed, 22 insertions(+) + +diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c +index 03d6a26687bc..86981f228c90 100644 +--- a/drivers/iommu/iommu.c ++++ b/drivers/iommu/iommu.c +@@ -7,6 +7,7 @@ + #define pr_fmt(fmt) "iommu: " fmt + + #include <linux/device.h> ++#include <linux/dmi.h> + #include <linux/kernel.h> + #include <linux/bug.h> + #include <linux/types.h> +@@ -2664,3 +2665,24 @@ int iommu_sva_get_pasid(struct iommu_sva *handle) + return ops->sva_get_pasid(handle); + } + EXPORT_SYMBOL_GPL(iommu_sva_get_pasid); ++ ++#ifdef CONFIG_ARM64 ++static int __init iommu_quirks(void) ++{ ++ const char *vendor, *name; ++ ++ vendor = dmi_get_system_info(DMI_SYS_VENDOR); ++ name = dmi_get_system_info(DMI_PRODUCT_NAME); ++ ++ if (vendor && ++ (strncmp(vendor, "GIGABYTE", 8) == 0 && name && ++ (strncmp(name, "R120", 4) == 0 || ++ strncmp(name, "R270", 4) == 0))) { ++ pr_warn("Gigabyte %s detected, force iommu passthrough mode", name); ++ iommu_def_domain_type = IOMMU_DOMAIN_IDENTITY; ++ } ++ ++ return 0; ++} ++arch_initcall(iommu_quirks); ++#endif +-- +2.26.2 + |