From: David Woodhouse dwmw@amazon.co.uk

commit c40aaaac1018ff1382f2d35df5129a6bcea3df6b upstream.

Instead of bailing out completely, such a unit can still be used for interrupt remapping.

Signed-off-by: David Woodhouse dwmw@amazon.co.uk Reviewed-by: Lu Baolu baolu.lu@linux.intel.com Link: https://lore.kernel.org/linux-iommu/549928db2de6532117f36c9c810373c14cf76f51... Signed-off-by: Joerg Roedel jroedel@suse.de [ context change due to moving drivers/iommu/dmar.c to drivers/iommu/intel/dmar.c ] Signed-off-by: Filippo Sironi sironi@amazon.de --- drivers/iommu/dmar.c | 44 ++++++++++++++++++++++++++++++-------------- 1 file changed, 30 insertions(+), 14 deletions(-)

diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c index d936ff765fe4..25a957c5640d 100644 --- a/drivers/iommu/dmar.c +++ b/drivers/iommu/dmar.c @@ -1029,8 +1029,8 @@ static int alloc_iommu(struct dmar_drhd_unit *drhd) { struct intel_iommu *iommu; u32 ver, sts; - int agaw = 0; - int msagaw = 0; + int agaw = -1; + int msagaw = -1; int err;

if (!drhd->reg_base_addr) { @@ -1055,17 +1055,28 @@ static int alloc_iommu(struct dmar_drhd_unit *drhd) }

err = -EINVAL; - agaw = iommu_calculate_agaw(iommu); - if (agaw < 0) { - pr_err("Cannot get a valid agaw for iommu (seq_id = %d)\n", - iommu->seq_id); - goto err_unmap; + if (cap_sagaw(iommu->cap) == 0) { + pr_info("%s: No supported address widths. Not attempting DMA translation.\n", + iommu->name); + drhd->ignored = 1; } - msagaw = iommu_calculate_max_sagaw(iommu); - if (msagaw < 0) { - pr_err("Cannot get a valid max agaw for iommu (seq_id = %d)\n", - iommu->seq_id); - goto err_unmap; + + if (!drhd->ignored) { + agaw = iommu_calculate_agaw(iommu); + if (agaw < 0) { + pr_err("Cannot get a valid agaw for iommu (seq_id = %d)\n", + iommu->seq_id); + drhd->ignored = 1; + } + } + if (!drhd->ignored) { + msagaw = iommu_calculate_max_sagaw(iommu); + if (msagaw < 0) { + pr_err("Cannot get a valid max agaw for iommu (seq_id = %d)\n", + iommu->seq_id); + drhd->ignored = 1; + agaw = -1; + } } iommu->agaw = agaw; iommu->msagaw = msagaw; @@ -1092,7 +1103,12 @@ static int alloc_iommu(struct dmar_drhd_unit *drhd)

raw_spin_lock_init(&iommu->register_lock);

- if (intel_iommu_enabled) { + /* + * This is only for hotplug; at boot time intel_iommu_enabled won't + * be set yet. When intel_iommu_init() runs, it registers the units + * present at boot time, then sets intel_iommu_enabled. + */ + if (intel_iommu_enabled && !drhd->ignored) { err = iommu_device_sysfs_add(&iommu->iommu, NULL, intel_iommu_groups, "%s", iommu->name); @@ -1121,7 +1137,7 @@ static int alloc_iommu(struct dmar_drhd_unit *drhd)

static void free_iommu(struct intel_iommu *iommu) { - if (intel_iommu_enabled) { + if (intel_iommu_enabled && iommu->iommu.ops) { iommu_device_unregister(&iommu->iommu); iommu_device_sysfs_remove(&iommu->iommu); }