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iommu/vt-d: Gracefully handle DMAR units with no supported address wi…
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…dths

commit c40aaaa 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.camel@infradead.org/
Signed-off-by: Joerg Roedel <jroedel@suse.de>
[ - context change due to moving drivers/iommu/dmar.c to
    drivers/iommu/intel/dmar.c
  - remove the unused err_unmap label
  - use iommu->iommu_dev instead of iommu->iommu.ops to decide whether
    when freeing ]
Signed-off-by: Filippo Sironi <sironi@amazon.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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David Woodhouse authored and Greg Kroah-Hartman committed Feb 3, 2021
1 parent ee607ba commit e4f10ae
Showing 1 changed file with 26 additions and 16 deletions.
42 changes: 26 additions & 16 deletions drivers/iommu/dmar.c
Original file line number Diff line number Diff line change
@@ -1012,8 +1012,8 @@ 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) {
@@ -1038,17 +1038,28 @@ 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;
@@ -1077,15 +1088,13 @@ static int alloc_iommu(struct dmar_drhd_unit *drhd)

drhd->iommu = iommu;

if (intel_iommu_enabled)
if (intel_iommu_enabled && !drhd->ignored)
iommu->iommu_dev = iommu_device_create(NULL, iommu,
intel_iommu_groups,
"%s", iommu->name);

return 0;

err_unmap:
unmap_iommu(iommu);
error_free_seq_id:
dmar_free_seq_id(iommu);
error:
@@ -1095,7 +1104,8 @@ static int alloc_iommu(struct dmar_drhd_unit *drhd)

static void free_iommu(struct intel_iommu *iommu)
{
iommu_device_destroy(iommu->iommu_dev);
if (intel_iommu_enabled && iommu->iommu_dev)
iommu_device_destroy(iommu->iommu_dev);

if (iommu->irq) {
if (iommu->pr_irq) {

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