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iommu/vt-d: Gracefully handle DMAR units with no supported address widths

Browse source 
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>
This commit is contained in:
David Woodhouse 2020-09-24 15:08:42 +01:00 committed by Joerg Roedel
parent d2ef096249
commit c40aaaac10
1 changed files with 30 additions and 14 deletions
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44
drivers/iommu/intel/dmar.c
View file

@ -1024,8 +1024,8 @@ 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) {
@ -1050,17 +1050,28 @@ 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;
@ -1087,7 +1098,12 @@ 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);
@ -1117,7 +1133,7 @@ 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);
}