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authorDonald Dutile <ddutile@redhat.com>2012-06-04 17:29:02 -0400
committerIngo Molnar <mingo@kernel.org>2012-06-08 12:15:43 +0200
commit6f5cf52114dd87f9ed091678f7dfc8ff21bbe2b3 (patch)
tree51d0e821a0eae76c34181a1f8286c1480d6bcbc4 /drivers/iommu
parentbf947fcb77ff858f223c49c76e2d130095fa2585 (diff)
iommu/dmar: Reserve mmio space used by the IOMMU, if the BIOS forgets to
Intel-iommu initialization doesn't currently reserve the memory used for the IOMMU registers. This can allow the pci resource allocator to assign a device BAR to the same address as the IOMMU registers. This can cause some not so nice side affects when the driver ioremap's that region. Introduced two helper functions to map & unmap the IOMMU registers as well as simplify the init and exit paths. Signed-off-by: Donald Dutile <ddutile@redhat.com> Acked-by: Chris Wright <chrisw@redhat.com> Cc: iommu@lists.linux-foundation.org Cc: suresh.b.siddha@intel.com Cc: dwmw2@infradead.org Link: http://lkml.kernel.org/r/1338845342-12464-3-git-send-email-ddutile@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'drivers/iommu')
-rw-r--r--drivers/iommu/dmar.c111
1 files changed, 84 insertions, 27 deletions
diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index 1e5a10de347..9ab6ebf46f7 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -570,14 +570,89 @@ int __init detect_intel_iommu(void)
}
+static void unmap_iommu(struct intel_iommu *iommu)
+{
+ iounmap(iommu->reg);
+ release_mem_region(iommu->reg_phys, iommu->reg_size);
+}
+
+/**
+ * map_iommu: map the iommu's registers
+ * @iommu: the iommu to map
+ * @phys_addr: the physical address of the base resgister
+ *
+ * Memory map the iommu's registers. Start w/ a single page, and
+ * possibly expand if that turns out to be insufficent.
+ */
+static int map_iommu(struct intel_iommu *iommu, u64 phys_addr)
+{
+ int map_size, err=0;
+
+ iommu->reg_phys = phys_addr;
+ iommu->reg_size = VTD_PAGE_SIZE;
+
+ if (!request_mem_region(iommu->reg_phys, iommu->reg_size, iommu->name)) {
+ pr_err("IOMMU: can't reserve memory\n");
+ err = -EBUSY;
+ goto out;
+ }
+
+ iommu->reg = ioremap(iommu->reg_phys, iommu->reg_size);
+ if (!iommu->reg) {
+ pr_err("IOMMU: can't map the region\n");
+ err = -ENOMEM;
+ goto release;
+ }
+
+ iommu->cap = dmar_readq(iommu->reg + DMAR_CAP_REG);
+ iommu->ecap = dmar_readq(iommu->reg + DMAR_ECAP_REG);
+
+ if (iommu->cap == (uint64_t)-1 && iommu->ecap == (uint64_t)-1) {
+ err = -EINVAL;
+ warn_invalid_dmar(phys_addr, " returns all ones");
+ goto unmap;
+ }
+
+ /* the registers might be more than one page */
+ map_size = max_t(int, ecap_max_iotlb_offset(iommu->ecap),
+ cap_max_fault_reg_offset(iommu->cap));
+ map_size = VTD_PAGE_ALIGN(map_size);
+ if (map_size > iommu->reg_size) {
+ iounmap(iommu->reg);
+ release_mem_region(iommu->reg_phys, iommu->reg_size);
+ iommu->reg_size = map_size;
+ if (!request_mem_region(iommu->reg_phys, iommu->reg_size,
+ iommu->name)) {
+ pr_err("IOMMU: can't reserve memory\n");
+ err = -EBUSY;
+ goto out;
+ }
+ iommu->reg = ioremap(iommu->reg_phys, iommu->reg_size);
+ if (!iommu->reg) {
+ pr_err("IOMMU: can't map the region\n");
+ err = -ENOMEM;
+ goto release;
+ }
+ }
+ err = 0;
+ goto out;
+
+unmap:
+ iounmap(iommu->reg);
+release:
+ release_mem_region(iommu->reg_phys, iommu->reg_size);
+out:
+ return err;
+}
+
int alloc_iommu(struct dmar_drhd_unit *drhd)
{
struct intel_iommu *iommu;
- int map_size;
u32 ver;
static int iommu_allocated = 0;
int agaw = 0;
int msagaw = 0;
+ int err;
if (!drhd->reg_base_addr) {
warn_invalid_dmar(0, "");
@@ -591,19 +666,13 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
iommu->seq_id = iommu_allocated++;
sprintf (iommu->name, "dmar%d", iommu->seq_id);
- iommu->reg = ioremap(drhd->reg_base_addr, VTD_PAGE_SIZE);
- if (!iommu->reg) {
- pr_err("IOMMU: can't map the region\n");
+ err = map_iommu(iommu, drhd->reg_base_addr);
+ if (err) {
+ pr_err("IOMMU: failed to map %s\n", iommu->name);
goto error;
}
- iommu->cap = dmar_readq(iommu->reg + DMAR_CAP_REG);
- iommu->ecap = dmar_readq(iommu->reg + DMAR_ECAP_REG);
-
- if (iommu->cap == (uint64_t)-1 && iommu->ecap == (uint64_t)-1) {
- warn_invalid_dmar(drhd->reg_base_addr, " returns all ones");
- goto err_unmap;
- }
+ err = -EINVAL;
agaw = iommu_calculate_agaw(iommu);
if (agaw < 0) {
pr_err("Cannot get a valid agaw for iommu (seq_id = %d)\n",
@@ -621,19 +690,6 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
iommu->node = -1;
- /* the registers might be more than one page */
- map_size = max_t(int, ecap_max_iotlb_offset(iommu->ecap),
- cap_max_fault_reg_offset(iommu->cap));
- map_size = VTD_PAGE_ALIGN(map_size);
- if (map_size > VTD_PAGE_SIZE) {
- iounmap(iommu->reg);
- iommu->reg = ioremap(drhd->reg_base_addr, map_size);
- if (!iommu->reg) {
- pr_err("IOMMU: can't map the region\n");
- goto error;
- }
- }
-
ver = readl(iommu->reg + DMAR_VER_REG);
pr_info("IOMMU %d: reg_base_addr %llx ver %d:%d cap %llx ecap %llx\n",
iommu->seq_id,
@@ -648,10 +704,10 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
return 0;
err_unmap:
- iounmap(iommu->reg);
+ unmap_iommu(iommu);
error:
kfree(iommu);
- return -1;
+ return err;
}
void free_iommu(struct intel_iommu *iommu)
@@ -662,7 +718,8 @@ void free_iommu(struct intel_iommu *iommu)
free_dmar_iommu(iommu);
if (iommu->reg)
- iounmap(iommu->reg);
+ unmap_iommu(iommu);
+
kfree(iommu);
}