Re: [PATCH v2] intel_iommu,dmar: reserve mmio of IOMMU registers

[Don Dutile]

On 04/05/2012 04:58 PM, Chris Wright wrote:

* Donald Dutile (ddut...@redhat.com) wrote:

--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -581,7 +581,7 @@ int __init detect_intel_iommu(void)
  int alloc_iommu(struct dmar_drhd_unit *drhd)
  {
        struct intel_iommu *iommu;
-       int map_size;
+       resource_size_t map_size;
        u32 ver;
        static int iommu_allocated = 0;
        int agaw = 0;
@@ -599,10 +599,17 @@ 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);

I think it'd be nice to create a helper function that does the request
and map.  This should include the map, read cap/ecap, calculate size and
possbily remap.  Would probably simplify the error cleanup too.

+       iommu->reg_phys = drhd->reg_base_addr;
+       iommu->reg_size = VTD_PAGE_SIZE;
+       if (!request_mem_region(iommu->reg_phys, iommu->reg_size, iommu->name)) 
{
+               printk(KERN_ERR "IOMMU: can't reserve memory\n");
+               goto error;
+       }
+
+       iommu->reg = ioremap(iommu->reg_phys, iommu->reg_size);
        if (!iommu->reg) {
                printk(KERN_ERR "IOMMU: can't map the region\n");
-               goto error;
+               goto err_release;
        }
        iommu->cap = dmar_readq(iommu->reg + DMAR_CAP_REG);
        iommu->ecap = dmar_readq(iommu->reg + DMAR_ECAP_REG);
@@ -635,19 +642,26 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
        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) {
+       if (map_size>  iommu->reg_size) {
                iounmap(iommu->reg);
-               iommu->reg = ioremap(drhd->reg_base_addr, map_size);
+               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)) {
+                       printk(KERN_ERR "IOMMU: can't reserve memory\n");
+                       goto error;
+               }
+               iommu->reg = ioremap(iommu->reg_phys, iommu->reg_size);
                if (!iommu->reg) {
                        printk(KERN_ERR "IOMMU: can't map the region\n");
-                       goto error;
+                       goto err_release;
                }
        }

        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,
-               (unsigned long long)drhd->reg_base_addr,
+               (unsigned long long)iommu->reg_phys,
                DMAR_VER_MAJOR(ver), DMAR_VER_MINOR(ver),
                (unsigned long long)iommu->cap,
                (unsigned long long)iommu->ecap);
@@ -659,6 +673,8 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)

   err_unmap:
        iounmap(iommu->reg);
+ err_release:
+       release_mem_region(iommu->reg_phys, iommu->reg_size);
   error:
        kfree(iommu);
        return -1;
@@ -671,8 +687,11 @@ void free_iommu(struct intel_iommu *iommu)

        free_dmar_iommu(iommu);

-       if (iommu->reg)
+       if (iommu->reg) {
                iounmap(iommu->reg);
+               release_mem_region(iommu->reg_phys, iommu->reg_size);
+       }
+
        kfree(iommu);
  }

diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index e6ca56d..c6d132b 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -308,6 +308,8 @@ enum {

  struct intel_iommu {
        void __iomem    *reg; /* Pointer to hardware regs, virtual addr */
+       resource_size_t reg_phys;
+       resource_size_t reg_size;

I'd make these u64

ok, will work up v3 tomorrow..

thanks for feedback!
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