1 files changed, 63 insertions, 19 deletions

diff --git a/drivers/misc/cxl/context.c b/drivers/misc/cxl/context.c
index 51fd6b524371..d1b55fe62817 100644
--- a/drivers/misc/cxl/context.c
+++ b/drivers/misc/cxl/context.c
@@ -100,6 +100,46 @@ int cxl_context_init(struct cxl_context *ctx, struct cxl_afu *afu, bool master,
         return 0;
 }
 
+static int cxl_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+        struct cxl_context *ctx = vma->vm_file->private_data;
+        unsigned long address = (unsigned long)vmf->virtual_address;
+        u64 area, offset;
+
+        offset = vmf->pgoff << PAGE_SHIFT;
+
+        pr_devel("%s: pe: %i address: 0x%lx offset: 0x%llx\n",
+                        __func__, ctx->pe, address, offset);
+
+        if (ctx->afu->current_mode == CXL_MODE_DEDICATED) {
+                area = ctx->afu->psn_phys;
+                if (offset > ctx->afu->adapter->ps_size)
+                        return VM_FAULT_SIGBUS;
+        } else {
+                area = ctx->psn_phys;
+                if (offset > ctx->psn_size)
+                        return VM_FAULT_SIGBUS;
+        }
+
+        mutex_lock(&ctx->status_mutex);
+
+        if (ctx->status != STARTED) {
+                mutex_unlock(&ctx->status_mutex);
+                pr_devel("%s: Context not started, failing problem state access\n", __func__);
+                return VM_FAULT_SIGBUS;
+        }
+
+        vm_insert_pfn(vma, address, (area + offset) >> PAGE_SHIFT);
+
+        mutex_unlock(&ctx->status_mutex);
+
+        return VM_FAULT_NOPAGE;
+}
+
+static const struct vm_operations_struct cxl_mmap_vmops = {
+        .fault = cxl_mmap_fault,
+};
+
 /*
  * Map a per-context mmio space into the given vma.
  */
@@ -108,26 +148,25 @@ int cxl_context_iomap(struct cxl_context *ctx, struct vm_area_struct *vma)
         u64 len = vma->vm_end - vma->vm_start;
         len = min(len, ctx->psn_size);
 
-        if (ctx->afu->current_mode == CXL_MODE_DEDICATED) {
-                vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
-                return vm_iomap_memory(vma, ctx->afu->psn_phys, ctx->afu->adapter->ps_size);
-        }
+        if (ctx->afu->current_mode != CXL_MODE_DEDICATED) {
+                /* make sure there is a valid per process space for this AFU */
+                if ((ctx->master && !ctx->afu->psa) || (!ctx->afu->pp_psa)) {
+                        pr_devel("AFU doesn't support mmio space\n");
+                        return -EINVAL;
+                }
 
-        /* make sure there is a valid per process space for this AFU */
-        if ((ctx->master && !ctx->afu->psa) || (!ctx->afu->pp_psa)) {
-                pr_devel("AFU doesn't support mmio space\n");
-                return -EINVAL;
+                /* Can't mmap until the AFU is enabled */
+                if (!ctx->afu->enabled)
+                        return -EBUSY;
         }
 
-        /* Can't mmap until the AFU is enabled */
-        if (!ctx->afu->enabled)
-                return -EBUSY;
-
         pr_devel("%s: mmio physical: %llx pe: %i master:%i\n", __func__,
                  ctx->psn_phys, ctx->pe , ctx->master);
 
+        vma->vm_flags |= VM_IO | VM_PFNMAP;
         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
-        return vm_iomap_memory(vma, ctx->psn_phys, len);
+        vma->vm_ops = &cxl_mmap_vmops;
+        return 0;
 }
 
 /*
@@ -150,12 +189,6 @@ static void __detach_context(struct cxl_context *ctx)
         afu_release_irqs(ctx);
         flush_work(&ctx->fault_work); /* Only needed for dedicated process */
         wake_up_all(&ctx->wq);
-
-        /* Release Problem State Area mapping */
-        mutex_lock(&ctx->mapping_lock);
-        if (ctx->mapping)
-                unmap_mapping_range(ctx->mapping, 0, 0, 1);
-        mutex_unlock(&ctx->mapping_lock);
 }
 
 /*
@@ -184,6 +217,17 @@ void cxl_context_detach_all(struct cxl_afu *afu)
                  * created and torn down after the IDR removed
                  */
                 __detach_context(ctx);
+
+                /*
+                 * We are force detaching - remove any active PSA mappings so
+                 * userspace cannot interfere with the card if it comes back.
+                 * Easiest way to exercise this is to unbind and rebind the
+                 * driver via sysfs while it is in use.
+                 */
+                mutex_lock(&ctx->mapping_lock);
+                if (ctx->mapping)
+                        unmap_mapping_range(ctx->mapping, 0, 0, 1);
+                mutex_unlock(&ctx->mapping_lock);
         }
         mutex_unlock(&afu->contexts_lock);
 }