1 files changed, 56 insertions, 0 deletions

diff --git a/drivers/staging/rdma/hfi1/chip.c b/drivers/staging/rdma/hfi1/chip.c
index fe73ebf077e4..7799652773d5 100644
--- a/drivers/staging/rdma/hfi1/chip.c
+++ b/drivers/staging/rdma/hfi1/chip.c
@@ -13943,6 +13943,50 @@ static int obtain_boardname(struct hfi1_devdata *dd)
         return 0;
 }
 
+/*
+ * Check the interrupt registers to make sure that they are mapped correctly.
+ * It is intended to help user identify any mismapping by VMM when the driver
+ * is running in a VM. This function should only be called before interrupt
+ * is set up properly.
+ *
+ * Return 0 on success, -EINVAL on failure.
+ */
+static int check_int_registers(struct hfi1_devdata *dd)
+{
+        u64 reg;
+        u64 all_bits = ~(u64)0;
+        u64 mask;
+
+        /* Clear CceIntMask[0] to avoid raising any interrupts */
+        mask = read_csr(dd, CCE_INT_MASK);
+        write_csr(dd, CCE_INT_MASK, 0ull);
+        reg = read_csr(dd, CCE_INT_MASK);
+        if (reg)
+                goto err_exit;
+
+        /* Clear all interrupt status bits */
+        write_csr(dd, CCE_INT_CLEAR, all_bits);
+        reg = read_csr(dd, CCE_INT_STATUS);
+        if (reg)
+                goto err_exit;
+
+        /* Set all interrupt status bits */
+        write_csr(dd, CCE_INT_FORCE, all_bits);
+        reg = read_csr(dd, CCE_INT_STATUS);
+        if (reg != all_bits)
+                goto err_exit;
+
+        /* Restore the interrupt mask */
+        write_csr(dd, CCE_INT_CLEAR, all_bits);
+        write_csr(dd, CCE_INT_MASK, mask);
+
+        return 0;
+err_exit:
+        write_csr(dd, CCE_INT_MASK, mask);
+        dd_dev_err(dd, "Interrupt registers not properly mapped by VMM\n");
+        return -EINVAL;
+}
+
 /**
  * Allocate and initialize the device structure for the hfi.
  * @dev: the pci_dev for hfi1_ib device
@@ -13967,6 +14011,7 @@ struct hfi1_devdata *hfi1_init_dd(struct pci_dev *pdev,
                 "RTL FPGA emulation",
                 "Functional simulator"
         };
+        struct pci_dev *parent = pdev->bus->self;
 
         dd = hfi1_alloc_devdata(pdev, NUM_IB_PORTS *
                                 sizeof(struct hfi1_pportdata));
@@ -14046,6 +14091,17 @@ struct hfi1_devdata *hfi1_init_dd(struct pci_dev *pdev,
                         & CCE_REVISION_CHIP_REV_MINOR_MASK;
 
         /*
+         * Check interrupt registers mapping if the driver has no access to
+         * the upstream component. In this case, it is likely that the driver
+         * is running in a VM.
+         */
+        if (!parent) {
+                ret = check_int_registers(dd);
+                if (ret)
+                        goto bail_cleanup;
+        }
+
+        /*
          * obtain the hardware ID - NOT related to unit, which is a
          * software enumeration
          */