[Qemu-devel] [PATCH for-2.6 1/2] Add param Error** to msi_init()

[Cao jin]

msi_init() is a supporting function in PCI device initialization, in order to
convert .init() to .realize(), it should be modified first.

Bonus: add more comment.
Signed-off-by: Cao jin <caoj.f...@cn.fujitsu.com>
---
 hw/pci/msi.c         | 17 +++++++++++++----
 include/hw/pci/msi.h |  4 ++--
 2 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/hw/pci/msi.c b/hw/pci/msi.c
index c1dd531..1f5d9e8 100644
--- a/hw/pci/msi.c
+++ b/hw/pci/msi.c
@@ -150,15 +150,23 @@ bool msi_enabled(const PCIDevice *dev)
          PCI_MSI_FLAGS_ENABLE);
 }
 
-int msi_init(struct PCIDevice *dev, uint8_t offset,
-             unsigned int nr_vectors, bool msi64bit, bool msi_per_vector_mask)
+/*
+ * @nr_vectors: Multiple Message Capable field of Message Control register
+ * @msi64bit: support 64-bit message address or not
+ * @msi_per_vector_mask: support per-vector masking or not
+ *
+ * return: MSI capability offset in config space
+ */
+int msi_init(struct PCIDevice *dev, uint8_t offset, unsigned int nr_vectors,
+             bool msi64bit, bool msi_per_vector_mask, Error **errp)
 {
     unsigned int vectors_order;
-    uint16_t flags;
+    uint16_t flags; /* Message Control register value */
     uint8_t cap_size;
     int config_offset;
 
     if (!msi_supported) {
+        error_setg(errp, "MSI/MSI-X is not supported by interrupt controller");
         return -ENOTSUP;
     }
 
@@ -182,7 +190,7 @@ int msi_init(struct PCIDevice *dev, uint8_t offset,
     }
 
     cap_size = msi_cap_sizeof(flags);
-    config_offset = pci_add_capability(dev, PCI_CAP_ID_MSI, offset, cap_size);
+    config_offset = pci_add_capability2(dev, PCI_CAP_ID_MSI, offset, cap_size, 
errp);
     if (config_offset < 0) {
         return config_offset;
     }
@@ -205,6 +213,7 @@ int msi_init(struct PCIDevice *dev, uint8_t offset,
         pci_set_long(dev->wmask + msi_mask_off(dev, msi64bit),
                      0xffffffff >> (PCI_MSI_VECTORS_MAX - nr_vectors));
     }
+
     return config_offset;
 }
 
diff --git a/include/hw/pci/msi.h b/include/hw/pci/msi.h
index 50e452b..da1dc1a 100644
--- a/include/hw/pci/msi.h
+++ b/include/hw/pci/msi.h
@@ -34,8 +34,8 @@ extern bool msi_supported;
 void msi_set_message(PCIDevice *dev, MSIMessage msg);
 MSIMessage msi_get_message(PCIDevice *dev, unsigned int vector);
 bool msi_enabled(const PCIDevice *dev);
-int msi_init(struct PCIDevice *dev, uint8_t offset,
-             unsigned int nr_vectors, bool msi64bit, bool msi_per_vector_mask);
+int msi_init(struct PCIDevice *dev, uint8_t offset, unsigned int nr_vectors,
+             bool msi64bit, bool msi_per_vector_mask, Error **errp);
 void msi_uninit(struct PCIDevice *dev);
 void msi_reset(PCIDevice *dev);
 void msi_notify(PCIDevice *dev, unsigned int vector);
-- 
2.1.0