[PATCH] hw/pci: Add parenthesis to PCI_BUILD_BDF macro

[Roque Arcudia Hernandez <roqueh@google.com>]

The bus parameter in the macro PCI_BUILD_BDF is not surrounded by
parenthesis. This can create a compile error when warnings are
treated as errors or can potentially create runtime errors due to the
operator precedence.

For instance:

 file.c:x:32: error: suggest parentheses around '-' inside '<<'
 [-Werror=parentheses]
   171 | uint16_t bdf = PCI_BUILD_BDF(a - b, sdev->devfn);
       |                              ~~^~~
 include/hw/pci/pci.h:19:41: note: in definition of macro
 'PCI_BUILD_BDF'
    19 | #define PCI_BUILD_BDF(bus, devfn)     ((bus << 8) | (devfn))
       |                                         ^~~
 cc1: all warnings being treated as errors

Signed-off-by: Roque Arcudia Hernandez <roqueh@google.com>
Reviewed-by: Nabih Estefan <nabihestefan@google.com>
---
 include/hw/pci/pci.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
index 35d4fe0bbf..1daec974da 100644
--- a/include/hw/pci/pci.h
+++ b/include/hw/pci/pci.h
@@ -16,7 +16,7 @@ extern bool pci_available;
 #define PCI_BUS_NUM(x)          (((x) >> 8) & 0xff)
 #define PCI_SLOT(devfn)         (((devfn) >> 3) & 0x1f)
 #define PCI_FUNC(devfn)         ((devfn) & 0x07)
-#define PCI_BUILD_BDF(bus, devfn)     ((bus << 8) | (devfn))
+#define PCI_BUILD_BDF(bus, devfn)     (((bus) << 8) | (devfn))
 #define PCI_BDF_TO_DEVFN(x)     ((x) & 0xff)
 #define PCI_BUS_MAX             256
 #define PCI_DEVFN_MAX           256
-- 
2.47.0.163.g1226f6d8fa-goog