On 2025/4/23 00:06, Jan Beulich wrote: > On 21.04.2025 08:18, Jiqian Chen wrote: >> --- a/xen/include/xen/pci_regs.h >> +++ b/xen/include/xen/pci_regs.h >> @@ -449,6 +449,7 @@ >> #define PCI_EXT_CAP_ID(header) ((header) & 0x0000ffff) >> #define PCI_EXT_CAP_VER(header) (((header) >> 16) & 0xf) >> #define PCI_EXT_CAP_NEXT(header) (((header) >> 20) & 0xffc) >> +#define PCI_EXT_CAP_NEXT_MASK 0xFFC00000U > > To avoid introducing redundancy, imo this addition calls for > > #define PCI_EXT_CAP_NEXT(header) MASK_EXTR(header, PCI_EXT_CAP_NEXT_MASK) When I tested this locally, I encountered errors: every next position address loss two bits zero. The next register has 12 bits, according to PCI spec, the bottom two bits are reserved zero, so "#define PCI_EXT_CAP_NEXT_MASK 0xFFC00000U" is fine, but if change this "#define PCI_EXT_CAP_NEXT(header) MASK_EXTR(header, PCI_EXT_CAP_NEXT_MASK)", I need to change PCI_EXT_CAP_NEXT_MASK to be 0xFFF00000U, is it fine?
> > now. > > Jan -- Best regards, Jiqian Chen.
