Have found the problem is grub2's setpci uses I/O-mapped read/write which are
limited up to PCI register 0xff. Below is the offending code:
static inline grub_uint8_t
grub_pci_read_byte (grub_pci_address_t addr)
{
grub_outl (addr & ~3, GRUB_PCI_ADDR_REG);
return grub_inb (GRUB_PCI_DATA_REG + (addr & 3));
}
The solution: To modify grub2 code to do memory mapped read/write to PCIe
register 0x209 (or up to full 4k) using formula along the lines of:
address=RCBA + -s [[[[<domain>]:]<bus>]:][<slot>][.[<func>]] .. whatever it is.
PCIUtil's setpci does allow 4k register read/writes, so there is a code base
for it already.
On Tuesday, 28 March 2023 at 08:56:10 pm AEDT, Nando <[email protected]>
wrote:
Hello everybody,
As per title, setpci.mod's setpci command can read/write up to 0xFF registers
but returns an incorrect (0xFF) value for any registers beyond 0xFF.. There is
a 4K PCIe configuration space (0xFFF) per device.
eg:
setpci -s 0:1f.0 0xf0.l -> returns correct valuesetpci -s 0:1f.0 0x200.l ->
returns 0xff (incorrect)
Extending setpci.mod in this way would bring it's functionality in line with
EFI Shells 'mm' command that can read/write all 4K PCIe registers, as well as
pciutils' setpci command that can do the same.
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