On Thu, Dec 17, 2020 at 09:29:26PM +0800, Jiahui Cen wrote: > There may be some differences in pci resource assignment between guest os > and firmware. > > Eg. A Bridge with Bus [d2] > -+-[0000:d2]---01.0-[d3]----01.0 > > where [d2:01.00] is a pcie-pci-bridge with BAR0 (mem, 64-bit, non-pref) > [size=256] > [d3:01.00] is a PCI Device with BAR0 (mem, 64-bit, pref) [size=128K] > BAR4 (mem, 64-bit, pref) [size=64M] > > In EDK2, the Resource Map would be: > PciBus: Resource Map for Bridge [D2|01|00] > Type = PMem64; Base = 0x8004000000; Length = 0x4100000; > Alignment = 0x3FFFFFF > Base = 0x8004000000; Length = 0x4000000; Alignment = > 0x3FFFFFF; Owner = PCI [D3|01|00:20] > Base = 0x8008000000; Length = 0x20000; Alignment = 0x1FFFF; > Owner = PCI [D3|01|00:10] > Type = Mem64; Base = 0x8008100000; Length = 0x100; Alignment = > 0xFFF > > While in Linux, kernel will use 0x2FFFFFF as the alignment to calculate > the PMem64 size, which would be 0x6000000. > > The diffences could result in resource assignment failure.
A bit more data here please. When does this result in a failure? > Using _DSM #5 method to inform guest os not to ignore the PCI configuration > that firmware has done at boot time could handle the differences. > > Signed-off-by: Jiahui Cen <[email protected]> > --- > hw/pci-host/gpex-acpi.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/hw/pci-host/gpex-acpi.c b/hw/pci-host/gpex-acpi.c > index 071aa11b5c..2b490f3379 100644 > --- a/hw/pci-host/gpex-acpi.c > +++ b/hw/pci-host/gpex-acpi.c > @@ -112,10 +112,19 @@ static void acpi_dsdt_add_pci_osc(Aml *dev) > UUID = aml_touuid("E5C937D0-3553-4D7A-9117-EA4D19C3434D"); > ifctx = aml_if(aml_equal(aml_arg(0), UUID)); > ifctx1 = aml_if(aml_equal(aml_arg(2), aml_int(0))); > - uint8_t byte_list[1] = {1}; > + uint8_t byte_list[1] = {0x21}; > buf = aml_buffer(1, byte_list); > aml_append(ifctx1, aml_return(buf)); > aml_append(ifctx, ifctx1); > + > + /* PCI Firmware Specification 3.2 > + * 4.6.5. _DSM for Ignoring PCI Boot Configurations > + * The UUID in _DSM in this context is > + * {E5C937D0-3553-4D7A-9117-EA4D19C3434D} > + */ > + ifctx1 = aml_if(aml_equal(aml_arg(2), aml_int(5))); > + aml_append(ifctx1, aml_return(aml_int(0))); > + aml_append(ifctx, ifctx1); > aml_append(method, ifctx); > > byte_list[0] = 0; > -- > 2.28.0
