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.
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 <cenjia...@huawei.com>
---
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
