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Re: [PATCH] acpi/gpex: Inform os to keep firmware resource map
From: |
Jiahui Cen |
Subject: |
Re: [PATCH] acpi/gpex: Inform os to keep firmware resource map |
Date: |
Thu, 17 Dec 2020 21:52:26 +0800 |
User-agent: |
Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 |
+Laszlo
On 2020/12/17 21:29, 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.
>
> 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 <cenjiahui@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;
>