Re: [Qemu-devel] [PATCH] hw/arm/acpi: enable SHPC native hot plug

[Igor Mammedov <imammedo@redhat.com>]

On Fri, 1 Mar 2019 10:28:30 +0800
Heyi Guo <guoheyi@huawei.com> wrote:

> After the introduction of generic PCIe root port and PCIe-PCI bridge,
> we will also have SHPC controller on ARM, so just enalbe SHPC native
> hot plug.

Just out of curiosity,
An understand the need for SHPC on plain PCI but in case of PCIe
why native PCIe hotplug isn't sufficient?

> Cc: Shannon Zhao <shannon.zhaosl@gmail.com>
> Cc: Peter Maydell <peter.maydell@linaro.org>
> Cc: "Michael S. Tsirkin" <mst@redhat.com>
> Cc: Igor Mammedov <imammedo@redhat.com>
> Signed-off-by: Heyi Guo <guoheyi@huawei.com>
> Signed-off-by: Heyi Guo <heyi.guo@linaro.org>
> ---
>  hw/arm/virt-acpi-build.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
> index 04b62c7..7849ec5 100644
> --- a/hw/arm/virt-acpi-build.c
> +++ b/hw/arm/virt-acpi-build.c
> @@ -265,7 +265,12 @@ static void acpi_dsdt_add_pci(Aml *scope, const MemMapEntry *memmap,
>          aml_create_dword_field(aml_arg(3), aml_int(8), "CDW3"));
>      aml_append(ifctx, aml_store(aml_name("CDW2"), aml_name("SUPP")));
>      aml_append(ifctx, aml_store(aml_name("CDW3"), aml_name("CTRL")));
> -    aml_append(ifctx, aml_store(aml_and(aml_name("CTRL"), aml_int(0x1D), NULL),
> +
> +    /*
> +     * Allow OS control for all 5 features:
> +     * PCIeHotplug SHPCHotplug PME AER PCIeCapability.
> +     */
> +    aml_append(ifctx, aml_store(aml_and(aml_name("CTRL"), aml_int(0x1F), NULL),
>                                  aml_name("CTRL")));
>  
>      ifctx1 = aml_if(aml_lnot(aml_equal(aml_arg(1), aml_int(0x1))));