RE: [PATCH v5 13/16] asm-generic/hyperv: introduce hv_device_id and auxiliary structures

[Michael Kelley <mikelley@microsoft.com>]

From: Wei Liu <wei.liu@kernel.org> Sent: Wednesday, January 20, 2021 4:01 AM
> 
> We will need to identify the device we want Microsoft Hypervisor to
> manipulate.  Introduce the data structures for that purpose.
> 
> They will be used in a later patch.
> 
> Signed-off-by: Sunil Muthuswamy <sunilmut@microsoft.com>
> Co-Developed-by: Sunil Muthuswamy <sunilmut@microsoft.com>
> Signed-off-by: Wei Liu <wei.liu@kernel.org>
> ---
>  include/asm-generic/hyperv-tlfs.h | 79 +++++++++++++++++++++++++++++++
>  1 file changed, 79 insertions(+)
> 
> diff --git a/include/asm-generic/hyperv-tlfs.h b/include/asm-generic/hyperv-tlfs.h
> index 8423bf53c237..42ff1326c6bd 100644
> --- a/include/asm-generic/hyperv-tlfs.h
> +++ b/include/asm-generic/hyperv-tlfs.h
> @@ -623,4 +623,83 @@ struct hv_set_vp_registers_input {
>  	} element[];
>  } __packed;
> 
> +enum hv_device_type {
> +	HV_DEVICE_TYPE_LOGICAL = 0,
> +	HV_DEVICE_TYPE_PCI = 1,
> +	HV_DEVICE_TYPE_IOAPIC = 2,
> +	HV_DEVICE_TYPE_ACPI = 3,
> +};
> +
> +typedef u16 hv_pci_rid;
> +typedef u16 hv_pci_segment;
> +typedef u64 hv_logical_device_id;
> +union hv_pci_bdf {
> +	u16 as_uint16;
> +
> +	struct {
> +		u8 function:3;
> +		u8 device:5;
> +		u8 bus;
> +	};
> +} __packed;
> +
> +union hv_pci_bus_range {
> +	u16 as_uint16;
> +
> +	struct {
> +		u8 subordinate_bus;
> +		u8 secondary_bus;
> +	};
> +} __packed;
> +
> +union hv_device_id {
> +	u64 as_uint64;
> +
> +	struct {
> +		u64 :62;
> +		u64 device_type:2;
> +	};

Are the above 4 lines extraneous junk? 
If not, a comment would be helpful.  And we
would normally label the 62 bit field as 
"reserved0" or something similar.

> +
> +	/* HV_DEVICE_TYPE_LOGICAL */
> +	struct {
> +		u64 id:62;
> +		u64 device_type:2;
> +	} logical;
> +
> +	/* HV_DEVICE_TYPE_PCI */
> +	struct {
> +		union {
> +			hv_pci_rid rid;
> +			union hv_pci_bdf bdf;
> +		};
> +
> +		hv_pci_segment segment;
> +		union hv_pci_bus_range shadow_bus_range;
> +
> +		u16 phantom_function_bits:2;
> +		u16 source_shadow:1;
> +
> +		u16 rsvdz0:11;
> +		u16 device_type:2;
> +	} pci;
> +
> +	/* HV_DEVICE_TYPE_IOAPIC */
> +	struct {
> +		u8 ioapic_id;
> +		u8 rsvdz0;
> +		u16 rsvdz1;
> +		u16 rsvdz2;
> +
> +		u16 rsvdz3:14;
> +		u16 device_type:2;
> +	} ioapic;
> +
> +	/* HV_DEVICE_TYPE_ACPI */
> +	struct {
> +		u32 input_mapping_base;
> +		u32 input_mapping_count:30;
> +		u32 device_type:2;
> +	} acpi;
> +} __packed;
> +
>  #endif
> --
> 2.20.1