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

Wei Liu
2021-02-03T13:27:02Z

On Tue, Feb 02, 2021 at 05:02:48PM +0000, Wei Liu wrote:
> On Tue, Jan 26, 2021 at 01:26:52AM +0000, Michael Kelley wrote:
> > 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.
> >
>
> No. It is not junk. I got this from a header in tree.
>
> I am inclined to just drop this hunk. If that breaks things, I will use
> "reserved0".
>

It turns out adding reserved0 is required. Dropping this hunk does not
work.

Wei.