Re: [PATCH v3 2/3] PCI: hv: Move retarget related structures into tlfs header

[Boqun Feng <boqun.feng@gmail.com>]

On Thu, Feb 13, 2020 at 04:17:34AM +0000, Dexuan Cui wrote:
> > From: linux-hyperv-owner@vger.kernel.org
> > <linux-hyperv-owner@vger.kernel.org> On Behalf Of Boqun Feng
> > Sent: Sunday, February 9, 2020 7:40 PM
> > 
> > Currently, retarget_msi_interrupt and other structures it relys on are
> > defined in pci-hyperv.c. However, those structures are actually defined
> > in Hypervisor Top-Level Functional Specification [1] and may be
> > different in sizes of fields or layout from architecture to
> > architecture. Let's move those definitions into x86's tlfs header file
> > to support virtual PCI on non-x86 architectures in the future. Note that
> > "__packed" attribute is added to these structures during the movement
> > for the same reason as we use the attribute for other TLFS structures in
> > the header file: make sure the structures meet the specification and
> > avoid anything unexpected from the compilers.
> > 
> > Additionally, rename struct retarget_msi_interrupt to
> > hv_retarget_msi_interrupt for the consistent naming convention, also
> > mirroring the name in TLFS.
> > 
> > diff --git a/arch/x86/include/asm/hyperv-tlfs.h
> > b/arch/x86/include/asm/hyperv-tlfs.h
> > +
> > +struct hv_device_interrupt_target {
> > +	u32 vector;
> > +	u32 flags;
> > +	union {
> > +		u64 vp_mask;
> > +		struct hv_vpset vp_set;
> > +	};
> > +} __packed;
> > +
> > +/* HvRetargetDeviceInterrupt hypercall */
> 
> Reviewed-by: Dexuan Cui <decui@microsoft.com>
> 

Thanks!

> Just a small thing: would it be slightly better if we change the name 
> in the above line to HVCALL_RETARGET_INTERRUPT ? 
> 
> HVCALL_RETARGET_INTERRUPT is a define, so it may help to locate the
> actual value of the define here. And, HVCALL_RETARGET_INTERRUPT is
> used several times in the patchset so IMO we'd better always use
> the same name.

This might be a good suggestion, however, throughout the TLFS header,
camel case is more commonly used for referencing hypercall. For example:

	/* HvCallSendSyntheticClusterIpi hypercall */

So I think it's better to let it as it is for this patch, and later on,
if we reach a consensus, we can convert the names all together.

Thoughts?

Regards,
Boqun