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

[Dexuan Cui <decui@microsoft.com>]

> 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>

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.