Re: [PATCH v5 6/9] PCI: hv: Export hv_build_devid_type_pci() and change return type

[Bjorn Helgaas <helgaas@kernel.org>]

On Fri, Jul 31, 2026 at 03:34:24PM -0700, Mukesh R wrote:
> On Hyper-V, most hypercalls related to PCI passthru to map/unmap regions,
> interrupts, etc need a device ID as a parameter. This device ID refers
> to that specific device during the lifetime of passthru. So,
> make hv_build_devid_type_pci() public and change return type to u64 to
> enforce it's size.

s/it's/its/

This patch doesn't have anything to do with the PCI core specifically,
so the "PCI: hv:" subject line looks a little funny and doesn't look
anything like previous history of these two files.

> Signed-off-by: Mukesh R <mrathor@linux.microsoft.com>
> Reviewed-by: Souradeep Chakrabarti <schakrabarti@linux.microsoft.com>
> ---
>  arch/x86/hyperv/irqdomain.c     | 9 +++++----
>  arch/x86/include/asm/mshyperv.h | 6 ++++++
>  2 files changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/hyperv/irqdomain.c b/arch/x86/hyperv/irqdomain.c
> index b3ad50a874dc..8780573a4332 100644
> --- a/arch/x86/hyperv/irqdomain.c
> +++ b/arch/x86/hyperv/irqdomain.c
> @@ -112,7 +112,7 @@ static int get_rid_cb(struct pci_dev *pdev, u16 alias, void *data)
>  	return 0;
>  }
>  
> -static union hv_device_id hv_build_devid_type_pci(struct pci_dev *pdev)
> +u64 hv_build_devid_type_pci(struct pci_dev *pdev)
>  {
>  	int pos;
>  	union hv_device_id hv_devid;
> @@ -172,8 +172,9 @@ static union hv_device_id hv_build_devid_type_pci(struct pci_dev *pdev)
>  	}
>  
>  out:
> -	return hv_devid;
> +	return hv_devid.as_uint64;
>  }
> +EXPORT_SYMBOL_GPL(hv_build_devid_type_pci);
>  
>  /*
>   * hv_map_msi_interrupt() - Map the MSI IRQ in the hypervisor.
> @@ -196,7 +197,7 @@ int hv_map_msi_interrupt(struct irq_data *data,
>  
>  	msidesc = irq_data_get_msi_desc(data);
>  	pdev = msi_desc_to_pci_dev(msidesc);
> -	hv_devid = hv_build_devid_type_pci(pdev);
> +	hv_devid.as_uint64 = hv_build_devid_type_pci(pdev);
>  	cpu = cpumask_first(irq_data_get_effective_affinity_mask(data));
>  
>  	return hv_map_interrupt(hv_devid, false, cpu, cfg->vector,
> @@ -271,7 +272,7 @@ static int hv_unmap_msi_interrupt(struct pci_dev *pdev,
>  {
>  	union hv_device_id hv_devid;
>  
> -	hv_devid = hv_build_devid_type_pci(pdev);
> +	hv_devid.as_uint64 = hv_build_devid_type_pci(pdev);
>  	return hv_unmap_interrupt(hv_devid.as_uint64, irq_entry);
>  }
>  
> diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
> index f64393e853ee..8ebbd1cb7c8c 100644
> --- a/arch/x86/include/asm/mshyperv.h
> +++ b/arch/x86/include/asm/mshyperv.h
> @@ -248,6 +248,12 @@ void hv_crash_asm_end(void);
>  static inline void hv_root_crash_init(void) {}
>  #endif  /* CONFIG_MSHV_ROOT && CONFIG_CRASH_DUMP */
>  
> +#ifdef CONFIG_PCI_MSI
> +u64 hv_build_devid_type_pci(struct pci_dev *pdev);
> +#else
> +static inline u64 hv_build_devid_type_pci(struct pci_dev *pdev) { return 0; }
> +#endif
> +
>  #else /* CONFIG_HYPERV */
>  static inline void hyperv_init(void) {}
>  static inline void hyperv_setup_mmu_ops(void) {}
> -- 
> 2.51.2.vfs.0.1
>