On Wed, May 13, 2026 at 08:08:37AM -0700, Souradeep Chakrabarti wrote:
> On Mon, May 11, 2026 at 07:02:56PM -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.
> >
> > An L1VH VM only contains VMBus based devices. A device ID for a VMBus
> > device is slightly different in that it uses the hv_pcibus_device info
> > for building it to make sure it matches exactly what the hypervisor
> > expects. This VMBus based device ID is needed when attaching devices in
> > an L1VH based guest VM. Add a function to build and export it. Before
> > building it, a check is done to make sure the device is a valid VMBus
> > device.
> >
> > In remaining cases, PCI device ID is used. So, also make PCI device ID
> > build function hv_build_devid_type_pci() public.
> >
Reviewed-by: Souradeep Chakrabarti <[email protected]>
> Reviewed-by: Souradeep Chakrabarti <[email protected]>
> > Signed-off-by: Mukesh R <[email protected]>
> > ---
> > arch/x86/hyperv/irqdomain.c | 9 +++++----
> > arch/x86/include/asm/mshyperv.h | 6 ++++++
> > drivers/pci/controller/pci-hyperv.c | 24 ++++++++++++++++++++++++
> > include/asm-generic/mshyperv.h | 11 +++++++++++
> > 4 files changed, 46 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..2ef34001f8d3 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 */
> >
> > +#if IS_ENABLED(CONFIG_HYPERV_IOMMU)
> > +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 /* IS_ENABLED(CONFIG_HYPERV_IOMMU) */
> > +
> > #else /* CONFIG_HYPERV */
> > static inline void hyperv_init(void) {}
> > static inline void hyperv_setup_mmu_ops(void) {}
> > diff --git a/drivers/pci/controller/pci-hyperv.c
> > b/drivers/pci/controller/pci-hyperv.c
> > index cfc8fa403dad..50d793ca8f31 100644
> > --- a/drivers/pci/controller/pci-hyperv.c
> > +++ b/drivers/pci/controller/pci-hyperv.c
> > @@ -573,6 +573,7 @@ struct hv_pci_compl {
> > };
> >
> > static void hv_pci_onchannelcallback(void *context);
> > +static bool hv_vmbus_pci_device(struct pci_bus *pbus);
> >
> > #ifdef CONFIG_X86
> > #define DELIVERY_MODE APIC_DELIVERY_MODE_FIXED
> > @@ -1005,6 +1006,24 @@ static struct irq_domain
> > *hv_pci_get_root_domain(void)
> > static void hv_arch_irq_unmask(struct irq_data *data) { }
> > #endif /* CONFIG_ARM64 */
> >
> > +u64 hv_pci_vmbus_device_id(struct pci_dev *pdev)
> > +{
> > + struct hv_pcibus_device *hbus;
> > + struct pci_bus *pbus = pdev->bus;
> > +
> > + if (!hv_vmbus_pci_device(pbus))
> > + return 0;
> > +
> > + hbus = container_of(pbus->sysdata, struct hv_pcibus_device, sysdata);
> > +
> > + return (hbus->hdev->dev_instance.b[5] << 24) |
> > + (hbus->hdev->dev_instance.b[4] << 16) |
> > + (hbus->hdev->dev_instance.b[7] << 8) |
> > + (hbus->hdev->dev_instance.b[6] & 0xf8) |
> > + PCI_FUNC(pdev->devfn);
> > +}
> > +EXPORT_SYMBOL_GPL(hv_pci_vmbus_device_id);
> > +
> > /**
> > * hv_pci_generic_compl() - Invoked for a completion packet
> > * @context: Set up by the sender of the packet.
> > @@ -1403,6 +1422,11 @@ static struct pci_ops hv_pcifront_ops = {
> > .write = hv_pcifront_write_config,
> > };
> >
> > +static bool hv_vmbus_pci_device(struct pci_bus *pbus)
> > +{
> > + return pbus->ops == &hv_pcifront_ops;
> > +}
> > +
> > /*
> > * Paravirtual backchannel
> > *
> > diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
> > index e8cbc4e3f7ad..25ac7ca0fd8b 100644
> > --- a/include/asm-generic/mshyperv.h
> > +++ b/include/asm-generic/mshyperv.h
> > @@ -204,6 +204,9 @@ extern u64 (*hv_read_reference_counter)(void);
> > /* Sentinel value for an uninitialized entry in hv_vp_index array */
> > #define VP_INVAL U32_MAX
> >
> > +/* Forward declarations */
> > +struct pci_dev;
> > +
> > int __init hv_common_init(void);
> > void __init hv_get_partition_id(void);
> > void __init hv_common_free(void);
> > @@ -316,6 +319,14 @@ void hv_para_set_synic_register(unsigned int reg, u64
> > val);
> > void hyperv_cleanup(void);
> > bool hv_query_ext_cap(u64 cap_query);
> > void hv_setup_dma_ops(struct device *dev, bool coherent);
> > +
> > +#if IS_ENABLED(CONFIG_PCI_HYPERV)
> > +u64 hv_pci_vmbus_device_id(struct pci_dev *pdev);
> > +#else
> > +static inline u64 hv_pci_vmbus_device_id(struct pci_dev *pdev)
> > +{ return 0; }
> > +#endif /* IS_ENABLED(CONFIG_PCI_HYPERV) */
> > +
> > #else /* CONFIG_HYPERV */
> > static inline void hv_identify_partition_type(void) {}
> > static inline bool hv_is_hyperv_initialized(void) { return false; }
> > --
> > 2.51.2.vfs.0.1
> >
