> > From: Wei Liu <[email protected]> > > On a nested root partition the vPCI MSI/MSI-X interrupts of vmbus devices > (e.g. the MANA NIC) are mapped in the hypervisor with a > MAP_DEVICE_INTERRUPT hypercall. This is done from hv_arch_irq_unmask() > -> hv_map_msi_interrupt() because the nested hypervisor performs the > interrupt remapping and a RETARGET_INTERRUPT is not usable there. > > The mapping was never removed: hv_arch_irq_unmask() called > hv_map_msi_interrupt(data, NULL), so the returned hv_interrupt_entry was > discarded, and hv_msi_free() tears the interrupt down with a vmbus > PCI_DELETE_INTERRUPT message (hv_int_desc_free()) without issuing > UNMAP_DEVICE_INTERRUPT. > > This has led to MSHV rejecting already-mapped (vp, vector) pair from being > used. When this happens during early boot, the system hangs. > > Keep the hypervisor mapping in sync with the kernel's interrupt lifecycle. > > The mapping is only created on x86 (hv_arch_irq_unmask() is a stub on > arm64), so the unmap hypercall is guarded accordingly. > > Signed-off-by: Wei Liu <[email protected]> > --- > drivers/pci/controller/pci-hyperv.c | 85 ++++++++++++++++++++++++++--- > 1 file changed, 78 insertions(+), 7 deletions(-) > > diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci- > hyperv.c > index cfc8fa403dad..5a36382742bf 100644 > --- a/drivers/pci/controller/pci-hyperv.c > +++ b/drivers/pci/controller/pci-hyperv.c > @@ -283,6 +283,35 @@ struct tran_int_desc { > u64 address; > } __packed; > > +/* > + * On a nested root partition a vPCI MSI is mapped in the hypervisor > +with a > + * MAP_DEVICE_INTERRUPT hypercall in hv_arch_irq_unmask(). Keep the > +entry the > + * hypervisor returns next to the per-interrupt transaction descriptor > +so the > + * mapping can be removed again with UNMAP_DEVICE_INTERRUPT when > the > +interrupt > + * is torn down. tran_int_desc stays first: chip_data is used as a > +struct > + * tran_int_desc throughout this driver. > + */ > +struct hv_msi_int_entry { > + struct tran_int_desc int_desc; > + struct hv_interrupt_entry hv_entry; > +}; > + > +/* chip_data is passed around as a struct tran_int_desc *, so it must > +be first. */ static_assert(offsetof(struct hv_msi_int_entry, int_desc) > +== 0); > + > +static void hv_vmbus_unmap_msi_interrupt(struct pci_dev *pdev > __maybe_unused, > + void *chip_data) > +{ > + struct hv_msi_int_entry *ie = chip_data; > + > + if (!ie || !ie->hv_entry.source) > + return; > +#ifdef CONFIG_X86 > + hv_unmap_msi_interrupt(pdev, &ie->hv_entry); #endif
Since you don't want to check the return value from hv_unmap_msi_interrupt(), add a (void) to the front to prevent some tools from giving warnings.
