From: Wei Liu <[email protected]> hv_compose_msi_msg() sends PCI_CREATE_INTERRUPT carrying int_desc.vector, and the vPCI backend programs the device with the address/data it returns for it.
An affinity change only ran irq_chip_set_affinity_parent(), which re-allocates the x86 vector and nothing else, and hv_arch_irq_unmask() then issued MAP_DEVICE_INTERRUPT for the new (VP, vector). Nothing re-composed the interrupt, so the device kept signalling the vector it was created with and the new mapping was never used. This led to loss of interrupts. Do the re-target where the vector is known and the interrupt is quiescent. If the vector changed, re-compose the VMBus interrupt for it, write the resulting message to the device, and only then map the new (vp, vector); the old mapping is destroyed as the new message is composed. Signed-off-by: Wei Liu <[email protected]> --- drivers/pci/controller/pci-hyperv.c | 41 +++++++++++++++++++++++++++-- 1 file changed, 39 insertions(+), 2 deletions(-) diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c index 5a36382742bf..5acb8e41567e 100644 --- a/drivers/pci/controller/pci-hyperv.c +++ b/drivers/pci/controller/pci-hyperv.c @@ -294,6 +294,7 @@ struct tran_int_desc { struct hv_msi_int_entry { struct tran_int_desc int_desc; struct hv_interrupt_entry hv_entry; + unsigned int mapped_vector; }; /* chip_data is passed around as a struct tran_int_desc *, so it must be first. */ @@ -742,6 +743,8 @@ static void hv_irq_retarget_interrupt(struct irq_data *data) "%s() failed: %#llx", __func__, res); } +static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg); + static void hv_arch_irq_unmask(struct irq_data *data) { if (hv_root_partition()) { @@ -752,9 +755,17 @@ static void hv_arch_irq_unmask(struct irq_data *data) * RETARGET_INTERRUPT. * * Keep the returned entry so the mapping can be removed again - * when the interrupt is torn down. + * when the interrupt is re-targeted or torn down. + * + * This is also the re-target point. The core calls us from + * __irq_move_irq() with the interrupt masked once the new + * vector has been assigned, so if the vector changed the vmbus + * interrupt is re-composed for it first -- PCI_CREATE_INTERRUPT + * carries the vector, so the device would otherwise keep + * signalling the one it was created with. */ struct hv_msi_int_entry *ie = data->chip_data; + unsigned int vec = hv_msi_get_int_vector(data); /* * A NULL chip_data means hv_compose_msi_msg() failed and the @@ -763,8 +774,29 @@ static void hv_arch_irq_unmask(struct irq_data *data) if (!ie) return; - if (hv_map_msi_interrupt(data, &ie->hv_entry)) + /* Already mapped for this vector, nothing changed. */ + if (ie->mapped_vector == vec && ie->hv_entry.source) + return; + + if (ie->mapped_vector && ie->mapped_vector != vec) { + struct msi_msg msg; + + hv_compose_msi_msg(data, &msg); + + ie = data->chip_data; + if (!ie) + return; + + if (data->chip->irq_write_msi_msg) + data->chip->irq_write_msi_msg(data, &msg); + } + + if (hv_map_msi_interrupt(data, &ie->hv_entry)) { memset(&ie->hv_entry, 0, sizeof(ie->hv_entry)); + ie->mapped_vector = 0; + return; + } + ie->mapped_vector = vec; } else { hv_irq_retarget_interrupt(data); } @@ -1974,6 +2006,11 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg) if (data->chip_data && !multi_msi) { int_desc = data->chip_data; data->chip_data = NULL; + /* + * The descriptor is about to be destroyed, so release the + * hypervisor mapping that belongs to it first. + */ + hv_vmbus_unmap_msi_interrupt(pdev, int_desc); hv_int_desc_free(hpdev, int_desc); } -- 2.53.0
