diff options
Diffstat (limited to 'drivers/pci/controller/pci-hyperv.c')
| -rw-r--r-- | drivers/pci/controller/pci-hyperv.c | 131 |
1 files changed, 94 insertions, 37 deletions
diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c index e7c6f6629e7c..084f5313895c 100644 --- a/drivers/pci/controller/pci-hyperv.c +++ b/drivers/pci/controller/pci-hyperv.c @@ -611,20 +611,7 @@ static unsigned int hv_msi_get_int_vector(struct irq_data *data) return cfg->vector; } -static int hv_msi_prepare(struct irq_domain *domain, struct device *dev, - int nvec, msi_alloc_info_t *info) -{ - int ret = pci_msi_prepare(domain, dev, nvec, info); - - /* - * By using the interrupt remapper in the hypervisor IOMMU, contiguous - * CPU vectors is not needed for multi-MSI - */ - if (info->type == X86_IRQ_ALLOC_TYPE_PCI_MSI) - info->flags &= ~X86_IRQ_ALLOC_CONTIGUOUS_VECTORS; - - return ret; -} +#define hv_msi_prepare pci_msi_prepare /** * hv_arch_irq_unmask() - "Unmask" the IRQ by setting its current @@ -735,9 +722,9 @@ exit_unlock: * during hibernation does not matter (at this time all the devices * have been frozen). Note: the correct affinity info is still updated * into the irqdata data structure in migrate_one_irq() -> - * irq_do_set_affinity() -> hv_set_affinity(), so later when the VM - * resumes, hv_pci_restore_msi_state() is able to correctly restore - * the interrupt with the correct affinity. + * irq_do_set_affinity(), so later when the VM resumes, + * hv_pci_restore_msi_state() is able to correctly restore the + * interrupt with the correct affinity. */ if (!hv_result_success(res) && hbus->state != hv_pcibus_removing) dev_err(&hbus->hdev->device, @@ -1613,8 +1600,8 @@ out: } static u32 hv_compose_msi_req_v1( - struct pci_create_interrupt *int_pkt, const struct cpumask *affinity, - u32 slot, u8 vector, u8 vector_count) + struct pci_create_interrupt *int_pkt, + u32 slot, u8 vector, u16 vector_count) { int_pkt->message_type.type = PCI_CREATE_INTERRUPT_MESSAGE; int_pkt->wslot.slot = slot; @@ -1632,6 +1619,35 @@ static u32 hv_compose_msi_req_v1( } /* + * The vCPU selected by hv_compose_multi_msi_req_get_cpu() and + * hv_compose_msi_req_get_cpu() is a "dummy" vCPU because the final vCPU to be + * interrupted is specified later in hv_irq_unmask() and communicated to Hyper-V + * via the HVCALL_RETARGET_INTERRUPT hypercall. But the choice of dummy vCPU is + * not irrelevant because Hyper-V chooses the physical CPU to handle the + * interrupts based on the vCPU specified in message sent to the vPCI VSP in + * hv_compose_msi_msg(). Hyper-V's choice of pCPU is not visible to the guest, + * but assigning too many vPCI device interrupts to the same pCPU can cause a + * performance bottleneck. So we spread out the dummy vCPUs to influence Hyper-V + * to spread out the pCPUs that it selects. + * + * For the single-MSI and MSI-X cases, it's OK for hv_compose_msi_req_get_cpu() + * to always return the same dummy vCPU, because a second call to + * hv_compose_msi_msg() contains the "real" vCPU, causing Hyper-V to choose a + * new pCPU for the interrupt. But for the multi-MSI case, the second call to + * hv_compose_msi_msg() exits without sending a message to the vPCI VSP, so the + * original dummy vCPU is used. This dummy vCPU must be round-robin'ed so that + * the pCPUs are spread out. All interrupts for a multi-MSI device end up using + * the same pCPU, even though the vCPUs will be spread out by later calls + * to hv_irq_unmask(), but that is the best we can do now. + * + * With Hyper-V in Nov 2022, the HVCALL_RETARGET_INTERRUPT hypercall does *not* + * cause Hyper-V to reselect the pCPU based on the specified vCPU. Such an + * enhancement is planned for a future version. With that enhancement, the + * dummy vCPU selection won't matter, and interrupts for the same multi-MSI + * device will be spread across multiple pCPUs. + */ + +/* * Create MSI w/ dummy vCPU set targeting just one vCPU, overwritten * by subsequent retarget in hv_irq_unmask(). */ @@ -1640,18 +1656,39 @@ static int hv_compose_msi_req_get_cpu(const struct cpumask *affinity) return cpumask_first_and(affinity, cpu_online_mask); } -static u32 hv_compose_msi_req_v2( - struct pci_create_interrupt2 *int_pkt, const struct cpumask *affinity, - u32 slot, u8 vector, u8 vector_count) +/* + * Make sure the dummy vCPU values for multi-MSI don't all point to vCPU0. + */ +static int hv_compose_multi_msi_req_get_cpu(void) { + static DEFINE_SPINLOCK(multi_msi_cpu_lock); + + /* -1 means starting with CPU 0 */ + static int cpu_next = -1; + + unsigned long flags; int cpu; + spin_lock_irqsave(&multi_msi_cpu_lock, flags); + + cpu_next = cpumask_next_wrap(cpu_next, cpu_online_mask, nr_cpu_ids, + false); + cpu = cpu_next; + + spin_unlock_irqrestore(&multi_msi_cpu_lock, flags); + + return cpu; +} + +static u32 hv_compose_msi_req_v2( + struct pci_create_interrupt2 *int_pkt, int cpu, + u32 slot, u8 vector, u16 vector_count) +{ int_pkt->message_type.type = PCI_CREATE_INTERRUPT_MESSAGE2; int_pkt->wslot.slot = slot; int_pkt->int_desc.vector = vector; int_pkt->int_desc.vector_count = vector_count; int_pkt->int_desc.delivery_mode = DELIVERY_MODE; - cpu = hv_compose_msi_req_get_cpu(affinity); int_pkt->int_desc.processor_array[0] = hv_cpu_number_to_vp_number(cpu); int_pkt->int_desc.processor_count = 1; @@ -1660,18 +1697,15 @@ static u32 hv_compose_msi_req_v2( } static u32 hv_compose_msi_req_v3( - struct pci_create_interrupt3 *int_pkt, const struct cpumask *affinity, - u32 slot, u32 vector, u8 vector_count) + struct pci_create_interrupt3 *int_pkt, int cpu, + u32 slot, u32 vector, u16 vector_count) { - int cpu; - int_pkt->message_type.type = PCI_CREATE_INTERRUPT_MESSAGE3; int_pkt->wslot.slot = slot; int_pkt->int_desc.vector = vector; int_pkt->int_desc.reserved = 0; int_pkt->int_desc.vector_count = vector_count; int_pkt->int_desc.delivery_mode = DELIVERY_MODE; - cpu = hv_compose_msi_req_get_cpu(affinity); int_pkt->int_desc.processor_array[0] = hv_cpu_number_to_vp_number(cpu); int_pkt->int_desc.processor_count = 1; @@ -1701,7 +1735,12 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg) struct compose_comp_ctxt comp; struct tran_int_desc *int_desc; struct msi_desc *msi_desc; - u8 vector, vector_count; + /* + * vector_count should be u16: see hv_msi_desc, hv_msi_desc2 + * and hv_msi_desc3. vector must be u32: see hv_msi_desc3. + */ + u16 vector_count; + u32 vector; struct { struct pci_packet pci_pkt; union { @@ -1710,12 +1749,18 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg) struct pci_create_interrupt3 v3; } int_pkts; } __packed ctxt; + bool multi_msi; u64 trans_id; u32 size; int ret; + int cpu; + + msi_desc = irq_data_get_msi_desc(data); + multi_msi = !msi_desc->pci.msi_attrib.is_msix && + msi_desc->nvec_used > 1; /* Reuse the previous allocation */ - if (data->chip_data) { + if (data->chip_data && multi_msi) { int_desc = data->chip_data; msg->address_hi = int_desc->address >> 32; msg->address_lo = int_desc->address & 0xffffffff; @@ -1723,7 +1768,6 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg) return; } - msi_desc = irq_data_get_msi_desc(data); pdev = msi_desc_to_pci_dev(msi_desc); dest = irq_data_get_effective_affinity_mask(data); pbus = pdev->bus; @@ -1733,11 +1777,18 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg) if (!hpdev) goto return_null_message; + /* Free any previous message that might have already been composed. */ + if (data->chip_data && !multi_msi) { + int_desc = data->chip_data; + data->chip_data = NULL; + hv_int_desc_free(hpdev, int_desc); + } + int_desc = kzalloc(sizeof(*int_desc), GFP_ATOMIC); if (!int_desc) goto drop_reference; - if (!msi_desc->pci.msi_attrib.is_msix && msi_desc->nvec_used > 1) { + if (multi_msi) { /* * If this is not the first MSI of Multi MSI, we already have * a mapping. Can exit early. @@ -1762,11 +1813,18 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg) */ vector = 32; vector_count = msi_desc->nvec_used; + cpu = hv_compose_multi_msi_req_get_cpu(); } else { vector = hv_msi_get_int_vector(data); vector_count = 1; + cpu = hv_compose_msi_req_get_cpu(dest); } + /* + * hv_compose_msi_req_v1 and v2 are for x86 only, meaning 'vector' + * can't exceed u8. Cast 'vector' down to u8 for v1/v2 explicitly + * for better readability. + */ memset(&ctxt, 0, sizeof(ctxt)); init_completion(&comp.comp_pkt.host_event); ctxt.pci_pkt.completion_func = hv_pci_compose_compl; @@ -1775,24 +1833,23 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg) switch (hbus->protocol_version) { case PCI_PROTOCOL_VERSION_1_1: size = hv_compose_msi_req_v1(&ctxt.int_pkts.v1, - dest, hpdev->desc.win_slot.slot, - vector, + (u8)vector, vector_count); break; case PCI_PROTOCOL_VERSION_1_2: case PCI_PROTOCOL_VERSION_1_3: size = hv_compose_msi_req_v2(&ctxt.int_pkts.v2, - dest, + cpu, hpdev->desc.win_slot.slot, - vector, + (u8)vector, vector_count); break; case PCI_PROTOCOL_VERSION_1_4: size = hv_compose_msi_req_v3(&ctxt.int_pkts.v3, - dest, + cpu, hpdev->desc.win_slot.slot, vector, vector_count); |