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Subject[PATCH] PCI: hv: use effective affinity mask
Date

The effective_affinity_mask is always set when an interrupt is assigned in
__assign_irq_vector() -> apic->cpu_mask_to_apicid(), e.g. for struct apic
apic_physflat: -> default_cpu_mask_to_apicid() ->
irq_data_update_effective_affinity(), but it looks d->common->affinity
remains all-1's before the user space or the kernel changes it later.

In the early allocation/initialization phase of an irq, we should use the
effective_affinity_mask, otherwise Hyper-V may not deliver the interrupt
to the expected cpu. Without the patch, if we assign 7 Mellanox ConnectX-3
VFs to a 32-vCPU VM, one of the VFs may fail to receive interrupts.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Cc: Jake Oshins <jakeo@microsoft.com>
Cc: Jork Loeser <jloeser@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
---

Please consider this for v4.14, if it's not too late.

drivers/pci/host/pci-hyperv.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c
index 5ccb47d..8b5f66d 100644
--- a/drivers/pci/host/pci-hyperv.c
+++ b/drivers/pci/host/pci-hyperv.c
@@ -879,7 +879,7 @@ static void hv_irq_unmask(struct irq_data *data)
int cpu;
u64 res;

- dest = irq_data_get_affinity_mask(data);
+ dest = irq_data_get_effective_affinity_mask(data);
pdev = msi_desc_to_pci_dev(msi_desc);
pbus = pdev->bus;
hbus = container_of(pbus->sysdata, struct hv_pcibus_device, sysdata);
@@ -1042,6 +1042,7 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
struct hv_pci_dev *hpdev;
struct pci_bus *pbus;
struct pci_dev *pdev;
+ struct cpumask *dest;
struct compose_comp_ctxt comp;
struct tran_int_desc *int_desc;
struct {
@@ -1056,6 +1057,7 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
int ret;

pdev = msi_desc_to_pci_dev(irq_data_get_msi_desc(data));
+ dest = irq_data_get_effective_affinity_mask(data);
pbus = pdev->bus;
hbus = container_of(pbus->sysdata, struct hv_pcibus_device, sysdata);
hpdev = get_pcichild_wslot(hbus, devfn_to_wslot(pdev->devfn));
@@ -1081,14 +1083,14 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
switch (pci_protocol_version) {
case PCI_PROTOCOL_VERSION_1_1:
size = hv_compose_msi_req_v1(&ctxt.int_pkts.v1,
- irq_data_get_affinity_mask(data),
+ dest,
hpdev->desc.win_slot.slot,
cfg->vector);
break;

case PCI_PROTOCOL_VERSION_1_2:
size = hv_compose_msi_req_v2(&ctxt.int_pkts.v2,
- irq_data_get_affinity_mask(data),
+ dest,
hpdev->desc.win_slot.slot,
cfg->vector);
break;
--
2.7.4
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