[azure 4.13][PATCH 19/19] PCI: hv: Use effective affinity mask

[Marcelo Henrique Cerri]

From: Dexuan Cui <decui at microsoft.com>

BugLink: http://bugs.launchpad.net/bugs/1736283

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.

Tested-by: Adrian Suhov <v-adsuho at microsoft.com>
Signed-off-by: Dexuan Cui <decui at microsoft.com>
Signed-off-by: Bjorn Helgaas <bhelgaas at google.com>
Reviewed-by: Jake Oshins <jakeo at microsoft.com>
Cc: stable at vger.kernel.org
Cc: Jork Loeser <jloeser at microsoft.com>
Cc: Stephen Hemminger <sthemmin at microsoft.com>
Cc: K. Y. Srinivasan <kys at microsoft.com>
(cherry picked from commit 79aa801e899417a56863d6713f76c4e108856000)
Signed-off-by: Dexuan Cui <decui at microsoft.com>
Signed-off-by: Marcelo Henrique Cerri <marcelo.cerri at canonical.com>
---
 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 d0756cd2d006..9ade00572399 100644
--- a/drivers/pci/host/pci-hyperv.c
+++ b/drivers/pci/host/pci-hyperv.c
@@ -878,7 +878,7 @@ 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);
@@ -1041,6 +1041,7 @@ 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 {
@@ -1055,6 +1056,7 @@ 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));
@@ -1080,14 +1082,14 @@ 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