RE: [PATCH] PCI: hv: use effective affinity mask

[Jake Oshins]

> -----Original Message-----
> From: Bjorn Helgaas [mailto:helgaas@xxxxxxxxxx]
> Sent: Tuesday, November 7, 2017 4:15 PM
> To: Jake Oshins <jakeo@xxxxxxxxxxxxx>
> Cc: Dexuan Cui <decui@xxxxxxxxxxxxx>; Bjorn Helgaas
> <bhelgaas@xxxxxxxxxx>; linux-pci@xxxxxxxxxxxxxxx; KY Srinivasan
> <kys@xxxxxxxxxxxxx>; Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>;
> devel@xxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Haiyang Zhang
> <haiyangz@xxxxxxxxxxxxx>; Jork Loeser <Jork.Loeser@xxxxxxxxxxxxx>;
> Chris Valean (Cloudbase Solutions SRL) <v-chvale@xxxxxxxxxxxxx>; Adrian
> Suhov (Cloudbase Solutions SRL) <v-adsuho@xxxxxxxxxxxxx>; Simon Xiao
> <sixiao@xxxxxxxxxxxxx>; 'Eyal Mizrachi' <eyalmi@xxxxxxxxxxxx>; Jack
> Morgenstein <jackm@xxxxxxxxxxxx>; Armen Guezalian
> <armeng@xxxxxxxxxxxx>; Firas Mahameed <firas@xxxxxxxxxxxx>;
> Tziporet Koren <tziporet@xxxxxxxxxxxx>; Daniel Jurgens
> <danielj@xxxxxxxxxxxx>
> Subject: Re: [PATCH] PCI: hv: use effective affinity mask
> 
> On Wed, Nov 01, 2017 at 08:52:56PM +0000, Jake Oshins wrote:
> > > -----Original Message-----
> > > From: Dexuan Cui
> > > Sent: Wednesday, November 1, 2017 1:31 PM
> > > To: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>; linux-pci@xxxxxxxxxxxxxxx;
> > > Jake Oshins <jakeo@xxxxxxxxxxxxx>; KY Srinivasan
> > > <kys@xxxxxxxxxxxxx>; Stephen Hemminger
> <sthemmin@xxxxxxxxxxxxx>
> > > Cc: devel@xxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> > > Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>; Jork Loeser
> > > <Jork.Loeser@xxxxxxxxxxxxx>; Chris Valean (Cloudbase Solutions SRL)
> > > <v- chvale@xxxxxxxxxxxxx>; Adrian Suhov (Cloudbase Solutions SRL)
> > > <v- adsuho@xxxxxxxxxxxxx>; Simon Xiao <sixiao@xxxxxxxxxxxxx>; 'Eyal
> > > Mizrachi' <eyalmi@xxxxxxxxxxxx>; Jack Morgenstein
> > > <jackm@xxxxxxxxxxxx>; Armen Guezalian <armeng@xxxxxxxxxxxx>;
> Firas
> > > Mahameed <firas@xxxxxxxxxxxx>; Tziporet Koren
> > > <tziporet@xxxxxxxxxxxx>; Daniel Jurgens <danielj@xxxxxxxxxxxx>
> > > Subject: [PATCH] PCI: hv: use effective affinity mask
> > >
> > >
> > > 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@xxxxxxxxxxxxx>
> > > Cc: Jake Oshins <jakeo@xxxxxxxxxxxxx>
> > > Cc: Jork Loeser <jloeser@xxxxxxxxxxxxx>
> > > Cc: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>
> > > Cc: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
> > > ---
> > >
> > > 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
> >
> > Signed-off-by: Jake Oshins <jakeo@xxxxxxxxxxxxx>
> 
> I'm not sure what this means.
> 
> Per Documentation/process/submitting-patches.rst, "Signed-off-by"
> means you were "involved in the development of the patch, or that he/she
> was in the patch's delivery path."  You weren't in the delivery path (I got it
> from Dexuan), and if you were involved in development, your Signed-off-by
> would normally appear in the original posting.
> 
> Should this be a Reviewed-by tag?

Sorry.  I forgot the protocol.  I'll fix that.

Reviewed-by: Jake Oshins <jakeo@xxxxxxxxxxxxx>