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SubjectRE: [PATCH] PCI: hv: use effective affinity mask
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Hi,

I've also tested this and it's working good. Kernels tested:
- next-20171109 on top of Ubuntu 16.04
- MSFT kernel - 4.14.0-rc5 with patch applied - on top of RHEL 7.3

Adrian

-----Original Message-----
From: Bjorn Helgaas [mailto:helgaas@kernel.org]
Sent: Wednesday, November 8, 2017 3:08 AM
To: Dexuan Cui <decui@microsoft.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>; linux-pci@vger.kernel.org; Jake Oshins <jakeo@microsoft.com>; KY Srinivasan <kys@microsoft.com>; Stephen Hemminger <sthemmin@microsoft.com>; devel@linuxdriverproject.org; linux-kernel@vger.kernel.org; Haiyang Zhang <haiyangz@microsoft.com>; Jork Loeser <Jork.Loeser@microsoft.com>; Chris Valean (Cloudbase Solutions SRL) <v-chvale@microsoft.com>; Adrian Suhov (Cloudbase Solutions SRL) <v-adsuho@microsoft.com>; Simon Xiao <sixiao@microsoft.com>; 'Eyal Mizrachi' <eyalmi@mellanox.com>; Jack Morgenstein <jackm@mellanox.com>; Armen Guezalian <armeng@mellanox.com>; Firas Mahameed <firas@mellanox.com>; Tziporet Koren <tziporet@mellanox.com>; Daniel Jurgens <danielj@mellanox.com>
Subject: Re: [PATCH] PCI: hv: use effective affinity mask

On Wed, Nov 01, 2017 at 08:30:53PM +0000, Dexuan Cui wrote:
>
> 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.

What would be the rationale for putting it in v4.14? After the merge window, I usually only merge fixes for problems introduced during the merge window, or for serious regressions. I can't tell if this fits into that or not.

> 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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