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Date:   Fri, 9 Jul 2021 19:15:24 +0000
From:   Wei Liu <wei.liu@kernel.org>
To:     Sunil Muthuswamy <sunilmut@microsoft.com>
Cc:     Wei Liu <wei.liu@kernel.org>, KY Srinivasan <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        Wei Liu <liuwe@microsoft.com>,
        Dexuan Cui <decui@microsoft.com>,
        Michael Kelley <mikelley@microsoft.com>,
        "linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
        "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Rob Herring <robh@kernel.org>,
        Bjorn Helgaas <bhelgaas@google.com>
Subject: Re: [EXTERNAL] Re: [PATCH 1/1] PCI: hv: Support for create interrupt
 v3
Message-ID: <20210709191524.vbtlyg42v77f5drw@liuwe-devbox-debian-v2>
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On Fri, Jul 09, 2021 at 04:42:13PM +0000, Sunil Muthuswamy wrote:
> > > +/*
> > > + * struct hv_msi_desc3 - 1.3 version of hv_msi_desc
> > > + *	Everything is the same as in 'hv_msi_desc2' except that the size
> > > + *	of the 'vector_count' field is larger to support bigger vector
> > > + *	values. For ex: LPI vectors on ARM.
> > > + */
> > > +struct hv_msi_desc3 {
> > > +	u32	vector;
> > > +	u8	delivery_mode;
> > > +	u8	reserved;
> > > +	u16	vector_count;
> > > +	u16	processor_count;
> > > +	u16	processor_array[32];
> > > +} __packed;
> > > +
> > >  /**
> > >   * struct tran_int_desc
> > >   * @reserved:		unused, padding
> > > @@ -383,6 +402,12 @@ struct pci_create_interrupt2 {
> > >  	struct hv_msi_desc2 int_desc;
> > >  } __packed;
> > >
> > > +struct pci_create_interrupt3 {
> > > +	struct pci_message message_type;
> > > +	union win_slot_encoding wslot;
> > > +	struct hv_msi_desc3 int_desc;
> > > +} __packed;
> > > +
> > >  struct pci_delete_interrupt {
> > >  	struct pci_message message_type;
> > >  	union win_slot_encoding wslot;
> > > @@ -1334,26 +1359,55 @@ static u32 hv_compose_msi_req_v1(
> > >  	return sizeof(*int_pkt);
> > >  }
> > >
> > > +static void hv_compose_msi_req_get_cpu(struct cpumask *affinity, int *cpu,
> > > +				       u16 *count)
> > 
> > Isn't count redundant here? I don't see how this can be used safely for
> > passing back more than 1 cpu, since if cpu is pointing to an array, its
> > size is not specified.
> > 
> > Wei.
> 
> Yes, it is at the moment. But, the function can be extended in the future to take
> a size as well. But, it will always be 1 and I preferred keeping that information
> with the implementation. If you have preference, I can hard code that in the
> caller. It seems fine for me either ways.

Since this is not too much trouble I would rather you remove count and
then introduce it when it is needed.

Wei.

> 
> - Sunil