From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Jan Beulich" <JBeulich@suse.com>
Subject: Re: [PATCH resend 1/3] VT-d: enable for multi-vector MSI
Date: Tue, 16 Jul 2013 12:32:37 +0100
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To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Keir Fraser <keir@xen.org>, xiantao.zhang@intel.com, xen-devel <xen-devel@lists.xen.org>
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>>> On 16.07.13 at 13:15, Andrew Cooper <andrew.cooper3@citrix.com> wrote:
> On 16/07/13 11:13, Jan Beulich wrote:
>> The main change being to make alloc_remap_entry() capable of allocating
>> a block of entries.
>>
>> Signed-off-by: Jan Beulich <jbeulich@suse.com>
>>
>> --- a/xen/drivers/passthrough/vtd/intremap.c
>> +++ b/xen/drivers/passthrough/vtd/intremap.c
>> @@ -194,18 +194,18 @@ static void free_remap_entry(struct iomm
>>  }
>>  
>>  /*
>> - * Look for a free intr remap entry.
>> + * Look for a free intr remap entry (or a contiguous set thereof).
>>   * Need hold iremap_lock, and setup returned entry before releasing lock.
>>   */
>> -static int alloc_remap_entry(struct iommu *iommu)
>> +static unsigned int alloc_remap_entry(struct iommu *iommu, unsigned int nr)
> 
> alloc_remap_entries() now that it unconditionally takes a count (and you
> already have to patch all callsites)

Actually I checked with Linux, and the use singular in the function
name too (albeit the name isn't identical).

>> @@ -555,31 +556,29 @@ static int msi_msg_to_remap_entry(
>>      struct iremap_entry *iremap_entry = NULL, *iremap_entries;
>>      struct iremap_entry new_ire;
>>      struct msi_msg_remap_entry *remap_rte;
>> -    int index;
>> +    unsigned int index, i, nr = 1;
> 
> Does this hardcoding of nr=1 defeat the purpose of the following logic?

In what way?

>>      unsigned long flags;
>>      struct ir_ctrl *ir_ctrl = iommu_ir_ctrl(iommu);
>>  
>> -    remap_rte = (struct msi_msg_remap_entry *) msg;
>> +    if ( msi_desc->msi_attrib.type == PCI_CAP_ID_MSI )
>> +        nr = msi_desc->msi.nvec;

The logic here makes the vector count 1 for MSI-X and msi.nvec
for MSI.

Jan