2015-01-20 23:04+0200, Nadav Amit:
> Radim Kr?má? wrote:
> > 2015-01-14 01:27+, Wu, Feng:
> >>> the new
> hardware even doesn't consider the TPR for lowest priority interrupts
> >>> delivery.
> >>>
> >>> A bold move ... what hardware was the first to do so?
> >>
> >> I think it was star
Radim Kr?má? wrote:
> 2015-01-14 01:27+, Wu, Feng:
>>> the new
hardware even doesn't consider the TPR for lowest priority interrupts
>>> delivery.
>>>
>>> A bold move ... what hardware was the first to do so?
>>
>> I think it was starting with Nehalem.
>
> Thanks, (Could be that QPI
2015-01-14 01:27+, Wu, Feng:
> > the new
> > > hardware even doesn't consider the TPR for lowest priority interrupts
> > delivery.
> >
> > A bold move ... what hardware was the first to do so?
>
> I think it was starting with Nehalem.
Thanks, (Could be that QPI can't inform about TPR change
On 14/01/2015 02:27, Wu, Feng wrote:
> As discussed with Paolo before, as the first stage, we only support single-CPU
> lowest priority for PI, since this is a new hardware feature enabling, Paolo
> trends
> to do simple things in the beginning.
:)
Nice way to sum it up!
Paolo
> Then we will
g; j...@8bytes.org;
> alex.william...@redhat.com; jiang@linux.intel.com; eric.au...@linaro.org;
> linux-ker...@vger.kernel.org; iommu@lists.linux-foundation.org;
> k...@vger.kernel.org
> Subject: Re: [v3 13/26] KVM: Define a new interface kvm_find_dest_vcpu() for
> VT-d PI
>
> 2015-
2015-01-13 00:27+, Wu, Feng:
> > On 09/01/2015 15:54, Radim Krčmář wrote:
> > > There are two points relevant to this patch in new KVM's implementation,
> > > ("KVM: x86: amend APIC lowest priority arbitration",
> > > https://lkml.org/lkml/2015/1/9/362)
> > >
> > > 1) lowest priority depends o
g; j...@8bytes.org;
> alex.william...@redhat.com; jiang@linux.intel.com; eric.au...@linaro.org;
> linux-ker...@vger.kernel.org; iommu@lists.linux-foundation.org;
> k...@vger.kernel.org
> Subject: Re: [v3 13/26] KVM: Define a new interface kvm_find_dest_vcpu() for
> VT-d PI
>
>
>
2014-12-12 23:14+0800, Feng Wu:
> This patch defines a new interface kvm_find_dest_vcpu for
> VT-d PI, which can returns the destination vCPU of the
> interrupt for guests.
>
> Since VT-d PI cannot handle broadcast/multicast interrupt,
> Here we only handle Fixed and Lowest priority interrupts.
>
2015-01-09 15:56+0100, Paolo Bonzini:
>
>
> On 09/01/2015 15:54, Radim Krčmář wrote:
> > There are two points relevant to this patch in new KVM's implementation,
> > ("KVM: x86: amend APIC lowest priority arbitration",
> > https://lkml.org/lkml/2015/1/9/362)
> >
> > 1) lowest priority depends o
2015-01-09 16:18+0100, Paolo Bonzini:
> On 09/01/2015 16:12, Radim Krčmář wrote:
> > > The chipset doesn't support it. :(
> >
> > I meant that we need to recompute PI entries for lowest priority
> > interrupts every time guest's TPR changes.
> >
> > Luckily, Linux doesn't use TPR, but other OS mi
On 09/01/2015 16:12, Radim Krčmář wrote:
> > The chipset doesn't support it. :(
>
> I meant that we need to recompute PI entries for lowest priority
> interrupts every time guest's TPR changes.
>
> Luckily, Linux doesn't use TPR, but other OS might be a reason to drop
> lowest priority from PI
On 09/01/2015 15:54, Radim Krčmář wrote:
> There are two points relevant to this patch in new KVM's implementation,
> ("KVM: x86: amend APIC lowest priority arbitration",
> https://lkml.org/lkml/2015/1/9/362)
>
> 1) lowest priority depends on TPR
> 2) there is no need for balancing
>
> (1) has
Paolo Bonzini wrote on 2014-12-23:
>> The problem is we still need to support PI with lowest priority
>> delivery mode
> even if guest does not configure irq affinity via /proc/irq/. Don't we?
>
> Yes, but we can get the basic support working first.
>
> I and Feng talked on irc and agreed to star
On Mon, Dec 22, 2014 at 12:23:36PM +0100, Paolo Bonzini wrote:
>
>
> On 22/12/2014 12:17, Wu, Feng wrote:
> >> Yes, and those need not be accelerated. But what if you set
> >> affinity to a single CPU?
> >
> > How do I set affinity to a single CPU if guest configure a lowest
> > priority interru
> The problem is we still need to support PI with lowest priority delivery mode
> even if guest does not configure irq affinity via /proc/irq/. Don't we?
Yes, but we can get the basic support working first.
I and Feng talked on irc and agreed to start with a simple implementation. Then
he can a
On 22/12/2014 12:17, Wu, Feng wrote:
>> Yes, and those need not be accelerated. But what if you set
>> affinity to a single CPU?
>
> How do I set affinity to a single CPU if guest configure a lowest
> priority interrupt? Thanks a lot!
I mean if the guest (via irqbalance and /proc/irq/) configur
Williamson; Jiang Liu
> Cc: iommu@lists.linux-foundation.org; linux-ker...@vger.kernel.org; KVM list;
> Eric Auger
> Subject: Re: [v3 13/26] KVM: Define a new interface kvm_find_dest_vcpu() for
> VT-d PI
>
>
>
> On 22/12/2014 12:04, Wu, Feng wrote:
> > > Can you s
On 22/12/2014 12:04, Wu, Feng wrote:
> > Can you support them only if the destination is a single CPU?
>
> Sorry, I am not quite understand this. I still don't understand the "single
> CPU" here.
> Lowest priority interrupts always have a cpumask which contains multiple CPU.
Yes, and those need
Williamson; Jiang Liu
> Cc: iommu@lists.linux-foundation.org; linux-ker...@vger.kernel.org; KVM list;
> Eric Auger
> Subject: Re: [v3 13/26] KVM: Define a new interface kvm_find_dest_vcpu() for
> VT-d PI
>
>
>
> On 22/12/2014 05:48, Wu, Feng wrote:
> > Do you mean w
On 22/12/2014 05:48, Wu, Feng wrote:
> Do you mean we don't support Lowest priority interrupts? As I mentioned
> before,
> Lowest priority interrupts is widely used in Linux, so I think supporting
> lowest priority
> interrupts is very important for Linux guest OS. Do you have any
> ideas/sugg
; Gleb Natapov; dw...@infradead.org;
> j...@8bytes.org; Alex Williamson; Jiang Liu
> Cc: iommu@lists.linux-foundation.org; linux-ker...@vger.kernel.org; KVM list;
> Eric Auger
> Subject: Re: [v3 13/26] KVM: Define a new interface kvm_find_dest_vcpu() for
> VT-d PI
>
>
>
> O
On 20/12/2014 00:48, Wu, Feng wrote:
> In my understanding, lowest priority interrupts are always delivered to a
> Single CPU, we need to find the right destination CPU from the cpumask.
Yes, but which CPU however differs every time the interrupt is
delivered. So the emulation here is a bit poo
; Gleb Natapov; dw...@infradead.org;
> j...@8bytes.org; Alex Williamson; Jiang Liu
> Cc: iommu@lists.linux-foundation.org; linux-ker...@vger.kernel.org; KVM list;
> Eric Auger
> Subject: Re: [v3 13/26] KVM: Define a new interface kvm_find_dest_vcpu() for
> VT-d PI
>
>
>
> On 19/12/2
On 19/12/2014 02:30, Wu, Feng wrote:
>>> How this can work well? All subsequent interrupts are delivered to
>>> one vCPU? It shouldn't be the best solution, need more consideration.
>>
>> Well, it's a hardware limitation. The alternative (which is easy to
>> implement) is to only do PI for singl
Wu, Feng wrote on 2014-12-19:
>
>
> Paolo Bonzini wrote on 2014-12-19:
>> jiang@linux.intel.com
>> Cc: eric.au...@linaro.org; linux-ker...@vger.kernel.org;
>> iommu@lists.linux-foundation.org; k...@vger.kernel.org
>> Subject: Re: [v3 13/26] KVM: Define a ne
@redhat.com; jiang@linux.intel.com
> Cc: eric.au...@linaro.org; linux-ker...@vger.kernel.org;
> iommu@lists.linux-foundation.org; k...@vger.kernel.org
> Subject: RE: [v3 13/26] KVM: Define a new interface kvm_find_dest_vcpu() for
> VT-d PI
>
> Paolo Bonzini wrote on 2014-12-19:
&g
.org; alex.william...@redhat.com; jiang@linux.intel.com
> Cc: eric.au...@linaro.org; linux-ker...@vger.kernel.org;
> iommu@lists.linux-foundation.org; k...@vger.kernel.org
> Subject: Re: [v3 13/26] KVM: Define a new interface kvm_find_dest_vcpu() for
> VT-d PI
>
>
>
>
Paolo Bonzini wrote on 2014-12-19:
>
>
> On 18/12/2014 15:49, Zhang, Yang Z wrote:
Here, we introduce a similar way with 'apic_arb_prio' to handle
guest lowest priority interrtups when VT-d PI is used. Here is the
ideas: - Each vCPU has a counter 'round_robin_counter'. - When
On 18/12/2014 15:49, Zhang, Yang Z wrote:
>>> Here, we introduce a similar way with 'apic_arb_prio' to handle
>>> guest lowest priority interrtups when VT-d PI is used. Here is
>>> the ideas: - Each vCPU has a counter 'round_robin_counter'. -
>>> When guests sets an interrupts to lowest priority,
Feng Wu wrote on 2014-12-12:
> This patch defines a new interface kvm_find_dest_vcpu for
> VT-d PI, which can returns the destination vCPU of the
> interrupt for guests.
>
> Since VT-d PI cannot handle broadcast/multicast interrupt,
> Here we only handle Fixed and Lowest priority interrupts.
>
>
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