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From: Peter Maydell <peter.maydell@linaro.org>
To: Christoffer Dall <christoffer.dall@arm.com>
Cc: Eric Auger <eric.auger@redhat.com>,
	Eric Auger <eric.auger.pro@gmail.com>,
	lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>,
	kvm-devel <kvm@vger.kernel.org>,
	kvmarm@lists.cs.columbia.edu, Marc Zyngier <marc.zyngier@arm.com>,
	Christoffer Dall <cdall@kernel.org>,
	Andre Przywara <andre.przywara@arm.com>,
	Andrew Jones <drjones@redhat.com>, Wei Huang <wei@redhat.com>
Subject: Re: [PATCH v3 02/12] KVM: arm/arm64: Document KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION
Date: Tue, 24 Apr 2018 17:50:37 +0100	[thread overview]
Message-ID: <CAFEAcA_EKuW6DWaHCvAftbL6QUSo6WY0cQmHrZhhbP5HoN_NqQ@mail.gmail.com> (raw)
In-Reply-To: <20180424164649.GA4533@C02W217FHV2R.local>

On 24 April 2018 at 17:46, Christoffer Dall <christoffer.dall@arm.com> wrote:
> On Fri, Apr 13, 2018 at 10:20:48AM +0200, Eric Auger wrote:
>> --- a/Documentation/virtual/kvm/devices/arm-vgic-v3.txt
>> +++ b/Documentation/virtual/kvm/devices/arm-vgic-v3.txt
>> @@ -27,9 +27,32 @@ Groups:
>>        VCPU and all of the redistributor pages are contiguous.
>>        Only valid for KVM_DEV_TYPE_ARM_VGIC_V3.
>>        This address needs to be 64K aligned.
>> +
>> +    KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION (rw, 64-bit)
>> +      The attr field of kvm_device_attr encodes 3 values:
>> +      bits:     | 63   ....  52  |  51   ....   16 | 15 - 12  |11 - 0
>> +      values:   |     count      |       base      |  flags   | index
>> +      - index encodes the unique redistributor region index
>
> I'm not entirely sure I understand the purpose of the index field.
> Isn't a redistributor region identified uniquely by its base address?

You need a way to tell the difference beween:
 (1) redistributors for CPUs 0..63 at 0x40000000, redistributors
     for 64..127 at 0x80000000
 (2) redistributors for CPUs 0..63 at 0x80000000, redistributors
     for 64..127 at 0x40000000

The index field tells you which order the redistributor
regions go in.

thanks
-- PMM

  reply	other threads:[~2018-04-24 16:51 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-13  8:20 [PATCH v3 00/12] KVM: arm/arm64: Allow multiple GICv3 redistributor regions Eric Auger
2018-04-13  8:20 ` [PATCH v3 01/12] KVM: arm/arm64: Set dist->spis to NULL after kfree Eric Auger
2018-04-13  8:20   ` Eric Auger
2018-04-24 21:06   ` Christoffer Dall
2018-04-13  8:20 ` [PATCH v3 02/12] KVM: arm/arm64: Document KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION Eric Auger
2018-04-13  9:00   ` Peter Maydell
2018-04-24 16:46   ` Christoffer Dall
2018-04-24 16:50     ` Peter Maydell [this message]
2018-04-24 20:34       ` Auger Eric
2018-04-24 21:12       ` Christoffer Dall
2018-04-13  8:20 ` [PATCH v3 03/12] KVM: arm/arm64: Replace the single rdist region by a list Eric Auger
2018-04-13  8:20   ` Eric Auger
2018-04-24 21:06   ` Christoffer Dall
2018-04-13  8:20 ` [PATCH v3 04/12] KVM: arm/arm64: Helper to locate free rdist index Eric Auger
2018-04-13  8:20   ` Eric Auger
2018-04-24 21:07   ` Christoffer Dall
2018-04-26  7:47     ` Auger Eric
2018-04-13  8:20 ` [PATCH v3 05/12] KVM: arm/arm64: Revisit Redistributor TYPER last bit computation Eric Auger
2018-04-24 21:06   ` Christoffer Dall
2018-04-13  8:20 ` [PATCH v3 06/12] KVM: arm/arm64: Helper to register a new redistributor region Eric Auger
2018-04-24 16:47   ` Christoffer Dall
2018-04-26  7:32     ` Auger Eric
2018-04-26 10:04       ` Christoffer Dall
2018-04-13  8:20 ` [PATCH v3 07/12] KVM: arm/arm64: Adapt vgic_v3_check_base to multiple rdist regions Eric Auger
2018-04-24 21:07   ` Christoffer Dall
2018-04-26  8:29     ` Auger Eric
2018-04-26 10:06       ` Christoffer Dall
2018-04-26 14:52         ` Auger Eric
2018-04-13  8:20 ` [PATCH v3 08/12] KVM: arm/arm64: Check vcpu redist base before registering an iodev Eric Auger
2018-04-24 21:07   ` Christoffer Dall
2018-04-26  9:25     ` Auger Eric
2018-04-26 10:12       ` Christoffer Dall
2018-04-13  8:20 ` [PATCH v3 09/12] KVM: arm/arm64: Check all vcpu redistributors are set on map_resources Eric Auger
2018-04-24 21:08   ` Christoffer Dall
2018-04-26  9:56     ` Auger Eric
2018-04-26 10:16       ` Christoffer Dall
2018-04-13  8:20 ` [PATCH v3 10/12] KVM: arm/arm64: Add KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION Eric Auger
2018-04-24 21:08   ` Christoffer Dall
2018-04-13  8:20 ` [PATCH v3 11/12] KVM: arm/arm64: Implement KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION Eric Auger
2018-04-24 21:06   ` Christoffer Dall
2018-04-30  7:25     ` Auger Eric
2018-04-27 19:14   ` Christoffer Dall
2018-04-13  8:20 ` [PATCH v3 12/12] KVM: arm/arm64: Bump VGIC_V3_MAX_CPUS to 512 Eric Auger

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