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From: Marc Zyngier <marc.zyngier@arm.com>
To: Eric Auger <eric.auger@redhat.com>
Cc: <eric.auger.pro@gmail.com>, <linux-kernel@vger.kernel.org>,
	<kvm@vger.kernel.org>, <kvmarm@lists.cs.columbia.edu>,
	<cdall@kernel.org>, <peter.maydell@linaro.org>,
	<andre.przywara@arm.com>, <drjones@redhat.com>, <wei@redhat.com>
Subject: Re: [PATCH v6 00/12] KVM: arm/arm64: Allow multiple GICv3 redistributor regions
Date: Sun, 20 May 2018 14:43:10 +0100	[thread overview]
Message-ID: <20180520144310.378a1712@why.wild-wind.fr.eu.org> (raw)
In-Reply-To: <1525088918-8600-1-git-send-email-eric.auger@redhat.com>

Hi Eric,

On Mon, 30 Apr 2018 13:48:26 +0200
Eric Auger <eric.auger@redhat.com> wrote:

> At the moment the KVM VGICv3 only supports a single redistributor
> region (whose base address is set through the GICv3 kvm device
> KVM_DEV_ARM_VGIC_GRP_ADDR/KVM_VGIC_V3_ADDR_TYPE_REDIST). There,
> all the redistributors are laid out contiguously. The size of this
> single redistributor region is not set explicitly but instead
> induced at a late stage by the number of online vcpus.
> 
> The GIC specification does not mandate all redistributors to be
> contiguous. Moreover DT and ACPI were specified so that multiple
> redistributors regions can be defined.
> 
> The current interface brings a limitation on QEMU where ARM
> virt machine available GPA holes only allowed to assign a
> redistributor region fitting a max of 123 vcpus. Overcoming this
> limitation would force either to create a new machine or relocate
> the single rdist region or allow the allocation of multiple rdist
> regions.
> 
> This series enables this last alternative. A new GICv3 KVM device
> KVM_DEV_ARM_VGIC_GRP_ADDR/KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION allows
> to register individual redistributor regions whose size is defined
> explicitly. Those rdist regions then are filled by vcpu rdist frames
> according to the need. The vgic init and related base address checks
> are impacted.

I've taken this series for a test run, and noticed that it breaks
kvmtool:

<quote>
maz@sy-borg:~$ ./kvmtool/lkvm run -c 1 -k Image --irqchip=gicv3
  # lkvm run -k Image -m 256 -c 1 --name guest-4929
  Info: Loaded kernel to 0x80080000 (20126208 bytes)
  Info: Placing fdt at 0x8fe00000 - 0x8fffffff
  Info: virtio-mmio.devices=0x200@0x10000:36

  Info: virtio-mmio.devices=0x200@0x10200:37

  Info: virtio-mmio.devices=0x200@0x10400:38

KVM_RUN failed: No such device or address
</quote>

Backing out the series results in a working setup.

I presume that the changes in the init has resulted in a stricter
initialization order that matches the QEMU flow, but that kvmtool
doesn't follow.

Could you please have a look at this? I'd like to have it in for 4.18,
just without regressions... ;-)

Thanks,

	M.
-- 
Without deviation from the norm, progress is not possible.

  parent reply	other threads:[~2018-05-20 13:43 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-30 11:48 Eric Auger
2018-04-30 11:48 ` [PATCH v6 01/12] KVM: arm/arm64: Set dist->spis to NULL after kfree Eric Auger
2018-04-30 11:48 ` [PATCH v6 02/12] KVM: arm/arm64: Document KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION Eric Auger
2018-04-30 11:48 ` [PATCH v6 03/12] KVM: arm/arm64: Replace the single rdist region by a list Eric Auger
2018-04-30 11:48 ` [PATCH v6 04/12] KVM: arm/arm64: Helper to locate free rdist index Eric Auger
2018-04-30 11:48 ` [PATCH v6 05/12] KVM: arm/arm64: Revisit Redistributor TYPER last bit computation Eric Auger
2018-04-30 11:48 ` [PATCH v6 06/12] KVM: arm/arm64: Adapt vgic_v3_check_base to multiple rdist regions Eric Auger
2018-04-30 11:48 ` [PATCH v6 07/12] KVM: arm/arm64: Helper to register a new redistributor region Eric Auger
2018-04-30 11:48 ` [PATCH v6 08/12] KVM: arm/arm64: Check vcpu redist base before registering an iodev Eric Auger
2018-04-30 11:48 ` [PATCH v6 09/12] KVM: arm/arm64: Check all vcpu redistributors are set on map_resources Eric Auger
2018-04-30 11:48 ` [PATCH v6 10/12] KVM: arm/arm64: Add KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION Eric Auger
2018-04-30 11:48 ` [PATCH v6 11/12] KVM: arm/arm64: Implement KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION Eric Auger
2018-04-30 11:48 ` [PATCH v6 12/12] KVM: arm/arm64: Bump VGIC_V3_MAX_CPUS to 512 Eric Auger
2018-05-20 13:43 ` Marc Zyngier [this message]
2018-05-20 21:28   ` [PATCH v6 00/12] KVM: arm/arm64: Allow multiple GICv3 redistributor regions Auger Eric

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