From: Peter Maydell <peter.maydell@linaro.org>
To: Eric Auger <eric.auger@redhat.com>
Cc: Zenghui Yu <yuzenghui@huawei.com>, Marc Zyngier <maz@kernel.org>,
qemu-arm <qemu-arm@nongnu.org>,
QEMU Developers <qemu-devel@nongnu.org>,
Eric Auger <eric.auger.pro@gmail.com>
Subject: Re: [Qemu-devel] [RFC 3/3] virt: Check KVM_CAP_ARM_IRQ_LINE_LAYOUT_2 for smp_cpus > 256
Date: Fri, 6 Sep 2019 11:16:31 +0100 [thread overview]
Message-ID: <CAFEAcA8PCRxTnfhOuo2e4C2xVnn7EX1RWEcKurhNohi-WS+qow@mail.gmail.com> (raw)
In-Reply-To: <20190827160554.30995-4-eric.auger@redhat.com>
On Tue, 27 Aug 2019 at 17:06, Eric Auger <eric.auger@redhat.com> wrote:
>
> Host kernel within [4.18, 5.3] report an erroneous KVM_MAX_VCPUS=512
> for ARM. The actual capability to instantiate more than 256 vcpus
> was fixed in 5.4 with the upgrade of the KVM_IRQ_LINE ABI to support
> vcpu id encoded on 12 bits instead of 8 and a redistributor consuming
> a single KVM IO device instead of 2.
>
> So let's check this capability when attempting to use more than 256
> vcpus.
>
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
> ---
> hw/arm/virt.c | 7 +++++++
> target/arm/kvm.c | 7 +++++++
> target/arm/kvm_arm.h | 13 +++++++++++++
> 3 files changed, 27 insertions(+)
>
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index 0d1629ccb3..bcc8d64384 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -1575,6 +1575,13 @@ static void machvirt_init(MachineState *machine)
> virt_max_cpus = GIC_NCPU;
> }
>
> + if (kvm_enabled() && max_cpus > 256 &&
> + !kvm_arm_irq_line_layout_2(MACHINE(vms))) {
> + error_report("Using more than 256 vcpus require a host kernel "
> + "with KVM_CAP_ARM_IRQ_LINE_LAYOUT_2");
> + exit(1);
> + }
Is there some place we could put this check that isn't specific
to the virt board, so that we don't need to duplicate it in
any other future KVM-supporting boards we add?
thanks
-- PMM
next prev parent reply other threads:[~2019-09-06 10:17 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-27 16:05 [Qemu-devel] [RFC 0/3] KVM/ARM: Fix >256 vcpus Eric Auger
2019-08-27 16:05 ` [Qemu-devel] [RFC 1/3] linux headers: update for KVM_CAP_ARM_IRQ_LINE_LAYOUT_2 Eric Auger
2019-08-27 16:05 ` [Qemu-devel] [RFC 2/3] intc/arm_gic: Support PPI injection for more than 256 vpus Eric Auger
2019-08-29 2:53 ` Zenghui Yu
2019-08-29 7:58 ` Auger Eric
2019-08-29 9:21 ` Auger Eric
2019-09-03 8:29 ` Peter Maydell
2019-09-03 8:40 ` Auger Eric
2019-09-06 10:14 ` Peter Maydell
2019-08-27 16:05 ` [Qemu-devel] [RFC 3/3] virt: Check KVM_CAP_ARM_IRQ_LINE_LAYOUT_2 for smp_cpus > 256 Eric Auger
2019-08-28 3:28 ` Richard Henderson
2019-08-28 6:19 ` Auger Eric
2019-09-06 10:16 ` Peter Maydell [this message]
2019-08-29 2:06 ` [Qemu-devel] [RFC 0/3] KVM/ARM: Fix >256 vcpus Zenghui Yu
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