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Re: [Qemu-arm] [RFC v2 3/3] virt: Check KVM_CAP_ARM_IRQ_LINE_LAYOUT_2 fo
From: |
Peter Maydell |
Subject: |
Re: [Qemu-arm] [RFC v2 3/3] virt: Check KVM_CAP_ARM_IRQ_LINE_LAYOUT_2 for smp_cpus > 256 |
Date: |
Thu, 12 Sep 2019 09:42:33 +0100 |
On Wed, 11 Sep 2019 at 16:51, Eric Auger <address@hidden> 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 <address@hidden>
> ---
> hw/arm/virt.c | 4 ++++
> target/arm/kvm.c | 21 +++++++++++++++++++++
> target/arm/kvm_arm.h | 15 +++++++++++++++
> 3 files changed, 40 insertions(+)
>
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index 0d1629ccb3..465e3140f7 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -1575,6 +1575,10 @@ static void machvirt_init(MachineState *machine)
> virt_max_cpus = GIC_NCPU;
> }
>
> + if (kvm_arm_irq_line_layout_mismatch(MACHINE(vms), max_cpus)) {
> + exit(1);
> + }
> +
Is there really no place to put this check in common code?
thanks
-- PMM