Re: [PATCH] iommu/hyper-v: Fix panic on a host without the 15-bit APIC ID support

[Woodhouse, David]

On Tue, 2020-12-01 at 16:45 -0800, Dexuan Cui wrote:
> The commit f36a74b9345a itself is good, but it causes a panic in a
> Linux VM that runs on a Hyper-V host that doesn't have the 15-bit
> Extended APIC ID support:
>     kernel BUG at arch/x86/kernel/apic/io_apic.c:2408!
> 
> This happens because the Hyper-V ioapic_ir_domain (which is defined in
> drivers/iommu/hyperv-iommu.c) can not be found. Fix the panic by
> properly claiming the only I/O APIC emulated by Hyper-V.
> 
> Cc: David Woodhouse <dwmw@xxxxxxxxxxxx>
> Cc: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
> Fixes: f36a74b9345a ("x86/ioapic: Use I/O-APIC ID for finding irqdomain, not index")
> Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx>

Oops, apologies for missing that.

Reviewed-by: David Woodhouse <dwmw@xxxxxxxxxxxx>



Amazon Development Centre (London) Ltd. Registered in England and Wales with registration number 04543232 with its registered office at 1 Principal Place, Worship Street, London EC2A 2FA, United Kingdom.