Re: [PATCH v4 35/49] KVM: arm64: GICv3: nv: Plug L1 LR sync into deactivation primitive

Marc Zyngier
2026-03-30T12:17:47Z

On Mon, 30 Mar 2026 12:51:51 +0100,
Vishnu Pajjuri <vishnu@os.amperecomputing.com> wrote:
>
> Hi Fuad Tabba,

To be brutally honest, I doubt Fuad really cares about NV,

> I'm trying to run nested VMs on Ampere platforms after this patch
> series(v6.19+) but nested VMs are not booting and triggering soft
> lockups on L0 and L0 hang. But just before this patch I could able to
> successfully boot the Nested VMs.

So the host dies? There isn't much here that interacts with the host
at all. Worse case, the L1 dies by not making progress.

>
> I bisected the failure to a single commit which is this patch which is
> causing the issue.
>
> I would like to understand from you that did you observed anything
> like that?

No. If I had, I wouldn't have merged the series.

>
> Were you able to boot Nested VMs successfully after v6.19+?

I boot L3s every day.

> LOG:
> [ 164.647367] Call trace:
> [ 164.647368] smp_call_function_many_cond+0x334/0x7a0 (P)
> [ 164.647372] smp_call_function_many+0x20/0x40
> [ 164.647374] kvm_make_all_cpus_request+0xec/0x1b8
> [ 164.647377] vgic_queue_irq_unlock+0x1c8/0x2c8
> [ 164.647380] kvm_vgic_inject_irq+0x194/0x1e0
> [ 164.647381] kvm_vm_ioctl_irq_line+0x170/0x400
> [ 164.647386] kvm_vm_ioctl+0x7b8/0xc88
> [ 164.647389] __arm64_sys_ioctl+0xb4/0x118
> [ 164.647393] invoke_syscall+0x6c/0x100
> [ 164.647397] el0_svc_common.constprop.0+0x48/0xf0
> [ 164.647398] do_el0_svc+0x24/0x38
> [ 164.647400] el0_svc+0x3c/0x170
> [ 164.647403] el0t_64_sync_handler+0xa0/0xe8
> [ 164.647405] el0t_64_sync+0x1b0/0x1b8

This trace is about interrupt injection from userspace, not
deactivation of a HW interrupt.

None of that makes much sense.

M.

--
Jazz isn't dead. It just smells funny.