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Re: [Qemu-ppc] [PATCH v2] spapr: check smp_threads <= vsmt
From: |
Greg Kurz |
Subject: |
Re: [Qemu-ppc] [PATCH v2] spapr: check smp_threads <= vsmt |
Date: |
Thu, 8 Feb 2018 13:03:19 +0100 |
On Thu, 8 Feb 2018 10:42:41 +0100
Laurent Vivier <address@hidden> wrote:
> We ignore silently the value of smp_threads when we set
> the default VSMT value, and if smp_threads is greater than VSMT
> kernel is going into trouble later.
>
> Fixes: 8904e5a750
> ("spapr: Adjust default VSMT value for better migration compatibility")
>
> Signed-off-by: Laurent Vivier <address@hidden>
> ---
>
Reviewed-by: Greg Kurz <address@hidden>
> Notes:
> v2: display a specific error message when the default VSMT is used
> fix subject
>
> hw/ppc/spapr.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 32a876be56..11de276cd5 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -2311,6 +2311,12 @@ static void spapr_set_vsmt_mode(sPAPRMachineState
> *spapr, Error **errp)
> * overwhelmingly common case in production systems.
> */
> spapr->vsmt = 8;
> + if (spapr->vsmt < smp_threads) {
> + error_setg(&local_err, "Cannot support %d threads/core"
> + " because it must be <= to default VSMT mode (%d)",
> + smp_threads, spapr->vsmt);
> + goto out;
> + }
> }
>
> /* KVM: If necessary, set the SMT mode: */