Re: [PATCH] spapr: Don't allow multiple active vCPUs at CAS

[David Gibson]

On Wed, Jan 22, 2020 at 02:11:12PM +0100, Greg Kurz wrote:
> According to the description of "ibm,client-architecture-support" that
> can found in LoPAPR "B.6.2.3 Root Node Methods":
> 
> If multiple partition processors or threads are active at the time of
> the ibm,client-architecture-support method call, or an error is detected
> in the format of the ibm,architecture.vec structure, the err? boolean
> shall be TRUE; else FALSE.
> 
> We certainly don't want to temper with the platform or with the PCR of
> the other vCPUs if they happen to be active. Ensure we have only one
> active vCPU and fail CAS otherwise. This is just for conformance and
> robustness, it doesn't fix any known bugs.
> 
> Signed-off-by: Greg Kurz <address@hidden>

Applied to ppc-for-5.0, thanks.

> ---
>  hw/ppc/spapr_hcall.c |   12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
> index ffb14641f9d3..b8bb66b5c0d4 100644
> --- a/hw/ppc/spapr_hcall.c
> +++ b/hw/ppc/spapr_hcall.c
> @@ -1676,6 +1676,18 @@ static target_ulong 
> h_client_architecture_support(PowerPCCPU *cpu,
>      Error *local_err = NULL;
>      bool raw_mode_supported = false;
>      bool guest_xive;
> +    CPUState *cs;
> +
> +    /* CAS is supposed to be called early when only the boot vCPU is active. 
> */
> +    CPU_FOREACH(cs) {
> +        if (cs == CPU(cpu)) {
> +            continue;
> +        }
> +        if (!cs->halted) {
> +            warn_report("guest has multiple active vCPUs at CAS, which is 
> not allowed");
> +            return H_MULTI_THREADS_ACTIVE;
> +        }
> +    }
>  
>      cas_pvr = cas_check_pvr(spapr, cpu, &addr, &raw_mode_supported, 
> &local_err);
>      if (local_err) {
> 

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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