Re: [Qemu-devel] [PATCH 13/13] target-ppc: Give a meaningful error if too many threads are specified

[Alexander Graf]

On 04.12.2012, at 04:11, David Gibson wrote:

> On Tue, Dec 04, 2012 at 01:42:17PM +1100, David Gibson wrote:
>> From: Mike Qiu <address@hidden>
> 
> Oops, messed this one up, build error for user only builds.  Fixed
> version below.
> 
> From d2cc6bcee4737647c4bbbf65d3c0129d4a119dd3 Mon Sep 17 00:00:00 2001
> From: Mike Qiu <address@hidden>
> Date: Tue, 4 Dec 2012 10:52:14 +1100
> Subject: [PATCH] target-ppc: Give a meaningful error if too many threads are
> specified
> 
> Currently the target-ppc tcg code only supports a single thread.  You can
> specify more, but they're treated identically to multiple cores.  On KVM
> we obviously can't support more threads than the hardware; if more are
> specified it will cause strange and cryptic errors.
> 
> This patch clarifies the situation by giving a simple meaningful error if
> more threads are specified than we can support.
> 
> Signed-off-by: Mike Qiu <address@hidden>
> Signed-off-by: David Gibson <address@hidden>
> ---
> target-ppc/translate_init.c |   12 ++++++++++++
> 1 file changed, 12 insertions(+)
> 
> diff --git a/target-ppc/translate_init.c b/target-ppc/translate_init.c
> index dba572f..bb054a7 100644
> --- a/target-ppc/translate_init.c
> +++ b/target-ppc/translate_init.c
> @@ -28,6 +28,7 @@
> #include <kvm.h>
> #include "kvm_ppc.h"
> #include "arch_init.h"
> +#include "cpus.h"
> 
> //#define PPC_DUMP_CPU
> //#define PPC_DEBUG_SPR
> @@ -10037,6 +10038,10 @@ static int ppc_fixup_cpu(CPUPPCState *env)
> 
> int cpu_ppc_register_internal (CPUPPCState *env, const ppc_def_t *def)
> {
> +#if !defined(CONFIG_USER_ONLY)
> +    int max_smt = kvmppc_smt_threads();

What if I am using TCG on PPC?


Alex

> +#endif
> +
>     env->msr_mask = def->msr_mask;
>     env->mmu_model = def->mmu_model;
>     env->excp_model = def->excp_model;
> @@ -10046,6 +10051,13 @@ int cpu_ppc_register_internal (CPUPPCState *env, 
> const ppc_def_t *def)
>     env->flags = def->flags;
>     env->bfd_mach = def->bfd_mach;
>     env->check_pow = def->check_pow;
> +#if !defined(CONFIG_USER_ONLY)
> +    if (smp_threads > max_smt) {
> +        fprintf(stderr, "Cannot support more than %d threads on PPC with 
> %s\n",
> +                max_smt, kvm_enabled() ? "KVM" : "TCG");
> +        exit(1);
> +    }
> +#endif
> 
> #if defined(TARGET_PPC64)
>     if (def->sps)
> 
> -- 
> 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
>