Re: [Qemu-devel] [PATCH] i386: do not migrate MSR_SMI_COUNT on machine types <2.12

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Paolo Bonzini (pbonzini@redhat.com) wrote:
> MSR_SMI_COUNT started being migrated in QEMU 2.12.  Do not migrate it
> on older machine types, or the subsection causes a load failure for
> guests that use SMM.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  include/hw/i386/pc.h  | 4 ++++
>  target/i386/cpu.c     | 2 ++
>  target/i386/cpu.h     | 1 +
>  target/i386/machine.c | 2 +-
>  4 files changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
> index 654003f44c..6894f37df1 100644
> --- a/include/hw/i386/pc.h
> +++ b/include/hw/i386/pc.h
> @@ -317,6 +317,10 @@ bool e820_get_entry(int, uint32_t, uint64_t *, uint64_t *);
>  #define PC_COMPAT_2_11 \
>      HW_COMPAT_2_11 \
>      {\
> +        .driver   = TYPE_X86_CPU,\
> +        .property = "x-migrate-smi-count",\
> +        .value    = "off",\
> +    },{\
>          .driver   = "Skylake-Server" "-" TYPE_X86_CPU,\
>          .property = "clflushopt",\
>          .value    = "off",\
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index e0e2f2eea1..92732ef1a0 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -5435,6 +5435,8 @@ static Property x86_cpu_properties[] = {
>                       false),
>      DEFINE_PROP_BOOL("vmware-cpuid-freq", X86CPU, vmware_cpuid_freq, true),
>      DEFINE_PROP_BOOL("tcg-cpuid", X86CPU, expose_tcg, true),
> +    DEFINE_PROP_BOOL("x-migrate-smi-count", X86CPU, migrate_smi_count,
> +                     false),

Shouldn't that be true?
(and then turned off in the compat)

Dave

>      /*
>       * lecacy_cache defaults to true unless the CPU model provides its
>       * own cache information (see x86_cpu_load_def()).
> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
> index 2c5a0d90a6..bcda6197a8 100644
> --- a/target/i386/cpu.h
> +++ b/target/i386/cpu.h
> @@ -1379,6 +1379,7 @@ struct X86CPU {
>      bool expose_kvm;
>      bool expose_tcg;
>      bool migratable;
> +    bool migrate_smi_count;
>      bool max_features; /* Enable all supported features automatically */
>      uint32_t apic_id;
>  
> diff --git a/target/i386/machine.c b/target/i386/machine.c
> index 8b64dff487..084c2c73a8 100644
> --- a/target/i386/machine.c
> +++ b/target/i386/machine.c
> @@ -400,7 +400,7 @@ static bool msr_smi_count_needed(void *opaque)
>      X86CPU *cpu = opaque;
>      CPUX86State *env = &cpu->env;
>  
> -    return env->msr_smi_count != 0;
> +    return cpu->migrate_smi_count && env->msr_smi_count != 0;
>  }
>  
>  static const VMStateDescription vmstate_msr_smi_count = {
> -- 
> 2.17.1
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK