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[PATCH] microvm: do not use the lastest cpu version

Ani Sinha posted 1 patch 1 month, 2 weeks ago
There is a newer version of this series
hw/i386/microvm.c |  2 +-
target/i386/cpu.c | 15 ---------------
target/i386/cpu.h |  4 ----
3 files changed, 1 insertion(+), 20 deletions(-)
[PATCH] microvm: do not use the lastest cpu version
Posted by Ani Sinha 1 month, 2 weeks ago 
Microvm machines are not versioned and therefore there is no requirement to use
the latest cpu model by default. Let microvms use the non-versioned cpu model.
Those users who need spefific cpu versions can use explicit commandline to
select the cpu version desired.

CC: imammedo@redhat.com
CC: zhao1.liu@intel.com
Signed-off-by: Ani Sinha <anisinha@redhat.com>
---
 hw/i386/microvm.c |  2 +-
 target/i386/cpu.c | 15 ---------------
 target/i386/cpu.h |  4 ----
 3 files changed, 1 insertion(+), 20 deletions(-)

Pipeline passes:
https://gitlab.com/anisinha/qemu/-/pipelines/1669159835
See also Igor's comment on
https://patchwork.ozlabs.org/project/qemu-devel/patch/20250128035526.3750043-1-anisinha@redhat.com/

diff --git a/hw/i386/microvm.c b/hw/i386/microvm.c
index a8d354aabe..b8be1542ff 100644
--- a/hw/i386/microvm.c
+++ b/hw/i386/microvm.c
@@ -458,7 +458,7 @@ static void microvm_machine_state_init(MachineState *machine)
 
     microvm_memory_init(mms);
 
-    x86_cpus_init(x86ms, CPU_VERSION_LATEST);
+    x86_cpus_init(x86ms, 1);
 
     microvm_devices_init(mms);
 }
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index b5dd60d281..6d251c0025 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -5513,18 +5513,6 @@ void x86_cpu_set_default_version(X86CPUVersion version)
     default_cpu_version = version;
 }
 
-static X86CPUVersion x86_cpu_model_last_version(const X86CPUModel *model)
-{
-    int v = 0;
-    const X86CPUVersionDefinition *vdef =
-        x86_cpu_def_get_versions(model->cpudef);
-    while (vdef->version) {
-        v = vdef->version;
-        vdef++;
-    }
-    return v;
-}
-
 /* Return the actual version being used for a specific CPU model */
 static X86CPUVersion x86_cpu_model_resolve_version(const X86CPUModel *model)
 {
@@ -5532,9 +5520,6 @@ static X86CPUVersion x86_cpu_model_resolve_version(const X86CPUModel *model)
     if (v == CPU_VERSION_AUTO) {
         v = default_cpu_version;
     }
-    if (v == CPU_VERSION_LATEST) {
-        return x86_cpu_model_last_version(model);
-    }
     return v;
 }
 
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index c67b42d34f..71f150a05f 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -2701,10 +2701,6 @@ void apic_handle_tpr_access_report(DeviceState *d, target_ulong ip,
                                    TPRAccess access);
 
 /* Special values for X86CPUVersion: */
-
-/* Resolve to latest CPU version */
-#define CPU_VERSION_LATEST -1
-
 /*
  * Resolve to version defined by current machine type.
  * See x86_cpu_set_default_version()
-- 
2.45.2
Re: [PATCH] microvm: do not use the lastest cpu version
Posted by Sergio Lopez Pascual 1 month, 1 week ago 
Ani Sinha <anisinha@redhat.com> writes:

> Microvm machines are not versioned and therefore there is no requirement to use
> the latest cpu model by default. Let microvms use the non-versioned cpu model.
> Those users who need spefific cpu versions can use explicit commandline to
> select the cpu version desired.
>
> CC: imammedo@redhat.com
> CC: zhao1.liu@intel.com
> Signed-off-by: Ani Sinha <anisinha@redhat.com>
> ---
>  hw/i386/microvm.c |  2 +-
>  target/i386/cpu.c | 15 ---------------
>  target/i386/cpu.h |  4 ----
>  3 files changed, 1 insertion(+), 20 deletions(-)

Reviewed-by: Sergio Lopez <slp@redhat.com>
Re: [PATCH] microvm: do not use the lastest cpu version
Posted by Igor Mammedov 1 month, 1 week ago 
On Thu, 13 Feb 2025 15:11:00 +0530
Ani Sinha <anisinha@redhat.com> wrote:

> Microvm machines are not versioned and therefore there is no requirement to use
> the latest cpu model by default. Let microvms use the non-versioned cpu model.
> Those users who need spefific cpu versions can use explicit commandline to
> select the cpu version desired.

Above says why we can do this but,
I'd also add here a reason why we are doing that to begin with. 

> 
> CC: imammedo@redhat.com
> CC: zhao1.liu@intel.com
> Signed-off-by: Ani Sinha <anisinha@redhat.com>

Reviewed-by: Igor Mammedov <imammedo@redhat.com>

> ---
>  hw/i386/microvm.c |  2 +-
>  target/i386/cpu.c | 15 ---------------
>  target/i386/cpu.h |  4 ----
>  3 files changed, 1 insertion(+), 20 deletions(-)
> 
> Pipeline passes:
> https://gitlab.com/anisinha/qemu/-/pipelines/1669159835
> See also Igor's comment on
> https://patchwork.ozlabs.org/project/qemu-devel/patch/20250128035526.3750043-1-anisinha@redhat.com/
> 
> diff --git a/hw/i386/microvm.c b/hw/i386/microvm.c
> index a8d354aabe..b8be1542ff 100644
> --- a/hw/i386/microvm.c
> +++ b/hw/i386/microvm.c
> @@ -458,7 +458,7 @@ static void microvm_machine_state_init(MachineState *machine)
>  
>      microvm_memory_init(mms);
>  
> -    x86_cpus_init(x86ms, CPU_VERSION_LATEST);
> +    x86_cpus_init(x86ms, 1);
>  
>      microvm_devices_init(mms);
>  }
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index b5dd60d281..6d251c0025 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -5513,18 +5513,6 @@ void x86_cpu_set_default_version(X86CPUVersion version)
>      default_cpu_version = version;
>  }
>  
> -static X86CPUVersion x86_cpu_model_last_version(const X86CPUModel *model)
> -{
> -    int v = 0;
> -    const X86CPUVersionDefinition *vdef =
> -        x86_cpu_def_get_versions(model->cpudef);
> -    while (vdef->version) {
> -        v = vdef->version;
> -        vdef++;
> -    }
> -    return v;
> -}
> -
>  /* Return the actual version being used for a specific CPU model */
>  static X86CPUVersion x86_cpu_model_resolve_version(const X86CPUModel *model)
>  {
> @@ -5532,9 +5520,6 @@ static X86CPUVersion x86_cpu_model_resolve_version(const X86CPUModel *model)
>      if (v == CPU_VERSION_AUTO) {
>          v = default_cpu_version;
>      }
> -    if (v == CPU_VERSION_LATEST) {
> -        return x86_cpu_model_last_version(model);
> -    }
>      return v;
>  }
>  
> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
> index c67b42d34f..71f150a05f 100644
> --- a/target/i386/cpu.h
> +++ b/target/i386/cpu.h
> @@ -2701,10 +2701,6 @@ void apic_handle_tpr_access_report(DeviceState *d, target_ulong ip,
>                                     TPRAccess access);
>  
>  /* Special values for X86CPUVersion: */
> -
> -/* Resolve to latest CPU version */
> -#define CPU_VERSION_LATEST -1
> -
>  /*
>   * Resolve to version defined by current machine type.
>   * See x86_cpu_set_default_version()

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