Patchwork [v2,1/1] target-i386: Fix default Hypervisor level for hypervisor-vendor=kvm.

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Submitter Don Slutz
Date Sept. 20, 2012, 8:06 p.m.
Message ID <1348171587-23725-2-git-send-email-Don@CloudSwitch.com>
Download mbox | patch
Permalink /patch/185475/
State New
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Comments

Don Slutz - Sept. 20, 2012, 8:06 p.m.
From http://lkml.indiana.edu/hypermail/linux/kernel/1205.0/00100.html
EAX should be KVM_CPUID_FEATURES (0x40000001) not 0.

Added hypervisor-vendor=kvm0 to get the older CPUID result. kvm1 selects the newer one.

Signed-off-by: Don Slutz <Don@CloudSwitch.com>
---
 target-i386/cpu.c |   17 +++++++++++++----
 1 files changed, 13 insertions(+), 4 deletions(-)
Eduardo Habkost - Sept. 21, 2012, 2:18 p.m.
On Thu, Sep 20, 2012 at 04:06:27PM -0400, Don Slutz wrote:
> From http://lkml.indiana.edu/hypermail/linux/kernel/1205.0/00100.html
> EAX should be KVM_CPUID_FEATURES (0x40000001) not 0.
> 
> Added hypervisor-vendor=kvm0 to get the older CPUID result. kvm1 selects the newer one.

Why not just make "hypervisor-vendor=kvm" control only the hypervisor
vendor string, and support something like "kvm-hypervisor-level=0" to
restore the old cpuid_hv_level=0 behavior?

This is similar to the kvmclock case: it would allow us to make
"hypervisor-vendor=kvm" use saner values as default, but letting old
machine-types to override it for compatibility if required.

> 
> Signed-off-by: Don Slutz <Don@CloudSwitch.com>
> ---
>  target-i386/cpu.c |   17 +++++++++++++----
>  1 files changed, 13 insertions(+), 4 deletions(-)
> 
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index 72a8442..e51b2b1 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -1250,9 +1250,12 @@ static char *x86_cpuid_get_hv_vendor(Object *obj, Error **errp)
>      } else if (!strcmp(value, CPUID_HV_VENDOR_XEN) &&
>                 env->cpuid_hv_level == CPUID_HV_LEVEL_XEN) {
>          pstrcpy(value, sizeof(value), "xen");
> -    } else if (!strcmp(value, CPUID_HV_VENDOR_KVM) &&
> -               env->cpuid_hv_level == 0) {
> -        pstrcpy(value, sizeof(value), "kvm");
> +    } else if (!strcmp(value, CPUID_HV_VENDOR_KVM)) {
> +        if (env->cpuid_hv_level == CPUID_HV_LEVEL_KVM) {
> +            pstrcpy(value, sizeof(value), "kvm1");
> +        } else if (env->cpuid_hv_level == 0) {
> +            pstrcpy(value, sizeof(value), "kvm0");
> +        }
>      }
>      return value;
>  }
> @@ -1288,7 +1291,13 @@ static void x86_cpuid_set_hv_vendor(Object *obj, const char *value,
>              env->cpuid_hv_level = CPUID_HV_LEVEL_XEN;
>          }
>          pstrcpy(adj_value, sizeof(adj_value), CPUID_HV_VENDOR_XEN);
> -    } else if (!strcmp(value, "kvm")) {
> +    } else if (!strcmp(value, "kvm") || !strcmp(value, "kvm1")) {
> +        if (env->cpuid_hv_level == 0) {
> +            env->cpuid_hv_level = CPUID_HV_LEVEL_KVM;
> +        }
> +        pstrcpy(adj_value, sizeof(adj_value), CPUID_HV_VENDOR_KVM);
> +    } else if (!strcmp(value, "kvm0")) {
> +        env->cpuid_hv_level = 0;
>          pstrcpy(adj_value, sizeof(adj_value), CPUID_HV_VENDOR_KVM);
>      } else {
>          pstrcpy(adj_value, sizeof(adj_value), value);
> -- 
> 1.7.1
>
Don Slutz - Sept. 21, 2012, 8:26 p.m.
On 09/21/12 10:18, Eduardo Habkost wrote:
> On Thu, Sep 20, 2012 at 04:06:27PM -0400, Don Slutz wrote:
>>  From http://lkml.indiana.edu/hypermail/linux/kernel/1205.0/00100.html
>> EAX should be KVM_CPUID_FEATURES (0x40000001) not 0.
>>
>> Added hypervisor-vendor=kvm0 to get the older CPUID result. kvm1 selects the newer one.
> Why not just make "hypervisor-vendor=kvm" control only the hypervisor
> vendor string, and support something like "kvm-hypervisor-level=0" to
> restore the old cpuid_hv_level=0 behavior?
   -cpu host,hypervisor-vendor=kvm,hypervisor-level=0

  Does this.
>
> This is similar to the kvmclock case: it would allow us to make
> "hypervisor-vendor=kvm" use saner values as default, but letting old
> machine-types to override it for compatibility if required.
Right now since I am using env->cpuid_hv_level == 0 as a flag. This 
means that:

   -cpu host,hypervisor-level=0,hypervisor-vendor=kvm

   -cpu host,hypervisor-vendor=kvm,hypervisor-level=0

end up with different CPUID data (Which I do not like). I will fix this in the next round.

Did you want me to drop kvm0 and kvm1?
    -Don

[...]
Eduardo Habkost - Sept. 21, 2012, 8:49 p.m.
On Fri, Sep 21, 2012 at 04:26:58PM -0400, Don Slutz wrote:
> On 09/21/12 10:18, Eduardo Habkost wrote:
> >On Thu, Sep 20, 2012 at 04:06:27PM -0400, Don Slutz wrote:
> >> From http://lkml.indiana.edu/hypermail/linux/kernel/1205.0/00100.html
> >>EAX should be KVM_CPUID_FEATURES (0x40000001) not 0.
> >>
> >>Added hypervisor-vendor=kvm0 to get the older CPUID result. kvm1 selects the newer one.
> >Why not just make "hypervisor-vendor=kvm" control only the hypervisor
> >vendor string, and support something like "kvm-hypervisor-level=0" to
> >restore the old cpuid_hv_level=0 behavior?
>   -cpu host,hypervisor-vendor=kvm,hypervisor-level=0
> 
>  Does this.

Good.  :-)

> >
> >This is similar to the kvmclock case: it would allow us to make
> >"hypervisor-vendor=kvm" use saner values as default, but letting old
> >machine-types to override it for compatibility if required.
> Right now since I am using env->cpuid_hv_level == 0 as a flag. This
> means that:
> 
>   -cpu host,hypervisor-level=0,hypervisor-vendor=kvm
> 
>   -cpu host,hypervisor-vendor=kvm,hypervisor-level=0
> 
> end up with different CPUID data (Which I do not like). I will fix this in the next round.

Right. This has to be fixed.

> 
> Did you want me to drop kvm0 and kvm1?

Yes, if level is already configurable using the hypervisor-level
property, I don't see the need for kvm0 and kvm1.

If you make kvm_arch_init_vcpu() actually use those fields, you will end
up implementing what's required to allow migration compatibility to be
kept (the only thing missing is to make the CPU class a child of
DeviceState, and add hypervisor-level=0 to the existing machine-types).
:-)
Don Slutz - Sept. 21, 2012, 9:28 p.m.
On 09/21/12 16:49, Eduardo Habkost wrote:
> On Fri, Sep 21, 2012 at 04:26:58PM -0400, Don Slutz wrote:
>> On 09/21/12 10:18, Eduardo Habkost wrote:
>>> On Thu, Sep 20, 2012 at 04:06:27PM -0400, Don Slutz wrote:
>>>>  From http://lkml.indiana.edu/hypermail/linux/kernel/1205.0/00100.html
>>>> EAX should be KVM_CPUID_FEATURES (0x40000001) not 0.
>>>>
>>>> Added hypervisor-vendor=kvm0 to get the older CPUID result. kvm1 selects the newer one.
>>> Why not just make "hypervisor-vendor=kvm" control only the hypervisor
>>> vendor string, and support something like "kvm-hypervisor-level=0" to
>>> restore the old cpuid_hv_level=0 behavior?
>>    -cpu host,hypervisor-vendor=kvm,hypervisor-level=0
>>
>>   Does this.
> Good.  :-)
>
>>> This is similar to the kvmclock case: it would allow us to make
>>> "hypervisor-vendor=kvm" use saner values as default, but letting old
>>> machine-types to override it for compatibility if required.
>> Right now since I am using env->cpuid_hv_level == 0 as a flag. This
>> means that:
>>
>>    -cpu host,hypervisor-level=0,hypervisor-vendor=kvm
>>
>>    -cpu host,hypervisor-vendor=kvm,hypervisor-level=0
>>
>> end up with different CPUID data (Which I do not like). I will fix this in the next round.
> Right. This has to be fixed.
>
>> Did you want me to drop kvm0 and kvm1?
> Yes, if level is already configurable using the hypervisor-level
> property, I don't see the need for kvm0 and kvm1.
>
> If you make kvm_arch_init_vcpu() actually use those fields, you will end
> up implementing what's required to allow migration compatibility to be
> kept (the only thing missing is to make the CPU class a child of
> DeviceState, and add hypervisor-level=0 to the existing machine-types).
> :-)
>
You mean like
   http://lists.gnu.org/archive/html/qemu-devel/2012-09/msg03402.html
and
   http://lists.gnu.org/archive/html/qemu-devel/2012-09/msg03405.html
already change kvm_arch_init_vcpu().  I did not know that I need to make 
the CPU class a child of DeviceState.
Nor that I needed to add hypervisor-vendor=kvm,hypervisor-level=0 to the 
existing machine-types.  Since without specifying hypervisor-level=0 it 
defaults to 0 and kvm_arch_init_vcpu() will default to setting 
hypervisor-vendor=kvm.
    -Don
Eduardo Habkost - Sept. 21, 2012, 9:53 p.m.
On Fri, Sep 21, 2012 at 05:28:27PM -0400, Don Slutz wrote:
> 
> On 09/21/12 16:49, Eduardo Habkost wrote:
> >On Fri, Sep 21, 2012 at 04:26:58PM -0400, Don Slutz wrote:
> >>On 09/21/12 10:18, Eduardo Habkost wrote:
> >>>On Thu, Sep 20, 2012 at 04:06:27PM -0400, Don Slutz wrote:
> >>>> From http://lkml.indiana.edu/hypermail/linux/kernel/1205.0/00100.html
> >>>>EAX should be KVM_CPUID_FEATURES (0x40000001) not 0.
> >>>>
> >>>>Added hypervisor-vendor=kvm0 to get the older CPUID result. kvm1 selects the newer one.
> >>>Why not just make "hypervisor-vendor=kvm" control only the hypervisor
> >>>vendor string, and support something like "kvm-hypervisor-level=0" to
> >>>restore the old cpuid_hv_level=0 behavior?
> >>   -cpu host,hypervisor-vendor=kvm,hypervisor-level=0
> >>
> >>  Does this.
> >Good.  :-)
> >
> >>>This is similar to the kvmclock case: it would allow us to make
> >>>"hypervisor-vendor=kvm" use saner values as default, but letting old
> >>>machine-types to override it for compatibility if required.
> >>Right now since I am using env->cpuid_hv_level == 0 as a flag. This
> >>means that:
> >>
> >>   -cpu host,hypervisor-level=0,hypervisor-vendor=kvm
> >>
> >>   -cpu host,hypervisor-vendor=kvm,hypervisor-level=0
> >>
> >>end up with different CPUID data (Which I do not like). I will fix this in the next round.
> >Right. This has to be fixed.
> >
> >>Did you want me to drop kvm0 and kvm1?
> >Yes, if level is already configurable using the hypervisor-level
> >property, I don't see the need for kvm0 and kvm1.
> >
> >If you make kvm_arch_init_vcpu() actually use those fields, you will end
> >up implementing what's required to allow migration compatibility to be
> >kept (the only thing missing is to make the CPU class a child of
> >DeviceState, and add hypervisor-level=0 to the existing machine-types).
> >:-)
> >
> You mean like
>   http://lists.gnu.org/archive/html/qemu-devel/2012-09/msg03402.html
> and
>   http://lists.gnu.org/archive/html/qemu-devel/2012-09/msg03405.html
> already change kvm_arch_init_vcpu().

Yes! Sorry, I hadn't reviewed all of your previous series yet.  :-)

> I did not know that I need to
> make the CPU class a child of DeviceState.

You don't. But we plan to do that, eventually, so we can put
CPU compatibility properties into machine-types.

> Nor that I needed to add hypervisor-vendor=kvm,hypervisor-level=0 to
> the existing machine-types.  Since without specifying
> hypervisor-level=0 it defaults to 0 and kvm_arch_init_vcpu() will
> default to setting hypervisor-vendor=kvm.

What I would like to do is: to change the default to 0x40000001 (that's
the correct value), but make the pc-1.1 and older machine-types keep the
hypervisor-level=0 default for compatibility.

(But to be able to do that, we need to first make the CPU class a child
of DeviceState, so that's something to be done later)
Don Slutz - Sept. 22, 2012, 3:26 a.m.
On 09/21/12 17:53, Eduardo Habkost wrote:
> On Fri, Sep 21, 2012 at 05:28:27PM -0400, Don Slutz wrote:
>> On 09/21/12 16:49, Eduardo Habkost wrote:
>>> On Fri, Sep 21, 2012 at 04:26:58PM -0400, Don Slutz wrote:
>>>> On 09/21/12 10:18, Eduardo Habkost wrote:
>>>>> On Thu, Sep 20, 2012 at 04:06:27PM -0400, Don Slutz wrote:
>>>>>>  From http://lkml.indiana.edu/hypermail/linux/kernel/1205.0/00100.html
>>>>>> EAX should be KVM_CPUID_FEATURES (0x40000001) not 0.
>>>>>>
>>>>>> Added hypervisor-vendor=kvm0 to get the older CPUID result. kvm1 selects the newer one.
>>>>> Why not just make "hypervisor-vendor=kvm" control only the hypervisor
>>>>> vendor string, and support something like "kvm-hypervisor-level=0" to
>>>>> restore the old cpuid_hv_level=0 behavior?
>>>>    -cpu host,hypervisor-vendor=kvm,hypervisor-level=0
>>>>
>>>>   Does this.
>>> Good.  :-)
>>>
>>>>> This is similar to the kvmclock case: it would allow us to make
>>>>> "hypervisor-vendor=kvm" use saner values as default, but letting old
>>>>> machine-types to override it for compatibility if required.
>>>> Right now since I am using env->cpuid_hv_level == 0 as a flag. This
>>>> means that:
>>>>
>>>>    -cpu host,hypervisor-level=0,hypervisor-vendor=kvm
>>>>
>>>>    -cpu host,hypervisor-vendor=kvm,hypervisor-level=0
>>>>
>>>> end up with different CPUID data (Which I do not like). I will fix this in the next round.
>>> Right. This has to be fixed.
>>>
>>>> Did you want me to drop kvm0 and kvm1?
>>> Yes, if level is already configurable using the hypervisor-level
>>> property, I don't see the need for kvm0 and kvm1.
>>>
>>> If you make kvm_arch_init_vcpu() actually use those fields, you will end
>>> up implementing what's required to allow migration compatibility to be
>>> kept (the only thing missing is to make the CPU class a child of
>>> DeviceState, and add hypervisor-level=0 to the existing machine-types).
>>> :-)
>>>
>> You mean like
>>    http://lists.gnu.org/archive/html/qemu-devel/2012-09/msg03402.html
>> and
>>    http://lists.gnu.org/archive/html/qemu-devel/2012-09/msg03405.html
>> already change kvm_arch_init_vcpu().
> Yes! Sorry, I hadn't reviewed all of your previous series yet.  :-)
>
>> I did not know that I need to
>> make the CPU class a child of DeviceState.
> You don't. But we plan to do that, eventually, so we can put
> CPU compatibility properties into machine-types.
>
>> Nor that I needed to add hypervisor-vendor=kvm,hypervisor-level=0 to
>> the existing machine-types.  Since without specifying
>> hypervisor-level=0 it defaults to 0 and kvm_arch_init_vcpu() will
>> default to setting hypervisor-vendor=kvm.
> What I would like to do is: to change the default to 0x40000001 (that's
> the correct value), but make the pc-1.1 and older machine-types keep the
> hypervisor-level=0 default for compatibility.
>
> (But to be able to do that, we need to first make the CPU class a child
> of DeviceState, so that's something to be done later)
>
Now that ([PATCH v5 00/17] Allow changing...):

http://lists.gnu.org/archive/html/qemu-devel/2012-09/msg03810.html

is released, this contains all that is left of the patch set.  So there 
will not be a v3.  This patch set is withdrawn.

    -Don

Patch

diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index 72a8442..e51b2b1 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -1250,9 +1250,12 @@  static char *x86_cpuid_get_hv_vendor(Object *obj, Error **errp)
     } else if (!strcmp(value, CPUID_HV_VENDOR_XEN) &&
                env->cpuid_hv_level == CPUID_HV_LEVEL_XEN) {
         pstrcpy(value, sizeof(value), "xen");
-    } else if (!strcmp(value, CPUID_HV_VENDOR_KVM) &&
-               env->cpuid_hv_level == 0) {
-        pstrcpy(value, sizeof(value), "kvm");
+    } else if (!strcmp(value, CPUID_HV_VENDOR_KVM)) {
+        if (env->cpuid_hv_level == CPUID_HV_LEVEL_KVM) {
+            pstrcpy(value, sizeof(value), "kvm1");
+        } else if (env->cpuid_hv_level == 0) {
+            pstrcpy(value, sizeof(value), "kvm0");
+        }
     }
     return value;
 }
@@ -1288,7 +1291,13 @@  static void x86_cpuid_set_hv_vendor(Object *obj, const char *value,
             env->cpuid_hv_level = CPUID_HV_LEVEL_XEN;
         }
         pstrcpy(adj_value, sizeof(adj_value), CPUID_HV_VENDOR_XEN);
-    } else if (!strcmp(value, "kvm")) {
+    } else if (!strcmp(value, "kvm") || !strcmp(value, "kvm1")) {
+        if (env->cpuid_hv_level == 0) {
+            env->cpuid_hv_level = CPUID_HV_LEVEL_KVM;
+        }
+        pstrcpy(adj_value, sizeof(adj_value), CPUID_HV_VENDOR_KVM);
+    } else if (!strcmp(value, "kvm0")) {
+        env->cpuid_hv_level = 0;
         pstrcpy(adj_value, sizeof(adj_value), CPUID_HV_VENDOR_KVM);
     } else {
         pstrcpy(adj_value, sizeof(adj_value), value);