[kvm-unit-tests PATCH] x86: Allow xapic ID writes to silently fail

[kvm-unit-tests PATCH] x86: Allow xapic ID writes to silently fail

[nadav.amit]

From: Nadav Amit <nadav.amit@gmail.com>

According to Intel SDM: "Some processors permit software to modify the
APIC ID.  However, the ability of software to modify the APIC ID is
processor model specific."

Allow this behavior not to cause failures.

Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Nadav Amit <nadav.amit@gmail.com>
---
 x86/apic.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/x86/apic.c b/x86/apic.c
index d1ed5ea..6772f3f 100644
--- a/x86/apic.c
+++ b/x86/apic.c
@@ -210,7 +210,7 @@ static void __test_apic_id(void * unused)
     newid = (id + 1) << 24;
     report("writeable xapic id",
             !test_for_exception(GP_VECTOR, do_write_apic_id, &newid) &&
-            id + 1 == apic_id());
+	    (id == apic_id() || id + 1 == apic_id()));
 
     if (!enable_x2apic())
         goto out;
-- 
2.19.1

Re: [kvm-unit-tests PATCH] x86: Allow xapic ID writes to silently fail

[Paolo Bonzini]

On 24/04/19 23:22, nadav.amit@gmail.com wrote:
> From: Nadav Amit <nadav.amit@gmail.com>
> 
> According to Intel SDM: "Some processors permit software to modify the
> APIC ID.  However, the ability of software to modify the APIC ID is
> processor model specific."
> 
> Allow this behavior not to cause failures.
> 
> Cc: Sean Christopherson <sean.j.christopherson@intel.com>
> Signed-off-by: Nadav Amit <nadav.amit@gmail.com>
> ---
>  x86/apic.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/x86/apic.c b/x86/apic.c
> index d1ed5ea..6772f3f 100644
> --- a/x86/apic.c
> +++ b/x86/apic.c
> @@ -210,7 +210,7 @@ static void __test_apic_id(void * unused)
>      newid = (id + 1) << 24;
>      report("writeable xapic id",
>              !test_for_exception(GP_VECTOR, do_write_apic_id, &newid) &&
> -            id + 1 == apic_id());
> +	    (id == apic_id() || id + 1 == apic_id()));
>  
>      if (!enable_x2apic())
>          goto out;
> 

Queued, thanks.

Paolo

Re: [kvm-unit-tests PATCH] x86: Allow xapic ID writes to silently fail

[Nadav Amit]

> On Apr 30, 2019, at 12:13 PM, Paolo Bonzini <pbonzini@redhat.com> wrote:
> 
> On 24/04/19 23:22, nadav.amit@gmail.com wrote:
>> From: Nadav Amit <nadav.amit@gmail.com>
>> 
>> According to Intel SDM: "Some processors permit software to modify the
>> APIC ID.  However, the ability of software to modify the APIC ID is
>> processor model specific."
>> 
>> Allow this behavior not to cause failures.
>> 
>> Cc: Sean Christopherson <sean.j.christopherson@intel.com>
>> Signed-off-by: Nadav Amit <nadav.amit@gmail.com>
>> ---
>> x86/apic.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/x86/apic.c b/x86/apic.c
>> index d1ed5ea..6772f3f 100644
>> --- a/x86/apic.c
>> +++ b/x86/apic.c
>> @@ -210,7 +210,7 @@ static void __test_apic_id(void * unused)
>>     newid = (id + 1) << 24;
>>     report("writeable xapic id",
>>             !test_for_exception(GP_VECTOR, do_write_apic_id, &newid) &&
>> -            id + 1 == apic_id());
>> +	    (id == apic_id() || id + 1 == apic_id()));
>> 
>>     if (!enable_x2apic())
>>         goto out;
> 
> Queued, thanks.

Thanks. Silly question - when you say “queued”, what do you mean exactly?

In other words, when will it be reflected on the kvm-unit-tests repository?
I want to send a few more fixes, but I lost track which ones I sent, so I
want to rebase first.

Re: [kvm-unit-tests PATCH] x86: Allow xapic ID writes to silently fail

[Paolo Bonzini]

On 30/04/19 21:34, Nadav Amit wrote:
>> Queued, thanks.
> Thanks. Silly question - when you say “queued”, what do you mean exactly?
> 
> In other words, when will it be reflected on the kvm-unit-tests repository?
> I want to send a few more fixes, but I lost track which ones I sent, so I
> want to rebase first.

Usually very soon (an hour or two), in this case I am travelling so it
will appear in about a week.  I have pushed what I have to a "next"
branch.  These are the commits from you:

      x86: Fix wrong test for 5-level page-table
      x86: Remove INIT deassert
      x86: Fix allowed IA32_VMX_VMCS_ENUM values
      x86: Wait for self IPI
      x86: Initialize vmcs_root
      x86: Allow xapic ID writes to silently fail

Thanks,

Paolo