Hyper-V Gen1 guests are getting stuck on boot when 'hv-passthrough' is
used. While 'hv-passthrough' is a debug only feature, this significantly
limit its usefullness. While debugging the problem, I found that there are
two loosely connected issues:
- 'hv-passthrough' enables 'hv-syndbg' and this is undesired.
- 'hv-syndbg's support by KVM is detected incorrectly when !CONFIG_SYNDBG.

Fix both issues; exclude 'hv-syndbg' from 'hv-passthrough' and don't allow
to turn on 'hv-syndbg' for !CONFIG_SYNDBG builds. 

Vitaly Kuznetsov (2):
  i386: Fix conditional CONFIG_SYNDBG enablement
  i386: Exclude 'hv-syndbg' from 'hv-passthrough'

 docs/system/i386/hyperv.rst | 13 +++++++++----
 target/i386/cpu.c           |  2 ++
 target/i386/kvm/kvm.c       | 18 ++++++++++++------
 3 files changed, 23 insertions(+), 10 deletions(-)

-- 
2.40.1

Vitaly Kuznetsov <vkuznets@redhat.com> writes:

> Hyper-V Gen1 guests are getting stuck on boot when 'hv-passthrough' is
> used. While 'hv-passthrough' is a debug only feature, this significantly
> limit its usefullness. While debugging the problem, I found that there are
> two loosely connected issues:
> - 'hv-passthrough' enables 'hv-syndbg' and this is undesired.
> - 'hv-syndbg's support by KVM is detected incorrectly when !CONFIG_SYNDBG.
>
> Fix both issues; exclude 'hv-syndbg' from 'hv-passthrough' and don't allow
> to turn on 'hv-syndbg' for !CONFIG_SYNDBG builds. 
>
> Vitaly Kuznetsov (2):
>   i386: Fix conditional CONFIG_SYNDBG enablement
>   i386: Exclude 'hv-syndbg' from 'hv-passthrough'
>
>  docs/system/i386/hyperv.rst | 13 +++++++++----
>  target/i386/cpu.c           |  2 ++
>  target/i386/kvm/kvm.c       | 18 ++++++++++++------
>  3 files changed, 23 insertions(+), 10 deletions(-)

Ping)

-- 
Vitaly

Vitaly Kuznetsov <vkuznets@redhat.com> writes:

> Vitaly Kuznetsov <vkuznets@redhat.com> writes:
>
>> Hyper-V Gen1 guests are getting stuck on boot when 'hv-passthrough' is
>> used. While 'hv-passthrough' is a debug only feature, this significantly
>> limit its usefullness. While debugging the problem, I found that there are
>> two loosely connected issues:
>> - 'hv-passthrough' enables 'hv-syndbg' and this is undesired.
>> - 'hv-syndbg's support by KVM is detected incorrectly when !CONFIG_SYNDBG.
>>
>> Fix both issues; exclude 'hv-syndbg' from 'hv-passthrough' and don't allow
>> to turn on 'hv-syndbg' for !CONFIG_SYNDBG builds. 
>>
>> Vitaly Kuznetsov (2):
>>   i386: Fix conditional CONFIG_SYNDBG enablement
>>   i386: Exclude 'hv-syndbg' from 'hv-passthrough'
>>
>>  docs/system/i386/hyperv.rst | 13 +++++++++----
>>  target/i386/cpu.c           |  2 ++
>>  target/i386/kvm/kvm.c       | 18 ++++++++++++------
>>  3 files changed, 23 insertions(+), 10 deletions(-)

Monthly ping)

-- 
Vitaly

Vitaly Kuznetsov <vkuznets@redhat.com> writes:

> Vitaly Kuznetsov <vkuznets@redhat.com> writes:
>
>> Vitaly Kuznetsov <vkuznets@redhat.com> writes:
>>
>>> Hyper-V Gen1 guests are getting stuck on boot when 'hv-passthrough' is
>>> used. While 'hv-passthrough' is a debug only feature, this significantly
>>> limit its usefullness. While debugging the problem, I found that there are
>>> two loosely connected issues:
>>> - 'hv-passthrough' enables 'hv-syndbg' and this is undesired.
>>> - 'hv-syndbg's support by KVM is detected incorrectly when !CONFIG_SYNDBG.
>>>
>>> Fix both issues; exclude 'hv-syndbg' from 'hv-passthrough' and don't allow
>>> to turn on 'hv-syndbg' for !CONFIG_SYNDBG builds. 
>>>
>>> Vitaly Kuznetsov (2):
>>>   i386: Fix conditional CONFIG_SYNDBG enablement
>>>   i386: Exclude 'hv-syndbg' from 'hv-passthrough'
>>>
>>>  docs/system/i386/hyperv.rst | 13 +++++++++----
>>>  target/i386/cpu.c           |  2 ++
>>>  target/i386/kvm/kvm.c       | 18 ++++++++++++------
>>>  3 files changed, 23 insertions(+), 10 deletions(-)
>
> Monthly ping)

Turns out these patches were never merged and honestly I forgot about
them myself. Will resend shortly.

-- 
Vitaly