Re: [PATCH v6 13/18] s390x: protvirt: Disable address checks for PV guest IO emulation

[David Hildenbrand]

On 05.03.20 12:26, Janosch Frank wrote:
> On 3/5/20 11:00 AM, David Hildenbrand wrote:
>> On 05.03.20 10:42, Janosch Frank wrote:
>>> On 3/4/20 6:55 PM, David Hildenbrand wrote:
>>>> On 04.03.20 12:42, Janosch Frank wrote:
>>>>> IO instruction data is routed through SIDAD for protected guests, so
>>>>> adresses do not need to be checked, as this is kernel memory.
>>>>>
>>>>> Signed-off-by: Janosch Frank <address@hidden>
>>>>> Reviewed-by: Thomas Huth <address@hidden>
>>>>> ---
>>>>>  target/s390x/ioinst.c | 26 +++++++++++++++++++-------
>>>>>  1 file changed, 19 insertions(+), 7 deletions(-)
>>>>>
>>>>> diff --git a/target/s390x/ioinst.c b/target/s390x/ioinst.c
>>>>> index c437a1d8c6..e4102430aa 100644
>>>>> --- a/target/s390x/ioinst.c
>>>>> +++ b/target/s390x/ioinst.c
>>>>> @@ -17,6 +17,16 @@
>>>>>  #include "trace.h"
>>>>>  #include "hw/s390x/s390-pci-bus.h"
>>>>>  
>>>>> +static uint64_t get_address_from_regs(CPUS390XState *env, uint32_t ipb,
>>>>> +                                      uint8_t *ar)
>>>>> +{
>>>>
>>>> Please add a comment here why this is done. (e.g., make all address
>>>> checks - like alignment checks - in the caller succeed, and we don't
>>>> need the address).
>>>
>>>      * Addresses for protected guests are all offsets into the
>>>
>>>
>>>      * satellite block which holds the IO control structures. Those
>>
>> maybe mention SIDA as well
> 
> huh? SIDA is the satellite block

Yes, please stick to a consistent terminology. Mix and matching "SIDA"
and "satellite block" does not improve readability IMHO.

-- 
Thanks,

David / dhildenb