Re: [PATCH] x86/vhpet: Fix type size in timer_int_route_valid

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 28/07/2020 12:09, Eslam Elnikety wrote:
> On 28.07.20 11:26, Andrew Cooper wrote:
>> On 28/07/2020 09:33, Eslam Elnikety wrote:
>>> The macro timer_int_route_cap evalutes to a 64 bit value. Extend the
>>> size of left side of timer_int_route_valid to match.
>>>
>>> This bug was discovered and resolved using Coverity Static Analysis
>>> Security Testing (SAST) by Synopsys, Inc.
>>>
>>> Signed-off-by: Eslam Elnikety <elnikety@xxxxxxxxxx>
>>> ---
>>>   xen/arch/x86/hvm/hpet.c | 2 +-
>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/xen/arch/x86/hvm/hpet.c b/xen/arch/x86/hvm/hpet.c
>>> index ca94e8b453..9afe6e6760 100644
>>> --- a/xen/arch/x86/hvm/hpet.c
>>> +++ b/xen/arch/x86/hvm/hpet.c
>>> @@ -66,7 +66,7 @@
>>>       MASK_EXTR(timer_config(h, n), HPET_TN_INT_ROUTE_CAP)
>>>     #define timer_int_route_valid(h, n) \
>>> -    ((1u << timer_int_route(h, n)) & timer_int_route_cap(h, n))
>>> +    ((1ULL << timer_int_route(h, n)) & timer_int_route_cap(h, n))
>>>     static inline uint64_t hpet_read_maincounter(HPETState *h,
>>> uint64_t guest_time)
>>>   {
>>
>> Does this work?
>
> Yes! This is better than my fix (and I like that it clarifies the
> route part of the config. Will you sign-off and send a patch?

Any chance I can persuade you, or someone else to do this?  Loads of the
macros can be removed by filling in proper bitfield names in place of
'_', resulting in rather better code.

~Andrew

>
>>
>> diff --git a/xen/arch/x86/hvm/hpet.c b/xen/arch/x86/hvm/hpet.c
>> index ca94e8b453..638f6174de 100644
>> --- a/xen/arch/x86/hvm/hpet.c
>> +++ b/xen/arch/x86/hvm/hpet.c
>> @@ -62,8 +62,7 @@
>>     #define timer_int_route(h, n)    MASK_EXTR(timer_config(h, n),
>> HPET_TN_ROUTE)
>>   -#define timer_int_route_cap(h, n) \
>> -    MASK_EXTR(timer_config(h, n), HPET_TN_INT_ROUTE_CAP)
>> +#define timer_int_route_cap(h, n) (h)->hpet.timers[(n)].route
>>     #define timer_int_route_valid(h, n) \
>>       ((1u << timer_int_route(h, n)) & timer_int_route_cap(h, n))
>> diff --git a/xen/include/asm-x86/hvm/vpt.h
>> b/xen/include/asm-x86/hvm/vpt.h
>> index f0e0eaec83..a41fc443cc 100644
>> --- a/xen/include/asm-x86/hvm/vpt.h
>> +++ b/xen/include/asm-x86/hvm/vpt.h
>> @@ -73,7 +73,13 @@ struct hpet_registers {
>>       uint64_t isr;               /* interrupt status reg */
>>       uint64_t mc64;              /* main counter */
>>       struct {                    /* timers */
>> -        uint64_t config;        /* configuration/cap */
>> +        union {
>> +            uint64_t config;    /* configuration/cap */
>> +            struct {
>> +                uint32_t _;
>> +                uint32_t route;
>> +            };
>> +        };
>>           uint64_t cmp;           /* comparator */
>>           uint64_t fsb;           /* FSB route, not supported now */
>>       } timers[HPET_TIMER_NUM];
>>
>>
>