On 2024/2/22 下午5:45, WANG Xuerui wrote:
Hi,
On 2/17/24 11:03, maobibo wrote:
Hi Xuerui,
Good catch, and thank for your patch.
On 2024/2/16 下午4:58, WANG Xuerui wrote:
[snip]
@@ -324,31 +319,33 @@ static int _kvm_get_cpucfg(int id, u64 *v)
if (cpu_has_lasx)
*v |= CPUCFG2_LASX;
- break;
+ return 0;
+ case 0 ... 1:
+ case 3 ... KVM_MAX_CPUCFG_REGS - 1:
+ /* no restrictions on other CPUCFG IDs' values */
+ *v = U64_MAX;
+ return 0;
how about something like this?
default:
/* no restrictions on other CPUCFG IDs' values */
*v = U64_MAX;
return 0;
I don't think this version correctly expresses the intent. Note that the
CPUCFG ID range check is squashed into the switch as well, so one switch
conveniently expresses the three intended cases at once:
* the special treatment of CPUCFG2,
+ case 0 ... 1:
+ case 3 ... KVM_MAX_CPUCFG_REGS - 1:
+ /* no restrictions on other CPUCFG IDs' values */
+ *v = U64_MAX;
+ return 0;
cpucfg6 checking will be added for PMU support soon. So it will be
case 6:
do something check for cpucfg6
return mask;
case 0 ... 1:
case 3 ... 5:
case 7 ... KVM_MAX_CPUCFG_REGS - 1:
*v = U64_MAX;
return 0;
If you think it is reasonable to add these separate "case" sentences, I
have no objection.
* all-allow rules for other in-range CPUCFG IDs, and
* rejection for out-of-range IDs.
static int kvm_check_cpucfg(int id, u64 val)
{
- u64 mask;
- int ret = 0;
-
- if (id < 0 && id >= KVM_MAX_CPUCFG_REGS)
- return -EINVAL;
you can modify && with ||, like this:
if (id < 0 || id >= KVM_MAX_CPUCFG_REGS)
return -EINVAL;
+ u64 mask = 0;
+ int ret;
Regards
Bibo Mao
Yet the suggestion here is conflating the latter two cases, with the
effect of allowing every ID that's not 2 to take any value (as expressed
by the U64_MAX mask), and *removing the range check* (because no return
path returns -EINVAL with this change).
So I'd like to stick to the current version, but thanks anyway for your
kind review and suggestion.
