On Thu, 13 Jul 2023 10:10:01 +0100, "chenxiang (M)" <chenxiang66@xxxxxxxxxxxxx> wrote: > > Hi Marc, > > > 在 2023/7/13 星期四 14:56, Marc Zyngier 写道: > > On Thu, 13 Jul 2023 03:35:39 +0100, > > "chenxiang (M)" <chenxiang66@xxxxxxxxxxxxx> wrote: > >> Hi Marc, > >> > >> > >> 在 2023/7/12 星期三 16:36, Marc Zyngier 写道: > >>> On Wed, 12 Jul 2023 08:55:05 +0100, > >>> chenxiang <chenxiang66@xxxxxxxxxxxxx> wrote: > >>>> From: Xiang Chen <chenxiang66@xxxxxxxxxxxxx> > >>>> > >>>> For those PMU system registers defined in sys_reg_descs[], use macro > >>>> PMU_SYS_REG() / PMU_PMEVCNTR_EL0 / PMU_PMEVTYPER_EL0 to define them, and > >>>> later two macros call macro PMU_SYS_REG() actually. > >>>> Currently the input parameter of PMU_SYS_REG() is other macro which is > >>>> calculation formula of the value of system registers, so for example, if > >>>> we want to "SYS_PMINTENSET_EL1" as the name of sys register, actually > >>>> the name will be as following: > >>>> (((3) << 19) | ((0) << 16) | ((9) << 12) | ((14) << 8) | ((1) << 5)) > >>>> > >>>> To fix the issue, use the name as a input parameter of PMU_SYS_REG like > >>>> MTE_REG or EL2_REG. > >>> Why is the name relevant? Is this related to tracing? > >> I think It is not related to tracing. I find the issue when i want to > >> know which system reigsters are set > >> when on live migration and printk the name of sys_reg_desc in function > >> kvm_sys_reg_set_user, > >> find the name of some registers are abnormal as followings: > >> > >> [ 227.145540] kvm_sys_reg_set_user 3427:SYS_FAR_EL1 > >> [ 227.158057] kvm_sys_reg_set_user 3427:SYS_PAR_EL1 > >> [ 227.170574] kvm_sys_reg_set_user 3427:(((3) << 19) | ((0) << 16) | > >> ((9) << 12) | ((14) << 8) | ((1) << 5)) > >> [ 227.188037] kvm_sys_reg_set_user 3427:(((3) << 19) | ((0) << 16) | > >> ((9) << 12) | ((14) << 8) | ((2) << 5)) > >> [ 227.205511] kvm_sys_reg_set_user 3427:SYS_MAIR_EL1 > >> [ 227.218117] kvm_sys_reg_set_user 3427:SYS_PIRE0_EL1 > > So what is this if not some form of tracing? > > Ah, i was misunderstood your question. I thought you aksed whether > it is related to kernel tracing (which is already existed in kernel) > such as tracepoint or debugfs. But that's my point: tracepoints such as kvm_sys_access already output the name (as well as the encoding), and are likely to be affected by this problem. And that's a much more interesting justification for this change. Thanks, M. -- Without deviation from the norm, progress is not possible.
