Re: Time to drop wrmsrl()/rdmsrl()?

From: Sean Christopherson

Date: Mon Dec 15 2025 - 15:15:23 EST


On Mon, Dec 15, 2025, Xin Li wrote:
> Hi Ingo,
>
> Keeping them around only causes churn now, so probably it is time to drop
> them?

+1, IMO keeping the old APIs is doing far more harm than good at this point.

> https://lore.kernel.org/lkml/aK8fmMGH0rB2LuA9@xxxxxxxxxx/
>
> https://lore.kernel.org/lkml/aR0vK3z1owwM8X8H@xxxxxxxxx/
>
>
> I think all of their uses were changed to wrmsrq()/rdmsrq(), but they are
> coming back, and with the latest Linux 6.19-rc1 tag, I get:
>
> $git grep -w rdmsrl
> arch/x86/events/amd/uncore.c: rdmsrl(hwc->event_base, new);
> arch/x86/include/asm/msr.h:#define rdmsrl(msr, val) rdmsrq(msr, val)
> arch/x86/kernel/cpu/resctrl/monitor.c: rdmsrl(MSR_IA32_QM_CTR, msr_val);
> drivers/hv/mshv_vtl_main.c: rdmsrl(reg_table[i].msr_addr, *reg64);
> drivers/idle/intel_idle.c: rdmsrl(MSR_PKG_CST_CONFIG_CONTROL, msr_val);
> drivers/idle/intel_idle.c: rdmsrl(MSR_PKG_CST_CONFIG_CONTROL, msr_val);
>
>
> Thanks!
> Xin