On 9/18/2020 3:18 PM, Andrew Jones wrote: > On Thu, Sep 17, 2020 at 08:00:55PM +0800, Peng Liang wrote: >> If we want to emulate ID registers, we need to initialize ID registers >> firstly. This commit is to add a helper function to traverse >> arm64_ftr_regs so that we can initialize ID registers from >> arm64_ftr_regs. >> >> Signed-off-by: zhanghailiang <[email protected]> >> Signed-off-by: Peng Liang <[email protected]> >> --- >> arch/arm64/include/asm/cpufeature.h | 2 ++ >> arch/arm64/kernel/cpufeature.c | 13 +++++++++++++ >> 2 files changed, 15 insertions(+) >> >> diff --git a/arch/arm64/include/asm/cpufeature.h >> b/arch/arm64/include/asm/cpufeature.h >> index 89b4f0142c28..2ba7c4f11d8a 100644 >> --- a/arch/arm64/include/asm/cpufeature.h >> +++ b/arch/arm64/include/asm/cpufeature.h >> @@ -79,6 +79,8 @@ struct arm64_ftr_reg { >> >> extern struct arm64_ftr_reg arm64_ftr_reg_ctrel0; >> >> +int arm64_cpu_ftr_regs_traverse(int (*op)(u32, u64, void *), void *argp); >> + >> /* >> * CPU capabilities: >> * >> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c >> index 6424584be01e..698b32705544 100644 >> --- a/arch/arm64/kernel/cpufeature.c >> +++ b/arch/arm64/kernel/cpufeature.c >> @@ -1112,6 +1112,19 @@ u64 read_sanitised_ftr_reg(u32 id) >> return regp->sys_val; >> } >> >> +int arm64_cpu_ftr_regs_traverse(int (*op)(u32, u64, void *), void *argp) >> +{ >> + int i, ret; >> + >> + for (i = 0; i < ARRAY_SIZE(arm64_ftr_regs); i++) { >> + ret = (*op)(arm64_ftr_regs[i].sys_id, >> + arm64_ftr_regs[i].reg->sys_val, argp); >> + if (ret < 0) >> + return ret; >> + } >> + return 0; >> +} >> + >> #define read_sysreg_case(r) \ >> case r: return read_sysreg_s(r) >> >> -- >> 2.26.2 >> > > Skimming the rest of the patches to see how this is used I only saw a > single callsite. Why wouldn't we just put this simple for-loop right > there at that callsite? Or, IOW, I think this traverse function should > be dropped. > > Thanks, > drew > > . >
arm64_ftr_regs is defined as a static array in arch/arm64/kernel/cpufeature.c, which is not a virtualization-related file. Putting this simple for-loop right there will make cpufeature.c depend on kvm_host.h. Is this a good idea? Thanks, Peng _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
