Re: [PATCH v1 4/4] x86/msr: Do not allow writes to MSR_IA32_ENERGY_PERF_BIAS

From: Shuah Khan
Date: Fri Oct 30 2020 - 13:12:54 EST


On 10/29/20 1:02 PM, Borislav Petkov wrote:
From: Borislav Petkov <bp@xxxxxxx>

Now that all in-kernel-tree users are converted to using the sysfs file,
remove the MSR from the "allowlist".

Signed-off-by: Borislav Petkov <bp@xxxxxxx>
---
arch/x86/kernel/msr.c | 3 ---
1 file changed, 3 deletions(-)

diff --git a/arch/x86/kernel/msr.c b/arch/x86/kernel/msr.c
index c0d409810658..b1147862730c 100644
--- a/arch/x86/kernel/msr.c
+++ b/arch/x86/kernel/msr.c
@@ -99,9 +99,6 @@ static int filter_write(u32 reg)
if (!__ratelimit(&fw_rs))
return 0;
- if (reg == MSR_IA32_ENERGY_PERF_BIAS)
- return 0;
-
pr_err("Write to unrecognized MSR 0x%x by %s (pid: %d). Please report to x86@xxxxxxxxxx.\n",
reg, current->comm, current->pid);


Thanks. Looks good to me.

Reviewed-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>

thanks,
-- Shuah