On 03/20/2013 11:28 AM, Rafael J. Wysocki wrote:
On Wednesday, March 20, 2013 09:17:24 AM dirk.brandewie@xxxxxxxxx wrote:
From: Dirk Brandewie <dirk.brandewie@xxxxxxxxx>
Some VMs seem to try to implement some MSRs but not all the registers
the driver needs. Check to make sure all the MSR that we need are
available. If any of the required MSRs are not available refuse to
load.
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@xxxxxxxxx>
Is this needed for v3.9? Any pointers to bug reports etc.?
Sorry I saw right after I sent the mail that the bug report was missing
https://bugzilla.redhat.com/show_bug.cgi?id=922923
Reported-by: Josh Stone <jistone@xxxxxxxxxx>
Would you like me to spin the patch?
Rafael
---
drivers/cpufreq/intel_pstate.c | 26 ++++++++++++++++++++++++++
1 files changed, 26 insertions(+), 0 deletions(-)
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index f6dd1e7..cd9c5f4 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -752,6 +752,29 @@ static struct cpufreq_driver intel_pstate_driver = {
static int __initdata no_load;
+static int intel_pstate_msrs_not_valid(void)
+{
+ /* Check that all the msr's we are using are valid. */
+ u64 aperf, mperf, tmp;
+
+ rdmsrl(MSR_IA32_APERF, aperf);
+ rdmsrl(MSR_IA32_MPERF, mperf);
+
+ if (!intel_pstate_min_pstate() ||
+ !intel_pstate_max_pstate() ||
+ !intel_pstate_turbo_pstate())
+ return -ENODEV;
+
+ rdmsrl(MSR_IA32_APERF, tmp);
+ if (!(tmp - aperf))
+ return -ENODEV;
+
+ rdmsrl(MSR_IA32_MPERF, tmp);
+ if (!(tmp - mperf))
+ return -ENODEV;
+
+ return 0;
+}
static int __init intel_pstate_init(void)
{
int cpu, rc = 0;
@@ -764,6 +787,9 @@ static int __init intel_pstate_init(void)
if (!id)
return -ENODEV;
+ if (intel_pstate_msrs_not_valid())
+ return -ENODEV;
+
pr_info("Intel P-state driver initializing.\n");
all_cpu_data = vmalloc(sizeof(void *) * num_possible_cpus());
--
To unsubscribe from this list: send the line "unsubscribe cpufreq" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
