Re: [PATCH] perf/x86: fix RAPL rdmsrl_safe() usage
> > Acked-by: Borislav Petkov > > Brown-Paper-Bag-Worn-By: Venkatesh Srinivas Again the bug is really in KVM. We wouldn't need all this crap if KVM didn't throw the bogus #GPs. I'm sure you missed plenty of MSR accesses elsewhere, and it's a ticking time bomb. If the VM lies to the kernel with the family-model you need to at least limit the consequences. KVM is spectacularly failing to do that by throwing bogus #GPs. The brown paper bad needs to be employed on the KVM code (or better the bug be fixed there, by defaulting to not #GP on unknown MSRs) -Andi -- a...@linux.intel.com -- Speaking for myself only -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] perf/x86: fix RAPL rdmsrl_safe() usage
On Wed, Apr 23, 2014 at 12:00 PM, Borislav Petkov wrote: > On Wed, Apr 23, 2014 at 07:04:19PM +0200, Stephane Eranian wrote: >> >> This patch fixes a bug introduced by commit 24223657. > > Maybe add > > Fixes: > > tag? > >> The rdmsrl_safe() function returns 0 on success. >> The current code was failing to detect the RAPL PMU >> on real hardware (missing /sys/devices/power) because >> the return value of rdmsrl_safe() was misinterpreted. >> >> Signed-off-by: Stephane Eranian > > Acked-by: Borislav Petkov Brown-Paper-Bag-Worn-By: Venkatesh Srinivas -- vs; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] perf/x86: fix RAPL rdmsrl_safe() usage
On Wed, Apr 23, 2014 at 07:04:19PM +0200, Stephane Eranian wrote: > > This patch fixes a bug introduced by commit 24223657. Maybe add Fixes: tag? > The rdmsrl_safe() function returns 0 on success. > The current code was failing to detect the RAPL PMU > on real hardware (missing /sys/devices/power) because > the return value of rdmsrl_safe() was misinterpreted. > > Signed-off-by: Stephane Eranian Acked-by: Borislav Petkov -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH] perf/x86: fix RAPL rdmsrl_safe() usage
This patch fixes a bug introduced by commit 24223657. The rdmsrl_safe() function returns 0 on success. The current code was failing to detect the RAPL PMU on real hardware (missing /sys/devices/power) because the return value of rdmsrl_safe() was misinterpreted. Signed-off-by: Stephane Eranian diff --git a/arch/x86/kernel/cpu/perf_event_intel_rapl.c b/arch/x86/kernel/cpu/perf_event_intel_rapl.c index 7c87424..619f769 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_rapl.c +++ b/arch/x86/kernel/cpu/perf_event_intel_rapl.c @@ -543,7 +543,8 @@ static int rapl_cpu_prepare(int cpu) if (phys_id < 0) return -1; - if (!rdmsrl_safe(MSR_RAPL_POWER_UNIT, _rapl_power_unit_bits)) + /* protect rdmsrl() to handle virtualization */ + if (rdmsrl_safe(MSR_RAPL_POWER_UNIT, _rapl_power_unit_bits)) return -1; pmu = kzalloc_node(sizeof(*pmu), GFP_KERNEL, cpu_to_node(cpu)); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH] perf/x86: fix RAPL rdmsrl_safe() usage
This patch fixes a bug introduced by commit 24223657. The rdmsrl_safe() function returns 0 on success. The current code was failing to detect the RAPL PMU on real hardware (missing /sys/devices/power) because the return value of rdmsrl_safe() was misinterpreted. Signed-off-by: Stephane Eranian eran...@google.com diff --git a/arch/x86/kernel/cpu/perf_event_intel_rapl.c b/arch/x86/kernel/cpu/perf_event_intel_rapl.c index 7c87424..619f769 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_rapl.c +++ b/arch/x86/kernel/cpu/perf_event_intel_rapl.c @@ -543,7 +543,8 @@ static int rapl_cpu_prepare(int cpu) if (phys_id 0) return -1; - if (!rdmsrl_safe(MSR_RAPL_POWER_UNIT, msr_rapl_power_unit_bits)) + /* protect rdmsrl() to handle virtualization */ + if (rdmsrl_safe(MSR_RAPL_POWER_UNIT, msr_rapl_power_unit_bits)) return -1; pmu = kzalloc_node(sizeof(*pmu), GFP_KERNEL, cpu_to_node(cpu)); -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] perf/x86: fix RAPL rdmsrl_safe() usage
On Wed, Apr 23, 2014 at 07:04:19PM +0200, Stephane Eranian wrote: This patch fixes a bug introduced by commit 24223657. Maybe add Fixes: commit-id tag? The rdmsrl_safe() function returns 0 on success. The current code was failing to detect the RAPL PMU on real hardware (missing /sys/devices/power) because the return value of rdmsrl_safe() was misinterpreted. Signed-off-by: Stephane Eranian eran...@google.com Acked-by: Borislav Petkov b...@suse.de -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. -- -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] perf/x86: fix RAPL rdmsrl_safe() usage
On Wed, Apr 23, 2014 at 12:00 PM, Borislav Petkov b...@alien8.de wrote: On Wed, Apr 23, 2014 at 07:04:19PM +0200, Stephane Eranian wrote: This patch fixes a bug introduced by commit 24223657. Maybe add Fixes: commit-id tag? The rdmsrl_safe() function returns 0 on success. The current code was failing to detect the RAPL PMU on real hardware (missing /sys/devices/power) because the return value of rdmsrl_safe() was misinterpreted. Signed-off-by: Stephane Eranian eran...@google.com Acked-by: Borislav Petkov b...@suse.de Brown-Paper-Bag-Worn-By: Venkatesh Srinivas venkate...@google.com -- vs; -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] perf/x86: fix RAPL rdmsrl_safe() usage
Acked-by: Borislav Petkov b...@suse.de Brown-Paper-Bag-Worn-By: Venkatesh Srinivas venkate...@google.com Again the bug is really in KVM. We wouldn't need all this crap if KVM didn't throw the bogus #GPs. I'm sure you missed plenty of MSR accesses elsewhere, and it's a ticking time bomb. If the VM lies to the kernel with the family-model you need to at least limit the consequences. KVM is spectacularly failing to do that by throwing bogus #GPs. The brown paper bad needs to be employed on the KVM code (or better the bug be fixed there, by defaulting to not #GP on unknown MSRs) -Andi -- a...@linux.intel.com -- Speaking for myself only -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
