| Message ID | 1466558908-3524-1-git-send-email-wanpeng.li@hotmail.com (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
On 22/06/2016 03:28, Wanpeng Li wrote: > > get_ratio: > - rdmsr(MSR_PLATFORM_INFO, lo, hi); > - ratio = (lo >> 8) & 0xff; > + if (!rdmsr_safe(MSR_PLATFORM_INFO, &lo, &hi)) > + ratio = (lo >> 8) & 0xff; This looks good, thanks. Paolo -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, 22 Jun 2016, Wanpeng Li wrote:
> After commit (fc141535ad8 : "x86 tsc_msr: Extend to include Intel Core
Where did you find that commit? It's neither in Linus tree nor in tip.
Thanks,
tglx
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2016-06-23 15:09 GMT+08:00 Thomas Gleixner <tglx@linutronix.de>: > On Wed, 22 Jun 2016, Wanpeng Li wrote: >> After commit (fc141535ad8 : "x86 tsc_msr: Extend to include Intel Core > > Where did you find that commit? It's neither in Linus tree nor in tip. It is reported by lkp. https://lkml.org/lkml/2016/6/20/110 The patch is against x86 branch on Len Brown's tree. And try to fix this commit: https://git.kernel.org/cgit/linux/kernel/git/lenb/linux.git/commit/?h=x86&id=fc141535ad8a67fd58623289c04e35465e2a07f2 -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Jacob, 2016-06-23 15:28 GMT+08:00 Wanpeng Li <kernellwp@gmail.com>: > 2016-06-23 15:09 GMT+08:00 Thomas Gleixner <tglx@linutronix.de>: >> On Wed, 22 Jun 2016, Wanpeng Li wrote: >>> After commit (fc141535ad8 : "x86 tsc_msr: Extend to include Intel Core >> >> Where did you find that commit? It's neither in Linus tree nor in tip. > > It is reported by lkp. https://lkml.org/lkml/2016/6/20/110 The patch > is against x86 branch on Len Brown's tree. And try to fix this commit: > https://git.kernel.org/cgit/linux/kernel/git/lenb/linux.git/commit/?h=x86&id=fc141535ad8a67fd58623289c04e35465e2a07f2 I prefer this patch can be applied separately instead of fold into the bad commit since it shows the issue when access MSR_PLATFORM_INFO in kvm guest and other guys who want to access MSR_PLATFORM_INFO later can find the changelog and make better decisions. Regards, Wanpeng Li -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Jun 23, 2016 at 3:09 PM, Thomas Gleixner <tglx@linutronix.de> wrote: > On Wed, 22 Jun 2016, Wanpeng Li wrote: >> After commit (fc141535ad8 : "x86 tsc_msr: Extend to include Intel Core > > Where did you find that commit? It's neither in Linus tree nor in tip. > It is in Len's tree, we are planing to resend the patchset with Wanpeng's fix merged with a credit to him in commit msg, thanks for Wanpeng's effort. thanks all. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Yu， 2016-06-23 15:37 GMT+08:00 Yu Chen <yu.chen.surf@gmail.com>: > On Thu, Jun 23, 2016 at 3:09 PM, Thomas Gleixner <tglx@linutronix.de> wrote: >> On Wed, 22 Jun 2016, Wanpeng Li wrote: >>> After commit (fc141535ad8 : "x86 tsc_msr: Extend to include Intel Core >> >> Where did you find that commit? It's neither in Linus tree nor in tip. >> > It is in Len's tree, we are planing to resend the patchset with Wanpeng's fix > merged with a credit to him in commit msg, thanks for Wanpeng's effort. > thanks all. I prefer this patch can be applied separately instead of fold into the bad commit since it shows the issue when access MSR_PLATFORM_INFO in kvm guest and other guys who want to access MSR_PLATFORM_INFO later can find the changelog and make better decisions. Regards, Wanpeng Li -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
2016-06-23 15:41 GMT+08:00 Wanpeng Li <kernellwp@gmail.com>: > Hi Yu， > 2016-06-23 15:37 GMT+08:00 Yu Chen <yu.chen.surf@gmail.com>: >> On Thu, Jun 23, 2016 at 3:09 PM, Thomas Gleixner <tglx@linutronix.de> wrote: >>> On Wed, 22 Jun 2016, Wanpeng Li wrote: >>>> After commit (fc141535ad8 : "x86 tsc_msr: Extend to include Intel Core >>> >>> Where did you find that commit? It's neither in Linus tree nor in tip. >>> >> It is in Len's tree, we are planing to resend the patchset with Wanpeng's fix >> merged with a credit to him in commit msg, thanks for Wanpeng's effort. >> thanks all. > > I prefer this patch can be applied separately instead of fold into the > bad commit since it shows the issue when access MSR_PLATFORM_INFO in > kvm guest and other guys who want to access MSR_PLATFORM_INFO later > can find the changelog and make better decisions. Thomas, does it make sense to keep separate? Regards, Wanpeng Li -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Ingo, Thomas, 2016-06-22 9:28 GMT+08:00 Wanpeng Li <kernellwp@gmail.com>: > From: Wanpeng Li <wanpeng.li@hotmail.com> > > ------------[ cut here ]------------ > WARNING: CPU: 0 PID: 0 at arch/x86/mm/extable.c:50 ex_handler_rdmsr_unsafe+0x6a/0x70 > unchecked MSR access error: RDMSR from 0xce > Modules linked in: > CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.7.0-rc3+ #1 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 > 0000000000000000 ffffffff81c03ce0 ffffffff813b3eae ffffffff81c03d30 > 0000000000000000 ffffffff81c03d20 ffffffff81067181 0000003200000001 > ffffffff81c03df8 ffffffff8179676c 0000000000000000 ffffffff81fcd2c0 > Call Trace: > dump_stack+0x67/0x99 > __warn+0xd1/0xf0 > warn_slowpath_fmt+0x4f/0x60 > ex_handler_rdmsr_unsafe+0x6a/0x70 > fixup_exception+0x39/0x50 > do_general_protection+0x93/0x1b0 > general_protection+0x22/0x30 > ? cpu_khz_from_msr+0xd8/0x1c0 > native_calibrate_cpu+0x30/0x5b0 > tsc_init+0x2b/0x297 > x86_late_time_init+0xf/0x11 > start_kernel+0x398/0x451 > ? set_init_arg+0x55/0x55 > x86_64_start_reservations+0x2f/0x31 > x86_64_start_kernel+0xea/0xed > > After commit (fc141535ad8 : "x86 tsc_msr: Extend to include Intel Core > Architecture"), rdmsr MSR_PLATFORM_INFO is used to get maximum non-turbo I just saw commit (fc273eeef314c : "x86 tsc_msr: Extend to include Intel Core Architecture") was merged in tip tree, then this patch is needed to fix that commit. The bug is reported by LKP several weeks ago, and kvm maintainer Paolo has already replied "This looks good" to this patch. Regards, Wanpeng Li > ratio for recent Intel Core Architecture which results in kvm guest rdmsr > unsafe warning. > > As Radim pointed out before: > > | MSR_PLATFORM_INFO: Intel changes it from family to family and there is > | no obvious overlap or default. If we picked 0 (any other fixed value), > | then the guest would have to know that 0 doesn't mean that > | MSR_PLATFORM_INFO returned 0, but that KVM doesn't emulate this MSR and > | the value cannot be used. This is very similar to handling a #GP in the > | guest, but also has a disadvantage, because KVM cannot say that > | MSR_PLATFORM_INFO is 0. Simple emulation is not possible. > > This patch fix it by using rdmsr_safe to read MSR_PLATFORM_INFO in kvm > guest in order that #GP can be fixed up, then tsc will be calibrated by > PIT, HPET etc. > > Reported-by: kernel test robot <xiaolong.ye@intel.com> > Cc: Len Brown <len.brown@intel.com> > Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> > Cc: Zhang Rui <rui.zhang@intel.com> > Cc: Chen Yu <yu.c.chen@intel.com> > Cc: Paolo Bonzini <pbonzini@redhat.com> > Cc: Radim Krčmář <rkrcmar@redhat.com> > Cc: jacob.jun.pan@intel.com > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: "H. Peter Anvin" <hpa@zytor.com> > Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> > --- > arch/x86/kernel/tsc_msr.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/kernel/tsc_msr.c b/arch/x86/kernel/tsc_msr.c > index e0c2b30..e6e465e 100644 > --- a/arch/x86/kernel/tsc_msr.c > +++ b/arch/x86/kernel/tsc_msr.c > @@ -70,7 +70,7 @@ static int match_cpu(u8 family, u8 model) > */ > unsigned long cpu_khz_from_msr(void) > { > - u32 lo, hi, ratio, freq_id, freq; > + u32 lo, hi, freq_id, freq, ratio = 0; > unsigned long res; > int cpu_index; > > @@ -123,8 +123,8 @@ unsigned long cpu_khz_from_msr(void) > } > > get_ratio: > - rdmsr(MSR_PLATFORM_INFO, lo, hi); > - ratio = (lo >> 8) & 0xff; > + if (!rdmsr_safe(MSR_PLATFORM_INFO, &lo, &hi)) > + ratio = (lo >> 8) & 0xff; > > done: > /* TSC frequency = maximum resolved freq * maximum resolved bus ratio */ > -- > 1.9.1 > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
* Wanpeng Li <kernellwp@gmail.com> wrote: > Hi Ingo, Thomas, > 2016-06-22 9:28 GMT+08:00 Wanpeng Li <kernellwp@gmail.com>: > > From: Wanpeng Li <wanpeng.li@hotmail.com> > > > > ------------[ cut here ]------------ > > WARNING: CPU: 0 PID: 0 at arch/x86/mm/extable.c:50 ex_handler_rdmsr_unsafe+0x6a/0x70 > > unchecked MSR access error: RDMSR from 0xce > > Modules linked in: > > CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.7.0-rc3+ #1 > > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 > > 0000000000000000 ffffffff81c03ce0 ffffffff813b3eae ffffffff81c03d30 > > 0000000000000000 ffffffff81c03d20 ffffffff81067181 0000003200000001 > > ffffffff81c03df8 ffffffff8179676c 0000000000000000 ffffffff81fcd2c0 > > Call Trace: > > dump_stack+0x67/0x99 > > __warn+0xd1/0xf0 > > warn_slowpath_fmt+0x4f/0x60 > > ex_handler_rdmsr_unsafe+0x6a/0x70 > > fixup_exception+0x39/0x50 > > do_general_protection+0x93/0x1b0 > > general_protection+0x22/0x30 > > ? cpu_khz_from_msr+0xd8/0x1c0 > > native_calibrate_cpu+0x30/0x5b0 > > tsc_init+0x2b/0x297 > > x86_late_time_init+0xf/0x11 > > start_kernel+0x398/0x451 > > ? set_init_arg+0x55/0x55 > > x86_64_start_reservations+0x2f/0x31 > > x86_64_start_kernel+0xea/0xed > > > > After commit (fc141535ad8 : "x86 tsc_msr: Extend to include Intel Core > > Architecture"), rdmsr MSR_PLATFORM_INFO is used to get maximum non-turbo > > I just saw commit (fc273eeef314c : "x86 tsc_msr: Extend to include > Intel Core Architecture") was merged in tip tree, then this patch is > needed to fix that commit. The bug is reported by LKP several weeks > ago, and kvm maintainer Paolo has already replied "This looks good" to > this patch. Applied, thanks! Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/x86/kernel/tsc_msr.c b/arch/x86/kernel/tsc_msr.c index e0c2b30..e6e465e 100644 --- a/arch/x86/kernel/tsc_msr.c +++ b/arch/x86/kernel/tsc_msr.c @@ -70,7 +70,7 @@ static int match_cpu(u8 family, u8 model) */ unsigned long cpu_khz_from_msr(void) { - u32 lo, hi, ratio, freq_id, freq; + u32 lo, hi, freq_id, freq, ratio = 0; unsigned long res; int cpu_index; @@ -123,8 +123,8 @@ unsigned long cpu_khz_from_msr(void) } get_ratio: - rdmsr(MSR_PLATFORM_INFO, lo, hi); - ratio = (lo >> 8) & 0xff; + if (!rdmsr_safe(MSR_PLATFORM_INFO, &lo, &hi)) + ratio = (lo >> 8) & 0xff; done: /* TSC frequency = maximum resolved freq * maximum resolved bus ratio */