Messages in this thread | | | From | KY Srinivasan <> | Subject | RE: [PATCH V2 1/1] X86: Hyper-V: Get the local APIC timer frequency from the hypervisor | Date | Fri, 27 Sep 2013 15:23:17 +0000 |
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> -----Original Message----- > From: Olaf Hering [mailto:olaf@aepfle.de] > Sent: Friday, September 27, 2013 8:10 AM > To: KY Srinivasan > Cc: x86@kernel.org; gregkh@linuxfoundation.org; linux-kernel@vger.kernel.org; > devel@linuxdriverproject.org; apw@canonical.com; jasowang@redhat.com; > tglx@linutronix.de; hpa@zytor.com; JBeulich@suse.com; bp@alien8.de > Subject: Re: [PATCH V2 1/1] X86: Hyper-V: Get the local APIC timer frequency > from the hypervisor > > On Tue, Sep 03, K. Y. Srinivasan wrote: > > > Hyper-V supports a mechanism for retrieving the local APIC frequency.Use this > and bypass > > the calibration code in the kernel. This would allow us to boot the Linux kernel > as a > > "modern VM" on Hyper-V where many of the legacy devices (such as PIT) are > not emulated. > > > + if (ms_hyperv.features & HV_X64_MSR_APIC_FREQUENCY_AVAILABLE) { > > + /* > > + * Get the APIC frequency. > > + */ > > + rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency); > > + hv_lapic_frequency /= HZ; > > This leads to build errors on 32bit: > > linux-3.12-rc2/arch/x86/kernel/cpu/mshyperv.c:88: undefined reference to > `__udivdi3' > > Up to now I have only tested on 64bit, sorry for that.
Thanks Olaf. I am travelling currently; I will fix it when I get back (early next week).
K. Y > > > Olaf
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