From: Olaf Hering <olaf@aepfle.de>
To: "K. Y. Srinivasan" <kys@microsoft.com>
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
Date: Fri, 27 Sep 2013 17:10:26 +0200 [thread overview]
Message-ID: <20130927151026.GA29416@aepfle.de> (raw)
In-Reply-To: <1378233023-4512-1-git-send-email-kys@microsoft.com>
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.
Olaf
next prev parent reply other threads:[~2013-09-27 15:10 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-03 18:30 K. Y. Srinivasan
2013-09-04 7:17 ` Jan Beulich
2013-09-04 15:03 ` KY Srinivasan
2013-09-04 9:40 ` Gleb Natapov
2013-09-04 15:16 ` KY Srinivasan
2013-09-05 14:16 ` Gleb Natapov
2013-09-13 0:06 ` KY Srinivasan
2013-09-13 0:28 ` H. Peter Anvin
2013-09-13 1:43 ` KY Srinivasan
2013-09-13 6:39 ` Jan Beulich
2013-09-13 14:28 ` KY Srinivasan
2013-09-13 9:55 ` Gleb Natapov
2013-09-13 14:28 ` KY Srinivasan
2013-09-17 13:59 ` Gleb Natapov
2013-09-17 19:53 ` KY Srinivasan
2013-09-18 5:43 ` Gleb Natapov
2013-09-23 13:02 ` KY Srinivasan
2013-09-23 15:50 ` H. Peter Anvin
2013-09-23 19:23 ` KY Srinivasan
2013-10-02 23:11 ` KY Srinivasan
2013-09-27 15:10 ` Olaf Hering [this message]
2013-09-27 15:23 ` KY Srinivasan
2013-09-27 15:32 ` Olaf Hering
2013-09-27 15:35 ` KY Srinivasan
2013-10-09 22:50 ` H. Peter Anvin
2013-10-10 0:04 ` KY Srinivasan
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