linux.git/arch/x86/kernel/cpu/mshyperv.c, branch v3.14 Linux kernel source tree x86, hyperv: Move a variable to avoid an unused variable warning 2013-11-06T18:02:05+00:00 H. Peter Anvin hpa@zytor.com 2013-11-06T18:00:05+00:00 4c08edd305019061bf1ac95ce089497bdbb8b8ac The variable hv_lapic_frequency causes an unused variable warning if CONFIG_X86_LOCAL_APIC is disabled. Since the variable is only used inside a small if statement, move the declaration of that variable into the if statement itself. Cc: K. Y. Srinivasan <kys@microsoft.com> Link: http://lkml.kernel.org/r/1381444224-3303-1-git-send-email-kys@microsoft.com Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> 
The variable hv_lapic_frequency causes an unused variable warning if
CONFIG_X86_LOCAL_APIC is disabled.  Since the variable is only used
inside a small if statement, move the declaration of that variable
into the if statement itself.

Cc: K. Y. Srinivasan <kys@microsoft.com>
Link: http://lkml.kernel.org/r/1381444224-3303-1-git-send-email-kys@microsoft.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
x86, hyperv: Fix build error due to missing <asm/apic.h> include 2013-10-30T22:37:47+00:00 David Rientjes rientjes@google.com 2013-10-11T23:07:31+00:00 d68ce0177c1e51fb332369e0c99852a6d05668af 9e7827b5ea4c ("x86, hyperv: Get the local APIC timer frequency from the hypervisor") breaks the build with some configs because apic.h isn't directly included: arch/x86/kernel/cpu/mshyperv.c: In function 'ms_hyperv_init_platform': arch/x86/kernel/cpu/mshyperv.c:90:3: error: 'lapic_timer_frequency' undeclared (first use in this function) arch/x86/kernel/cpu/mshyperv.c:90:3: note: each undeclared identifier is reported only once for each function it appears in Fix it by including asm/apic.h. Signed-off-by: David Rientjes <rientjes@google.com> Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1310111604160.31170@chino.kir.corp.google.com Acked-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> 
9e7827b5ea4c ("x86, hyperv: Get the local APIC timer frequency from the
hypervisor") breaks the build with some configs because apic.h isn't
directly included:

arch/x86/kernel/cpu/mshyperv.c: In function 'ms_hyperv_init_platform':
arch/x86/kernel/cpu/mshyperv.c:90:3: error: 'lapic_timer_frequency' undeclared (first use in this function)
arch/x86/kernel/cpu/mshyperv.c:90:3: note: each undeclared identifier is reported only once for each function it appears in

Fix it by including asm/apic.h.

Signed-off-by: David Rientjes <rientjes@google.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1310111604160.31170@chino.kir.corp.google.com
Acked-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
x86, hyperv: Correctly guard the local APIC calibration code 2013-10-10T22:21:38+00:00 K. Y. Srinivasan kys@microsoft.com 2013-10-10T22:30:24+00:00 90ab9d5510932e146a9443bf5a591f95d5b5ada8 The code that gets the local APIC timer frequency from the hypervisor rather depends on there being a local APIC. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Link: http://lkml.kernel.org/r/1381444224-3303-1-git-send-email-kys@microsoft.com Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> 
The code that gets the local APIC timer frequency from the hypervisor
rather depends on there being a local APIC.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Link: http://lkml.kernel.org/r/1381444224-3303-1-git-send-email-kys@microsoft.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
x86, hyperv: Get the local APIC timer frequency from the hypervisor 2013-10-10T18:44:12+00:00 K. Y. Srinivasan kys@microsoft.com 2013-09-30T15:28:52+00:00 9e7827b5ea4ca93b4d864bc07c0fafb838d496b1 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. I would like to thank Olaf Hering <olaf@aepfle.de>, Jan Beulich <JBeulich@suse.com> and H. Peter Anvin <h.peter.anvin@intel.com> for their help in this effort. In this version of the patch, I have addressed Jan's comments. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Link: http://lkml.kernel.org/r/1380554932-9888-1-git-send-email-olaf@aepfle.de Tested-by: Olaf Hering <olaf@aepfle.de> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> 
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.

I would like to thank Olaf Hering <olaf@aepfle.de>, Jan Beulich <JBeulich@suse.com> and
H. Peter Anvin <h.peter.anvin@intel.com> for their help in this effort.

In this version of the patch, I have addressed Jan's comments.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Link: http://lkml.kernel.org/r/1380554932-9888-1-git-send-email-olaf@aepfle.de
Tested-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
x86: Correctly detect hypervisor 2013-08-05T13:35:33+00:00 Jason Wang jasowang@redhat.com 2013-07-25T08:54:35+00:00 9df56f19a500bea90d160be1bf77e4fbcd204d3f We try to handle the hypervisor compatibility mode by detecting hypervisor through a specific order. This is not robust, since hypervisors may implement each others features. This patch tries to handle this situation by always choosing the last one in the CPUID leaves. This is done by letting .detect() return a priority instead of true/false and just re-using the CPUID leaf where the signature were found as the priority (or 1 if it was found by DMI). Then we can just pick hypervisor who has the highest priority. Other sophisticated detection method could also be implemented on top. Suggested by H. Peter Anvin and Paolo Bonzini. Acked-by: K. Y. Srinivasan <kys@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Doug Covelli <dcovelli@vmware.com> Cc: Borislav Petkov <bp@suse.de> Cc: Dan Hecht <dhecht@vmware.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Gleb Natapov <gleb@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Jason Wang <jasowang@redhat.com> Link: http://lkml.kernel.org/r/1374742475-2485-4-git-send-email-jasowang@redhat.com Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> 
We try to handle the hypervisor compatibility mode by detecting hypervisor
through a specific order. This is not robust, since hypervisors may implement
each others features.

This patch tries to handle this situation by always choosing the last one in the
CPUID leaves. This is done by letting .detect() return a priority instead of
true/false and just re-using the CPUID leaf where the signature were found as
the priority (or 1 if it was found by DMI). Then we can just pick hypervisor who
has the highest priority. Other sophisticated detection method could also be
implemented on top.

Suggested by H. Peter Anvin and Paolo Bonzini.

Acked-by: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Doug Covelli <dcovelli@vmware.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Dan Hecht <dhecht@vmware.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Link: http://lkml.kernel.org/r/1374742475-2485-4-git-send-email-jasowang@redhat.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
x86, hyperv: Handle Xen emulation of Hyper-V more gracefully 2013-04-18T15:59:20+00:00 K. Y. Srinivasan kys@microsoft.com 2013-04-18T15:44:46+00:00 7eff7ded02d1b15ba8321664839b353fa6c0c1e4 Install the Hyper-V specific interrupt handler only when needed. This would permit us to get rid of the Xen check. Note that when the vmbus drivers invokes the call to register its handler, we are sure to be running on Hyper-V. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Link: http://lkml.kernel.org/r/1366299886-6399-1-git-send-email-kys@microsoft.com Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> 
Install the Hyper-V specific interrupt handler only when needed. This would
permit us to get rid of the Xen check. Note that when the vmbus drivers invokes
the call to register its handler, we are sure to be running on Hyper-V.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Link: http://lkml.kernel.org/r/1366299886-6399-1-git-send-email-kys@microsoft.com
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
X86: Handle Hyper-V vmbus interrupts as special hypervisor interrupts 2013-02-13T00:27:15+00:00 K. Y. Srinivasan kys@microsoft.com 2013-02-04T01:22:39+00:00 bc2b0331e077f576369a2b6c75d15ed4de4ef91f Starting with win8, vmbus interrupts can be delivered on any VCPU in the guest and furthermore can be concurrently active on multiple VCPUs. Support this interrupt delivery model by setting up a separate IDT entry for Hyper-V vmbus. interrupts. I would like to thank Jan Beulich <JBeulich@suse.com> and Thomas Gleixner <tglx@linutronix.de>, for their help. In this version of the patch, based on the feedback, I have merged the IDT vector for Xen and Hyper-V and made the necessary adjustments. Furhermore, based on Jan's feedback I have added the necessary compilation switches. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Link: http://lkml.kernel.org/r/1359940959-32168-3-git-send-email-kys@microsoft.com Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> 
Starting with win8, vmbus interrupts can be delivered on any VCPU in the guest
and furthermore can be concurrently active on multiple VCPUs. Support this
interrupt delivery model by setting up a separate IDT entry for Hyper-V vmbus.
interrupts. I would like to thank Jan Beulich <JBeulich@suse.com> and
Thomas Gleixner <tglx@linutronix.de>, for their help.

In this version of the patch, based on the feedback, I have merged the IDT
vector for Xen and Hyper-V and made the necessary adjustments. Furhermore,
based on Jan's feedback I have added the necessary compilation switches.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Link: http://lkml.kernel.org/r/1359940959-32168-3-git-send-email-kys@microsoft.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
X86: Add a check to catch Xen emulation of Hyper-V 2013-02-13T00:27:03+00:00 K. Y. Srinivasan kys@microsoft.com 2013-02-04T01:22:38+00:00 db34bbb767bdfa1ebed7214b876fe01c5b7ee457 Xen emulates Hyper-V to host enlightened Windows. Looks like this emulation may be turned on by default even for Linux guests. Check and fail Hyper-V detection if we are on Xen. [ hpa: the problem here is that Xen doesn't emulate Hyper-V well enough, and if the Xen support isn't compiled in, we end up stubling over the Hyper-V emulation and try to activate it -- and it fails. ] Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Link: http://lkml.kernel.org/r/1359940959-32168-2-git-send-email-kys@microsoft.com Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> 
Xen emulates Hyper-V to host enlightened Windows. Looks like this
emulation may be turned on by default even for Linux guests. Check and
fail Hyper-V detection if we are on Xen.

[ hpa: the problem here is that Xen doesn't emulate Hyper-V well
  enough, and if the Xen support isn't compiled in, we end up stubling
  over the Hyper-V emulation and try to activate it -- and it fails. ]

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Link: http://lkml.kernel.org/r/1359940959-32168-2-git-send-email-kys@microsoft.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
x86: Hyper-V: register clocksource only if its advertised 2013-02-13T00:25:48+00:00 Olaf Hering [mailto:olaf@aepfle.de] 2013-02-04T01:22:37+00:00 32068f6527b8f1822a30671dedaf59c567325026 Enable hyperv_clocksource only if its advertised as a feature. XenServer 6 returns the signature which is checked in ms_hyperv_platform(), but it does not offer all features. Currently the clocksource is enabled unconditionally in ms_hyperv_init_platform(), and the result is a hanging guest. Hyper-V spec Bit 1 indicates the availability of Partition Reference Counter. Register the clocksource only if this bit is set. The guest in question prints this in dmesg: [ 0.000000] Hypervisor detected: Microsoft HyperV [ 0.000000] HyperV: features 0x70, hints 0x0 This bug can be reproduced easily be setting 'viridian=1' in a HVM domU .cfg file. A workaround without this patch is to boot the HVM guest with 'clocksource=jiffies'. Signed-off-by: Olaf Hering <olaf@aepfle.de> Link: http://lkml.kernel.org/r/1359940959-32168-1-git-send-email-kys@microsoft.com Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: <stable@vger.kernel.org> Cc: Greg KH <gregkh@linuxfoundation.org> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> 
Enable hyperv_clocksource only if its advertised as a feature.
XenServer 6 returns the signature which is checked in
ms_hyperv_platform(), but it does not offer all features. Currently the
clocksource is enabled unconditionally in ms_hyperv_init_platform(), and
the result is a hanging guest.

Hyper-V spec Bit 1 indicates the availability of Partition Reference
Counter.  Register the clocksource only if this bit is set.

The guest in question prints this in dmesg:
 [    0.000000] Hypervisor detected: Microsoft HyperV
 [    0.000000] HyperV: features 0x70, hints 0x0

This bug can be reproduced easily be setting 'viridian=1' in a HVM domU
.cfg file. A workaround without this patch is to boot the HVM guest with
'clocksource=jiffies'.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Link: http://lkml.kernel.org/r/1359940959-32168-1-git-send-email-kys@microsoft.com
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Cc: <stable@vger.kernel.org>
Cc: Greg KH <gregkh@linuxfoundation.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
x86: Hyper-V: Integrate the clocksource with Hyper-V detection code 2011-09-08T08:33:59+00:00 K. Y. Srinivasan kys@microsoft.com 2011-09-07T22:25:10+00:00 6f4151c89b7d036c755d8cf74729e09b76fa6676 The Hyper-V clocksource driver is best integrated with Hyper-V detection code since: (a) Linux guests running on Hyper-V require it (b) Integration into that code significanly reduces code size Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com> Cc: gregkh@suse.de Cc: devel@linuxdriverproject.org Cc: virtualization@lists.osdl.org Link: http://lkml.kernel.org/r/1315434310-4827-1-git-send-email-kys@microsoft.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> 
The Hyper-V clocksource driver is best integrated with Hyper-V
detection code since: 

  (a) Linux guests running on Hyper-V require it

  (b) Integration into that code significanly reduces code size

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Cc: gregkh@suse.de
Cc: devel@linuxdriverproject.org
Cc: virtualization@lists.osdl.org
Link: http://lkml.kernel.org/r/1315434310-4827-1-git-send-email-kys@microsoft.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>