<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/arch/x86/kernel/cpu/mshyperv.c, branch v7.2</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>Merge tag 'x86-cpu-2026-06-14' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip</title>
<updated>2026-06-15T09:55:17+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2026-06-15T09:55:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=ff5ccdb8d5bd242f1064c6f7996603e47e28d095'/>
<id>ff5ccdb8d5bd242f1064c6f7996603e47e28d095</id>
<content type='text'>
Pull x86 cpuid updates from Ingo Molnar:

 - CPUID API updates (Ahmed S. Darwish):
    - Introduce a centralized CPUID parser
    - Introduce a centralized CPUID data model
    - Introduce &lt;asm/cpuid/leaf_types.h&gt;
    - Rename cpuid_leaf()/cpuid_subleaf() APIs
    - treewide: Explicitly include the x86 CPUID headers

 - Update to x86-cpuid-db v3.1 (Maciej Wieczor-Retman)

 - Continued removal of pre-i586 support and related simplifications
   (Ingo Molnar)

 - Add Intel CPU model number for rugged Panther Lake (Tony Luck)

 - Misc fixes, updates and cleanups by Arnd Bergmann, Chao Gao, Lukas
   Bulwahn, Sohil Mehta, Maciej Wieczor-Retman.

* tag 'x86-cpu-2026-06-14' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip: (25 commits)
  x86/cpu: Make CONFIG_X86_CX8 unconditional
  x86/cpu: Remove unused !CONFIG_X86_TSC code
  x86/cpuid: Update bitfields to x86-cpuid-db v3.1
  tools/x86/kcpuid: Update bitfields to x86-cpuid-db v3.1
  x86/cpu: Make CONFIG_X86_TSC unconditional
  MAINTAINERS: Drop obsolete FPU EMULATOR section
  x86/cpu: Fix a F00F bug warning and clean up surrounding code
  x86/cpu: Add Intel CPU model number for rugged Panther Lake
  x86/cpuid: Introduce a centralized CPUID parser
  x86/cpu: Introduce a centralized CPUID data model
  x86/cpuid: Introduce &lt;asm/cpuid/leaf_types.h&gt;
  x86/cpuid: Rename cpuid_leaf()/cpuid_subleaf() APIs
  x86/cpu: Do not include the CPUID API header in asm/processor.h
  Documentation: core-api/cpu_hotplug: Remove stale cpu0_hotplug docs
  x86/cpu, cpufreq: Remove AMD ELAN support
  x86/fpu: Remove the math-emu/ FPU emulation library
  x86/fpu: Remove the 'no387' boot option
  x86/fpu: Remove MATH_EMULATION and related glue code
  treewide: Explicitly include the x86 CPUID headers
  x86/cpu: Remove the CONFIG_X86_INVD_BUG quirk
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull x86 cpuid updates from Ingo Molnar:

 - CPUID API updates (Ahmed S. Darwish):
    - Introduce a centralized CPUID parser
    - Introduce a centralized CPUID data model
    - Introduce &lt;asm/cpuid/leaf_types.h&gt;
    - Rename cpuid_leaf()/cpuid_subleaf() APIs
    - treewide: Explicitly include the x86 CPUID headers

 - Update to x86-cpuid-db v3.1 (Maciej Wieczor-Retman)

 - Continued removal of pre-i586 support and related simplifications
   (Ingo Molnar)

 - Add Intel CPU model number for rugged Panther Lake (Tony Luck)

 - Misc fixes, updates and cleanups by Arnd Bergmann, Chao Gao, Lukas
   Bulwahn, Sohil Mehta, Maciej Wieczor-Retman.

* tag 'x86-cpu-2026-06-14' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip: (25 commits)
  x86/cpu: Make CONFIG_X86_CX8 unconditional
  x86/cpu: Remove unused !CONFIG_X86_TSC code
  x86/cpuid: Update bitfields to x86-cpuid-db v3.1
  tools/x86/kcpuid: Update bitfields to x86-cpuid-db v3.1
  x86/cpu: Make CONFIG_X86_TSC unconditional
  MAINTAINERS: Drop obsolete FPU EMULATOR section
  x86/cpu: Fix a F00F bug warning and clean up surrounding code
  x86/cpu: Add Intel CPU model number for rugged Panther Lake
  x86/cpuid: Introduce a centralized CPUID parser
  x86/cpu: Introduce a centralized CPUID data model
  x86/cpuid: Introduce &lt;asm/cpuid/leaf_types.h&gt;
  x86/cpuid: Rename cpuid_leaf()/cpuid_subleaf() APIs
  x86/cpu: Do not include the CPUID API header in asm/processor.h
  Documentation: core-api/cpu_hotplug: Remove stale cpu0_hotplug docs
  x86/cpu, cpufreq: Remove AMD ELAN support
  x86/fpu: Remove the math-emu/ FPU emulation library
  x86/fpu: Remove the 'no387' boot option
  x86/fpu: Remove MATH_EMULATION and related glue code
  treewide: Explicitly include the x86 CPUID headers
  x86/cpu: Remove the CONFIG_X86_INVD_BUG quirk
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/irq: Make irqstats array based</title>
<updated>2026-05-26T14:21:12+00:00</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@kernel.org</email>
</author>
<published>2026-05-17T20:01:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=2b57c69917eeba3ee657f252257e37f31916ba2a'/>
<id>2b57c69917eeba3ee657f252257e37f31916ba2a</id>
<content type='text'>
Having the x86 specific interrupt statistics as a data structure with
individual members instead of an array is just stupid as it requires
endless copy and paste in arch_show_interrupts() and arch_irq_stat_cpu(),
where the latter does not even take the latest interrupt additions into
account. The resulting #ifdef orgy is just disgusting.

Convert it to an array of counters, which does not make a difference in the
actual interrupt hotpath increment as the array index is constant and
therefore not any different than the member based access.

But in arch_show_interrupts() and arch_irq_stat_cpu() this just turns into
a loop, which reduces the text size by ~2k (~12%):

   text	   data	    bss	    dec	    hex	filename
  19643	  15250	    904	  35797	   8bd5	../build/arch/x86/kernel/irq.o
  17355	  15250	    904	  33509	   82e5	../build/arch/x86/kernel/irq.o

Adding a new vector or software counter only requires to update the table
and everything just works. Using the core provided emit function which
speeds up 0 outputs makes it significantly faster.

Signed-off-by: Thomas Gleixner &lt;tglx@kernel.org&gt;
Tested-by: Michael Kelley &lt;mhklinux@outlook.com&gt;
Reviewed-by: Radu Rendec &lt;radu@rendec.net&gt;
Link: https://patch.msgid.link/20260517194931.196070643@kernel.org
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Having the x86 specific interrupt statistics as a data structure with
individual members instead of an array is just stupid as it requires
endless copy and paste in arch_show_interrupts() and arch_irq_stat_cpu(),
where the latter does not even take the latest interrupt additions into
account. The resulting #ifdef orgy is just disgusting.

Convert it to an array of counters, which does not make a difference in the
actual interrupt hotpath increment as the array index is constant and
therefore not any different than the member based access.

But in arch_show_interrupts() and arch_irq_stat_cpu() this just turns into
a loop, which reduces the text size by ~2k (~12%):

   text	   data	    bss	    dec	    hex	filename
  19643	  15250	    904	  35797	   8bd5	../build/arch/x86/kernel/irq.o
  17355	  15250	    904	  33509	   82e5	../build/arch/x86/kernel/irq.o

Adding a new vector or software counter only requires to update the table
and everything just works. Using the core provided emit function which
speeds up 0 outputs makes it significantly faster.

Signed-off-by: Thomas Gleixner &lt;tglx@kernel.org&gt;
Tested-by: Michael Kelley &lt;mhklinux@outlook.com&gt;
Reviewed-by: Radu Rendec &lt;radu@rendec.net&gt;
Link: https://patch.msgid.link/20260517194931.196070643@kernel.org
</pre>
</div>
</content>
</entry>
<entry>
<title>treewide: Explicitly include the x86 CPUID headers</title>
<updated>2026-05-06T12:29:59+00:00</updated>
<author>
<name>Ahmed S. Darwish</name>
<email>darwi@linutronix.de</email>
</author>
<published>2026-03-27T02:15:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=7b49a3fb69e785a2425c8dc7dbd0779a0a4c0eb2'/>
<id>7b49a3fb69e785a2425c8dc7dbd0779a0a4c0eb2</id>
<content type='text'>
Modify all CPUID call sites which implicitly include any of the CPUID
headers to explicitly include them instead.

For KVM's reverse_cpuid.h, just include &lt;asm/cpuid/types.h&gt; since it
references the CPUID_EAX..EDX symbols without using the CPUID APIs.

Note, this allows removing the inclusion of &lt;asm/cpuid/api.h&gt; from within
&lt;asm/processor.h&gt; next.  That allows the CPUID API headers to include
&lt;asm/processor.h&gt; without introducing a circular dependency.

Signed-off-by: Ahmed S. Darwish &lt;darwi@linutronix.de&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Link: https://lore.kernel.org/20260327021645.555257-1-darwi@linutronix.de
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Modify all CPUID call sites which implicitly include any of the CPUID
headers to explicitly include them instead.

For KVM's reverse_cpuid.h, just include &lt;asm/cpuid/types.h&gt; since it
references the CPUID_EAX..EDX symbols without using the CPUID APIs.

Note, this allows removing the inclusion of &lt;asm/cpuid/api.h&gt; from within
&lt;asm/processor.h&gt; next.  That allows the CPUID API headers to include
&lt;asm/processor.h&gt; without introducing a circular dependency.

Signed-off-by: Ahmed S. Darwish &lt;darwi@linutronix.de&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Link: https://lore.kernel.org/20260327021645.555257-1-darwi@linutronix.de
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'hyperv-next-signed-20260421' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux</title>
<updated>2026-04-22T16:50:46+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2026-04-22T16:50:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=8fd12b03c7c888303c3c45559d8c3e270a916f9f'/>
<id>8fd12b03c7c888303c3c45559d8c3e270a916f9f</id>
<content type='text'>
Pull Hyper-V updates from Wei Liu:

 - Fix cross-compilation for hv tools (Aditya Garg)

 - Fix vmemmap_shift exceeding MAX_FOLIO_ORDER in mshv_vtl (Naman Jain)

 - Limit channel interrupt scan to relid high water mark (Michael
   Kelley)

 - Export hv_vmbus_exists() and use it in pci-hyperv (Dexuan Cui)

 - Fix cleanup and shutdown issues for MSHV (Jork Loeser)

 - Introduce more tracing support for MSHV (Stanislav Kinsburskii)

* tag 'hyperv-next-signed-20260421' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
  x86/hyperv: Skip LP/VP creation on kexec
  x86/hyperv: move stimer cleanup to hv_machine_shutdown()
  Drivers: hv: vmbus: fix hyperv_cpuhp_online variable shadowing
  mshv: Add tracepoint for GPA intercept handling
  mshv_vtl: Fix vmemmap_shift exceeding MAX_FOLIO_ORDER
  tools: hv: Fix cross-compilation
  Drivers: hv: vmbus: Export hv_vmbus_exists() and use it in pci-hyperv
  mshv: Introduce tracing support
  Drivers: hv: vmbus: Limit channel interrupt scan to relid high water mark
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull Hyper-V updates from Wei Liu:

 - Fix cross-compilation for hv tools (Aditya Garg)

 - Fix vmemmap_shift exceeding MAX_FOLIO_ORDER in mshv_vtl (Naman Jain)

 - Limit channel interrupt scan to relid high water mark (Michael
   Kelley)

 - Export hv_vmbus_exists() and use it in pci-hyperv (Dexuan Cui)

 - Fix cleanup and shutdown issues for MSHV (Jork Loeser)

 - Introduce more tracing support for MSHV (Stanislav Kinsburskii)

* tag 'hyperv-next-signed-20260421' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
  x86/hyperv: Skip LP/VP creation on kexec
  x86/hyperv: move stimer cleanup to hv_machine_shutdown()
  Drivers: hv: vmbus: fix hyperv_cpuhp_online variable shadowing
  mshv: Add tracepoint for GPA intercept handling
  mshv_vtl: Fix vmemmap_shift exceeding MAX_FOLIO_ORDER
  tools: hv: Fix cross-compilation
  Drivers: hv: vmbus: Export hv_vmbus_exists() and use it in pci-hyperv
  mshv: Introduce tracing support
  Drivers: hv: vmbus: Limit channel interrupt scan to relid high water mark
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/hyperv: Skip LP/VP creation on kexec</title>
<updated>2026-04-22T06:23:25+00:00</updated>
<author>
<name>Jork Loeser</name>
<email>jloeser@linux.microsoft.com</email>
</author>
<published>2026-04-08T01:36:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=5170a82e89211d876af17bf3d94a511fb2bb4921'/>
<id>5170a82e89211d876af17bf3d94a511fb2bb4921</id>
<content type='text'>
After a kexec the logical processors and virtual processors already
exist in the hypervisor because they were created by the previous
kernel. Attempting to add them again causes either a BUG_ON or
corrupted VP state leading to MCEs in the new kernel.

Add hv_lp_exists() to probe whether an LP is already present by
calling HVCALL_GET_LOGICAL_PROCESSOR_RUN_TIME. When it succeeds the
LP exists and we skip the add-LP and create-VP loops entirely.

Also add hv_call_notify_all_processors_started() which informs the
hypervisor that all processors are online. This is required after
adding LPs (fresh boot) and is a no-op on kexec since we skip that
path.

Co-developed-by: Anirudh Rayabharam &lt;anrayabh@linux.microsoft.com&gt;
Signed-off-by: Anirudh Rayabharam &lt;anrayabh@linux.microsoft.com&gt;
Co-developed-by: Stanislav Kinsburskii &lt;stanislav.kinsburskii@gmail.com&gt;
Signed-off-by: Stanislav Kinsburskii &lt;stanislav.kinsburskii@gmail.com&gt;
Co-developed-by: Mukesh Rathor &lt;mrathor@linux.microsoft.com&gt;
Signed-off-by: Mukesh Rathor &lt;mrathor@linux.microsoft.com&gt;
Signed-off-by: Jork Loeser &lt;jloeser@linux.microsoft.com&gt;
Reviewed-by: Stanislav Kinsburskii &lt;skinsburskii@linux.microsoft.com&gt;
Signed-off-by: Wei Liu &lt;wei.liu@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
After a kexec the logical processors and virtual processors already
exist in the hypervisor because they were created by the previous
kernel. Attempting to add them again causes either a BUG_ON or
corrupted VP state leading to MCEs in the new kernel.

Add hv_lp_exists() to probe whether an LP is already present by
calling HVCALL_GET_LOGICAL_PROCESSOR_RUN_TIME. When it succeeds the
LP exists and we skip the add-LP and create-VP loops entirely.

Also add hv_call_notify_all_processors_started() which informs the
hypervisor that all processors are online. This is required after
adding LPs (fresh boot) and is a no-op on kexec since we skip that
path.

Co-developed-by: Anirudh Rayabharam &lt;anrayabh@linux.microsoft.com&gt;
Signed-off-by: Anirudh Rayabharam &lt;anrayabh@linux.microsoft.com&gt;
Co-developed-by: Stanislav Kinsburskii &lt;stanislav.kinsburskii@gmail.com&gt;
Signed-off-by: Stanislav Kinsburskii &lt;stanislav.kinsburskii@gmail.com&gt;
Co-developed-by: Mukesh Rathor &lt;mrathor@linux.microsoft.com&gt;
Signed-off-by: Mukesh Rathor &lt;mrathor@linux.microsoft.com&gt;
Signed-off-by: Jork Loeser &lt;jloeser@linux.microsoft.com&gt;
Reviewed-by: Stanislav Kinsburskii &lt;skinsburskii@linux.microsoft.com&gt;
Signed-off-by: Wei Liu &lt;wei.liu@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/hyperv: move stimer cleanup to hv_machine_shutdown()</title>
<updated>2026-04-22T06:23:25+00:00</updated>
<author>
<name>Jork Loeser</name>
<email>jloeser@linux.microsoft.com</email>
</author>
<published>2026-04-08T01:36:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=f7ce370b525a02127527b0f54ee877413705a709'/>
<id>f7ce370b525a02127527b0f54ee877413705a709</id>
<content type='text'>
Move hv_stimer_global_cleanup() from vmbus's hv_kexec_handler() to
hv_machine_shutdown() in the platform code. This ensures stimer cleanup
happens before the vmbus unload, which is required for root partition
kexec to work correctly.

Co-developed-by: Anirudh Rayabharam &lt;anrayabh@linux.microsoft.com&gt;
Signed-off-by: Anirudh Rayabharam &lt;anrayabh@linux.microsoft.com&gt;
Signed-off-by: Jork Loeser &lt;jloeser@linux.microsoft.com&gt;
Reviewed-by: Stanislav Kinsburskii &lt;skinsburskii@linux.microsoft.com&gt;
Signed-off-by: Wei Liu &lt;wei.liu@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Move hv_stimer_global_cleanup() from vmbus's hv_kexec_handler() to
hv_machine_shutdown() in the platform code. This ensures stimer cleanup
happens before the vmbus unload, which is required for root partition
kexec to work correctly.

Co-developed-by: Anirudh Rayabharam &lt;anrayabh@linux.microsoft.com&gt;
Signed-off-by: Anirudh Rayabharam &lt;anrayabh@linux.microsoft.com&gt;
Signed-off-by: Jork Loeser &lt;jloeser@linux.microsoft.com&gt;
Reviewed-by: Stanislav Kinsburskii &lt;skinsburskii@linux.microsoft.com&gt;
Signed-off-by: Wei Liu &lt;wei.liu@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Drivers: hv: Move add_interrupt_randomness() to hypervisor callback sysvec</title>
<updated>2026-04-04T19:01:56+00:00</updated>
<author>
<name>Michael Kelley</name>
<email>mhklinux@outlook.com</email>
</author>
<published>2026-04-02T20:24:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=e8be82c2d77ec1bb0148406e54b105028a83537e'/>
<id>e8be82c2d77ec1bb0148406e54b105028a83537e</id>
<content type='text'>
The Hyper-V ISRs, for normal guests and when running in the hypervisor root
patition, are calling add_interrupt_randomness() as a primary source of
entropy. The call is currently in the ISRs as a common place to handle both
x86/x64 and arm64.

On x86/x64, hypervisor interrupts come through a custom sysvec entry, and
do not go through a generic interrupt handler.

On arm64, hypervisor interrupts come through an emulated GICv3. GICv3 uses
the generic handler handle_percpu_devid_irq(), which does not do
add_interrupt_randomness() -- unlike its counterpart
handle_percpu_irq().

But handle_percpu_devid_irq() is now updated to do the
add_interrupt_randomness(). So add_interrupt_randomness() is now needed
only in Hyper-V's x86/x64 custom sysvec path.

Move add_interrupt_randomness() from the Hyper-V ISRs into the Hyper-V
x86/x64 custom sysvec path, matching the existing STIMER0 sysvec path.

With this change, add_interrupt_randomness() is no longer called from any
device drivers, which is appropriate.

Signed-off-by: Michael Kelley &lt;mhklinux@outlook.com&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@kernel.org&gt;
Acked-by: Wei Liu &lt;wei.liu@kernel.org&gt;
Link: https://patch.msgid.link/20260402202400.1707-3-mhklkml@zohomail.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The Hyper-V ISRs, for normal guests and when running in the hypervisor root
patition, are calling add_interrupt_randomness() as a primary source of
entropy. The call is currently in the ISRs as a common place to handle both
x86/x64 and arm64.

On x86/x64, hypervisor interrupts come through a custom sysvec entry, and
do not go through a generic interrupt handler.

On arm64, hypervisor interrupts come through an emulated GICv3. GICv3 uses
the generic handler handle_percpu_devid_irq(), which does not do
add_interrupt_randomness() -- unlike its counterpart
handle_percpu_irq().

But handle_percpu_devid_irq() is now updated to do the
add_interrupt_randomness(). So add_interrupt_randomness() is now needed
only in Hyper-V's x86/x64 custom sysvec path.

Move add_interrupt_randomness() from the Hyper-V ISRs into the Hyper-V
x86/x64 custom sysvec path, matching the existing STIMER0 sysvec path.

With this change, add_interrupt_randomness() is no longer called from any
device drivers, which is appropriate.

Signed-off-by: Michael Kelley &lt;mhklinux@outlook.com&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@kernel.org&gt;
Acked-by: Wei Liu &lt;wei.liu@kernel.org&gt;
Link: https://patch.msgid.link/20260402202400.1707-3-mhklkml@zohomail.com
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/hyperv: print out reserved vectors in hexadecimal</title>
<updated>2026-02-24T17:10:44+00:00</updated>
<author>
<name>Wei Liu</name>
<email>wei.liu@kernel.org</email>
</author>
<published>2026-02-24T17:08:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=f69cfd8e8fd13b5d57e638fa1542fcd56f594ef0'/>
<id>f69cfd8e8fd13b5d57e638fa1542fcd56f594ef0</id>
<content type='text'>
Signed-off-by: Wei Liu &lt;wei.liu@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Signed-off-by: Wei Liu &lt;wei.liu@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/hyperv: Reserve 3 interrupt vectors used exclusively by MSHV</title>
<updated>2026-02-18T23:18:30+00:00</updated>
<author>
<name>Mukesh Rathor</name>
<email>mrathor@linux.microsoft.com</email>
</author>
<published>2026-02-17T23:11:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=fe9f15983c4823a8473e289b4a302946a4864ef5'/>
<id>fe9f15983c4823a8473e289b4a302946a4864ef5</id>
<content type='text'>
MSVC compiler, used to compile the Microsoft Hypervisor, currently
has an assert intrinsic that uses interrupt vector 0x29 to create an
exception. This will cause hypervisor to then crash and collect core. As
such, if this interrupt number is assigned to a device by Linux and the
device generates it, hypervisor will crash. There are two other such
vectors hard coded in the hypervisor, 0x2C and 0x2D for debug purposes.

Fortunately, the three vectors are part of the kernel driver space and
that makes it feasible to reserve them early so they are not assigned
later.

Signed-off-by: Mukesh Rathor &lt;mrathor@linux.microsoft.com&gt;
Signed-off-by: Wei Liu &lt;wei.liu@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
MSVC compiler, used to compile the Microsoft Hypervisor, currently
has an assert intrinsic that uses interrupt vector 0x29 to create an
exception. This will cause hypervisor to then crash and collect core. As
such, if this interrupt number is assigned to a device by Linux and the
device generates it, hypervisor will crash. There are two other such
vectors hard coded in the hypervisor, 0x2C and 0x2D for debug purposes.

Fortunately, the three vectors are part of the kernel driver space and
that makes it feasible to reserve them early so they are not assigned
later.

Signed-off-by: Mukesh Rathor &lt;mrathor@linux.microsoft.com&gt;
Signed-off-by: Wei Liu &lt;wei.liu@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mshv: Cleanly shutdown root partition with MSHV</title>
<updated>2025-12-05T23:25:05+00:00</updated>
<author>
<name>Praveen K Paladugu</name>
<email>prapal@linux.microsoft.com</email>
</author>
<published>2025-12-05T20:17:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=615a6e7d83f958e7ef3bc818e818f7c6433b4c2a'/>
<id>615a6e7d83f958e7ef3bc818e818f7c6433b4c2a</id>
<content type='text'>
Root partitions running on MSHV currently attempt ACPI power-off, which
MSHV intercepts and triggers a Machine Check Exception (MCE), leading
to a kernel panic.

Root partitions panic with a trace similar to:

  [   81.306348] reboot: Power down
  [   81.314709] mce: [Hardware Error]: CPU 0: Machine Check Exception: 4 Bank 0: b2000000c0060001
  [   81.314711] mce: [Hardware Error]: TSC 3b8cb60a66 PPIN 11d98332458e4ea9
  [   81.314713] mce: [Hardware Error]: PROCESSOR 0:606a6 TIME 1759339405 SOCKET 0 APIC 0 microcode ffffffff
  [   81.314715] mce: [Hardware Error]: Run the above through 'mcelog --ascii'
  [   81.314716] mce: [Hardware Error]: Machine check: Processor context corrupt
  [   81.314717] Kernel panic - not syncing: Fatal machine check

To avoid this, configure the sleep state in the hypervisor and invoke
the HVCALL_ENTER_SLEEP_STATE hypercall as the final step in the shutdown
sequence. This ensures a clean and safe shutdown of the root partition.

Signed-off-by: Praveen K Paladugu &lt;prapal@linux.microsoft.com&gt;
Co-developed-by: Anatol Belski &lt;anbelski@linux.microsoft.com&gt;
Signed-off-by: Anatol Belski &lt;anbelski@linux.microsoft.com&gt;
Reviewed-by: Easwar Hariharan &lt;easwar.hariharan@linux.microsoft.com&gt;
Acked-by: Stanislav Kinsburskii &lt;skinsburskii@linux.microsoft.com&gt;
Signed-off-by: Wei Liu &lt;wei.liu@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Root partitions running on MSHV currently attempt ACPI power-off, which
MSHV intercepts and triggers a Machine Check Exception (MCE), leading
to a kernel panic.

Root partitions panic with a trace similar to:

  [   81.306348] reboot: Power down
  [   81.314709] mce: [Hardware Error]: CPU 0: Machine Check Exception: 4 Bank 0: b2000000c0060001
  [   81.314711] mce: [Hardware Error]: TSC 3b8cb60a66 PPIN 11d98332458e4ea9
  [   81.314713] mce: [Hardware Error]: PROCESSOR 0:606a6 TIME 1759339405 SOCKET 0 APIC 0 microcode ffffffff
  [   81.314715] mce: [Hardware Error]: Run the above through 'mcelog --ascii'
  [   81.314716] mce: [Hardware Error]: Machine check: Processor context corrupt
  [   81.314717] Kernel panic - not syncing: Fatal machine check

To avoid this, configure the sleep state in the hypervisor and invoke
the HVCALL_ENTER_SLEEP_STATE hypercall as the final step in the shutdown
sequence. This ensures a clean and safe shutdown of the root partition.

Signed-off-by: Praveen K Paladugu &lt;prapal@linux.microsoft.com&gt;
Co-developed-by: Anatol Belski &lt;anbelski@linux.microsoft.com&gt;
Signed-off-by: Anatol Belski &lt;anbelski@linux.microsoft.com&gt;
Reviewed-by: Easwar Hariharan &lt;easwar.hariharan@linux.microsoft.com&gt;
Acked-by: Stanislav Kinsburskii &lt;skinsburskii@linux.microsoft.com&gt;
Signed-off-by: Wei Liu &lt;wei.liu@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
