<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/arch/x86/kernel/cpu/microcode/core.c, branch v6.18</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>x86/microcode: Add microcode loader debugging functionality</title>
<updated>2025-09-04T14:15:19+00:00</updated>
<author>
<name>Borislav Petkov (AMD)</name>
<email>bp@alien8.de</email>
</author>
<published>2025-08-20T13:50:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=43181a47263dd9f2bee0afd688a841b09f9b7d12'/>
<id>43181a47263dd9f2bee0afd688a841b09f9b7d12</id>
<content type='text'>
Instead of adding ad-hoc debugging glue to the microcode loader each
time I need it, add debugging functionality which is not built by
default.

Simulate all patch handling the loader does except the actual loading of
the microcode patch into the hardware.

Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Link: https://lore.kernel.org/20250820135043.19048-3-bp@kernel.org
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Instead of adding ad-hoc debugging glue to the microcode loader each
time I need it, add debugging functionality which is not built by
default.

Simulate all patch handling the loader does except the actual loading of
the microcode patch into the hardware.

Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Link: https://lore.kernel.org/20250820135043.19048-3-bp@kernel.org
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/microcode: Add microcode= cmdline parsing</title>
<updated>2025-09-04T14:02:20+00:00</updated>
<author>
<name>Borislav Petkov (AMD)</name>
<email>bp@alien8.de</email>
</author>
<published>2025-08-20T13:50:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=632ff61706473127cdc3b779bf24d368e3856ab3'/>
<id>632ff61706473127cdc3b779bf24d368e3856ab3</id>
<content type='text'>
Add a "microcode=" command line argument after which all options can be
passed in a comma-separated list.

Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Reviewed-by: Sohil Mehta &lt;sohil.mehta@intel.com&gt;
Reviewed-by: Chang S. Bae &lt;chang.seok.bae@intel.com&gt;
Link: https://lore.kernel.org/20250820135043.19048-2-bp@kernel.org
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Add a "microcode=" command line argument after which all options can be
passed in a comma-separated list.

Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Reviewed-by: Sohil Mehta &lt;sohil.mehta@intel.com&gt;
Reviewed-by: Chang S. Bae &lt;chang.seok.bae@intel.com&gt;
Link: https://lore.kernel.org/20250820135043.19048-2-bp@kernel.org
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/microcode: Move away from using a fake platform device</title>
<updated>2025-07-09T11:12:08+00:00</updated>
<author>
<name>Greg Kroah-Hartman</name>
<email>gregkh@linuxfoundation.org</email>
</author>
<published>2025-07-01T10:54:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=9b355cdb63b1e43434d7ac57430d3e68de58338d'/>
<id>9b355cdb63b1e43434d7ac57430d3e68de58338d</id>
<content type='text'>
Downloading firmware needs a device to hang off of, and so a platform device
seemed like the simplest way to do this.  Now that we have a faux device
interface, use that instead as this "microcode device" is not anything
resembling a platform device at all.

Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Reviewed-by: Sohil Mehta &lt;sohil.mehta@intel.com&gt;
Link: https://lore.kernel.org/2025070121-omission-small-9308@gregkh
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Downloading firmware needs a device to hang off of, and so a platform device
seemed like the simplest way to do this.  Now that we have a faux device
interface, use that instead as this "microcode device" is not anything
resembling a platform device at all.

Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Reviewed-by: Sohil Mehta &lt;sohil.mehta@intel.com&gt;
Link: https://lore.kernel.org/2025070121-omission-small-9308@gregkh
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/cpuid: Rename have_cpuid_p() to cpuid_feature()</title>
<updated>2025-05-15T16:23:55+00:00</updated>
<author>
<name>Ahmed S. Darwish</name>
<email>darwi@linutronix.de</email>
</author>
<published>2025-05-08T15:02:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=2f924ca36d2f788d40a57ea48825ff51cba4e700'/>
<id>2f924ca36d2f788d40a57ea48825ff51cba4e700</id>
<content type='text'>
In order to let all the APIs under &lt;cpuid/api.h&gt; have a shared "cpuid_"
namespace, rename have_cpuid_p() to cpuid_feature().

Adjust all call-sites accordingly.

Suggested-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Signed-off-by: Ahmed S. Darwish &lt;darwi@linutronix.de&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: H. Peter Anvin &lt;hpa@zytor.com&gt;
Cc: Andrew Cooper &lt;andrew.cooper3@citrix.com&gt;
Cc: John Ogness &lt;john.ogness@linutronix.de&gt;
Cc: x86-cpuid@lists.linux.dev
Link: https://lore.kernel.org/r/20250508150240.172915-4-darwi@linutronix.de
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
In order to let all the APIs under &lt;cpuid/api.h&gt; have a shared "cpuid_"
namespace, rename have_cpuid_p() to cpuid_feature().

Adjust all call-sites accordingly.

Suggested-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Signed-off-by: Ahmed S. Darwish &lt;darwi@linutronix.de&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: H. Peter Anvin &lt;hpa@zytor.com&gt;
Cc: Andrew Cooper &lt;andrew.cooper3@citrix.com&gt;
Cc: John Ogness &lt;john.ogness@linutronix.de&gt;
Cc: x86-cpuid@lists.linux.dev
Link: https://lore.kernel.org/r/20250508150240.172915-4-darwi@linutronix.de
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'x86/msr' into x86/core, to resolve conflicts</title>
<updated>2025-05-13T08:42:06+00:00</updated>
<author>
<name>Ingo Molnar</name>
<email>mingo@kernel.org</email>
</author>
<published>2025-05-13T08:42:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=1f82e8e1ca18aa0b020538a3f227f5d56382638e'/>
<id>1f82e8e1ca18aa0b020538a3f227f5d56382638e</id>
<content type='text'>
 Conflicts:
	arch/x86/boot/startup/sme.c
	arch/x86/coco/sev/core.c
	arch/x86/kernel/fpu/core.c
	arch/x86/kernel/fpu/xstate.c

 Semantic conflict:
	arch/x86/include/asm/sev-internal.h

Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
 Conflicts:
	arch/x86/boot/startup/sme.c
	arch/x86/coco/sev/core.c
	arch/x86/kernel/fpu/core.c
	arch/x86/kernel/fpu/xstate.c

 Semantic conflict:
	arch/x86/include/asm/sev-internal.h

Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'x86/microcode' into x86/core, to merge dependent commits</title>
<updated>2025-05-13T08:37:52+00:00</updated>
<author>
<name>Ingo Molnar</name>
<email>mingo@kernel.org</email>
</author>
<published>2025-05-13T08:37:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=69cb33e2f81a3265383f0c8bbd27c32b4a5a6bf3'/>
<id>69cb33e2f81a3265383f0c8bbd27c32b4a5a6bf3</id>
<content type='text'>
Prepare to resolve conflicts with an upstream series of fixes that conflict
with pending x86 changes:

  6f5bf947bab0 Merge tag 'its-for-linus-20250509' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Prepare to resolve conflicts with an upstream series of fixes that conflict
with pending x86 changes:

  6f5bf947bab0 Merge tag 'its-for-linus-20250509' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/microcode: Consolidate the loader enablement checking</title>
<updated>2025-05-05T08:51:00+00:00</updated>
<author>
<name>Borislav Petkov (AMD)</name>
<email>bp@alien8.de</email>
</author>
<published>2025-04-14T09:59:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=5214a9f6c0f56644acb9d2cbb58facf1856d322b'/>
<id>5214a9f6c0f56644acb9d2cbb58facf1856d322b</id>
<content type='text'>
Consolidate the whole logic which determines whether the microcode loader
should be enabled or not into a single function and call it everywhere.

Well, almost everywhere - not in mk_early_pgtbl_32() because there the kernel
is running without paging enabled and checking dis_ucode_ldr et al would
require physical addresses and uglification of the code.

But since this is 32-bit, the easier thing to do is to simply map the initrd
unconditionally especially since that mapping is getting removed later anyway
by zap_early_initrd_mapping() and avoid the uglification.

In doing so, address the issue of old 486er machines without CPUID
support, not booting current kernels.

  [ mingo: Fix no previous prototype for ‘microcode_loader_disabled’ [-Wmissing-prototypes] ]

Fixes: 4c585af7180c1 ("x86/boot/32: Temporarily map initrd for microcode loading")
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Cc: &lt;stable@kernel.org&gt;
Link: https://lore.kernel.org/r/CANpbe9Wm3z8fy9HbgS8cuhoj0TREYEEkBipDuhgkWFvqX0UoVQ@mail.gmail.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Consolidate the whole logic which determines whether the microcode loader
should be enabled or not into a single function and call it everywhere.

Well, almost everywhere - not in mk_early_pgtbl_32() because there the kernel
is running without paging enabled and checking dis_ucode_ldr et al would
require physical addresses and uglification of the code.

But since this is 32-bit, the easier thing to do is to simply map the initrd
unconditionally especially since that mapping is getting removed later anyway
by zap_early_initrd_mapping() and avoid the uglification.

In doing so, address the issue of old 486er machines without CPUID
support, not booting current kernels.

  [ mingo: Fix no previous prototype for ‘microcode_loader_disabled’ [-Wmissing-prototypes] ]

Fixes: 4c585af7180c1 ("x86/boot/32: Temporarily map initrd for microcode loading")
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Cc: &lt;stable@kernel.org&gt;
Link: https://lore.kernel.org/r/CANpbe9Wm3z8fy9HbgS8cuhoj0TREYEEkBipDuhgkWFvqX0UoVQ@mail.gmail.com
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/msr: Add explicit includes of &lt;asm/msr.h&gt;</title>
<updated>2025-05-02T08:23:47+00:00</updated>
<author>
<name>Xin Li (Intel)</name>
<email>xin@zytor.com</email>
</author>
<published>2025-05-01T05:42:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=efef7f184f2eaf29a1ca676712d0e6e851cd0191'/>
<id>efef7f184f2eaf29a1ca676712d0e6e851cd0191</id>
<content type='text'>
For historic reasons there are some TSC-related functions in the
&lt;asm/msr.h&gt; header, even though there's an &lt;asm/tsc.h&gt; header.

To facilitate the relocation of rdtsc{,_ordered}() from &lt;asm/msr.h&gt;
to &lt;asm/tsc.h&gt; and to eventually eliminate the inclusion of
&lt;asm/msr.h&gt; in &lt;asm/tsc.h&gt;, add an explicit &lt;asm/msr.h&gt; dependency
to the source files that reference definitions from &lt;asm/msr.h&gt;.

[ mingo: Clarified the changelog. ]

Signed-off-by: Xin Li (Intel) &lt;xin@zytor.com&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Acked-by: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Acked-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Acked-by: Ilpo Järvinen &lt;ilpo.jarvinen@linux.intel.com&gt;
Cc: Andy Lutomirski &lt;luto@kernel.org&gt;
Cc: Brian Gerst &lt;brgerst@gmail.com&gt;
Cc: Juergen Gross &lt;jgross@suse.com&gt;
Cc: H. Peter Anvin &lt;hpa@zytor.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Kees Cook &lt;keescook@chromium.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Borislav Petkov &lt;bp@alien8.de&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Josh Poimboeuf &lt;jpoimboe@redhat.com&gt;
Cc: Uros Bizjak &lt;ubizjak@gmail.com&gt;
Link: https://lore.kernel.org/r/20250501054241.1245648-1-xin@zytor.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
For historic reasons there are some TSC-related functions in the
&lt;asm/msr.h&gt; header, even though there's an &lt;asm/tsc.h&gt; header.

To facilitate the relocation of rdtsc{,_ordered}() from &lt;asm/msr.h&gt;
to &lt;asm/tsc.h&gt; and to eventually eliminate the inclusion of
&lt;asm/msr.h&gt; in &lt;asm/tsc.h&gt;, add an explicit &lt;asm/msr.h&gt; dependency
to the source files that reference definitions from &lt;asm/msr.h&gt;.

[ mingo: Clarified the changelog. ]

Signed-off-by: Xin Li (Intel) &lt;xin@zytor.com&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Acked-by: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Acked-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Acked-by: Ilpo Järvinen &lt;ilpo.jarvinen@linux.intel.com&gt;
Cc: Andy Lutomirski &lt;luto@kernel.org&gt;
Cc: Brian Gerst &lt;brgerst@gmail.com&gt;
Cc: Juergen Gross &lt;jgross@suse.com&gt;
Cc: H. Peter Anvin &lt;hpa@zytor.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Kees Cook &lt;keescook@chromium.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Borislav Petkov &lt;bp@alien8.de&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Josh Poimboeuf &lt;jpoimboe@redhat.com&gt;
Cc: Uros Bizjak &lt;ubizjak@gmail.com&gt;
Link: https://lore.kernel.org/r/20250501054241.1245648-1-xin@zytor.com
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/microcode/AMD: Do not return error when microcode update is not necessary</title>
<updated>2025-04-30T15:10:46+00:00</updated>
<author>
<name>Annie Li</name>
<email>jiayanli@google.com</email>
</author>
<published>2025-04-30T05:34:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=b43dc4ab097859c24e2a6993119c927cffc856aa'/>
<id>b43dc4ab097859c24e2a6993119c927cffc856aa</id>
<content type='text'>
After

  6f059e634dcd("x86/microcode: Clarify the late load logic"),

if the load is up-to-date, the AMD side returns UCODE_OK which leads to
load_late_locked() returning -EBADFD.

Handle UCODE_OK in the switch case to avoid this error.

  [ bp: Massage commit message. ]

Fixes: 6f059e634dcd ("x86/microcode: Clarify the late load logic")
Signed-off-by: Annie Li &lt;jiayanli@google.com&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Link: https://lore.kernel.org/20250430053424.77438-1-jiayanli@google.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
After

  6f059e634dcd("x86/microcode: Clarify the late load logic"),

if the load is up-to-date, the AMD side returns UCODE_OK which leads to
load_late_locked() returning -EBADFD.

Handle UCODE_OK in the switch case to avoid this error.

  [ bp: Massage commit message. ]

Fixes: 6f059e634dcd ("x86/microcode: Clarify the late load logic")
Signed-off-by: Annie Li &lt;jiayanli@google.com&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Link: https://lore.kernel.org/20250430053424.77438-1-jiayanli@google.com
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/microcode: Remove unused struct cpu_info_ctx</title>
<updated>2024-05-06T09:00:57+00:00</updated>
<author>
<name>Dr. David Alan Gilbert</name>
<email>linux@treblig.org</email>
</author>
<published>2024-05-06T00:43:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=57f6d0aed7b0a6829044c7f1cea57b1e3ddb9a47'/>
<id>57f6d0aed7b0a6829044c7f1cea57b1e3ddb9a47</id>
<content type='text'>
This looks unused since

  2071c0aeda22 ("x86/microcode: Simplify init path even more")

Signed-off-by: Dr. David Alan Gilbert &lt;linux@treblig.org&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Link: https://lore.kernel.org/r/20240506004300.770564-1-linux@treblig.org
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This looks unused since

  2071c0aeda22 ("x86/microcode: Simplify init path even more")

Signed-off-by: Dr. David Alan Gilbert &lt;linux@treblig.org&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Link: https://lore.kernel.org/r/20240506004300.770564-1-linux@treblig.org
</pre>
</div>
</content>
</entry>
</feed>
