<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/arch/x86/kernel/cpu/common.c, branch linux-6.9.y</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>x86/cpu: Provide default cache line size if not enumerated</title>
<updated>2024-06-21T12:40:10+00:00</updated>
<author>
<name>Dave Hansen</name>
<email>dave.hansen@linux.intel.com</email>
</author>
<published>2024-05-17T20:05:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2c1830c4b8c59004a2f96b513d8229a4bb0d586f'/>
<id>2c1830c4b8c59004a2f96b513d8229a4bb0d586f</id>
<content type='text'>
[ Upstream commit 2a38e4ca302280fdcce370ba2bee79bac16c4587 ]

tl;dr: CPUs with CPUID.80000008H but without CPUID.01H:EDX[CLFSH]
will end up reporting cache_line_size()==0 and bad things happen.
Fill in a default on those to avoid the problem.

Long Story:

The kernel dies a horrible death if c-&gt;x86_cache_alignment (aka.
cache_line_size() is 0.  Normally, this value is populated from
c-&gt;x86_clflush_size.

Right now the code is set up to get c-&gt;x86_clflush_size from two
places.  First, modern CPUs get it from CPUID.  Old CPUs that don't
have leaf 0x80000008 (or CPUID at all) just get some sane defaults
from the kernel in get_cpu_address_sizes().

The vast majority of CPUs that have leaf 0x80000008 also get
-&gt;x86_clflush_size from CPUID.  But there are oddballs.

Intel Quark CPUs[1] and others[2] have leaf 0x80000008 but don't set
CPUID.01H:EDX[CLFSH], so they skip over filling in -&gt;x86_clflush_size:

	cpuid(0x00000001, &amp;tfms, &amp;misc, &amp;junk, &amp;cap0);
	if (cap0 &amp; (1&lt;&lt;19))
		c-&gt;x86_clflush_size = ((misc &gt;&gt; 8) &amp; 0xff) * 8;

So they: land in get_cpu_address_sizes() and see that CPUID has level
0x80000008 and jump into the side of the if() that does not fill in
c-&gt;x86_clflush_size.  That assigns a 0 to c-&gt;x86_cache_alignment, and
hilarity ensues in code like:

        buffer = kzalloc(ALIGN(sizeof(*buffer), cache_line_size()),
                         GFP_KERNEL);

To fix this, always provide a sane value for -&gt;x86_clflush_size.

Big thanks to Andy Shevchenko for finding and reporting this and also
providing a first pass at a fix. But his fix was only partial and only
worked on the Quark CPUs.  It would not, for instance, have worked on
the QEMU config.

1. https://raw.githubusercontent.com/InstLatx64/InstLatx64/master/GenuineIntel/GenuineIntel0000590_Clanton_03_CPUID.txt
2. You can also get this behavior if you use "-cpu 486,+clzero"
   in QEMU.

[ dhansen: remove 'vp_bits_from_cpuid' reference in changelog
	   because bpetkov brutally murdered it recently. ]

Fixes: fbf6449f84bf ("x86/sev-es: Set x86_virt_bits to the correct value straight away, instead of a two-phase approach")
Reported-by: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Signed-off-by: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Tested-by: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Tested-by: Jörn Heusipp &lt;osmanx@heusipp.de&gt;
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20240516173928.3960193-1-andriy.shevchenko@linux.intel.com/
Link: https://lore.kernel.org/lkml/5e31cad3-ad4d-493e-ab07-724cfbfaba44@heusipp.de/
Link: https://lore.kernel.org/all/20240517200534.8EC5F33E%40davehans-spike.ostc.intel.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 2a38e4ca302280fdcce370ba2bee79bac16c4587 ]

tl;dr: CPUs with CPUID.80000008H but without CPUID.01H:EDX[CLFSH]
will end up reporting cache_line_size()==0 and bad things happen.
Fill in a default on those to avoid the problem.

Long Story:

The kernel dies a horrible death if c-&gt;x86_cache_alignment (aka.
cache_line_size() is 0.  Normally, this value is populated from
c-&gt;x86_clflush_size.

Right now the code is set up to get c-&gt;x86_clflush_size from two
places.  First, modern CPUs get it from CPUID.  Old CPUs that don't
have leaf 0x80000008 (or CPUID at all) just get some sane defaults
from the kernel in get_cpu_address_sizes().

The vast majority of CPUs that have leaf 0x80000008 also get
-&gt;x86_clflush_size from CPUID.  But there are oddballs.

Intel Quark CPUs[1] and others[2] have leaf 0x80000008 but don't set
CPUID.01H:EDX[CLFSH], so they skip over filling in -&gt;x86_clflush_size:

	cpuid(0x00000001, &amp;tfms, &amp;misc, &amp;junk, &amp;cap0);
	if (cap0 &amp; (1&lt;&lt;19))
		c-&gt;x86_clflush_size = ((misc &gt;&gt; 8) &amp; 0xff) * 8;

So they: land in get_cpu_address_sizes() and see that CPUID has level
0x80000008 and jump into the side of the if() that does not fill in
c-&gt;x86_clflush_size.  That assigns a 0 to c-&gt;x86_cache_alignment, and
hilarity ensues in code like:

        buffer = kzalloc(ALIGN(sizeof(*buffer), cache_line_size()),
                         GFP_KERNEL);

To fix this, always provide a sane value for -&gt;x86_clflush_size.

Big thanks to Andy Shevchenko for finding and reporting this and also
providing a first pass at a fix. But his fix was only partial and only
worked on the Quark CPUs.  It would not, for instance, have worked on
the QEMU config.

1. https://raw.githubusercontent.com/InstLatx64/InstLatx64/master/GenuineIntel/GenuineIntel0000590_Clanton_03_CPUID.txt
2. You can also get this behavior if you use "-cpu 486,+clzero"
   in QEMU.

[ dhansen: remove 'vp_bits_from_cpuid' reference in changelog
	   because bpetkov brutally murdered it recently. ]

Fixes: fbf6449f84bf ("x86/sev-es: Set x86_virt_bits to the correct value straight away, instead of a two-phase approach")
Reported-by: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Signed-off-by: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Tested-by: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Tested-by: Jörn Heusipp &lt;osmanx@heusipp.de&gt;
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20240516173928.3960193-1-andriy.shevchenko@linux.intel.com/
Link: https://lore.kernel.org/lkml/5e31cad3-ad4d-493e-ab07-724cfbfaba44@heusipp.de/
Link: https://lore.kernel.org/all/20240517200534.8EC5F33E%40davehans-spike.ostc.intel.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/cpu: Get rid of an unnecessary local variable in get_cpu_address_sizes()</title>
<updated>2024-06-21T12:40:10+00:00</updated>
<author>
<name>Borislav Petkov (AMD)</name>
<email>bp@alien8.de</email>
</author>
<published>2024-03-16T12:07:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f4c64848b3da1059d14c7303fca7ba5fb811d093'/>
<id>f4c64848b3da1059d14c7303fca7ba5fb811d093</id>
<content type='text'>
[ Upstream commit 95bfb35269b2e85cff0dd2c957b2d42ebf95ae5f ]

Drop 'vp_bits_from_cpuid' as it is not really needed.

No functional changes.

Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Link: https://lore.kernel.org/r/20240316120706.4352-1-bp@alien8.de
Stable-dep-of: 2a38e4ca3022 ("x86/cpu: Provide default cache line size if not enumerated")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 95bfb35269b2e85cff0dd2c957b2d42ebf95ae5f ]

Drop 'vp_bits_from_cpuid' as it is not really needed.

No functional changes.

Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Link: https://lore.kernel.org/r/20240316120706.4352-1-bp@alien8.de
Stable-dep-of: 2a38e4ca3022 ("x86/cpu: Provide default cache line size if not enumerated")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/topology/intel: Unlock CPUID before evaluating anything</title>
<updated>2024-06-12T09:39:58+00:00</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2024-05-30T15:29:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f7c6d909a2d412e6d7cf36d7a60d26f6fbcdfa39'/>
<id>f7c6d909a2d412e6d7cf36d7a60d26f6fbcdfa39</id>
<content type='text'>
commit 0c2f6d04619ec2b53ad4b0b591eafc9389786e86 upstream.

Intel CPUs have a MSR bit to limit CPUID enumeration to leaf two. If
this bit is set by the BIOS then CPUID evaluation including topology
enumeration does not work correctly as the evaluation code does not try
to analyze any leaf greater than two.

This went unnoticed before because the original topology code just
repeated evaluation several times and managed to overwrite the initial
limited information with the correct one later. The new evaluation code
does it once and therefore ends up with the limited and wrong
information.

Cure this by unlocking CPUID right before evaluating anything which
depends on the maximum CPUID leaf being greater than two instead of
rereading stuff after unlock.

Fixes: 22d63660c35e ("x86/cpu: Use common topology code for Intel")
Reported-by: Peter Schneider &lt;pschneider1968@googlemail.com&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Tested-by: Peter Schneider &lt;pschneider1968@googlemail.com&gt;
Cc: &lt;stable@kernel.org&gt;
Link: https://lore.kernel.org/r/fd3f73dc-a86f-4bcf-9c60-43556a21eb42@googlemail.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 0c2f6d04619ec2b53ad4b0b591eafc9389786e86 upstream.

Intel CPUs have a MSR bit to limit CPUID enumeration to leaf two. If
this bit is set by the BIOS then CPUID evaluation including topology
enumeration does not work correctly as the evaluation code does not try
to analyze any leaf greater than two.

This went unnoticed before because the original topology code just
repeated evaluation several times and managed to overwrite the initial
limited information with the correct one later. The new evaluation code
does it once and therefore ends up with the limited and wrong
information.

Cure this by unlocking CPUID right before evaluating anything which
depends on the maximum CPUID leaf being greater than two instead of
rereading stuff after unlock.

Fixes: 22d63660c35e ("x86/cpu: Use common topology code for Intel")
Reported-by: Peter Schneider &lt;pschneider1968@googlemail.com&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Tested-by: Peter Schneider &lt;pschneider1968@googlemail.com&gt;
Cc: &lt;stable@kernel.org&gt;
Link: https://lore.kernel.org/r/fd3f73dc-a86f-4bcf-9c60-43556a21eb42@googlemail.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/bugs: Rename various 'ia32_cap' variables to 'x86_arch_cap_msr'</title>
<updated>2024-04-11T08:30:33+00:00</updated>
<author>
<name>Ingo Molnar</name>
<email>mingo@kernel.org</email>
</author>
<published>2024-04-11T07:25:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d0485730d2189ffe5d986d4e9e191f1e4d5ffd24'/>
<id>d0485730d2189ffe5d986d4e9e191f1e4d5ffd24</id>
<content type='text'>
So we are using the 'ia32_cap' value in a number of places,
which got its name from MSR_IA32_ARCH_CAPABILITIES MSR register.

But there's very little 'IA32' about it - this isn't 32-bit only
code, nor does it originate from there, it's just a historic
quirk that many Intel MSR names are prefixed with IA32_.

This is already clear from the helper method around the MSR:
x86_read_arch_cap_msr(), which doesn't have the IA32 prefix.

So rename 'ia32_cap' to 'x86_arch_cap_msr' to be consistent with
its role and with the naming of the helper function.

Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Josh Poimboeuf &lt;jpoimboe@redhat.com&gt;
Cc: Nikolay Borisov &lt;nik.borisov@suse.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Sean Christopherson &lt;seanjc@google.com&gt;
Link: https://lore.kernel.org/r/9592a18a814368e75f8f4b9d74d3883aa4fd1eaf.1712813475.git.jpoimboe@kernel.org
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
So we are using the 'ia32_cap' value in a number of places,
which got its name from MSR_IA32_ARCH_CAPABILITIES MSR register.

But there's very little 'IA32' about it - this isn't 32-bit only
code, nor does it originate from there, it's just a historic
quirk that many Intel MSR names are prefixed with IA32_.

This is already clear from the helper method around the MSR:
x86_read_arch_cap_msr(), which doesn't have the IA32 prefix.

So rename 'ia32_cap' to 'x86_arch_cap_msr' to be consistent with
its role and with the naming of the helper function.

Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Josh Poimboeuf &lt;jpoimboe@redhat.com&gt;
Cc: Nikolay Borisov &lt;nik.borisov@suse.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Sean Christopherson &lt;seanjc@google.com&gt;
Link: https://lore.kernel.org/r/9592a18a814368e75f8f4b9d74d3883aa4fd1eaf.1712813475.git.jpoimboe@kernel.org
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/bhi: Enumerate Branch History Injection (BHI) bug</title>
<updated>2024-04-08T17:27:05+00:00</updated>
<author>
<name>Pawan Gupta</name>
<email>pawan.kumar.gupta@linux.intel.com</email>
</author>
<published>2024-03-11T15:57:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=be482ff9500999f56093738f9219bbabc729d163'/>
<id>be482ff9500999f56093738f9219bbabc729d163</id>
<content type='text'>
Mitigation for BHI is selected based on the bug enumeration. Add bits
needed to enumerate BHI bug.

Signed-off-by: Pawan Gupta &lt;pawan.kumar.gupta@linux.intel.com&gt;
Signed-off-by: Daniel Sneddon &lt;daniel.sneddon@linux.intel.com&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Alexandre Chartre &lt;alexandre.chartre@oracle.com&gt;
Reviewed-by: Josh Poimboeuf &lt;jpoimboe@kernel.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Mitigation for BHI is selected based on the bug enumeration. Add bits
needed to enumerate BHI bug.

Signed-off-by: Pawan Gupta &lt;pawan.kumar.gupta@linux.intel.com&gt;
Signed-off-by: Daniel Sneddon &lt;daniel.sneddon@linux.intel.com&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Alexandre Chartre &lt;alexandre.chartre@oracle.com&gt;
Reviewed-by: Josh Poimboeuf &lt;jpoimboe@kernel.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>x86/cpu: Ensure that CPU info updates are propagated on UP</title>
<updated>2024-03-23T11:22:04+00:00</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2024-03-22T18:56:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c90399fbd74a0713d5972a6d931e4a9918621e88'/>
<id>c90399fbd74a0713d5972a6d931e4a9918621e88</id>
<content type='text'>
The boot sequence evaluates CPUID information twice:

  1) During early boot

  2) When finalizing the early setup right before
     mitigations are selected and alternatives are patched.

In both cases the evaluation is stored in boot_cpu_data, but on UP the
copying of boot_cpu_data to the per CPU info of the boot CPU happens
between #1 and #2. So any update which happens in #2 is never propagated to
the per CPU info instance.

Consolidate the whole logic and copy boot_cpu_data right before applying
alternatives as that's the point where boot_cpu_data is in it's final
state and not supposed to change anymore.

This also removes the voodoo mb() from smp_prepare_cpus_common() which
had absolutely no purpose.

Fixes: 71eb4893cfaf ("x86/percpu: Cure per CPU madness on UP")
Reported-by: Guenter Roeck &lt;linux@roeck-us.net&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Tested-by: Guenter Roeck &lt;linux@roeck-us.net&gt;
Link: https://lore.kernel.org/r/20240322185305.127642785@linutronix.de
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The boot sequence evaluates CPUID information twice:

  1) During early boot

  2) When finalizing the early setup right before
     mitigations are selected and alternatives are patched.

In both cases the evaluation is stored in boot_cpu_data, but on UP the
copying of boot_cpu_data to the per CPU info of the boot CPU happens
between #1 and #2. So any update which happens in #2 is never propagated to
the per CPU info instance.

Consolidate the whole logic and copy boot_cpu_data right before applying
alternatives as that's the point where boot_cpu_data is in it's final
state and not supposed to change anymore.

This also removes the voodoo mb() from smp_prepare_cpus_common() which
had absolutely no purpose.

Fixes: 71eb4893cfaf ("x86/percpu: Cure per CPU madness on UP")
Reported-by: Guenter Roeck &lt;linux@roeck-us.net&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Tested-by: Guenter Roeck &lt;linux@roeck-us.net&gt;
Link: https://lore.kernel.org/r/20240322185305.127642785@linutronix.de
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'rfds-for-linus-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2024-03-12T16:31:39+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2024-03-12T16:31:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0e33cf955f07e3991e45109cb3e29fbc9ca51d06'/>
<id>0e33cf955f07e3991e45109cb3e29fbc9ca51d06</id>
<content type='text'>
Pull x86 RFDS mitigation from Dave Hansen:
 "RFDS is a CPU vulnerability that may allow a malicious userspace to
  infer stale register values from kernel space. Kernel registers can
  have all kinds of secrets in them so the mitigation is basically to
  wait until the kernel is about to return to userspace and has user
  values in the registers. At that point there is little chance of
  kernel secrets ending up in the registers and the microarchitectural
  state can be cleared.

  This leverages some recent robustness fixes for the existing MDS
  vulnerability. Both MDS and RFDS use the VERW instruction for
  mitigation"

* tag 'rfds-for-linus-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  KVM/x86: Export RFDS_NO and RFDS_CLEAR to guests
  x86/rfds: Mitigate Register File Data Sampling (RFDS)
  Documentation/hw-vuln: Add documentation for RFDS
  x86/mmio: Disable KVM mitigation when X86_FEATURE_CLEAR_CPU_BUF is set
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull x86 RFDS mitigation from Dave Hansen:
 "RFDS is a CPU vulnerability that may allow a malicious userspace to
  infer stale register values from kernel space. Kernel registers can
  have all kinds of secrets in them so the mitigation is basically to
  wait until the kernel is about to return to userspace and has user
  values in the registers. At that point there is little chance of
  kernel secrets ending up in the registers and the microarchitectural
  state can be cleared.

  This leverages some recent robustness fixes for the existing MDS
  vulnerability. Both MDS and RFDS use the VERW instruction for
  mitigation"

* tag 'rfds-for-linus-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  KVM/x86: Export RFDS_NO and RFDS_CLEAR to guests
  x86/rfds: Mitigate Register File Data Sampling (RFDS)
  Documentation/hw-vuln: Add documentation for RFDS
  x86/mmio: Disable KVM mitigation when X86_FEATURE_CLEAR_CPU_BUF is set
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'x86-core-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2024-03-12T02:53:15+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2024-03-12T02:53:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=685d98211273f60e38a6d361b62d7016c545297e'/>
<id>685d98211273f60e38a6d361b62d7016c545297e</id>
<content type='text'>
Pull core x86 updates from Ingo Molnar:

 - The biggest change is the rework of the percpu code, to support the
   'Named Address Spaces' GCC feature, by Uros Bizjak:

      - This allows C code to access GS and FS segment relative memory
        via variables declared with such attributes, which allows the
        compiler to better optimize those accesses than the previous
        inline assembly code.

      - The series also includes a number of micro-optimizations for
        various percpu access methods, plus a number of cleanups of %gs
        accesses in assembly code.

      - These changes have been exposed to linux-next testing for the
        last ~5 months, with no known regressions in this area.

 - Fix/clean up __switch_to()'s broken but accidentally working handling
   of FPU switching - which also generates better code

 - Propagate more RIP-relative addressing in assembly code, to generate
   slightly better code

 - Rework the CPU mitigations Kconfig space to be less idiosyncratic, to
   make it easier for distros to follow &amp; maintain these options

 - Rework the x86 idle code to cure RCU violations and to clean up the
   logic

 - Clean up the vDSO Makefile logic

 - Misc cleanups and fixes

* tag 'x86-core-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (52 commits)
  x86/idle: Select idle routine only once
  x86/idle: Let prefer_mwait_c1_over_halt() return bool
  x86/idle: Cleanup idle_setup()
  x86/idle: Clean up idle selection
  x86/idle: Sanitize X86_BUG_AMD_E400 handling
  sched/idle: Conditionally handle tick broadcast in default_idle_call()
  x86: Increase brk randomness entropy for 64-bit systems
  x86/vdso: Move vDSO to mmap region
  x86/vdso/kbuild: Group non-standard build attributes and primary object file rules together
  x86/vdso: Fix rethunk patching for vdso-image-{32,64}.o
  x86/retpoline: Ensure default return thunk isn't used at runtime
  x86/vdso: Use CONFIG_COMPAT_32 to specify vdso32
  x86/vdso: Use $(addprefix ) instead of $(foreach )
  x86/vdso: Simplify obj-y addition
  x86/vdso: Consolidate targets and clean-files
  x86/bugs: Rename CONFIG_RETHUNK              =&gt; CONFIG_MITIGATION_RETHUNK
  x86/bugs: Rename CONFIG_CPU_SRSO             =&gt; CONFIG_MITIGATION_SRSO
  x86/bugs: Rename CONFIG_CPU_IBRS_ENTRY       =&gt; CONFIG_MITIGATION_IBRS_ENTRY
  x86/bugs: Rename CONFIG_CPU_UNRET_ENTRY      =&gt; CONFIG_MITIGATION_UNRET_ENTRY
  x86/bugs: Rename CONFIG_SLS                  =&gt; CONFIG_MITIGATION_SLS
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull core x86 updates from Ingo Molnar:

 - The biggest change is the rework of the percpu code, to support the
   'Named Address Spaces' GCC feature, by Uros Bizjak:

      - This allows C code to access GS and FS segment relative memory
        via variables declared with such attributes, which allows the
        compiler to better optimize those accesses than the previous
        inline assembly code.

      - The series also includes a number of micro-optimizations for
        various percpu access methods, plus a number of cleanups of %gs
        accesses in assembly code.

      - These changes have been exposed to linux-next testing for the
        last ~5 months, with no known regressions in this area.

 - Fix/clean up __switch_to()'s broken but accidentally working handling
   of FPU switching - which also generates better code

 - Propagate more RIP-relative addressing in assembly code, to generate
   slightly better code

 - Rework the CPU mitigations Kconfig space to be less idiosyncratic, to
   make it easier for distros to follow &amp; maintain these options

 - Rework the x86 idle code to cure RCU violations and to clean up the
   logic

 - Clean up the vDSO Makefile logic

 - Misc cleanups and fixes

* tag 'x86-core-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (52 commits)
  x86/idle: Select idle routine only once
  x86/idle: Let prefer_mwait_c1_over_halt() return bool
  x86/idle: Cleanup idle_setup()
  x86/idle: Clean up idle selection
  x86/idle: Sanitize X86_BUG_AMD_E400 handling
  sched/idle: Conditionally handle tick broadcast in default_idle_call()
  x86: Increase brk randomness entropy for 64-bit systems
  x86/vdso: Move vDSO to mmap region
  x86/vdso/kbuild: Group non-standard build attributes and primary object file rules together
  x86/vdso: Fix rethunk patching for vdso-image-{32,64}.o
  x86/retpoline: Ensure default return thunk isn't used at runtime
  x86/vdso: Use CONFIG_COMPAT_32 to specify vdso32
  x86/vdso: Use $(addprefix ) instead of $(foreach )
  x86/vdso: Simplify obj-y addition
  x86/vdso: Consolidate targets and clean-files
  x86/bugs: Rename CONFIG_RETHUNK              =&gt; CONFIG_MITIGATION_RETHUNK
  x86/bugs: Rename CONFIG_CPU_SRSO             =&gt; CONFIG_MITIGATION_SRSO
  x86/bugs: Rename CONFIG_CPU_IBRS_ENTRY       =&gt; CONFIG_MITIGATION_IBRS_ENTRY
  x86/bugs: Rename CONFIG_CPU_UNRET_ENTRY      =&gt; CONFIG_MITIGATION_UNRET_ENTRY
  x86/bugs: Rename CONFIG_SLS                  =&gt; CONFIG_MITIGATION_SLS
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'x86-cleanups-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2024-03-12T02:37:56+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2024-03-12T02:37:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=fcc196579aa1fc167d6778948bff69fae6116737'/>
<id>fcc196579aa1fc167d6778948bff69fae6116737</id>
<content type='text'>
Pull x86 cleanups from Ingo Molnar:
 "Misc cleanups, including a large series from Thomas Gleixner to cure
  sparse warnings"

* tag 'x86-cleanups-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/nmi: Drop unused declaration of proc_nmi_enabled()
  x86/callthunks: Use EXPORT_PER_CPU_SYMBOL_GPL() for per CPU variables
  x86/cpu: Provide a declaration for itlb_multihit_kvm_mitigation
  x86/cpu: Use EXPORT_PER_CPU_SYMBOL_GPL() for x86_spec_ctrl_current
  x86/uaccess: Add missing __force to casts in __access_ok() and valid_user_address()
  x86/percpu: Cure per CPU madness on UP
  smp: Consolidate smp_prepare_boot_cpu()
  x86/msr: Add missing __percpu annotations
  x86/msr: Prepare for including &lt;linux/percpu.h&gt; into &lt;asm/msr.h&gt;
  perf/x86/amd/uncore: Fix __percpu annotation
  x86/nmi: Remove an unnecessary IS_ENABLED(CONFIG_SMP)
  x86/apm_32: Remove dead function apm_get_battery_status()
  x86/insn-eval: Fix function param name in get_eff_addr_sib()
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull x86 cleanups from Ingo Molnar:
 "Misc cleanups, including a large series from Thomas Gleixner to cure
  sparse warnings"

* tag 'x86-cleanups-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/nmi: Drop unused declaration of proc_nmi_enabled()
  x86/callthunks: Use EXPORT_PER_CPU_SYMBOL_GPL() for per CPU variables
  x86/cpu: Provide a declaration for itlb_multihit_kvm_mitigation
  x86/cpu: Use EXPORT_PER_CPU_SYMBOL_GPL() for x86_spec_ctrl_current
  x86/uaccess: Add missing __force to casts in __access_ok() and valid_user_address()
  x86/percpu: Cure per CPU madness on UP
  smp: Consolidate smp_prepare_boot_cpu()
  x86/msr: Add missing __percpu annotations
  x86/msr: Prepare for including &lt;linux/percpu.h&gt; into &lt;asm/msr.h&gt;
  perf/x86/amd/uncore: Fix __percpu annotation
  x86/nmi: Remove an unnecessary IS_ENABLED(CONFIG_SMP)
  x86/apm_32: Remove dead function apm_get_battery_status()
  x86/insn-eval: Fix function param name in get_eff_addr_sib()
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'x86_sev_for_v6.9_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2024-03-12T00:44:11+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2024-03-12T00:44:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=38b334fc767e44816be087b3ec5d84b1438b735f'/>
<id>38b334fc767e44816be087b3ec5d84b1438b735f</id>
<content type='text'>
Pull x86 SEV updates from Borislav Petkov:

 - Add the x86 part of the SEV-SNP host support.

   This will allow the kernel to be used as a KVM hypervisor capable of
   running SNP (Secure Nested Paging) guests. Roughly speaking, SEV-SNP
   is the ultimate goal of the AMD confidential computing side,
   providing the most comprehensive confidential computing environment
   up to date.

   This is the x86 part and there is a KVM part which did not get ready
   in time for the merge window so latter will be forthcoming in the
   next cycle.

 - Rework the early code's position-dependent SEV variable references in
   order to allow building the kernel with clang and -fPIE/-fPIC and
   -mcmodel=kernel

 - The usual set of fixes, cleanups and improvements all over the place

* tag 'x86_sev_for_v6.9_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits)
  x86/sev: Disable KMSAN for memory encryption TUs
  x86/sev: Dump SEV_STATUS
  crypto: ccp - Have it depend on AMD_IOMMU
  iommu/amd: Fix failure return from snp_lookup_rmpentry()
  x86/sev: Fix position dependent variable references in startup code
  crypto: ccp: Make snp_range_list static
  x86/Kconfig: Remove CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
  Documentation: virt: Fix up pre-formatted text block for SEV ioctls
  crypto: ccp: Add the SNP_SET_CONFIG command
  crypto: ccp: Add the SNP_COMMIT command
  crypto: ccp: Add the SNP_PLATFORM_STATUS command
  x86/cpufeatures: Enable/unmask SEV-SNP CPU feature
  KVM: SEV: Make AVIC backing, VMSA and VMCB memory allocation SNP safe
  crypto: ccp: Add panic notifier for SEV/SNP firmware shutdown on kdump
  iommu/amd: Clean up RMP entries for IOMMU pages during SNP shutdown
  crypto: ccp: Handle legacy SEV commands when SNP is enabled
  crypto: ccp: Handle non-volatile INIT_EX data when SNP is enabled
  crypto: ccp: Handle the legacy TMR allocation when SNP is enabled
  x86/sev: Introduce an SNP leaked pages list
  crypto: ccp: Provide an API to issue SEV and SNP commands
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull x86 SEV updates from Borislav Petkov:

 - Add the x86 part of the SEV-SNP host support.

   This will allow the kernel to be used as a KVM hypervisor capable of
   running SNP (Secure Nested Paging) guests. Roughly speaking, SEV-SNP
   is the ultimate goal of the AMD confidential computing side,
   providing the most comprehensive confidential computing environment
   up to date.

   This is the x86 part and there is a KVM part which did not get ready
   in time for the merge window so latter will be forthcoming in the
   next cycle.

 - Rework the early code's position-dependent SEV variable references in
   order to allow building the kernel with clang and -fPIE/-fPIC and
   -mcmodel=kernel

 - The usual set of fixes, cleanups and improvements all over the place

* tag 'x86_sev_for_v6.9_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits)
  x86/sev: Disable KMSAN for memory encryption TUs
  x86/sev: Dump SEV_STATUS
  crypto: ccp - Have it depend on AMD_IOMMU
  iommu/amd: Fix failure return from snp_lookup_rmpentry()
  x86/sev: Fix position dependent variable references in startup code
  crypto: ccp: Make snp_range_list static
  x86/Kconfig: Remove CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
  Documentation: virt: Fix up pre-formatted text block for SEV ioctls
  crypto: ccp: Add the SNP_SET_CONFIG command
  crypto: ccp: Add the SNP_COMMIT command
  crypto: ccp: Add the SNP_PLATFORM_STATUS command
  x86/cpufeatures: Enable/unmask SEV-SNP CPU feature
  KVM: SEV: Make AVIC backing, VMSA and VMCB memory allocation SNP safe
  crypto: ccp: Add panic notifier for SEV/SNP firmware shutdown on kdump
  iommu/amd: Clean up RMP entries for IOMMU pages during SNP shutdown
  crypto: ccp: Handle legacy SEV commands when SNP is enabled
  crypto: ccp: Handle non-volatile INIT_EX data when SNP is enabled
  crypto: ccp: Handle the legacy TMR allocation when SNP is enabled
  x86/sev: Introduce an SNP leaked pages list
  crypto: ccp: Provide an API to issue SEV and SNP commands
  ...
</pre>
</div>
</content>
</entry>
</feed>
