linux.git/arch/x86/kernel/cpu/microcode/core.c, branch v6.5 Linux kernel source tree x86/microcode: move to use bus_get_dev_root() 2023-03-17T14:29:26+00:00 Greg Kroah-Hartman gregkh@linuxfoundation.org 2023-03-13T18:28:51+00:00 216f58beb26e683e6d437c43e6aaf8e7b8631447 Direct access to the struct bus_type dev_root pointer is going away soon so replace that with a call to bus_get_dev_root() instead, which is what it is there for. Cc: Borislav Petkov <bp@alien8.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: x86@kernel.org Cc: "H. Peter Anvin" <hpa@zytor.com> Link: https://lore.kernel.org/r/20230313182918.1312597-9-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Direct access to the struct bus_type dev_root pointer is going away soon
so replace that with a call to bus_get_dev_root() instead, which is what
it is there for.

Cc: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: https://lore.kernel.org/r/20230313182918.1312597-9-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
x86/microcode/core: Return an error only when necessary 2023-02-06T12:41:31+00:00 Borislav Petkov (AMD) bp@alien8.de 2023-01-30T12:48:04+00:00 f33e0c893b22bf94d7985f1f2aa3872237560c74 Return an error from the late loading function which is run on each CPU only when an error has actually been encountered during the update. Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20230130161709.11615-5-bp@alien8.de 
Return an error from the late loading function which is run on each CPU
only when an error has actually been encountered during the update.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230130161709.11615-5-bp@alien8.de
x86/microcode/AMD: Add a @cpu parameter to the reloading functions 2023-02-06T11:14:20+00:00 Borislav Petkov (AMD) bp@alien8.de 2023-01-25T23:08:03+00:00 a5ad92134bd153a9ccdcddf09a95b088f36c3cce Will be used in a subsequent change. Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20230130161709.11615-3-bp@alien8.de 
Will be used in a subsequent change.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230130161709.11615-3-bp@alien8.de
x86/microcode: Allow only "1" as a late reload trigger value 2023-01-31T15:47:03+00:00 Ashok Raj ashok.raj@intel.com 2023-01-30T21:39:48+00:00 25d0dc4b957cc8674f8554e85f18a00467e876d7 Microcode gets reloaded late only if "1" is written to the reload file. However, the code silently treats any other unsigned integer as a successful write even though no actions are performed to load microcode. Make the loader more strict to accept only "1" as a trigger value and return an error otherwise. [ bp: Massage commit message. ] Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20230130213955.6046-3-ashok.raj@intel.com 
Microcode gets reloaded late only if "1" is written to the reload file.
However, the code silently treats any other unsigned integer as a
successful write even though no actions are performed to load microcode.

Make the loader more strict to accept only "1" as a trigger value and
return an error otherwise.

  [ bp: Massage commit message. ]

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230130213955.6046-3-ashok.raj@intel.com
x86/microcode: Adjust late loading result reporting message 2023-01-21T13:55:20+00:00 Ashok Raj ashok.raj@intel.com 2023-01-09T15:35:52+00:00 6eab3abac7043226e5375e9ead0c7607ced6767b During late microcode loading, the "Reload completed" message is issued unconditionally, regardless of success or failure. Adjust the message to report the result of the update. [ bp: Massage. ] Fixes: 9bd681251b7c ("x86/microcode: Announce reload operation's completion") Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/lkml/874judpqqd.ffs@tglx/ 
During late microcode loading, the "Reload completed" message is issued
unconditionally, regardless of success or failure.

Adjust the message to report the result of the update.

  [ bp: Massage. ]

Fixes: 9bd681251b7c ("x86/microcode: Announce reload operation's completion")
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Link: https://lore.kernel.org/lkml/874judpqqd.ffs@tglx/
x86/microcode: Check CPU capabilities after late microcode update correctly 2023-01-21T13:53:20+00:00 Ashok Raj ashok.raj@intel.com 2023-01-09T15:35:51+00:00 c0dd9245aa9e25a697181f6085692272c9ec61bc The kernel caches each CPU's feature bits at boot in an x86_capability[] structure. However, the capabilities in the BSP's copy can be turned off as a result of certain command line parameters or configuration restrictions, for example the SGX bit. This can cause a mismatch when comparing the values before and after the microcode update. Another example is X86_FEATURE_SRBDS_CTRL which gets added only after microcode update: --- cpuid.before 2023-01-21 14:54:15.652000747 +0100 +++ cpuid.after 2023-01-21 14:54:26.632001024 +0100 @@ -10,7 +10,7 @@ CPU: 0x00000004 0x04: eax=0x00000000 ebx=0x00000000 ecx=0x00000000 edx=0x00000000 0x00000005 0x00: eax=0x00000040 ebx=0x00000040 ecx=0x00000003 edx=0x11142120 0x00000006 0x00: eax=0x000027f7 ebx=0x00000002 ecx=0x00000001 edx=0x00000000 - 0x00000007 0x00: eax=0x00000000 ebx=0x029c6fbf ecx=0x40000000 edx=0xbc002400 + 0x00000007 0x00: eax=0x00000000 ebx=0x029c6fbf ecx=0x40000000 edx=0xbc002e00 ^^^ and which proves for a gazillionth time that late loading is a bad bad idea. microcode_check() is called after an update to report any previously cached CPUID bits which might have changed due to the update. Therefore, store the cached CPU caps before the update and compare them with the CPU caps after the microcode update has succeeded. Thus, the comparison is done between the CPUID *hardware* bits before and after the upgrade instead of using the cached, possibly runtime modified values in BSP's boot_cpu_data copy. As a result, false warnings about CPUID bits changes are avoided. [ bp: - Massage. - Add SRBDS_CTRL example. - Add kernel-doc. - Incorporate forgotten review feedback from dhansen. ] Fixes: 1008c52c09dc ("x86/CPU: Add a microcode loader callback") Signed-off-by: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20230109153555.4986-3-ashok.raj@intel.com 
The kernel caches each CPU's feature bits at boot in an x86_capability[]
structure. However, the capabilities in the BSP's copy can be turned off
as a result of certain command line parameters or configuration
restrictions, for example the SGX bit. This can cause a mismatch when
comparing the values before and after the microcode update.

Another example is X86_FEATURE_SRBDS_CTRL which gets added only after
microcode update:

  --- cpuid.before	2023-01-21 14:54:15.652000747 +0100
  +++ cpuid.after	2023-01-21 14:54:26.632001024 +0100
  @@ -10,7 +10,7 @@ CPU:
      0x00000004 0x04: eax=0x00000000 ebx=0x00000000 ecx=0x00000000 edx=0x00000000
      0x00000005 0x00: eax=0x00000040 ebx=0x00000040 ecx=0x00000003 edx=0x11142120
      0x00000006 0x00: eax=0x000027f7 ebx=0x00000002 ecx=0x00000001 edx=0x00000000
  -   0x00000007 0x00: eax=0x00000000 ebx=0x029c6fbf ecx=0x40000000 edx=0xbc002400
  +   0x00000007 0x00: eax=0x00000000 ebx=0x029c6fbf ecx=0x40000000 edx=0xbc002e00
  									     ^^^

and which proves for a gazillionth time that late loading is a bad bad
idea.

microcode_check() is called after an update to report any previously
cached CPUID bits which might have changed due to the update.

Therefore, store the cached CPU caps before the update and compare them
with the CPU caps after the microcode update has succeeded.

Thus, the comparison is done between the CPUID *hardware* bits before
and after the upgrade instead of using the cached, possibly runtime
modified values in BSP's boot_cpu_data copy.

As a result, false warnings about CPUID bits changes are avoided.

  [ bp:
  	- Massage.
	- Add SRBDS_CTRL example.
	- Add kernel-doc.
	- Incorporate forgotten review feedback from dhansen.
	]

Fixes: 1008c52c09dc ("x86/CPU: Add a microcode loader callback")
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230109153555.4986-3-ashok.raj@intel.com
x86/microcode: Add a parameter to microcode_check() to store CPU capabilities 2023-01-20T20:45:13+00:00 Ashok Raj ashok.raj@intel.com 2023-01-09T15:35:50+00:00 ab31c74455c64e69342ddab21fd9426fcbfefde7 Add a parameter to store CPU capabilities before performing a microcode update so that CPU capabilities can be compared before and after update. [ bp: Massage. ] Signed-off-by: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20230109153555.4986-2-ashok.raj@intel.com 
Add a parameter to store CPU capabilities before performing a microcode
update so that CPU capabilities can be compared before and after update.

  [ bp: Massage. ]

Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230109153555.4986-2-ashok.raj@intel.com
x86/microcode: Use the DEVICE_ATTR_RO() macro 2023-01-18T11:02:20+00:00 Guangju Wang[baidu] wgj900@163.com 2023-01-18T02:35:54+00:00 59047d942bedc4ce88a2121a9f9e656b9532dd30 Use DEVICE_ATTR_RO() helper instead of open-coded DEVICE_ATTR(), which makes the code a bit shorter and easier to read. No change in functionality. Signed-off-by: Guangju Wang[baidu] <wgj900@163.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20230118023554.1898-1-wgj900@163.com 
Use DEVICE_ATTR_RO() helper instead of open-coded DEVICE_ATTR(),
which makes the code a bit shorter and easier to read.

No change in functionality.

Signed-off-by: Guangju Wang[baidu] <wgj900@163.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230118023554.1898-1-wgj900@163.com
x86/microcode: Drop struct ucode_cpu_info.valid 2022-11-02T15:45:46+00:00 Borislav Petkov bp@suse.de 2022-10-19T17:25:27+00:00 254ed7cf4dd79a18bbc496ab53f6c82d45431c78 It is not needed anymore. Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Ashok Raj <ashok.raj@intel.com> Link: https://lore.kernel.org/r/20221028142638.28498-6-bp@alien8.de 
It is not needed anymore.

Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
Link: https://lore.kernel.org/r/20221028142638.28498-6-bp@alien8.de
x86/microcode: Do some minor fixups 2022-11-02T15:45:46+00:00 Borislav Petkov bp@suse.de 2022-10-19T17:20:47+00:00 2e6ff4052d89ff9eeaddece14ba88c40bf8b2721 Improve debugging printks and fixup formatting. Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Ashok Raj <ashok.raj@intel.com> Link: https://lore.kernel.org/r/20221028142638.28498-5-bp@alien8.de 
Improve debugging printks and fixup formatting.

Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
Link: https://lore.kernel.org/r/20221028142638.28498-5-bp@alien8.de