[PATCH] arch/x86: Fix boot_cpu_data.microcode version output

[PATCH] arch/x86: Fix boot_cpu_data.microcode version output

[Prarit Bhargava]

On systems where a runtime microcode update has occurred the microcode
version output in a MCE log record is wrong because
boot_cpu_data.microcode is not updated during runtime.

Update boot_cpu_data.microcode when the BSP's microcode is updated.

Fixes: fa94d0c6e0f3 ("x86/MCE: Save microcode revision in machine check records")
Suggested-by: Borislav Petkov <bp@alien8.com>
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Cc: stable@vger.kernel.org
Cc: sironi@amazon.de
Cc: tony.luck@intel.com
---
 arch/x86/kernel/cpu/microcode/amd.c   | 4 ++++
 arch/x86/kernel/cpu/microcode/intel.c | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index 0624957aa068..7f5b32535ac7 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -537,6 +537,10 @@ static enum ucode_state apply_microcode_amd(int cpu)
 	uci->cpu_sig.rev = mc_amd->hdr.patch_id;
 	c->microcode = mc_amd->hdr.patch_id;
 
+	/* Update boot_cpu_data's revision too, if we're on the BSP: */
+	if (c->cpu_index == boot_cpu_data.cpu_index)
+		boot_cpu_data.microcode = rev;
+
 	return UCODE_UPDATED;
 }
 
diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index 97ccf4c3b45b..256d336cbc04 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -851,6 +851,10 @@ static enum ucode_state apply_microcode_intel(int cpu)
 	uci->cpu_sig.rev = rev;
 	c->microcode = rev;
 
+	/* Update boot_cpu_data's revision too, if we're on the BSP: */
+	if (c->cpu_index == boot_cpu_data.cpu_index)
+		boot_cpu_data.microcode = rev;
+
 	return UCODE_UPDATED;
 }
 
-- 
2.17.0

Re: [PATCH] arch/x86: Fix boot_cpu_data.microcode version output

[Prarit Bhargava]

On 07/30/2018 01:49 PM, Prarit Bhargava wrote:
> On systems where a runtime microcode update has occurred the microcode
> version output in a MCE log record is wrong because
> boot_cpu_data.microcode is not updated during runtime.
> 
> Update boot_cpu_data.microcode when the BSP's microcode is updated.
> 
> Fixes: fa94d0c6e0f3 ("x86/MCE: Save microcode revision in machine check records")
> Suggested-by: Borislav Petkov <bp@alien8.com>
> Signed-off-by: Prarit Bhargava <prarit@redhat.com>
> Cc: stable@vger.kernel.org
> Cc: sironi@amazon.de
> Cc: tony.luck@intel.com
> ---
>  arch/x86/kernel/cpu/microcode/amd.c   | 4 ++++
>  arch/x86/kernel/cpu/microcode/intel.c | 4 ++++
>  2 files changed, 8 insertions(+)
> 
> diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
> index 0624957aa068..7f5b32535ac7 100644
> --- a/arch/x86/kernel/cpu/microcode/amd.c
> +++ b/arch/x86/kernel/cpu/microcode/amd.c
> @@ -537,6 +537,10 @@ static enum ucode_state apply_microcode_amd(int cpu)
>  	uci->cpu_sig.rev = mc_amd->hdr.patch_id;
>  	c->microcode = mc_amd->hdr.patch_id;
>  
> +	/* Update boot_cpu_data's revision too, if we're on the BSP: */
> +	if (c->cpu_index == boot_cpu_data.cpu_index)
> +		boot_cpu_data.microcode = rev;
> +

Borislav, hold off on this.  I want to double check something with AMD.

I think this has to be

	boot_cpu_data.microcode = mc_amd->hdr.patch_id;

I'm going to grab some old/new microcode and test.  I do know that the Intel
update below works.

P.

>  	return UCODE_UPDATED;
>  }
>  
> diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
> index 97ccf4c3b45b..256d336cbc04 100644
> --- a/arch/x86/kernel/cpu/microcode/intel.c
> +++ b/arch/x86/kernel/cpu/microcode/intel.c
> @@ -851,6 +851,10 @@ static enum ucode_state apply_microcode_intel(int cpu)
>  	uci->cpu_sig.rev = rev;
>  	c->microcode = rev;
>  
> +	/* Update boot_cpu_data's revision too, if we're on the BSP: */
> +	if (c->cpu_index == boot_cpu_data.cpu_index)
> +		boot_cpu_data.microcode = rev;
> +
>  	return UCODE_UPDATED;
>  }
>  
> 

Re: [PATCH] arch/x86: Fix boot_cpu_data.microcode version output

[Borislav Petkov]

On Mon, Jul 30, 2018 at 01:53:50PM -0400, Prarit Bhargava wrote:
> I think this has to be
> 
> 	boot_cpu_data.microcode = mc_amd->hdr.patch_id;

Yes, it does.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
--

[PATCH v2] arch/x86: Fix boot_cpu_data.microcode version output

[Prarit Bhargava]

I tested this on AMD Ryzen & Intel Broadwell system and dumped the
boot_cpu_data before and after a microcode update.  On the Intel
system I also did a fatal MCE using mce-inject to confirm the output
from the mce handling code.

P.

---8<---

On systems where a runtime microcode update has occurred the microcode
version output in a MCE log record is wrong because
boot_cpu_data.microcode is not updated during runtime.

Update boot_cpu_data.microcode when the BSP's microcode is updated.

Fixes: fa94d0c6e0f3 ("x86/MCE: Save microcode revision in machine check records")
Suggested-by: Borislav Petkov <bp@alien8.com>
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Cc: stable@vger.kernel.org
Cc: sironi@amazon.de
Cc: tony.luck@intel.com
---
Changes in v2: Use mc_amd->hdr.patch_id on AMD

 arch/x86/kernel/cpu/microcode/amd.c   | 4 ++++
 arch/x86/kernel/cpu/microcode/intel.c | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index 0624957aa068..63b072377ba4 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -537,6 +537,10 @@ static enum ucode_state apply_microcode_amd(int cpu)
 	uci->cpu_sig.rev = mc_amd->hdr.patch_id;
 	c->microcode = mc_amd->hdr.patch_id;
 
+	/* Update boot_cpu_data's revision too, if we're on the BSP: */
+	if (c->cpu_index == boot_cpu_data.cpu_index)
+		boot_cpu_data.microcode =  mc_amd->hdr.patch_id;
+
 	return UCODE_UPDATED;
 }
 
diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index 97ccf4c3b45b..256d336cbc04 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -851,6 +851,10 @@ static enum ucode_state apply_microcode_intel(int cpu)
 	uci->cpu_sig.rev = rev;
 	c->microcode = rev;
 
+	/* Update boot_cpu_data's revision too, if we're on the BSP: */
+	if (c->cpu_index == boot_cpu_data.cpu_index)
+		boot_cpu_data.microcode = rev;
+
 	return UCODE_UPDATED;
 }
 
-- 
2.17.0

Re: [PATCH v2] arch/x86: Fix boot_cpu_data.microcode version output

[Borislav Petkov]

On Tue, Jul 31, 2018 at 11:46:09AM +0000, Sironi, Filippo wrote:
> There may be a chance of skipping this code, I think.
> 
> If the microcode is loaded on the hyperthread sibling of the boot cpu
> before being loaded on the boot cpu, the boot cpu will exit earlier
> from apply_microcode_intel() - in if (rev >= mc->hdr.rev) { ... }.
> 
> (This seems to be possible in apply_microcode_amd() as well.)
> 
> In my tree with the aforementioned change - Intel only - I also had
> the following patch:

Yap, good catch.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
--