linux-kernel - Re: [PATCH 06/13] x86/microcode/AMD: Rework container parsing

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Message-ID: <20170118145849.cc3ybid3wom3ro3x@pd.tnic>
Date:   Wed, 18 Jan 2017 15:58:50 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     X86 ML <x86@...nel.org>, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 06/13] x86/microcode/AMD: Rework container parsing

On Wed, Jan 18, 2017 at 03:44:46PM +0100, Borislav Petkov wrote:
> And in a future patch, I'll check desc->mc after that function returns
> and not eq_id. (I had to do eq_id because of the global this_equiv_id
> but that's gone now too).

... which is pretty nice, I can get rid of eq_id now as it is private to
the container scanning code now and the callers shouldn't care. Cool.

Now on to test whether that actually makes sense :-)

---
From: Borislav Petkov <bp@...e.de>
Date: Wed, 18 Jan 2017 15:55:26 +0100
Subject: [PATCH] x86/microcode/AMD: Remove struct cont_desc.eq_id

The equivalence ID was needed outside of the container scanning logic
but now, after this has been cleaned up, not anymore. Now, cont_desc.mc
is used to denote whether the container we're looking at has the proper
microcode patch for this CPU or not.

Signed-off-by: Borislav Petkov <bp@...e.de>
---
 arch/x86/kernel/cpu/microcode/amd.c | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index 5e1b57747c2f..7889ae492af0 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -49,7 +49,6 @@ struct cont_desc {
 	struct microcode_amd *mc;
 	u32		     cpuid_1_eax;
 	u32		     psize;
-	u16		     eq_id;
 	u8		     *data;
 	size_t		     size;
 };
@@ -92,10 +91,8 @@ static ssize_t parse_container(u8 *ucode, ssize_t size, struct cont_desc *desc)
 	/* Am I looking at an equivalence table header? */
 	if (hdr[0] != UCODE_MAGIC ||
 	    hdr[1] != UCODE_EQUIV_CPU_TABLE_TYPE ||
-	    hdr[2] == 0) {
-		desc->eq_id = 0;
+	    hdr[2] == 0)
 		return CONTAINER_HDR_SZ;
-	}
 
 	buf = ucode;
 
@@ -147,9 +144,8 @@ static ssize_t parse_container(u8 *ucode, ssize_t size, struct cont_desc *desc)
 	 * buffer.
 	 */
 	if (desc->mc) {
-		desc->eq_id = eq_id;
-		desc->data  = ucode;
-		desc->size  = orig_size - size;
+		desc->data = ucode;
+		desc->size = orig_size - size;
 
 		return 0;
 	}
@@ -220,8 +216,6 @@ apply_microcode_early_amd(u32 cpuid_1_eax, void *ucode, size_t size, bool save_p
 	desc.cpuid_1_eax = cpuid_1_eax;
 
 	scan_containers(ucode, size, &desc);
-	if (!desc.eq_id)
-		return ret;
 
 	mc = desc.mc;
 	if (!mc)
@@ -341,7 +335,7 @@ int __init save_microcode_in_initrd_amd(unsigned int cpuid_1_eax)
 	desc.cpuid_1_eax = cpuid_1_eax;
 
 	scan_containers(cp.data, cp.size, &desc);
-	if (!desc.eq_id)
+	if (!desc.mc)
 		return -EINVAL;
 
 	ret = load_microcode_amd(smp_processor_id(), x86_family(cpuid_1_eax),
-- 
2.11.0

-- 
Regards/Gruss,
    Boris.

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