[PATCH 3/4] x86/microcode/AMD: Fix mixed steppings support

[Borislav Petkov]

From: "Borislav Petkov (AMD)" <bp@xxxxxxxxx>

The AMD side of the loader has always claimed to support mixed
steppings. But somewhere along the way, it broke that by assuming that
the cached patch blob is a single one instead of it being one per
*node*.

So turn it into a per-node one so that each node can stash the blob
relevant for it.

  [ NB: Fixes tag is not really the exactly correct one but it is good
    enough. ]

Fixes: fe055896c040 ("x86/microcode: Merge the early microcode loader")
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
---
 arch/x86/kernel/cpu/microcode/amd.c | 34 ++++++++++++++++++-----------
 1 file changed, 21 insertions(+), 13 deletions(-)

diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index b8d73f133193..ac59783e6e9f 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -55,7 +55,9 @@ struct cont_desc {
 };
 
 static u32 ucode_new_rev;
-static u8 amd_ucode_patch[PATCH_MAX_SIZE];
+
+/* One blob per node. */
+static u8 amd_ucode_patch[MAX_NUMNODES][PATCH_MAX_SIZE];
 
 /*
  * Microcode patch container file is prepended to the initrd in cpio
@@ -428,7 +430,7 @@ apply_microcode_early_amd(u32 cpuid_1_eax, void *ucode, size_t size, bool save_p
 	patch	= (u8 (*)[PATCH_MAX_SIZE])__pa_nodebug(&amd_ucode_patch);
 #else
 	new_rev = &ucode_new_rev;
-	patch	= &amd_ucode_patch;
+	patch	= &amd_ucode_patch[0];
 #endif
 
 	desc.cpuid_1_eax = cpuid_1_eax;
@@ -580,10 +582,10 @@ int __init save_microcode_in_initrd_amd(unsigned int cpuid_1_eax)
 
 void reload_ucode_amd(unsigned int cpu)
 {
-	struct microcode_amd *mc;
 	u32 rev, dummy __always_unused;
+	struct microcode_amd *mc;
 
-	mc = (struct microcode_amd *)amd_ucode_patch;
+	mc = (struct microcode_amd *)amd_ucode_patch[cpu_to_node(cpu)];
 
 	rdmsr(MSR_AMD64_PATCH_LEVEL, rev, dummy);
 
@@ -851,6 +853,8 @@ static enum ucode_state __load_microcode_amd(u8 family, const u8 *data,
 
 static enum ucode_state load_microcode_amd(u8 family, const u8 *data, size_t size)
 {
+	struct cpuinfo_x86 *c;
+	unsigned int nid, cpu;
 	struct ucode_patch *p;
 	enum ucode_state ret;
 
@@ -863,18 +867,22 @@ static enum ucode_state load_microcode_amd(u8 family, const u8 *data, size_t siz
 		return ret;
 	}
 
-	p = find_patch(0);
-	if (!p) {
-		return ret;
-	} else {
-		if (boot_cpu_data.microcode >= p->patch_id)
-			return ret;
+	for_each_node(nid) {
+		cpu = cpumask_first(cpumask_of_node(nid));
+		c = &cpu_data(cpu);
+
+		p = find_patch(cpu);
+		if (!p)
+			continue;
+
+		if (c->microcode >= p->patch_id)
+			continue;
 
 		ret = UCODE_NEW;
-	}
 
-	memset(amd_ucode_patch, 0, PATCH_MAX_SIZE);
-	memcpy(amd_ucode_patch, p->data, min_t(u32, p->size, PATCH_MAX_SIZE));
+		memset(&amd_ucode_patch[nid], 0, PATCH_MAX_SIZE);
+		memcpy(&amd_ucode_patch[nid], p->data, min_t(u32, p->size, PATCH_MAX_SIZE));
+	}
 
 	return ret;
 }
-- 
2.35.1