Merge tag 'x86_urgent_for_v6.12_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Borislav Petkov:

 - Prevent a certain range of pages which get marked as hypervisor-only,
   to get allocated to a CoCo (SNP) guest which cannot use them and thus
   fail booting

 - Fix the microcode loader on AMD to pay attention to the stepping of a
   patch and to handle the case where a BIOS config option splits the
   machine into logical NUMA nodes per L3 cache slice

 - Disable LAM from being built by default due to security concerns

* tag 'x86_urgent_for_v6.12_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/sev: Ensure that RMP table fixups are reserved
  x86/microcode/AMD: Split load_microcode_amd()
  x86/microcode/AMD: Pay attention to the stepping dynamically
  x86/lam: Disable ADDRESS_MASKING in most cases

3 files changed, 38 insertions, 16 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 2852fcd82cbd..16354dfa6d96 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2257,6 +2257,7 @@ config RANDOMIZE_MEMORY_PHYSICAL_PADDING
 config ADDRESS_MASKING
 	bool "Linear Address Masking support"
 	depends on X86_64
+	depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS
 	help
 	  Linear Address Masking (LAM) modifies the checking that is applied
 	  to 64-bit linear addresses, allowing software to use of the
diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index f63b051f25a0..31a73715d755 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -584,7 +584,7 @@ void __init load_ucode_amd_bsp(struct early_load_data *ed, unsigned int cpuid_1_
 		native_rdmsr(MSR_AMD64_PATCH_LEVEL, ed->new_rev, dummy);
 }
 
-static enum ucode_state load_microcode_amd(u8 family, const u8 *data, size_t size);
+static enum ucode_state _load_microcode_amd(u8 family, const u8 *data, size_t size);
 
 static int __init save_microcode_in_initrd(void)
 {
@@ -605,7 +605,7 @@ static int __init save_microcode_in_initrd(void)
 	if (!desc.mc)
 		return -EINVAL;
 
-	ret = load_microcode_amd(x86_family(cpuid_1_eax), desc.data, desc.size);
+	ret = _load_microcode_amd(x86_family(cpuid_1_eax), desc.data, desc.size);
 	if (ret > UCODE_UPDATED)
 		return -EINVAL;
 
@@ -613,16 +613,19 @@ static int __init save_microcode_in_initrd(void)
 }
 early_initcall(save_microcode_in_initrd);
 
-static inline bool patch_cpus_equivalent(struct ucode_patch *p, struct ucode_patch *n)
+static inline bool patch_cpus_equivalent(struct ucode_patch *p,
+					 struct ucode_patch *n,
+					 bool ignore_stepping)
 {
 	/* Zen and newer hardcode the f/m/s in the patch ID */
         if (x86_family(bsp_cpuid_1_eax) >= 0x17) {
 		union cpuid_1_eax p_cid = ucode_rev_to_cpuid(p->patch_id);
 		union cpuid_1_eax n_cid = ucode_rev_to_cpuid(n->patch_id);
 
-		/* Zap stepping */
-		p_cid.stepping = 0;
-		n_cid.stepping = 0;
+		if (ignore_stepping) {
+			p_cid.stepping = 0;
+			n_cid.stepping = 0;
+		}
 
 		return p_cid.full == n_cid.full;
 	} else {
@@ -644,13 +647,13 @@ static struct ucode_patch *cache_find_patch(struct ucode_cpu_info *uci, u16 equi
 	WARN_ON_ONCE(!n.patch_id);
 
 	list_for_each_entry(p, &microcode_cache, plist)
-		if (patch_cpus_equivalent(p, &n))
+		if (patch_cpus_equivalent(p, &n, false))
 			return p;
 
 	return NULL;
 }
 
-static inline bool patch_newer(struct ucode_patch *p, struct ucode_patch *n)
+static inline int patch_newer(struct ucode_patch *p, struct ucode_patch *n)
 {
 	/* Zen and newer hardcode the f/m/s in the patch ID */
         if (x86_family(bsp_cpuid_1_eax) >= 0x17) {
@@ -659,6 +662,9 @@ static inline bool patch_newer(struct ucode_patch *p, struct ucode_patch *n)
 		zp.ucode_rev = p->patch_id;
 		zn.ucode_rev = n->patch_id;
 
+		if (zn.stepping != zp.stepping)
+			return -1;
+
 		return zn.rev > zp.rev;
 	} else {
 		return n->patch_id > p->patch_id;
@@ -668,10 +674,14 @@ static inline bool patch_newer(struct ucode_patch *p, struct ucode_patch *n)
 static void update_cache(struct ucode_patch *new_patch)
 {
 	struct ucode_patch *p;
+	int ret;
 
 	list_for_each_entry(p, &microcode_cache, plist) {
-		if (patch_cpus_equivalent(p, new_patch)) {
-			if (!patch_newer(p, new_patch)) {
+		if (patch_cpus_equivalent(p, new_patch, true)) {
+			ret = patch_newer(p, new_patch);
+			if (ret < 0)
+				continue;
+			else if (!ret) {
 				/* we already have the latest patch */
 				kfree(new_patch->data);
 				kfree(new_patch);
@@ -944,21 +954,30 @@ static enum ucode_state __load_microcode_amd(u8 family, const u8 *data,
 	return UCODE_OK;
 }
 
-static enum ucode_state load_microcode_amd(u8 family, const u8 *data, size_t size)
+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;
 
 	/* free old equiv table */
 	free_equiv_cpu_table();
 
 	ret = __load_microcode_amd(family, data, size);
-	if (ret != UCODE_OK) {
+	if (ret != UCODE_OK)
 		cleanup();
+
+	return ret;
+}
+
+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;
+
+	ret = _load_microcode_amd(family, data, size);
+	if (ret != UCODE_OK)
 		return ret;
-	}
 
 	for_each_node(nid) {
 		cpu = cpumask_first(cpumask_of_node(nid));
diff --git a/arch/x86/virt/svm/sev.c b/arch/x86/virt/svm/sev.c
index 0ce17766c0e5..9a6a943d8e41 100644
--- a/arch/x86/virt/svm/sev.c
+++ b/arch/x86/virt/svm/sev.c
@@ -173,6 +173,8 @@ static void __init __snp_fixup_e820_tables(u64 pa)
 		e820__range_update(pa, PMD_SIZE, E820_TYPE_RAM, E820_TYPE_RESERVED);
 		e820__range_update_table(e820_table_kexec, pa, PMD_SIZE, E820_TYPE_RAM, E820_TYPE_RESERVED);
 		e820__range_update_table(e820_table_firmware, pa, PMD_SIZE, E820_TYPE_RAM, E820_TYPE_RESERVED);
+		if (!memblock_is_region_reserved(pa, PMD_SIZE))
+			memblock_reserve(pa, PMD_SIZE);
 	}
 }