Merge tag 'x86-urgent-2025-12-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Ingo Molnar:

 - Fix FPU core dumps on certain CPU models

 - Fix htmldocs build warning

 - Export TLB tracing event name via header

 - Remove unused constant from <linux/mm_types.h>

 - Fix comments

 - Fix whitespace noise in documentation

 - Fix variadic structure's definition to un-confuse UBSAN

 - Fix posted MSI interrupts irq_retrigger() bug

 - Fix asm build failure with older GCC builds

* tag 'x86-urgent-2025-12-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/bug: Fix old GCC compile fails
  x86/msi: Make irq_retrigger() functional for posted MSI
  x86/platform/uv: Fix UBSAN array-index-out-of-bounds
  mm: Remove tlb_flush_reason::NR_TLB_FLUSH_REASONS from <linux/mm_types.h>
  x86/mm/tlb/trace: Export the TLB_REMOTE_WRONG_CPU enum in <trace/events/tlb.h>
  x86/sgx: Remove unmatched quote in __sgx_encl_extend function comment
  x86/boot/Documentation: Fix whitespace noise in boot.rst
  x86/fpu: Fix FPU state core dump truncation on CPUs with no extended xfeatures
  x86/boot/Documentation: Fix htmldocs build warning due to malformed table in boot.rst

6 files changed, 35 insertions, 5 deletions

diff --git a/arch/x86/include/asm/bug.h b/arch/x86/include/asm/bug.h
index d561a8443c13..9b4e04690e1a 100644
--- a/arch/x86/include/asm/bug.h
+++ b/arch/x86/include/asm/bug.h
@@ -15,7 +15,7 @@ extern void __WARN_trap(struct bug_entry *bug, ...);
 /*
  * Despite that some emulators terminate on UD2, we use it for WARN().
  */
-#define ASM_UD2		_ASM_BYTES(0x0f, 0x0b)
+#define ASM_UD2		__ASM_FORM(ud2)
 #define INSN_UD2	0x0b0f
 #define LEN_UD2		2
 
diff --git a/arch/x86/include/asm/irq_remapping.h b/arch/x86/include/asm/irq_remapping.h
index 5a0d42464d44..4e55d1755846 100644
--- a/arch/x86/include/asm/irq_remapping.h
+++ b/arch/x86/include/asm/irq_remapping.h
@@ -87,4 +87,11 @@ static inline void panic_if_irq_remap(const char *msg)
 }
 
 #endif /* CONFIG_IRQ_REMAP */
+
+#ifdef CONFIG_X86_POSTED_MSI
+void intel_ack_posted_msi_irq(struct irq_data *irqd);
+#else
+#define intel_ack_posted_msi_irq	NULL
+#endif
+
 #endif /* __X86_IRQ_REMAPPING_H */
diff --git a/arch/x86/include/asm/uv/bios.h b/arch/x86/include/asm/uv/bios.h
index 6989b824fd32..d0b62e255290 100644
--- a/arch/x86/include/asm/uv/bios.h
+++ b/arch/x86/include/asm/uv/bios.h
@@ -122,7 +122,7 @@ struct uv_systab {
 	struct {
 		u32 type:8;	/* type of entry */
 		u32 offset:24;	/* byte offset from struct start to entry */
-	} entry[1];		/* additional entries follow */
+	} entry[];		/* additional entries follow */
 };
 extern struct uv_systab *uv_systab;
 
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index 66f1efa16fbb..9322a9287dc7 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -242,7 +242,7 @@ static int __sgx_encl_add_page(struct sgx_encl *encl,
 /*
  * If the caller requires measurement of the page as a proof for the content,
  * use EEXTEND to add a measurement for 256 bytes of the page. Repeat this
- * operation until the entire page is measured."
+ * operation until the entire page is measured.
  */
 static int __sgx_encl_extend(struct sgx_encl *encl,
 			     struct sgx_epc_page *epc_page)
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 48113c5193aa..76153dfb58c9 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -1946,7 +1946,7 @@ static int dump_xsave_layout_desc(struct coredump_params *cprm)
 		};
 
 		if (!dump_emit(cprm, &xc, sizeof(xc)))
-			return 0;
+			return -1;
 
 		num_records++;
 	}
@@ -1984,7 +1984,7 @@ int elf_coredump_extra_notes_write(struct coredump_params *cprm)
 		return 1;
 
 	num_records = dump_xsave_layout_desc(cprm);
-	if (!num_records)
+	if (num_records < 0)
 		return 1;
 
 	/* Total size should be equal to the number of records */
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index 86f4e574de02..b2fe6181960c 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -397,6 +397,7 @@ DEFINE_IDTENTRY_SYSVEC_SIMPLE(sysvec_kvm_posted_intr_nested_ipi)
 
 /* Posted Interrupt Descriptors for coalesced MSIs to be posted */
 DEFINE_PER_CPU_ALIGNED(struct pi_desc, posted_msi_pi_desc);
+static DEFINE_PER_CPU_CACHE_HOT(bool, posted_msi_handler_active);
 
 void intel_posted_msi_init(void)
 {
@@ -414,6 +415,25 @@ void intel_posted_msi_init(void)
 	this_cpu_write(posted_msi_pi_desc.ndst, destination);
 }
 
+void intel_ack_posted_msi_irq(struct irq_data *irqd)
+{
+	irq_move_irq(irqd);
+
+	/*
+	 * Handle the rare case that irq_retrigger() raised the actual
+	 * assigned vector on the target CPU, which means that it was not
+	 * invoked via the posted MSI handler below. In that case APIC EOI
+	 * is required as otherwise the ISR entry becomes stale and lower
+	 * priority interrupts are never going to be delivered after that.
+	 *
+	 * If the posted handler invoked the device interrupt handler then
+	 * the EOI would be premature because it would acknowledge the
+	 * posted vector.
+	 */
+	if (unlikely(!__this_cpu_read(posted_msi_handler_active)))
+		apic_eoi();
+}
+
 static __always_inline bool handle_pending_pir(unsigned long *pir, struct pt_regs *regs)
 {
 	unsigned long pir_copy[NR_PIR_WORDS];
@@ -446,6 +466,8 @@ DEFINE_IDTENTRY_SYSVEC(sysvec_posted_msi_notification)
 
 	pid = this_cpu_ptr(&posted_msi_pi_desc);
 
+	/* Mark the handler active for intel_ack_posted_msi_irq() */
+	__this_cpu_write(posted_msi_handler_active, true);
 	inc_irq_stat(posted_msi_notification_count);
 	irq_enter();
 
@@ -474,6 +496,7 @@ DEFINE_IDTENTRY_SYSVEC(sysvec_posted_msi_notification)
 
 	apic_eoi();
 	irq_exit();
+	__this_cpu_write(posted_msi_handler_active, false);
 	set_irq_regs(old_regs);
 }
 #endif /* X86_POSTED_MSI */