Merge branch 'stable/bug-fixes-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen

* 'stable/bug-fixes-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen: Allow PV-OPS kernel to detect whether XSAVE is supported
  xen: just completely disable XSAVE
  xen/debug: Don't be so verbose with WARN on 1-1 mapping errors.
  xen: events: fix error checks in bind_*_to_irqhandler()

arch/x86/xen/enlighten.c

@@ -238,6 +238,7 @@ static void xen_cpuid(unsigned int *ax, unsigned int *bx,
 static __init void xen_init_cpuid_mask(void)
 {
 	unsigned int ax, bx, cx, dx;
+	unsigned int xsave_mask;
 
 	cpuid_leaf1_edx_mask =
 		~((1 << X86_FEATURE_MCE)  |  /* disable MCE */
@@ -249,24 +250,16 @@ static __init void xen_init_cpuid_mask(void)
 		cpuid_leaf1_edx_mask &=
 			~((1 << X86_FEATURE_APIC) |  /* disable local APIC */
 			  (1 << X86_FEATURE_ACPI));  /* disable ACPI */
-
 	ax = 1;
-	cx = 0;
 	xen_cpuid(&ax, &bx, &cx, &dx);
 
-	/* cpuid claims we support xsave; try enabling it to see what happens */
-	if (cx & (1 << (X86_FEATURE_XSAVE % 32))) {
-		unsigned long cr4;
-
-		set_in_cr4(X86_CR4_OSXSAVE);
-		
-		cr4 = read_cr4();
+	xsave_mask =
+		(1 << (X86_FEATURE_XSAVE % 32)) |
+		(1 << (X86_FEATURE_OSXSAVE % 32));
 
-		if ((cr4 & X86_CR4_OSXSAVE) == 0)
-			cpuid_leaf1_ecx_mask &= ~(1 << (X86_FEATURE_XSAVE % 32));
-
-		clear_in_cr4(X86_CR4_OSXSAVE);
-	}
+	/* Xen will set CR4.OSXSAVE if supported and not disabled by force */
+	if ((cx & xsave_mask) != xsave_mask)
+		cpuid_leaf1_ecx_mask &= ~xsave_mask; /* disable XSAVE & OSXSAVE */
 }
 
 static void xen_set_debugreg(int reg, unsigned long val)

arch/x86/xen/mmu.c

@@ -565,13 +565,13 @@ pte_t xen_make_pte_debug(pteval_t pte)
 	if (io_page &&
 	    (xen_initial_domain() || addr >= ISA_END_ADDRESS)) {
 		other_addr = pfn_to_mfn(addr >> PAGE_SHIFT) << PAGE_SHIFT;
-		WARN(addr != other_addr,
+		WARN_ONCE(addr != other_addr,
 			"0x%lx is using VM_IO, but it is 0x%lx!\n",
 			(unsigned long)addr, (unsigned long)other_addr);
 	} else {
 		pteval_t iomap_set = (_pte.pte & PTE_FLAGS_MASK) & _PAGE_IOMAP;
 		other_addr = (_pte.pte & PTE_PFN_MASK);
-		WARN((addr == other_addr) && (!io_page) && (!iomap_set),
+		WARN_ONCE((addr == other_addr) && (!io_page) && (!iomap_set),
 			"0x%lx is missing VM_IO (and wasn't fixed)!\n",
 			(unsigned long)addr);
 	}

drivers/xen/events.c

@@ -912,8 +912,7 @@ int bind_evtchn_to_irqhandler(unsigned int evtchn,
 			      unsigned long irqflags,
 			      const char *devname, void *dev_id)
 {
-	unsigned int irq;
-	int retval;
+	int irq, retval;
 
 	irq = bind_evtchn_to_irq(evtchn);
 	if (irq < 0)
@@ -955,8 +954,7 @@ int bind_virq_to_irqhandler(unsigned int virq, unsigned int cpu,
 			    irq_handler_t handler,
 			    unsigned long irqflags, const char *devname, void *dev_id)
 {
-	unsigned int irq;
-	int retval;
+	int irq, retval;
 
 	irq = bind_virq_to_irq(virq, cpu);
 	if (irq < 0)