Merge tag 'for-linus-6.6a-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen fixes from Juergen Gross:

 - remove some unused functions in the Xen event channel handling

 - fix a regression (introduced during the merge window) when booting as
   Xen PV guest

 - small cleanup removing another strncpy() instance

* tag 'for-linus-6.6a-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/efi: refactor deprecated strncpy
  x86/xen: allow nesting of same lazy mode
  x86/xen: move paravirt lazy code
  arm/xen: remove lazy mode related definitions
  xen: simplify evtchn_do_upcall() call maze

Author: torvalds

arch/arm/xen/enlighten.c

@@ -207,7 +207,7 @@ static void xen_power_off(void)
 
 static irqreturn_t xen_arm_callback(int irq, void *arg)
 {
-	xen_hvm_evtchn_do_upcall();
+	xen_evtchn_do_upcall();
 	return IRQ_HANDLED;
 }
 

arch/x86/entry/common.c

@@ -294,7 +294,7 @@ static void __xen_pv_evtchn_do_upcall(struct pt_regs *regs)
 
 	inc_irq_stat(irq_hv_callback_count);
 
-	xen_hvm_evtchn_do_upcall();
+	xen_evtchn_do_upcall();
 
 	set_irq_regs(old_regs);
 }

arch/x86/include/asm/paravirt_types.h

@@ -9,13 +9,6 @@ struct paravirt_patch_site {
 	u8 type;		/* type of this instruction */
 	u8 len;			/* length of original instruction */
 };
-
-/* Lazy mode for batching updates / context switch */
-enum paravirt_lazy_mode {
-	PARAVIRT_LAZY_NONE,
-	PARAVIRT_LAZY_MMU,
-	PARAVIRT_LAZY_CPU,
-};
 #endif
 
 #ifdef CONFIG_PARAVIRT
@@ -549,14 +542,6 @@ int paravirt_disable_iospace(void);
 	__PVOP_VCALL(op, PVOP_CALL_ARG1(arg1), PVOP_CALL_ARG2(arg2),	\
 		     PVOP_CALL_ARG3(arg3), PVOP_CALL_ARG4(arg4))
 
-enum paravirt_lazy_mode paravirt_get_lazy_mode(void);
-void paravirt_start_context_switch(struct task_struct *prev);
-void paravirt_end_context_switch(struct task_struct *next);
-
-void paravirt_enter_lazy_mmu(void);
-void paravirt_leave_lazy_mmu(void);
-void paravirt_flush_lazy_mmu(void);
-
 void _paravirt_nop(void);
 void paravirt_BUG(void);
 unsigned long paravirt_ret0(void);

arch/x86/include/asm/xen/hypervisor.h

@@ -36,6 +36,7 @@
 extern struct shared_info *HYPERVISOR_shared_info;
 extern struct start_info *xen_start_info;
 
+#include <asm/bug.h>
 #include <asm/processor.h>
 
 #define XEN_SIGNATURE "XenVMMXenVMM"
@@ -63,4 +64,40 @@ void __init xen_pvh_init(struct boot_params *boot_params);
 void __init mem_map_via_hcall(struct boot_params *boot_params_p);
 #endif
 
+/* Lazy mode for batching updates / context switch */
+enum xen_lazy_mode {
+	XEN_LAZY_NONE,
+	XEN_LAZY_MMU,
+	XEN_LAZY_CPU,
+};
+
+DECLARE_PER_CPU(enum xen_lazy_mode, xen_lazy_mode);
+DECLARE_PER_CPU(unsigned int, xen_lazy_nesting);
+
+static inline void enter_lazy(enum xen_lazy_mode mode)
+{
+	enum xen_lazy_mode old_mode = this_cpu_read(xen_lazy_mode);
+
+	if (mode == old_mode) {
+		this_cpu_inc(xen_lazy_nesting);
+		return;
+	}
+
+	BUG_ON(old_mode != XEN_LAZY_NONE);
+
+	this_cpu_write(xen_lazy_mode, mode);
+}
+
+static inline void leave_lazy(enum xen_lazy_mode mode)
+{
+	BUG_ON(this_cpu_read(xen_lazy_mode) != mode);
+
+	if (this_cpu_read(xen_lazy_nesting) == 0)
+		this_cpu_write(xen_lazy_mode, XEN_LAZY_NONE);
+	else
+		this_cpu_dec(xen_lazy_nesting);
+}
+
+enum xen_lazy_mode xen_get_lazy_mode(void);
+
 #endif /* _ASM_X86_XEN_HYPERVISOR_H */

arch/x86/kernel/paravirt.c

@@ -143,66 +143,7 @@ int paravirt_disable_iospace(void)
 	return request_resource(&ioport_resource, &reserve_ioports);
 }
 
-static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LAZY_NONE;
-
-static inline void enter_lazy(enum paravirt_lazy_mode mode)
-{
-	BUG_ON(this_cpu_read(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE);
-
-	this_cpu_write(paravirt_lazy_mode, mode);
-}
-
-static void leave_lazy(enum paravirt_lazy_mode mode)
-{
-	BUG_ON(this_cpu_read(paravirt_lazy_mode) != mode);
-
-	this_cpu_write(paravirt_lazy_mode, PARAVIRT_LAZY_NONE);
-}
-
-void paravirt_enter_lazy_mmu(void)
-{
-	enter_lazy(PARAVIRT_LAZY_MMU);
-}
-
-void paravirt_leave_lazy_mmu(void)
-{
-	leave_lazy(PARAVIRT_LAZY_MMU);
-}
-
-void paravirt_flush_lazy_mmu(void)
-{
-	preempt_disable();
-
-	if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) {
-		arch_leave_lazy_mmu_mode();
-		arch_enter_lazy_mmu_mode();
-	}
-
-	preempt_enable();
-}
-
 #ifdef CONFIG_PARAVIRT_XXL
-void paravirt_start_context_switch(struct task_struct *prev)
-{
-	BUG_ON(preemptible());
-
-	if (this_cpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) {
-		arch_leave_lazy_mmu_mode();
-		set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES);
-	}
-	enter_lazy(PARAVIRT_LAZY_CPU);
-}
-
-void paravirt_end_context_switch(struct task_struct *next)
-{
-	BUG_ON(preemptible());
-
-	leave_lazy(PARAVIRT_LAZY_CPU);
-
-	if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES))
-		arch_enter_lazy_mmu_mode();
-}
-
 static noinstr void pv_native_write_cr2(unsigned long val)
 {
 	native_write_cr2(val);
@@ -229,14 +170,6 @@ static noinstr void pv_native_safe_halt(void)
 }
 #endif
 
-enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
-{
-	if (in_interrupt())
-		return PARAVIRT_LAZY_NONE;
-
-	return this_cpu_read(paravirt_lazy_mode);
-}
-
 struct pv_info pv_info = {
 	.name = "bare hardware",
 #ifdef CONFIG_PARAVIRT_XXL

arch/x86/xen/efi.c

@@ -138,7 +138,7 @@ void __init xen_efi_init(struct boot_params *boot_params)
 	if (efi_systab_xen == NULL)
 		return;
 
-	strncpy((char *)&boot_params->efi_info.efi_loader_signature, "Xen",
+	strscpy((char *)&boot_params->efi_info.efi_loader_signature, "Xen",
 			sizeof(boot_params->efi_info.efi_loader_signature));
 	boot_params->efi_info.efi_systab = (__u32)__pa(efi_systab_xen);
 	boot_params->efi_info.efi_systab_hi = (__u32)(__pa(efi_systab_xen) >> 32);

arch/x86/xen/enlighten.c

@@ -32,7 +32,7 @@ EXPORT_SYMBOL_GPL(hypercall_page);
  * &HYPERVISOR_shared_info->vcpu_info[cpu]. See xen_hvm_init_shared_info
  * and xen_vcpu_setup for details. By default it points to share_info->vcpu_info
  * but during boot it is switched to point to xen_vcpu_info.
- * The pointer is used in __xen_evtchn_do_upcall to acknowledge pending events.
+ * The pointer is used in xen_evtchn_do_upcall to acknowledge pending events.
  */
 DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu);
 DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info);

arch/x86/xen/enlighten_hvm.c

@@ -136,7 +136,7 @@ DEFINE_IDTENTRY_SYSVEC(sysvec_xen_hvm_callback)
 
 	inc_irq_stat(irq_hv_callback_count);
 
-	xen_hvm_evtchn_do_upcall();
+	xen_evtchn_do_upcall();
 
 	set_irq_regs(old_regs);
 }

arch/x86/xen/enlighten_pv.c

@@ -101,6 +101,17 @@ struct tls_descs {
 	struct desc_struct desc[3];
 };
 
+DEFINE_PER_CPU(enum xen_lazy_mode, xen_lazy_mode) = XEN_LAZY_NONE;
+DEFINE_PER_CPU(unsigned int, xen_lazy_nesting);
+
+enum xen_lazy_mode xen_get_lazy_mode(void)
+{
+	if (in_interrupt())
+		return XEN_LAZY_NONE;
+
+	return this_cpu_read(xen_lazy_mode);
+}
+
 /*
  * Updating the 3 TLS descriptors in the GDT on every task switch is
  * surprisingly expensive so we avoid updating them if they haven't
@@ -362,10 +373,25 @@ static noinstr unsigned long xen_get_debugreg(int reg)
 	return HYPERVISOR_get_debugreg(reg);
 }
 
+static void xen_start_context_switch(struct task_struct *prev)
+{
+	BUG_ON(preemptible());
+
+	if (this_cpu_read(xen_lazy_mode) == XEN_LAZY_MMU) {
+		arch_leave_lazy_mmu_mode();
+		set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES);
+	}
+	enter_lazy(XEN_LAZY_CPU);
+}
+
 static void xen_end_context_switch(struct task_struct *next)
 {
+	BUG_ON(preemptible());
+
 	xen_mc_flush();
-	paravirt_end_context_switch(next);
+	leave_lazy(XEN_LAZY_CPU);
+	if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES))
+		arch_enter_lazy_mmu_mode();
 }
 
 static unsigned long xen_store_tr(void)
@@ -472,7 +498,7 @@ static void xen_set_ldt(const void *addr, unsigned entries)
 
 	MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
 
-	xen_mc_issue(PARAVIRT_LAZY_CPU);
+	xen_mc_issue(XEN_LAZY_CPU);
 }
 
 static void xen_load_gdt(const struct desc_ptr *dtr)
@@ -568,7 +594,7 @@ static void xen_load_tls(struct thread_struct *t, unsigned int cpu)
 	 * exception between the new %fs descriptor being loaded and
 	 * %fs being effectively cleared at __switch_to().
 	 */
-	if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU)
+	if (xen_get_lazy_mode() == XEN_LAZY_CPU)
 		loadsegment(fs, 0);
 
 	xen_mc_batch();
@@ -577,7 +603,7 @@ static void xen_load_tls(struct thread_struct *t, unsigned int cpu)
 	load_TLS_descriptor(t, cpu, 1);
 	load_TLS_descriptor(t, cpu, 2);
 
-	xen_mc_issue(PARAVIRT_LAZY_CPU);
+	xen_mc_issue(XEN_LAZY_CPU);
 }
 
 static void xen_load_gs_index(unsigned int idx)
@@ -909,7 +935,7 @@ static void xen_load_sp0(unsigned long sp0)
 
 	mcs = xen_mc_entry(0);
 	MULTI_stack_switch(mcs.mc, __KERNEL_DS, sp0);
-	xen_mc_issue(PARAVIRT_LAZY_CPU);
+	xen_mc_issue(XEN_LAZY_CPU);
 	this_cpu_write(cpu_tss_rw.x86_tss.sp0, sp0);
 }
 
@@ -973,7 +999,7 @@ static void xen_write_cr0(unsigned long cr0)
 
 	MULTI_fpu_taskswitch(mcs.mc, (cr0 & X86_CR0_TS) != 0);
 
-	xen_mc_issue(PARAVIRT_LAZY_CPU);
+	xen_mc_issue(XEN_LAZY_CPU);
 }
 
 static void xen_write_cr4(unsigned long cr4)
@@ -1156,7 +1182,7 @@ static const typeof(pv_ops) xen_cpu_ops __initconst = {
 #endif
 		.io_delay = xen_io_delay,
 
-		.start_context_switch = paravirt_start_context_switch,
+		.start_context_switch = xen_start_context_switch,
 		.end_context_switch = xen_end_context_switch,
 	},
 };