x86/paravirt: Have only one paravirt patch function

There is no need any longer to have different paravirt patch functions
for native and Xen. Eliminate native_patch() and rename
paravirt_patch_default() to paravirt_patch().

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210311142319.4723-15-jgross@suse.com

Author: jgross1

arch/x86/include/asm/paravirt_types.h

@@ -68,19 +68,6 @@ struct pv_info {
 	const char *name;
 };
 
-struct pv_init_ops {
-	/*
-	 * Patch may replace one of the defined code sequences with
-	 * arbitrary code, subject to the same register constraints.
-	 * This generally means the code is not free to clobber any
-	 * registers other than EAX.  The patch function should return
-	 * the number of bytes of code generated, as we nop pad the
-	 * rest in generic code.
-	 */
-	unsigned (*patch)(u8 type, void *insn_buff,
-			  unsigned long addr, unsigned len);
-} __no_randomize_layout;
-
 #ifdef CONFIG_PARAVIRT_XXL
 struct pv_lazy_ops {
 	/* Set deferred update mode, used for batching operations. */
@@ -276,7 +263,6 @@ struct pv_lock_ops {
  * number for each function using the offset which we use to indicate
  * what to patch. */
 struct paravirt_patch_template {
-	struct pv_init_ops	init;
 	struct pv_cpu_ops	cpu;
 	struct pv_irq_ops	irq;
 	struct pv_mmu_ops	mmu;
@@ -317,10 +303,7 @@ extern void (*paravirt_iret)(void);
 /* Simple instruction patching code. */
 #define NATIVE_LABEL(a,x,b) "\n\t.globl " a #x "_" #b "\n" a #x "_" #b ":\n\t"
 
-unsigned paravirt_patch_default(u8 type, void *insn_buff, unsigned long addr, unsigned len);
-unsigned paravirt_patch_insns(void *insn_buff, unsigned len, const char *start, const char *end);
-
-unsigned native_patch(u8 type, void *insn_buff, unsigned long addr, unsigned len);
+unsigned int paravirt_patch(u8 type, void *insn_buff, unsigned long addr, unsigned int len);
 
 int paravirt_disable_iospace(void);
 

arch/x86/kernel/Makefile

@@ -35,7 +35,6 @@ KASAN_SANITIZE_sev-es.o					:= n
 KCSAN_SANITIZE := n
 
 OBJECT_FILES_NON_STANDARD_test_nx.o			:= y
-OBJECT_FILES_NON_STANDARD_paravirt_patch.o		:= y
 
 ifdef CONFIG_FRAME_POINTER
 OBJECT_FILES_NON_STANDARD_ftrace_$(BITS).o		:= y
@@ -121,7 +120,7 @@ obj-$(CONFIG_AMD_NB)		+= amd_nb.o
 obj-$(CONFIG_DEBUG_NMI_SELFTEST) += nmi_selftest.o
 
 obj-$(CONFIG_KVM_GUEST)		+= kvm.o kvmclock.o
-obj-$(CONFIG_PARAVIRT)		+= paravirt.o paravirt_patch.o
+obj-$(CONFIG_PARAVIRT)		+= paravirt.o
 obj-$(CONFIG_PARAVIRT_SPINLOCKS)+= paravirt-spinlocks.o
 obj-$(CONFIG_PARAVIRT_CLOCK)	+= pvclock.o
 obj-$(CONFIG_X86_PMEM_LEGACY_DEVICE) += pmem.o

arch/x86/kernel/alternative.c

@@ -616,7 +616,7 @@ void __init_or_module apply_paravirt(struct paravirt_patch_site *start,
 		BUG_ON(p->len > MAX_PATCH_LEN);
 		/* prep the buffer with the original instructions */
 		memcpy(insn_buff, p->instr, p->len);
-		used = pv_ops.init.patch(p->type, insn_buff, (unsigned long)p->instr, p->len);
+		used = paravirt_patch(p->type, insn_buff, (unsigned long)p->instr, p->len);
 
 		BUG_ON(used > p->len);
 

arch/x86/kernel/paravirt.c

@@ -99,8 +99,8 @@ void __init native_pv_lock_init(void)
 		static_branch_disable(&virt_spin_lock_key);
 }
 
-unsigned paravirt_patch_default(u8 type, void *insn_buff,
-				unsigned long addr, unsigned len)
+unsigned int paravirt_patch(u8 type, void *insn_buff, unsigned long addr,
+			    unsigned int len)
 {
 	/*
 	 * Neat trick to map patch type back to the call within the
@@ -121,19 +121,6 @@ unsigned paravirt_patch_default(u8 type, void *insn_buff,
 	return ret;
 }
 
-unsigned paravirt_patch_insns(void *insn_buff, unsigned len,
-			      const char *start, const char *end)
-{
-	unsigned insn_len = end - start;
-
-	/* Alternative instruction is too large for the patch site and we cannot continue: */
-	BUG_ON(insn_len > len || start == NULL);
-
-	memcpy(insn_buff, start, insn_len);
-
-	return insn_len;
-}
-
 struct static_key paravirt_steal_enabled;
 struct static_key paravirt_steal_rq_enabled;
 
@@ -252,9 +239,6 @@ struct pv_info pv_info = {
 #define PTE_IDENT	__PV_IS_CALLEE_SAVE(_paravirt_ident_64)
 
 struct paravirt_patch_template pv_ops = {
-	/* Init ops. */
-	.init.patch		= native_patch,
-
 	/* Cpu ops. */
 	.cpu.io_delay		= native_io_delay,
 

arch/x86/kernel/paravirt_patch.c

@@ -1231,7 +1231,6 @@ asmlinkage __visible void __init xen_start_kernel(void)
 
 	/* Install Xen paravirt ops */
 	pv_info = xen_info;
-	pv_ops.init.patch = paravirt_patch_default;
 	pv_ops.cpu = xen_cpu_ops;
 	paravirt_iret = xen_iret;
 	xen_init_irq_ops();