From 5c22c4726e4a9c6b2e182c0b21c2d3dd63f608c4 Mon Sep 17 00:00:00 2001
From: Hou Wenlong <houwenlong.hwl@antgroup.com>
Date: Fri, 9 Jun 2023 17:45:31 +0800
Subject: x86/paravirt: Use relative reference for the original instruction
 offset

Similar to the alternative patching, use a relative reference for original
instruction offset rather than absolute one, which saves 8 bytes for one
PARA_SITE entry on x86_64.  As a result, a R_X86_64_PC32 relocation is
generated instead of an R_X86_64_64 one, which also reduces relocation
metadata on relocatable builds. Hardcode the alignment to 4 now.

  [ bp: Massage commit message. ]

Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/9e6053107fbaabc0d33e5d2865c5af2c67ec9925.1686301237.git.houwenlong.hwl@antgroup.com
---
 arch/x86/include/asm/paravirt.h       | 10 +++++-----
 arch/x86/include/asm/paravirt_types.h |  8 ++++----
 arch/x86/kernel/alternative.c         |  8 +++++---
 arch/x86/kernel/callthunks.c          |  2 +-
 4 files changed, 15 insertions(+), 13 deletions(-)

(limited to 'arch/x86')

diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 6c8ff12140ae..d9384e9d97f6 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -743,16 +743,16 @@ void native_pv_lock_init(void) __init;
 
 #else  /* __ASSEMBLY__ */
 
-#define _PVSITE(ptype, ops, word, algn)		\
+#define _PVSITE(ptype, ops)			\
 771:;						\
 	ops;					\
 772:;						\
 	.pushsection .parainstructions,"a";	\
-	 .align	algn;				\
-	 word 771b;				\
+	 .align	4;				\
+	 .long 771b-.;				\
 	 .byte ptype;				\
 	 .byte 772b-771b;			\
-	 _ASM_ALIGN;				\
+	 .align 4;				\
 	.popsection
 
 
@@ -760,7 +760,7 @@ void native_pv_lock_init(void) __init;
 #ifdef CONFIG_PARAVIRT_XXL
 
 #define PARA_PATCH(off)		((off) / 8)
-#define PARA_SITE(ptype, ops)	_PVSITE(ptype, ops, .quad, 8)
+#define PARA_SITE(ptype, ops)	_PVSITE(ptype, ops)
 #define PARA_INDIRECT(addr)	*addr(%rip)
 
 #ifdef CONFIG_DEBUG_ENTRY
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 772d03487520..e1bfb719fca3 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -5,7 +5,7 @@
 #ifndef __ASSEMBLY__
 /* These all sit in the .parainstructions section to tell us what to patch. */
 struct paravirt_patch_site {
-	u8 *instr;		/* original instructions */
+	s32 instr_offset;	/* original instructions */
 	u8 type;		/* type of this instruction */
 	u8 len;			/* length of original instruction */
 };
@@ -263,11 +263,11 @@ extern struct paravirt_patch_template pv_ops;
 #define _paravirt_alt(insn_string, type)		\
 	"771:\n\t" insn_string "\n" "772:\n"		\
 	".pushsection .parainstructions,\"a\"\n"	\
-	_ASM_ALIGN "\n"					\
-	_ASM_PTR " 771b\n"				\
+	"  .align 4\n"					\
+	"  .long 771b-.\n"				\
 	"  .byte " type "\n"				\
 	"  .byte 772b-771b\n"				\
-	_ASM_ALIGN "\n"					\
+	"  .align 4\n"					\
 	".popsection\n"
 
 /* Generate patchable code, with the default asm parameters. */
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 73be3931e4f0..be35c8ccf826 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -1431,20 +1431,22 @@ void __init_or_module apply_paravirt(struct paravirt_patch_site *start,
 {
 	struct paravirt_patch_site *p;
 	char insn_buff[MAX_PATCH_LEN];
+	u8 *instr;
 
 	for (p = start; p < end; p++) {
 		unsigned int used;
 
+		instr = (u8 *)&p->instr_offset + p->instr_offset;
 		BUG_ON(p->len > MAX_PATCH_LEN);
 		/* prep the buffer with the original instructions */
-		memcpy(insn_buff, p->instr, p->len);
-		used = paravirt_patch(p->type, insn_buff, (unsigned long)p->instr, p->len);
+		memcpy(insn_buff, instr, p->len);
+		used = paravirt_patch(p->type, insn_buff, (unsigned long)instr, p->len);
 
 		BUG_ON(used > p->len);
 
 		/* Pad the rest with nops */
 		add_nops(insn_buff + used, p->len - used);
-		text_poke_early(p->instr, insn_buff, p->len);
+		text_poke_early(instr, insn_buff, p->len);
 	}
 }
 extern struct paravirt_patch_site __start_parainstructions[],
diff --git a/arch/x86/kernel/callthunks.c b/arch/x86/kernel/callthunks.c
index e9ad518a5003..57e5c2e75c2a 100644
--- a/arch/x86/kernel/callthunks.c
+++ b/arch/x86/kernel/callthunks.c
@@ -240,7 +240,7 @@ patch_paravirt_call_sites(struct paravirt_patch_site *start,
 	struct paravirt_patch_site *p;
 
 	for (p = start; p < end; p++)
-		patch_call(p->instr, ct);
+		patch_call((void *)&p->instr_offset + p->instr_offset, ct);
 }
 
 static __init_or_module void
-- 
cgit v1.2.3


From fe22bc430c9d24394e541e16e0941a075f02fcb7 Mon Sep 17 00:00:00 2001
From: Hou Wenlong <houwenlong.hwl@antgroup.com>
Date: Fri, 9 Jun 2023 17:45:32 +0800
Subject: x86/paravirt: Make the struct paravirt_patch_site packed

Similar to struct alt_instr, make the struct paravirt_patch_site packed
and get rid of all the .align directives and save 2 bytes for one
PARA_SITE entry on X86_64.

  [ bp: Massage commit message. ]

Suggested-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/6dcb20159ded36586c5f7f2ae159e4e030256627.1686301237.git.houwenlong.hwl@antgroup.com
---
 arch/x86/include/asm/paravirt.h       | 2 --
 arch/x86/include/asm/paravirt_types.h | 4 +---
 2 files changed, 1 insertion(+), 5 deletions(-)

(limited to 'arch/x86')

diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index d9384e9d97f6..693c61dbdd9c 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -748,11 +748,9 @@ void native_pv_lock_init(void) __init;
 	ops;					\
 772:;						\
 	.pushsection .parainstructions,"a";	\
-	 .align	4;				\
 	 .long 771b-.;				\
 	 .byte ptype;				\
 	 .byte 772b-771b;			\
-	 .align 4;				\
 	.popsection
 
 
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index e1bfb719fca3..f4fb2e3ec7b8 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -8,7 +8,7 @@ struct paravirt_patch_site {
 	s32 instr_offset;	/* original instructions */
 	u8 type;		/* type of this instruction */
 	u8 len;			/* length of original instruction */
-};
+} __packed;
 #endif
 
 #ifdef CONFIG_PARAVIRT
@@ -263,11 +263,9 @@ extern struct paravirt_patch_template pv_ops;
 #define _paravirt_alt(insn_string, type)		\
 	"771:\n\t" insn_string "\n" "772:\n"		\
 	".pushsection .parainstructions,\"a\"\n"	\
-	"  .align 4\n"					\
 	"  .long 771b-.\n"				\
 	"  .byte " type "\n"				\
 	"  .byte 772b-771b\n"				\
-	"  .align 4\n"					\
 	".popsection\n"
 
 /* Generate patchable code, with the default asm parameters. */
-- 
cgit v1.2.3


From 772ca413537eca9010e93922699537f56db9c8c4 Mon Sep 17 00:00:00 2001
From: Juergen Gross <jgross@suse.com>
Date: Wed, 29 Nov 2023 14:33:28 +0100
Subject: x86/paravirt: Introduce ALT_NOT_XEN

Introduce the macro ALT_NOT_XEN as a short form of
ALT_NOT(X86_FEATURE_XENPV).

No functional changes.

Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20231129133332.31043-2-jgross@suse.com
---
 arch/x86/include/asm/paravirt.h       | 42 +++++++++++++++--------------------
 arch/x86/include/asm/paravirt_types.h |  3 +++
 2 files changed, 21 insertions(+), 24 deletions(-)

(limited to 'arch/x86')

diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 693c61dbdd9c..aa76ac7c806c 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -142,8 +142,7 @@ static inline void write_cr0(unsigned long x)
 static __always_inline unsigned long read_cr2(void)
 {
 	return PVOP_ALT_CALLEE0(unsigned long, mmu.read_cr2,
-				"mov %%cr2, %%rax;",
-				ALT_NOT(X86_FEATURE_XENPV));
+				"mov %%cr2, %%rax;", ALT_NOT_XEN);
 }
 
 static __always_inline void write_cr2(unsigned long x)
@@ -154,13 +153,12 @@ static __always_inline void write_cr2(unsigned long x)
 static inline unsigned long __read_cr3(void)
 {
 	return PVOP_ALT_CALL0(unsigned long, mmu.read_cr3,
-			      "mov %%cr3, %%rax;", ALT_NOT(X86_FEATURE_XENPV));
+			      "mov %%cr3, %%rax;", ALT_NOT_XEN);
 }
 
 static inline void write_cr3(unsigned long x)
 {
-	PVOP_ALT_VCALL1(mmu.write_cr3, x,
-			"mov %%rdi, %%cr3", ALT_NOT(X86_FEATURE_XENPV));
+	PVOP_ALT_VCALL1(mmu.write_cr3, x, "mov %%rdi, %%cr3", ALT_NOT_XEN);
 }
 
 static inline void __write_cr4(unsigned long x)
@@ -182,7 +180,7 @@ extern noinstr void pv_native_wbinvd(void);
 
 static __always_inline void wbinvd(void)
 {
-	PVOP_ALT_VCALL0(cpu.wbinvd, "wbinvd", ALT_NOT(X86_FEATURE_XENPV));
+	PVOP_ALT_VCALL0(cpu.wbinvd, "wbinvd", ALT_NOT_XEN);
 }
 
 static inline u64 paravirt_read_msr(unsigned msr)
@@ -390,27 +388,25 @@ static inline void paravirt_release_p4d(unsigned long pfn)
 static inline pte_t __pte(pteval_t val)
 {
 	return (pte_t) { PVOP_ALT_CALLEE1(pteval_t, mmu.make_pte, val,
-					  "mov %%rdi, %%rax",
-					  ALT_NOT(X86_FEATURE_XENPV)) };
+					  "mov %%rdi, %%rax", ALT_NOT_XEN) };
 }
 
 static inline pteval_t pte_val(pte_t pte)
 {
 	return PVOP_ALT_CALLEE1(pteval_t, mmu.pte_val, pte.pte,
-				"mov %%rdi, %%rax", ALT_NOT(X86_FEATURE_XENPV));
+				"mov %%rdi, %%rax", ALT_NOT_XEN);
 }
 
 static inline pgd_t __pgd(pgdval_t val)
 {
 	return (pgd_t) { PVOP_ALT_CALLEE1(pgdval_t, mmu.make_pgd, val,
-					  "mov %%rdi, %%rax",
-					  ALT_NOT(X86_FEATURE_XENPV)) };
+					  "mov %%rdi, %%rax", ALT_NOT_XEN) };
 }
 
 static inline pgdval_t pgd_val(pgd_t pgd)
 {
 	return PVOP_ALT_CALLEE1(pgdval_t, mmu.pgd_val, pgd.pgd,
-				"mov %%rdi, %%rax", ALT_NOT(X86_FEATURE_XENPV));
+				"mov %%rdi, %%rax", ALT_NOT_XEN);
 }
 
 #define  __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION
@@ -444,14 +440,13 @@ static inline void set_pmd(pmd_t *pmdp, pmd_t pmd)
 static inline pmd_t __pmd(pmdval_t val)
 {
 	return (pmd_t) { PVOP_ALT_CALLEE1(pmdval_t, mmu.make_pmd, val,
-					  "mov %%rdi, %%rax",
-					  ALT_NOT(X86_FEATURE_XENPV)) };
+					  "mov %%rdi, %%rax", ALT_NOT_XEN) };
 }
 
 static inline pmdval_t pmd_val(pmd_t pmd)
 {
 	return PVOP_ALT_CALLEE1(pmdval_t, mmu.pmd_val, pmd.pmd,
-				"mov %%rdi, %%rax", ALT_NOT(X86_FEATURE_XENPV));
+				"mov %%rdi, %%rax", ALT_NOT_XEN);
 }
 
 static inline void set_pud(pud_t *pudp, pud_t pud)
@@ -464,7 +459,7 @@ static inline pud_t __pud(pudval_t val)
 	pudval_t ret;
 
 	ret = PVOP_ALT_CALLEE1(pudval_t, mmu.make_pud, val,
-			       "mov %%rdi, %%rax", ALT_NOT(X86_FEATURE_XENPV));
+			       "mov %%rdi, %%rax", ALT_NOT_XEN);
 
 	return (pud_t) { ret };
 }
@@ -472,7 +467,7 @@ static inline pud_t __pud(pudval_t val)
 static inline pudval_t pud_val(pud_t pud)
 {
 	return PVOP_ALT_CALLEE1(pudval_t, mmu.pud_val, pud.pud,
-				"mov %%rdi, %%rax", ALT_NOT(X86_FEATURE_XENPV));
+				"mov %%rdi, %%rax", ALT_NOT_XEN);
 }
 
 static inline void pud_clear(pud_t *pudp)
@@ -492,8 +487,7 @@ static inline void set_p4d(p4d_t *p4dp, p4d_t p4d)
 static inline p4d_t __p4d(p4dval_t val)
 {
 	p4dval_t ret = PVOP_ALT_CALLEE1(p4dval_t, mmu.make_p4d, val,
-					"mov %%rdi, %%rax",
-					ALT_NOT(X86_FEATURE_XENPV));
+					"mov %%rdi, %%rax", ALT_NOT_XEN);
 
 	return (p4d_t) { ret };
 }
@@ -501,7 +495,7 @@ static inline p4d_t __p4d(p4dval_t val)
 static inline p4dval_t p4d_val(p4d_t p4d)
 {
 	return PVOP_ALT_CALLEE1(p4dval_t, mmu.p4d_val, p4d.p4d,
-				"mov %%rdi, %%rax", ALT_NOT(X86_FEATURE_XENPV));
+				"mov %%rdi, %%rax", ALT_NOT_XEN);
 }
 
 static inline void __set_pgd(pgd_t *pgdp, pgd_t pgd)
@@ -687,17 +681,17 @@ bool __raw_callee_save___native_vcpu_is_preempted(long cpu);
 static __always_inline unsigned long arch_local_save_flags(void)
 {
 	return PVOP_ALT_CALLEE0(unsigned long, irq.save_fl, "pushf; pop %%rax;",
-				ALT_NOT(X86_FEATURE_XENPV));
+				ALT_NOT_XEN);
 }
 
 static __always_inline void arch_local_irq_disable(void)
 {
-	PVOP_ALT_VCALLEE0(irq.irq_disable, "cli;", ALT_NOT(X86_FEATURE_XENPV));
+	PVOP_ALT_VCALLEE0(irq.irq_disable, "cli;", ALT_NOT_XEN);
 }
 
 static __always_inline void arch_local_irq_enable(void)
 {
-	PVOP_ALT_VCALLEE0(irq.irq_enable, "sti;", ALT_NOT(X86_FEATURE_XENPV));
+	PVOP_ALT_VCALLEE0(irq.irq_enable, "sti;", ALT_NOT_XEN);
 }
 
 static __always_inline unsigned long arch_local_irq_save(void)
@@ -769,7 +763,7 @@ void native_pv_lock_init(void) __init;
 .endm
 
 #define SAVE_FLAGS	ALTERNATIVE "PARA_IRQ_save_fl;", "pushf; pop %rax;", \
-				    ALT_NOT(X86_FEATURE_XENPV)
+				    ALT_NOT_XEN
 #endif
 #endif /* CONFIG_PARAVIRT_XXL */
 #endif	/* CONFIG_X86_64 */
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index f4fb2e3ec7b8..483e19e5ca7a 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -557,5 +557,8 @@ extern struct paravirt_patch_site __parainstructions[],
 	__parainstructions_end[];
 
 #endif	/* __ASSEMBLY__ */
+
+#define ALT_NOT_XEN	ALT_NOT(X86_FEATURE_XENPV)
+
 #endif  /* CONFIG_PARAVIRT */
 #endif	/* _ASM_X86_PARAVIRT_TYPES_H */
-- 
cgit v1.2.3


From 9824b00c2b58f9e1072ef3ece571a2cfc71089d4 Mon Sep 17 00:00:00 2001
From: Juergen Gross <jgross@suse.com>
Date: Wed, 29 Nov 2023 14:33:29 +0100
Subject: x86/paravirt: Move some functions and defines to alternative.c

As a preparation for replacing paravirt patching completely by
alternative patching, move some backend functions and #defines to
the alternatives code and header.

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20231129133332.31043-3-jgross@suse.com
---
 arch/x86/include/asm/alternative.h        | 16 ++++++++++++++++
 arch/x86/include/asm/paravirt.h           | 12 ------------
 arch/x86/include/asm/paravirt_types.h     |  4 +---
 arch/x86/include/asm/qspinlock_paravirt.h |  4 ++--
 arch/x86/kernel/alternative.c             | 10 ++++++++++
 arch/x86/kernel/kvm.c                     |  4 ++--
 arch/x86/kernel/paravirt.c                | 30 +++++++++---------------------
 arch/x86/xen/irq.c                        |  2 +-
 8 files changed, 41 insertions(+), 41 deletions(-)

(limited to 'arch/x86')

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 65f79092c9d9..ce788ab4e77c 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -330,6 +330,22 @@ static inline int alternatives_text_reserved(void *start, void *end)
  */
 #define ASM_NO_INPUT_CLOBBER(clbr...) "i" (0) : clbr
 
+/* Macro for creating assembler functions avoiding any C magic. */
+#define DEFINE_ASM_FUNC(func, instr, sec)		\
+	asm (".pushsection " #sec ", \"ax\"\n"		\
+	     ".global " #func "\n\t"			\
+	     ".type " #func ", @function\n\t"		\
+	     ASM_FUNC_ALIGN "\n"			\
+	     #func ":\n\t"				\
+	     ASM_ENDBR					\
+	     instr "\n\t"				\
+	     ASM_RET					\
+	     ".size " #func ", . - " #func "\n\t"	\
+	     ".popsection")
+
+void BUG_func(void);
+void nop_func(void);
+
 #else /* __ASSEMBLY__ */
 
 #ifdef CONFIG_SMP
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index aa76ac7c806c..f18bfa7f3070 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -720,18 +720,6 @@ static __always_inline unsigned long arch_local_irq_save(void)
 #undef PVOP_VCALL4
 #undef PVOP_CALL4
 
-#define DEFINE_PARAVIRT_ASM(func, instr, sec)		\
-	asm (".pushsection " #sec ", \"ax\"\n"		\
-	     ".global " #func "\n\t"			\
-	     ".type " #func ", @function\n\t"		\
-	     ASM_FUNC_ALIGN "\n"			\
-	     #func ":\n\t"				\
-	     ASM_ENDBR					\
-	     instr "\n\t"				\
-	     ASM_RET					\
-	     ".size " #func ", . - " #func "\n\t"	\
-	     ".popsection")
-
 extern void default_banner(void);
 void native_pv_lock_init(void) __init;
 
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 483e19e5ca7a..166e9618158f 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -540,8 +540,6 @@ int paravirt_disable_iospace(void);
 	__PVOP_VCALL(op, PVOP_CALL_ARG1(arg1), PVOP_CALL_ARG2(arg2),	\
 		     PVOP_CALL_ARG3(arg3), PVOP_CALL_ARG4(arg4))
 
-void _paravirt_nop(void);
-void paravirt_BUG(void);
 unsigned long paravirt_ret0(void);
 #ifdef CONFIG_PARAVIRT_XXL
 u64 _paravirt_ident_64(u64);
@@ -551,7 +549,7 @@ void pv_native_irq_enable(void);
 unsigned long pv_native_read_cr2(void);
 #endif
 
-#define paravirt_nop	((void *)_paravirt_nop)
+#define paravirt_nop	((void *)nop_func)
 
 extern struct paravirt_patch_site __parainstructions[],
 	__parainstructions_end[];
diff --git a/arch/x86/include/asm/qspinlock_paravirt.h b/arch/x86/include/asm/qspinlock_paravirt.h
index 85b6e3609cb9..ef9697f20129 100644
--- a/arch/x86/include/asm/qspinlock_paravirt.h
+++ b/arch/x86/include/asm/qspinlock_paravirt.h
@@ -56,8 +56,8 @@ __PV_CALLEE_SAVE_REGS_THUNK(__pv_queued_spin_unlock_slowpath, ".spinlock.text");
 	"pop    %rdx\n\t"						\
 	FRAME_END
 
-DEFINE_PARAVIRT_ASM(__raw_callee_save___pv_queued_spin_unlock,
-		    PV_UNLOCK_ASM, .spinlock.text);
+DEFINE_ASM_FUNC(__raw_callee_save___pv_queued_spin_unlock,
+		PV_UNLOCK_ASM, .spinlock.text);
 
 #else /* CONFIG_64BIT */
 
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index be35c8ccf826..ca25dd280b8c 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -385,6 +385,16 @@ apply_relocation(u8 *buf, size_t len, u8 *dest, u8 *src, size_t src_len)
 	}
 }
 
+/* Low-level backend functions usable from alternative code replacements. */
+DEFINE_ASM_FUNC(nop_func, "", .entry.text);
+EXPORT_SYMBOL_GPL(nop_func);
+
+noinstr void BUG_func(void)
+{
+	BUG();
+}
+EXPORT_SYMBOL_GPL(BUG_func);
+
 /*
  * Replace instructions with better alternatives for this CPU type. This runs
  * before SMP is initialized to avoid SMP problems with self modifying code.
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 0ddb3bd0f1aa..c461c1a4b6af 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -803,8 +803,8 @@ extern bool __raw_callee_save___kvm_vcpu_is_preempted(long);
  "cmpb   $0, " __stringify(KVM_STEAL_TIME_preempted) "+steal_time(%rax)\n\t" \
  "setne  %al\n\t"
 
-DEFINE_PARAVIRT_ASM(__raw_callee_save___kvm_vcpu_is_preempted,
-		    PV_VCPU_PREEMPTED_ASM, .text);
+DEFINE_ASM_FUNC(__raw_callee_save___kvm_vcpu_is_preempted,
+		PV_VCPU_PREEMPTED_ASM, .text);
 #endif
 
 static void __init kvm_guest_init(void)
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 97f1436c1a20..acc5b1004f0f 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -34,14 +34,8 @@
 #include <asm/io_bitmap.h>
 #include <asm/gsseg.h>
 
-/*
- * nop stub, which must not clobber anything *including the stack* to
- * avoid confusing the entry prologues.
- */
-DEFINE_PARAVIRT_ASM(_paravirt_nop, "", .entry.text);
-
 /* stub always returning 0. */
-DEFINE_PARAVIRT_ASM(paravirt_ret0, "xor %eax,%eax", .entry.text);
+DEFINE_ASM_FUNC(paravirt_ret0, "xor %eax,%eax", .entry.text);
 
 void __init default_banner(void)
 {
@@ -49,12 +43,6 @@ void __init default_banner(void)
 	       pv_info.name);
 }
 
-/* Undefined instruction for dealing with missing ops pointers. */
-noinstr void paravirt_BUG(void)
-{
-	BUG();
-}
-
 static unsigned paravirt_patch_call(void *insn_buff, const void *target,
 				    unsigned long addr, unsigned len)
 {
@@ -64,11 +52,11 @@ static unsigned paravirt_patch_call(void *insn_buff, const void *target,
 }
 
 #ifdef CONFIG_PARAVIRT_XXL
-DEFINE_PARAVIRT_ASM(_paravirt_ident_64, "mov %rdi, %rax", .text);
-DEFINE_PARAVIRT_ASM(pv_native_save_fl, "pushf; pop %rax", .noinstr.text);
-DEFINE_PARAVIRT_ASM(pv_native_irq_disable, "cli", .noinstr.text);
-DEFINE_PARAVIRT_ASM(pv_native_irq_enable, "sti", .noinstr.text);
-DEFINE_PARAVIRT_ASM(pv_native_read_cr2, "mov %cr2, %rax", .noinstr.text);
+DEFINE_ASM_FUNC(_paravirt_ident_64, "mov %rdi, %rax", .text);
+DEFINE_ASM_FUNC(pv_native_save_fl, "pushf; pop %rax", .noinstr.text);
+DEFINE_ASM_FUNC(pv_native_irq_disable, "cli", .noinstr.text);
+DEFINE_ASM_FUNC(pv_native_irq_enable, "sti", .noinstr.text);
+DEFINE_ASM_FUNC(pv_native_read_cr2, "mov %cr2, %rax", .noinstr.text);
 #endif
 
 DEFINE_STATIC_KEY_TRUE(virt_spin_lock_key);
@@ -96,9 +84,9 @@ unsigned int paravirt_patch(u8 type, void *insn_buff, unsigned long addr,
 	unsigned ret;
 
 	if (opfunc == NULL)
-		/* If there's no function, patch it with paravirt_BUG() */
-		ret = paravirt_patch_call(insn_buff, paravirt_BUG, addr, len);
-	else if (opfunc == _paravirt_nop)
+		/* If there's no function, patch it with BUG_func() */
+		ret = paravirt_patch_call(insn_buff, BUG_func, addr, len);
+	else if (opfunc == nop_func)
 		ret = 0;
 	else
 		/* Otherwise call the function. */
diff --git a/arch/x86/xen/irq.c b/arch/x86/xen/irq.c
index 6092fea7d651..39982f955cfe 100644
--- a/arch/x86/xen/irq.c
+++ b/arch/x86/xen/irq.c
@@ -45,7 +45,7 @@ static const typeof(pv_ops) xen_irq_ops __initconst = {
 		/* Initial interrupt flag handling only called while interrupts off. */
 		.save_fl = __PV_IS_CALLEE_SAVE(paravirt_ret0),
 		.irq_disable = __PV_IS_CALLEE_SAVE(paravirt_nop),
-		.irq_enable = __PV_IS_CALLEE_SAVE(paravirt_BUG),
+		.irq_enable = __PV_IS_CALLEE_SAVE(BUG_func),
 
 		.safe_halt = xen_safe_halt,
 		.halt = xen_halt,
-- 
cgit v1.2.3


From da0fe6e68e104f79c1fef5c62a17bdd1634ea61c Mon Sep 17 00:00:00 2001
From: Juergen Gross <jgross@suse.com>
Date: Sun, 10 Dec 2023 07:21:36 +0100
Subject: x86/alternative: Add indirect call patching

In order to prepare replacing of paravirt patching with alternative
patching, add the capability to replace an indirect call with a direct
one.

This is done via a new flag ALT_FLAG_CALL as the target of the CALL
instruction needs to be evaluated using the value of the location
addressed by the indirect call.

For convenience, add a macro for a default CALL instruction. In case it
is being used without the new flag being set, it will result in a BUG()
when being executed. As in most cases, the feature used will be
X86_FEATURE_ALWAYS so add another macro ALT_CALL_ALWAYS usable for the
flags parameter of the ALTERNATIVE macros.

For a complete replacement, handle the special cases of calling a nop
function and an indirect call of NULL the same way as paravirt does.

  [ bp: Massage commit message, fixup the debug output and clarify flow
    more. ]

Co-developed-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20231210062138.2417-4-jgross@suse.com
---
 arch/x86/include/asm/alternative.h |  9 ++++++
 arch/x86/kernel/alternative.c      | 58 ++++++++++++++++++++++++++++++++++++--
 2 files changed, 64 insertions(+), 3 deletions(-)

(limited to 'arch/x86')

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index ce788ab4e77c..472334eed6f3 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -10,6 +10,9 @@
 
 #define ALT_FLAG_NOT		(1 << 0)
 #define ALT_NOT(feature)	((ALT_FLAG_NOT << ALT_FLAGS_SHIFT) | (feature))
+#define ALT_FLAG_DIRECT_CALL	(1 << 1)
+#define ALT_DIRECT_CALL(feature) ((ALT_FLAG_DIRECT_CALL << ALT_FLAGS_SHIFT) | (feature))
+#define ALT_CALL_ALWAYS		ALT_DIRECT_CALL(X86_FEATURE_ALWAYS)
 
 #ifndef __ASSEMBLY__
 
@@ -150,6 +153,8 @@ static inline int alternatives_text_reserved(void *start, void *end)
 }
 #endif	/* CONFIG_SMP */
 
+#define ALT_CALL_INSTR		"call BUG_func"
+
 #define b_replacement(num)	"664"#num
 #define e_replacement(num)	"665"#num
 
@@ -386,6 +391,10 @@ void nop_func(void);
 	.byte \alt_len
 .endm
 
+.macro ALT_CALL_INSTR
+	call BUG_func
+.endm
+
 /*
  * Define an alternative between two instructions. If @feature is
  * present, early code in apply_alternatives() replaces @oldinstr with
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index ca25dd280b8c..657305137bf9 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -395,6 +395,53 @@ noinstr void BUG_func(void)
 }
 EXPORT_SYMBOL_GPL(BUG_func);
 
+#define CALL_RIP_REL_OPCODE	0xff
+#define CALL_RIP_REL_MODRM	0x15
+
+/*
+ * Rewrite the "call BUG_func" replacement to point to the target of the
+ * indirect pv_ops call "call *disp(%ip)".
+ */
+static int alt_replace_call(u8 *instr, u8 *insn_buff, struct alt_instr *a)
+{
+	void *target, *bug = &BUG_func;
+	s32 disp;
+
+	if (a->replacementlen != 5 || insn_buff[0] != CALL_INSN_OPCODE) {
+		pr_err("ALT_FLAG_DIRECT_CALL set for a non-call replacement instruction\n");
+		BUG();
+	}
+
+	if (a->instrlen != 6 ||
+	    instr[0] != CALL_RIP_REL_OPCODE ||
+	    instr[1] != CALL_RIP_REL_MODRM) {
+		pr_err("ALT_FLAG_DIRECT_CALL set for unrecognized indirect call\n");
+		BUG();
+	}
+
+	/* Skip CALL_RIP_REL_OPCODE and CALL_RIP_REL_MODRM */
+	disp = *(s32 *)(instr + 2);
+#ifdef CONFIG_X86_64
+	/* ff 15 00 00 00 00   call   *0x0(%rip) */
+	/* target address is stored at "next instruction + disp". */
+	target = *(void **)(instr + a->instrlen + disp);
+#else
+	/* ff 15 00 00 00 00   call   *0x0 */
+	/* target address is stored at disp. */
+	target = *(void **)disp;
+#endif
+	if (!target)
+		target = bug;
+
+	/* (BUG_func - .) + (target - BUG_func) := target - . */
+	*(s32 *)(insn_buff + 1) += target - bug;
+
+	if (target == &nop_func)
+		return 0;
+
+	return 5;
+}
+
 /*
  * Replace instructions with better alternatives for this CPU type. This runs
  * before SMP is initialized to avoid SMP problems with self modifying code.
@@ -452,16 +499,21 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
 			continue;
 		}
 
-		DPRINTK(ALT, "feat: %s%d*32+%d, old: (%pS (%px) len: %d), repl: (%px, len: %d)",
-			(a->flags & ALT_FLAG_NOT) ? "!" : "",
+		DPRINTK(ALT, "feat: %d32+%d, old: (%pS (%px) len: %d), repl: (%px, len: %d) flags: 0x%x",
 			a->cpuid >> 5,
 			a->cpuid & 0x1f,
 			instr, instr, a->instrlen,
-			replacement, a->replacementlen);
+			replacement, a->replacementlen, a->flags);
 
 		memcpy(insn_buff, replacement, a->replacementlen);
 		insn_buff_sz = a->replacementlen;
 
+		if (a->flags & ALT_FLAG_DIRECT_CALL) {
+			insn_buff_sz = alt_replace_call(instr, insn_buff, a);
+			if (insn_buff_sz < 0)
+				continue;
+		}
+
 		for (; insn_buff_sz < a->instrlen; insn_buff_sz++)
 			insn_buff[insn_buff_sz] = 0x90;
 
-- 
cgit v1.2.3


From 60bc276b129eef8113f9d9b0a5cd5ae7f4c90acb Mon Sep 17 00:00:00 2001
From: Juergen Gross <jgross@suse.com>
Date: Sun, 10 Dec 2023 07:21:37 +0100
Subject: x86/paravirt: Switch mixed paravirt/alternative calls to alternatives

Instead of stacking alternative and paravirt patching, use the new
ALT_FLAG_CALL flag to switch those mixed calls to pure alternative
handling.

Eliminate the need to be careful regarding the sequence of alternative
and paravirt patching.

  [ bp: Touch up commit message. ]

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20231210062138.2417-5-jgross@suse.com
---
 arch/x86/include/asm/alternative.h    |  5 +++--
 arch/x86/include/asm/paravirt.h       | 12 +++++------
 arch/x86/include/asm/paravirt_types.h | 40 +++++++++++++++++++----------------
 arch/x86/kernel/alternative.c         |  1 -
 arch/x86/kernel/callthunks.c          | 17 +++++++--------
 arch/x86/kernel/module.c              | 20 +++++-------------
 6 files changed, 44 insertions(+), 51 deletions(-)

(limited to 'arch/x86')

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 472334eed6f3..fcd20c6dc7f9 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -89,6 +89,8 @@ struct alt_instr {
 	u8  replacementlen;	/* length of new instruction */
 } __packed;
 
+extern struct alt_instr __alt_instructions[], __alt_instructions_end[];
+
 /*
  * Debug flag that can be tested to see whether alternative
  * instructions were patched in already:
@@ -104,11 +106,10 @@ extern void apply_fineibt(s32 *start_retpoline, s32 *end_retpoine,
 			  s32 *start_cfi, s32 *end_cfi);
 
 struct module;
-struct paravirt_patch_site;
 
 struct callthunk_sites {
 	s32				*call_start, *call_end;
-	struct paravirt_patch_site	*pv_start, *pv_end;
+	struct alt_instr		*alt_start, *alt_end;
 };
 
 #ifdef CONFIG_CALL_THUNKS
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index f18bfa7f3070..973c2ac2d25c 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -738,20 +738,20 @@ void native_pv_lock_init(void) __init;
 
 #ifdef CONFIG_X86_64
 #ifdef CONFIG_PARAVIRT_XXL
+#ifdef CONFIG_DEBUG_ENTRY
 
 #define PARA_PATCH(off)		((off) / 8)
 #define PARA_SITE(ptype, ops)	_PVSITE(ptype, ops)
 #define PARA_INDIRECT(addr)	*addr(%rip)
 
-#ifdef CONFIG_DEBUG_ENTRY
 .macro PARA_IRQ_save_fl
-	PARA_SITE(PARA_PATCH(PV_IRQ_save_fl),
-		  ANNOTATE_RETPOLINE_SAFE;
-		  call PARA_INDIRECT(pv_ops+PV_IRQ_save_fl);)
+	ANNOTATE_RETPOLINE_SAFE;
+	call PARA_INDIRECT(pv_ops+PV_IRQ_save_fl);
 .endm
 
-#define SAVE_FLAGS	ALTERNATIVE "PARA_IRQ_save_fl;", "pushf; pop %rax;", \
-				    ALT_NOT_XEN
+#define SAVE_FLAGS ALTERNATIVE_2 "PARA_IRQ_save_fl;",			\
+				 "ALT_CALL_INSTR;", ALT_CALL_ALWAYS,	\
+				 "pushf; pop %rax;", ALT_NOT_XEN
 #endif
 #endif /* CONFIG_PARAVIRT_XXL */
 #endif	/* CONFIG_X86_64 */
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 166e9618158f..9cad536fc08d 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -276,15 +276,11 @@ extern struct paravirt_patch_template pv_ops;
 #define NATIVE_LABEL(a,x,b) "\n\t.globl " a #x "_" #b "\n" a #x "_" #b ":\n\t"
 
 unsigned int paravirt_patch(u8 type, void *insn_buff, unsigned long addr, unsigned int len);
+#define paravirt_ptr(op)	[paravirt_opptr] "m" (pv_ops.op)
 
 int paravirt_disable_iospace(void);
 
-/*
- * This generates an indirect call based on the operation type number.
- * The type number, computed in PARAVIRT_PATCH, is derived from the
- * offset into the paravirt_patch_template structure, and can therefore be
- * freely converted back into a structure offset.
- */
+/* This generates an indirect call based on the operation type number. */
 #define PARAVIRT_CALL					\
 	ANNOTATE_RETPOLINE_SAFE				\
 	"call *%[paravirt_opptr];"
@@ -317,12 +313,6 @@ int paravirt_disable_iospace(void);
  * However, x86_64 also has to clobber all caller saved registers, which
  * unfortunately, are quite a bit (r8 - r11)
  *
- * The call instruction itself is marked by placing its start address
- * and size into the .parainstructions section, so that
- * apply_paravirt() in arch/i386/kernel/alternative.c can do the
- * appropriate patching under the control of the backend pv_init_ops
- * implementation.
- *
  * Unfortunately there's no way to get gcc to generate the args setup
  * for the call, and then allow the call itself to be generated by an
  * inline asm.  Because of this, we must do the complete arg setup and
@@ -421,14 +411,27 @@ int paravirt_disable_iospace(void);
 		__mask & __eax;						\
 	})
 
-
+/*
+ * Use alternative patching for paravirt calls:
+ * - For replacing an indirect call with a direct one, use the "normal"
+ *   ALTERNATIVE() macro with the indirect call as the initial code sequence,
+ *   which will be replaced with the related direct call by using the
+ *   ALT_FLAG_DIRECT_CALL special case and the "always on" feature.
+ * - In case the replacement is either a direct call or a short code sequence
+ *   depending on a feature bit, the ALTERNATIVE_2() macro is being used.
+ *   The indirect call is the initial code sequence again, while the special
+ *   code sequence is selected with the specified feature bit. In case the
+ *   feature is not active, the direct call is used as above via the
+ *   ALT_FLAG_DIRECT_CALL special case and the "always on" feature.
+ */
 #define ____PVOP_CALL(ret, op, call_clbr, extra_clbr, ...)	\
 	({								\
 		PVOP_CALL_ARGS;						\
 		PVOP_TEST_NULL(op);					\
-		asm volatile(paravirt_alt(PARAVIRT_CALL)		\
+		asm volatile(ALTERNATIVE(PARAVIRT_CALL, ALT_CALL_INSTR,	\
+				ALT_CALL_ALWAYS)			\
 			     : call_clbr, ASM_CALL_CONSTRAINT		\
-			     : paravirt_type(op),			\
+			     : paravirt_ptr(op),			\
 			       ##__VA_ARGS__				\
 			     : "memory", "cc" extra_clbr);		\
 		ret;							\
@@ -439,10 +442,11 @@ int paravirt_disable_iospace(void);
 	({								\
 		PVOP_CALL_ARGS;						\
 		PVOP_TEST_NULL(op);					\
-		asm volatile(ALTERNATIVE(paravirt_alt(PARAVIRT_CALL),	\
-					 alt, cond)			\
+		asm volatile(ALTERNATIVE_2(PARAVIRT_CALL,		\
+				 ALT_CALL_INSTR, ALT_CALL_ALWAYS,	\
+				 alt, cond)				\
 			     : call_clbr, ASM_CALL_CONSTRAINT		\
-			     : paravirt_type(op),			\
+			     : paravirt_ptr(op),			\
 			       ##__VA_ARGS__				\
 			     : "memory", "cc" extra_clbr);		\
 		ret;							\
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 657305137bf9..48938bc36d71 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -160,7 +160,6 @@ extern s32 __retpoline_sites[], __retpoline_sites_end[];
 extern s32 __return_sites[], __return_sites_end[];
 extern s32 __cfi_sites[], __cfi_sites_end[];
 extern s32 __ibt_endbr_seal[], __ibt_endbr_seal_end[];
-extern struct alt_instr __alt_instructions[], __alt_instructions_end[];
 extern s32 __smp_locks[], __smp_locks_end[];
 void text_poke_early(void *addr, const void *opcode, size_t len);
 
diff --git a/arch/x86/kernel/callthunks.c b/arch/x86/kernel/callthunks.c
index 57e5c2e75c2a..64ad2ddea121 100644
--- a/arch/x86/kernel/callthunks.c
+++ b/arch/x86/kernel/callthunks.c
@@ -233,14 +233,13 @@ patch_call_sites(s32 *start, s32 *end, const struct core_text *ct)
 }
 
 static __init_or_module void
-patch_paravirt_call_sites(struct paravirt_patch_site *start,
-			  struct paravirt_patch_site *end,
-			  const struct core_text *ct)
+patch_alt_call_sites(struct alt_instr *start, struct alt_instr *end,
+		     const struct core_text *ct)
 {
-	struct paravirt_patch_site *p;
+	struct alt_instr *a;
 
-	for (p = start; p < end; p++)
-		patch_call((void *)&p->instr_offset + p->instr_offset, ct);
+	for (a = start; a < end; a++)
+		patch_call((void *)&a->instr_offset + a->instr_offset, ct);
 }
 
 static __init_or_module void
@@ -248,7 +247,7 @@ callthunks_setup(struct callthunk_sites *cs, const struct core_text *ct)
 {
 	prdbg("Patching call sites %s\n", ct->name);
 	patch_call_sites(cs->call_start, cs->call_end, ct);
-	patch_paravirt_call_sites(cs->pv_start, cs->pv_end, ct);
+	patch_alt_call_sites(cs->alt_start, cs->alt_end, ct);
 	prdbg("Patching call sites done%s\n", ct->name);
 }
 
@@ -257,8 +256,8 @@ void __init callthunks_patch_builtin_calls(void)
 	struct callthunk_sites cs = {
 		.call_start	= __call_sites,
 		.call_end	= __call_sites_end,
-		.pv_start	= __parainstructions,
-		.pv_end		= __parainstructions_end
+		.alt_start	= __alt_instructions,
+		.alt_end	= __alt_instructions_end
 	};
 
 	if (!cpu_feature_enabled(X86_FEATURE_CALL_DEPTH))
diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
index 5f71a0cf4399..e18914c0e38a 100644
--- a/arch/x86/kernel/module.c
+++ b/arch/x86/kernel/module.c
@@ -276,7 +276,7 @@ int module_finalize(const Elf_Ehdr *hdr,
 		    struct module *me)
 {
 	const Elf_Shdr *s, *alt = NULL, *locks = NULL,
-		*para = NULL, *orc = NULL, *orc_ip = NULL,
+		*orc = NULL, *orc_ip = NULL,
 		*retpolines = NULL, *returns = NULL, *ibt_endbr = NULL,
 		*calls = NULL, *cfi = NULL;
 	char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
@@ -286,8 +286,6 @@ int module_finalize(const Elf_Ehdr *hdr,
 			alt = s;
 		if (!strcmp(".smp_locks", secstrings + s->sh_name))
 			locks = s;
-		if (!strcmp(".parainstructions", secstrings + s->sh_name))
-			para = s;
 		if (!strcmp(".orc_unwind", secstrings + s->sh_name))
 			orc = s;
 		if (!strcmp(".orc_unwind_ip", secstrings + s->sh_name))
@@ -304,14 +302,6 @@ int module_finalize(const Elf_Ehdr *hdr,
 			ibt_endbr = s;
 	}
 
-	/*
-	 * See alternative_instructions() for the ordering rules between the
-	 * various patching types.
-	 */
-	if (para) {
-		void *pseg = (void *)para->sh_addr;
-		apply_paravirt(pseg, pseg + para->sh_size);
-	}
 	if (retpolines || cfi) {
 		void *rseg = NULL, *cseg = NULL;
 		unsigned int rsize = 0, csize = 0;
@@ -341,7 +331,7 @@ int module_finalize(const Elf_Ehdr *hdr,
 		void *aseg = (void *)alt->sh_addr;
 		apply_alternatives(aseg, aseg + alt->sh_size);
 	}
-	if (calls || para) {
+	if (calls || alt) {
 		struct callthunk_sites cs = {};
 
 		if (calls) {
@@ -349,9 +339,9 @@ int module_finalize(const Elf_Ehdr *hdr,
 			cs.call_end = (void *)calls->sh_addr + calls->sh_size;
 		}
 
-		if (para) {
-			cs.pv_start = (void *)para->sh_addr;
-			cs.pv_end = (void *)para->sh_addr + para->sh_size;
+		if (alt) {
+			cs.alt_start = (void *)alt->sh_addr;
+			cs.alt_end = (void *)alt->sh_addr + alt->sh_size;
 		}
 
 		callthunks_patch_module_calls(&cs, me);
-- 
cgit v1.2.3


From f7af6977621a41661696d94c0c0a20c761404476 Mon Sep 17 00:00:00 2001
From: Juergen Gross <jgross@suse.com>
Date: Sun, 10 Dec 2023 07:21:38 +0100
Subject: x86/paravirt: Remove no longer needed paravirt patching code

Now that paravirt is using the alternatives patching infrastructure,
remove the paravirt patching code.

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20231210062138.2417-6-jgross@suse.com
---
 arch/x86/include/asm/paravirt.h       | 13 -------
 arch/x86/include/asm/paravirt_types.h | 38 --------------------
 arch/x86/include/asm/text-patching.h  | 12 -------
 arch/x86/kernel/alternative.c         | 67 ++---------------------------------
 arch/x86/kernel/paravirt.c            | 30 ----------------
 arch/x86/kernel/vmlinux.lds.S         | 13 -------
 arch/x86/tools/relocs.c               |  2 +-
 7 files changed, 3 insertions(+), 172 deletions(-)

(limited to 'arch/x86')

diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 973c2ac2d25c..8bcf7584e7dd 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -725,23 +725,10 @@ void native_pv_lock_init(void) __init;
 
 #else  /* __ASSEMBLY__ */
 
-#define _PVSITE(ptype, ops)			\
-771:;						\
-	ops;					\
-772:;						\
-	.pushsection .parainstructions,"a";	\
-	 .long 771b-.;				\
-	 .byte ptype;				\
-	 .byte 772b-771b;			\
-	.popsection
-
-
 #ifdef CONFIG_X86_64
 #ifdef CONFIG_PARAVIRT_XXL
 #ifdef CONFIG_DEBUG_ENTRY
 
-#define PARA_PATCH(off)		((off) / 8)
-#define PARA_SITE(ptype, ops)	_PVSITE(ptype, ops)
 #define PARA_INDIRECT(addr)	*addr(%rip)
 
 .macro PARA_IRQ_save_fl
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 9cad536fc08d..d8e85d2cf8d5 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -2,15 +2,6 @@
 #ifndef _ASM_X86_PARAVIRT_TYPES_H
 #define _ASM_X86_PARAVIRT_TYPES_H
 
-#ifndef __ASSEMBLY__
-/* These all sit in the .parainstructions section to tell us what to patch. */
-struct paravirt_patch_site {
-	s32 instr_offset;	/* original instructions */
-	u8 type;		/* type of this instruction */
-	u8 len;			/* length of original instruction */
-} __packed;
-#endif
-
 #ifdef CONFIG_PARAVIRT
 
 #ifndef __ASSEMBLY__
@@ -250,32 +241,6 @@ struct paravirt_patch_template {
 extern struct pv_info pv_info;
 extern struct paravirt_patch_template pv_ops;
 
-#define PARAVIRT_PATCH(x)					\
-	(offsetof(struct paravirt_patch_template, x) / sizeof(void *))
-
-#define paravirt_type(op)				\
-	[paravirt_typenum] "i" (PARAVIRT_PATCH(op)),	\
-	[paravirt_opptr] "m" (pv_ops.op)
-/*
- * Generate some code, and mark it as patchable by the
- * apply_paravirt() alternate instruction patcher.
- */
-#define _paravirt_alt(insn_string, type)		\
-	"771:\n\t" insn_string "\n" "772:\n"		\
-	".pushsection .parainstructions,\"a\"\n"	\
-	"  .long 771b-.\n"				\
-	"  .byte " type "\n"				\
-	"  .byte 772b-771b\n"				\
-	".popsection\n"
-
-/* Generate patchable code, with the default asm parameters. */
-#define paravirt_alt(insn_string)					\
-	_paravirt_alt(insn_string, "%c[paravirt_typenum]")
-
-/* Simple instruction patching code. */
-#define NATIVE_LABEL(a,x,b) "\n\t.globl " a #x "_" #b "\n" a #x "_" #b ":\n\t"
-
-unsigned int paravirt_patch(u8 type, void *insn_buff, unsigned long addr, unsigned int len);
 #define paravirt_ptr(op)	[paravirt_opptr] "m" (pv_ops.op)
 
 int paravirt_disable_iospace(void);
@@ -555,9 +520,6 @@ unsigned long pv_native_read_cr2(void);
 
 #define paravirt_nop	((void *)nop_func)
 
-extern struct paravirt_patch_site __parainstructions[],
-	__parainstructions_end[];
-
 #endif	/* __ASSEMBLY__ */
 
 #define ALT_NOT_XEN	ALT_NOT(X86_FEATURE_XENPV)
diff --git a/arch/x86/include/asm/text-patching.h b/arch/x86/include/asm/text-patching.h
index 29832c338cdc..0b70653a98c1 100644
--- a/arch/x86/include/asm/text-patching.h
+++ b/arch/x86/include/asm/text-patching.h
@@ -6,18 +6,6 @@
 #include <linux/stddef.h>
 #include <asm/ptrace.h>
 
-struct paravirt_patch_site;
-#ifdef CONFIG_PARAVIRT
-void apply_paravirt(struct paravirt_patch_site *start,
-		    struct paravirt_patch_site *end);
-#else
-static inline void apply_paravirt(struct paravirt_patch_site *start,
-				  struct paravirt_patch_site *end)
-{}
-#define __parainstructions	NULL
-#define __parainstructions_end	NULL
-#endif
-
 /*
  * Currently, the max observed size in the kernel code is
  * JUMP_LABEL_NOP_SIZE/RELATIVEJUMP_SIZE, which are 5.
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 48938bc36d71..f26983a3e035 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -1472,48 +1472,6 @@ int alternatives_text_reserved(void *start, void *end)
 }
 #endif /* CONFIG_SMP */
 
-#ifdef CONFIG_PARAVIRT
-
-/* Use this to add nops to a buffer, then text_poke the whole buffer. */
-static void __init_or_module add_nops(void *insns, unsigned int len)
-{
-	while (len > 0) {
-		unsigned int noplen = len;
-		if (noplen > ASM_NOP_MAX)
-			noplen = ASM_NOP_MAX;
-		memcpy(insns, x86_nops[noplen], noplen);
-		insns += noplen;
-		len -= noplen;
-	}
-}
-
-void __init_or_module apply_paravirt(struct paravirt_patch_site *start,
-				     struct paravirt_patch_site *end)
-{
-	struct paravirt_patch_site *p;
-	char insn_buff[MAX_PATCH_LEN];
-	u8 *instr;
-
-	for (p = start; p < end; p++) {
-		unsigned int used;
-
-		instr = (u8 *)&p->instr_offset + p->instr_offset;
-		BUG_ON(p->len > MAX_PATCH_LEN);
-		/* prep the buffer with the original instructions */
-		memcpy(insn_buff, instr, p->len);
-		used = paravirt_patch(p->type, insn_buff, (unsigned long)instr, p->len);
-
-		BUG_ON(used > p->len);
-
-		/* Pad the rest with nops */
-		add_nops(insn_buff + used, p->len - used);
-		text_poke_early(instr, insn_buff, p->len);
-	}
-}
-extern struct paravirt_patch_site __start_parainstructions[],
-	__stop_parainstructions[];
-#endif	/* CONFIG_PARAVIRT */
-
 /*
  * Self-test for the INT3 based CALL emulation code.
  *
@@ -1649,28 +1607,11 @@ void __init alternative_instructions(void)
 	 */
 
 	/*
-	 * Paravirt patching and alternative patching can be combined to
-	 * replace a function call with a short direct code sequence (e.g.
-	 * by setting a constant return value instead of doing that in an
-	 * external function).
-	 * In order to make this work the following sequence is required:
-	 * 1. set (artificial) features depending on used paravirt
-	 *    functions which can later influence alternative patching
-	 * 2. apply paravirt patching (generally replacing an indirect
-	 *    function call with a direct one)
-	 * 3. apply alternative patching (e.g. replacing a direct function
-	 *    call with a custom code sequence)
-	 * Doing paravirt patching after alternative patching would clobber
-	 * the optimization of the custom code with a function call again.
+	 * Make sure to set (artificial) features depending on used paravirt
+	 * functions which can later influence alternative patching.
 	 */
 	paravirt_set_cap();
 
-	/*
-	 * First patch paravirt functions, such that we overwrite the indirect
-	 * call with the direct call.
-	 */
-	apply_paravirt(__parainstructions, __parainstructions_end);
-
 	__apply_fineibt(__retpoline_sites, __retpoline_sites_end,
 			__cfi_sites, __cfi_sites_end, true);
 
@@ -1681,10 +1622,6 @@ void __init alternative_instructions(void)
 	apply_retpolines(__retpoline_sites, __retpoline_sites_end);
 	apply_returns(__return_sites, __return_sites_end);
 
-	/*
-	 * Then patch alternatives, such that those paravirt calls that are in
-	 * alternatives can be overwritten by their immediate fragments.
-	 */
 	apply_alternatives(__alt_instructions, __alt_instructions_end);
 
 	/*
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index acc5b1004f0f..5358d43886ad 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -43,14 +43,6 @@ void __init default_banner(void)
 	       pv_info.name);
 }
 
-static unsigned paravirt_patch_call(void *insn_buff, const void *target,
-				    unsigned long addr, unsigned len)
-{
-	__text_gen_insn(insn_buff, CALL_INSN_OPCODE,
-			(void *)addr, target, CALL_INSN_SIZE);
-	return CALL_INSN_SIZE;
-}
-
 #ifdef CONFIG_PARAVIRT_XXL
 DEFINE_ASM_FUNC(_paravirt_ident_64, "mov %rdi, %rax", .text);
 DEFINE_ASM_FUNC(pv_native_save_fl, "pushf; pop %rax", .noinstr.text);
@@ -73,28 +65,6 @@ static void native_tlb_remove_table(struct mmu_gather *tlb, void *table)
 	tlb_remove_page(tlb, table);
 }
 
-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
-	 * corresponding structure.
-	 */
-	void *opfunc = *((void **)&pv_ops + type);
-	unsigned ret;
-
-	if (opfunc == NULL)
-		/* If there's no function, patch it with BUG_func() */
-		ret = paravirt_patch_call(insn_buff, BUG_func, addr, len);
-	else if (opfunc == nop_func)
-		ret = 0;
-	else
-		/* Otherwise call the function. */
-		ret = paravirt_patch_call(insn_buff, opfunc, addr, len);
-
-	return ret;
-}
-
 struct static_key paravirt_steal_enabled;
 struct static_key paravirt_steal_rq_enabled;
 
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 54a5596adaa6..a349dbfc6d5a 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -267,19 +267,6 @@ SECTIONS
 	}
 #endif
 
-	/*
-	 * start address and size of operations which during runtime
-	 * can be patched with virtualization friendly instructions or
-	 * baremetal native ones. Think page table operations.
-	 * Details in paravirt_types.h
-	 */
-	. = ALIGN(8);
-	.parainstructions : AT(ADDR(.parainstructions) - LOAD_OFFSET) {
-		__parainstructions = .;
-		*(.parainstructions)
-		__parainstructions_end = .;
-	}
-
 #ifdef CONFIG_RETPOLINE
 	/*
 	 * List of instructions that call/jmp/jcc to retpoline thunks
diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
index d30949e25ebd..a3bae2b24626 100644
--- a/arch/x86/tools/relocs.c
+++ b/arch/x86/tools/relocs.c
@@ -66,7 +66,7 @@ static const char * const sym_regex_kernel[S_NSYMTYPES] = {
 	[S_REL] =
 	"^(__init_(begin|end)|"
 	"__x86_cpu_dev_(start|end)|"
-	"(__parainstructions|__alt_instructions)(_end)?|"
+	"__alt_instructions(_end)?|"
 	"(__iommu_table|__apicdrivers|__smp_locks)(_end)?|"
 	"__(start|end)_pci_.*|"
 #if CONFIG_FW_LOADER
-- 
cgit v1.2.3


From 7991ed43587d1106315208cc289c851d6915d4a3 Mon Sep 17 00:00:00 2001
From: "Borislav Petkov (AMD)" <bp@alien8.de>
Date: Sat, 30 Dec 2023 12:20:04 +0100
Subject: x86/alternative: Correct feature bit debug output

In

  https://lore.kernel.org/r/20231206110636.GBZXBVvCWj2IDjVk4c@fat_crate.local

I wanted to adjust the alternative patching debug output to the new
changes introduced by

  da0fe6e68e10 ("x86/alternative: Add indirect call patching")

but removed the '*' which denotes the ->x86_capability word. The correct
output should be, for example:

  [    0.230071] SMP alternatives: feat: 11*32+15, old: (entry_SYSCALL_64_after_hwframe+0x5a/0x77 (ffffffff81c000c2) len: 16), repl: (ffffffff89ae896a, len: 5) flags: 0x0

while the incorrect one says "... 1132+15" currently.

Add back the '*'.

Fixes: da0fe6e68e10 ("x86/alternative: Add indirect call patching")
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20231206110636.GBZXBVvCWj2IDjVk4c@fat_crate.local
---
 arch/x86/kernel/alternative.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'arch/x86')

diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index f26983a3e035..f7ea108fbd88 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -498,7 +498,7 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
 			continue;
 		}
 
-		DPRINTK(ALT, "feat: %d32+%d, old: (%pS (%px) len: %d), repl: (%px, len: %d) flags: 0x%x",
+		DPRINTK(ALT, "feat: %d*32+%d, old: (%pS (%px) len: %d), repl: (%px, len: %d) flags: 0x%x",
 			a->cpuid >> 5,
 			a->cpuid & 0x1f,
 			instr, instr, a->instrlen,
-- 
cgit v1.2.3