---
v2: Fix #UD recovery for INVVPID (unintended flow change spotted by Andrew Cooper).
--- a/xen/include/asm-x86/asm_defns.h
+++ b/xen/include/asm-x86/asm_defns.h
@@ -67,6 +67,30 @@ void ret_from_intr(void);
#define ASSERT_NOT_IN_ATOMIC
#endif
+#else
+
+#ifdef __clang__ /* clang's builtin assember can't do .subsection */
+
+#define UNLIKELY_START_SECTION ".pushsection .fixup,\"ax\""
+#define UNLIKELY_END_SECTION ".popsection"
+
+#else
+
+#define UNLIKELY_START_SECTION ".subsection 1"
+#define UNLIKELY_END_SECTION ".subsection 0"
+
+#endif
+
+#define UNLIKELY_START(cond, tag) \
+ "j" #cond " .Lunlikely%=.tag;\n\t" \
+ UNLIKELY_START_SECTION "\n" \
+ ".Lunlikely%=.tag:"
+
+#define UNLIKELY_END(tag) \
+ "jmp .Llikely%=.tag;\n\t" \
+ UNLIKELY_END_SECTION "\n" \
+ ".Llikely%=.tag:"
+
#endif
#endif /* __X86_ASM_DEFNS_H__ */
--- a/xen/include/asm-x86/hvm/vmx/vmx.h
+++ b/xen/include/asm-x86/hvm/vmx/vmx.h
@@ -285,7 +285,9 @@ static inline void __vmptrld(u64 addr)
asm volatile ( VMPTRLD_OPCODE
MODRM_EAX_06
/* CF==1 or ZF==1 --> crash (ud2) */
- "ja 1f ; ud2 ; 1:\n"
+ UNLIKELY_START(be, vmptrld)
+ "\tud2\n"
+ UNLIKELY_END_SECTION
:
: "a" (&addr)
: "memory");
@@ -296,7 +298,9 @@ static inline void __vmpclear(u64 addr)
asm volatile ( VMCLEAR_OPCODE
MODRM_EAX_06
/* CF==1 or ZF==1 --> crash (ud2) */
- "ja 1f ; ud2 ; 1:\n"
+ UNLIKELY_START(be, vmclear)
+ "\tud2\n"
+ UNLIKELY_END_SECTION
:
: "a" (&addr)
: "memory");
@@ -309,7 +313,9 @@ static inline unsigned long __vmread(uns
asm volatile ( VMREAD_OPCODE
MODRM_EAX_ECX
/* CF==1 or ZF==1 --> crash (ud2) */
- "ja 1f ; ud2 ; 1:\n"
+ UNLIKELY_START(be, vmread)
+ "\tud2\n"
+ UNLIKELY_END_SECTION
: "=c" (ecx)
: "a" (field)
: "memory");
@@ -322,7 +328,9 @@ static inline void __vmwrite(unsigned lo
asm volatile ( VMWRITE_OPCODE
MODRM_EAX_ECX
/* CF==1 or ZF==1 --> crash (ud2) */
- "ja 1f ; ud2 ; 1:\n"
+ UNLIKELY_START(be, vmwrite)
+ "\tud2\n"
+ UNLIKELY_END_SECTION
:
: "a" (field) , "c" (value)
: "memory");
@@ -360,7 +368,9 @@ static inline void __invept(int type, u6
asm volatile ( INVEPT_OPCODE
MODRM_EAX_08
/* CF==1 or ZF==1 --> crash (ud2) */
- "ja 1f ; ud2 ; 1:\n"
+ UNLIKELY_START(be, invept)
+ "\tud2\n"
+ UNLIKELY_END_SECTION
:
: "a" (&operand), "c" (type)
: "memory" );
@@ -377,7 +387,10 @@ static inline void __invvpid(int type, u
/* Fix up #UD exceptions which occur when TLBs are flushed before VMXON. */
asm volatile ( "1: " INVVPID_OPCODE MODRM_EAX_08
/* CF==1 or ZF==1 --> crash (ud2) */
- "ja 2f ; ud2 ; 2:\n"
+ UNLIKELY_START(be, invvpid)
+ "\tud2\n"
+ UNLIKELY_END_SECTION "\n"
+ "2:"
_ASM_EXTABLE(1b, 2b)
:
: "a" (&operand), "c" (type)
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