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| author | Jan Beulich <jbeulich@suse.com> | 2013-09-09 10:22:23 +0200 |
|---|---|---|
| committer | Jan Beulich <jbeulich@suse.com> | 2013-09-09 10:22:23 +0200 |
| commit | b0df10407df96fe25f3c1a2bffc4be0696d328b4 (patch) | |
| tree | 36f131f4dc6846a4d47e45dee8ee2c4f36c758ea /xen/include/asm-x86 | |
| parent | 71eb3a65e305d2cde6a2fcdae186a7f333c9b778 (diff) | |
| download | xen-b0df10407df96fe25f3c1a2bffc4be0696d328b4.tar.gz xen-b0df10407df96fe25f3c1a2bffc4be0696d328b4.tar.bz2 xen-b0df10407df96fe25f3c1a2bffc4be0696d328b4.zip | |
VMX: move various uses of UD2 out of fast paths
... at once making conditional forward jumps, which are statically
predicted to be not taken, only used for the unlikely (error) cases.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Tim Deegan <tim@xen.org>
Diffstat (limited to 'xen/include/asm-x86')
| -rw-r--r-- | xen/include/asm-x86/asm_defns.h | 24 | ||||
| -rw-r--r-- | xen/include/asm-x86/hvm/vmx/vmx.h | 25 |
2 files changed, 43 insertions, 6 deletions
diff --git a/xen/include/asm-x86/asm_defns.h b/xen/include/asm-x86/asm_defns.h index 81d490559c..8fc1a2c4c5 100644 --- 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__ */ diff --git a/xen/include/asm-x86/hvm/vmx/vmx.h b/xen/include/asm-x86/hvm/vmx/vmx.h index f4d759bd5a..a7b667e31e 100644 --- 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(unsigned long field) 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 long field, unsigned long value) 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, u64 eptp, u64 gpa) 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, u16 vpid, u64 gva) /* 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) |