From: Denis Mukhin <dmuk...@ford.com> Improve error handling in VMX wrappers by switching to `asm goto()` where possible.
vmread_safe() kept as is because the minimally required baseline GCC does not support output operands in `asm goto`. Resolves: https://gitlab.com/xen-project/xen/-/work_items/210 Signed-off-by: Denis Mukhin <dmuk...@ford.com> --- xen/arch/x86/include/asm/hvm/vmx/vmx.h | 141 +++++++++++++------------ 1 file changed, 73 insertions(+), 68 deletions(-) diff --git a/xen/arch/x86/include/asm/hvm/vmx/vmx.h b/xen/arch/x86/include/asm/hvm/vmx/vmx.h index ed6a6986b9..19d41f7b90 100644 --- a/xen/arch/x86/include/asm/hvm/vmx/vmx.h +++ b/xen/arch/x86/include/asm/hvm/vmx/vmx.h @@ -294,54 +294,57 @@ extern uint8_t posted_intr_vector; static always_inline void __vmptrld(u64 addr) { - asm volatile ( "vmptrld %0\n" - /* CF==1 or ZF==1 --> BUG() */ - UNLIKELY_START(be, vmptrld) - _ASM_BUGFRAME_TEXT(0) - UNLIKELY_END_SECTION - : - : "m" (addr), - _ASM_BUGFRAME_INFO(BUGFRAME_bug, __LINE__, __FILE__, 0) - : "memory" ); + asm goto ( "vmptrld %[addr]\n" + "jbe %l[vmfail]\n\t" + : + : [addr] "m" (addr) + : "memory" + : vmfail ); + return; + + vmfail: + BUG(); } static always_inline void __vmpclear(u64 addr) { - asm volatile ( "vmclear %0\n" - /* CF==1 or ZF==1 --> BUG() */ - UNLIKELY_START(be, vmclear) - _ASM_BUGFRAME_TEXT(0) - UNLIKELY_END_SECTION - : - : "m" (addr), - _ASM_BUGFRAME_INFO(BUGFRAME_bug, __LINE__, __FILE__, 0) - : "memory" ); + asm goto ( "vmclear %[addr]\n" + "jbe %l[vmfail]\n\t" + : + : [addr] "m" (addr) + : "memory" + : vmfail ); + return; + + vmfail: + BUG(); } static always_inline void __vmread(unsigned long field, unsigned long *value) { - asm volatile ( "vmread %1, %0\n\t" - /* CF==1 or ZF==1 --> BUG() */ - UNLIKELY_START(be, vmread) - _ASM_BUGFRAME_TEXT(0) - UNLIKELY_END_SECTION - : "=rm" (*value) - : "r" (field), - _ASM_BUGFRAME_INFO(BUGFRAME_bug, __LINE__, __FILE__, 0) - ); + bool vmfail; + + asm volatile ( "vmread %[field], %[value]\n\t" + "setbe %[vmfail]\n\t" + : [value] "=rm" (*value), [vmfail] "=rm" (vmfail) + : [field] "r" (field) + : "cc" ); + if ( vmfail ) + BUG(); } static always_inline void __vmwrite(unsigned long field, unsigned long value) { - asm volatile ( "vmwrite %1, %0\n" - /* CF==1 or ZF==1 --> BUG() */ - UNLIKELY_START(be, vmwrite) - _ASM_BUGFRAME_TEXT(0) - UNLIKELY_END_SECTION - : - : "r" (field) , "rm" (value), - _ASM_BUGFRAME_INFO(BUGFRAME_bug, __LINE__, __FILE__, 0) - ); + asm goto ( "vmwrite %[value], %[field]\n\t" + "jbe %l[vmfail]\n\t" + : + : [field] "r" (field), [value] "rm" (value) + : + : vmfail ); + return; + + vmfail: + BUG(); } static inline enum vmx_insn_errno vmread_safe(unsigned long field, @@ -369,22 +372,22 @@ static inline enum vmx_insn_errno vmread_safe(unsigned long field, static inline enum vmx_insn_errno vmwrite_safe(unsigned long field, unsigned long value) { - unsigned long ret = VMX_INSN_SUCCEED; - bool fail_invalid, fail_valid; + unsigned long ret; - asm volatile ( "vmwrite %[value], %[field]\n\t" - ASM_FLAG_OUT(, "setc %[invalid]\n\t") - ASM_FLAG_OUT(, "setz %[valid]\n\t") - : ASM_FLAG_OUT("=@ccc", [invalid] "=rm") (fail_invalid), - ASM_FLAG_OUT("=@ccz", [valid] "=rm") (fail_valid) - : [field] "r" (field), - [value] "rm" (value) ); + asm goto ( "vmwrite %[value], %[field]\n\t" + "jc %l[vmfail_invalid]\n\t" + "jz %l[vmfail_error]\n\t" + : + : [field] "r" (field), [value] "rm" (value) + : + : vmfail_invalid, vmfail_error ); + return VMX_INSN_SUCCEED; - if ( unlikely(fail_invalid) ) - ret = VMX_INSN_FAIL_INVALID; - else if ( unlikely(fail_valid) ) - __vmread(VM_INSTRUCTION_ERROR, &ret); + vmfail_invalid: + return VMX_INSN_FAIL_INVALID; + vmfail_error: + __vmread(VM_INSTRUCTION_ERROR, &ret); return ret; } @@ -402,15 +405,16 @@ static always_inline void __invept(unsigned long type, uint64_t eptp) !cpu_has_vmx_ept_invept_single_context ) type = INVEPT_ALL_CONTEXT; - asm volatile ( "invept %0, %1\n" - /* CF==1 or ZF==1 --> BUG() */ - UNLIKELY_START(be, invept) - _ASM_BUGFRAME_TEXT(0) - UNLIKELY_END_SECTION - : - : "m" (operand), "r" (type), - _ASM_BUGFRAME_INFO(BUGFRAME_bug, __LINE__, __FILE__, 0) - : "memory" ); + asm goto ( "invept %[operand], %[type]\n" + "jbe %l[vmfail]\n\t" + : + : [operand] "m" (operand), [type] "r" (type) + : "memory" + : vmfail ); + return; + + vmfail: + BUG(); } static always_inline void __invvpid(unsigned long type, u16 vpid, u64 gva) @@ -422,16 +426,17 @@ static always_inline void __invvpid(unsigned long type, u16 vpid, u64 gva) } operand = {vpid, 0, gva}; /* Fix up #UD exceptions which occur when TLBs are flushed before VMXON. */ - asm volatile ( "1: invvpid %0, %1\n" - /* CF==1 or ZF==1 --> BUG() */ - UNLIKELY_START(be, invvpid) - _ASM_BUGFRAME_TEXT(0) - UNLIKELY_END_SECTION "\n" - "2:" _ASM_EXTABLE(1b, 2b) - : - : "m" (operand), "r" (type), - _ASM_BUGFRAME_INFO(BUGFRAME_bug, __LINE__, __FILE__, 0) - : "memory" ); + asm goto ( "1: invvpid %[operand], %[type]\n" + " jbe %l[vmfail]\n\t" + "2:" _ASM_EXTABLE(1b, 2b) + : + : [operand] "m" (operand), [type] "r" (type) + : "memory" + : vmfail ); + return; + + vmfail: + BUG(); } static inline void ept_sync_all(void) -- 2.34.1
