diff options
Diffstat (limited to 'arch/x86/kvm/vmx/ops.h')
| -rw-r--r-- | arch/x86/kvm/vmx/ops.h | 27 |
1 files changed, 21 insertions, 6 deletions
diff --git a/arch/x86/kvm/vmx/ops.h b/arch/x86/kvm/vmx/ops.h index 45eaedee2ac0..19717d0a1100 100644 --- a/arch/x86/kvm/vmx/ops.h +++ b/arch/x86/kvm/vmx/ops.h @@ -13,6 +13,8 @@ #define __ex(x) __kvm_handle_fault_on_reboot(x) asmlinkage void vmread_error(unsigned long field, bool fault); +__attribute__((regparm(0))) void vmread_error_trampoline(unsigned long field, + bool fault); void vmwrite_error(unsigned long field, unsigned long value); void vmclear_error(struct vmcs *vmcs, u64 phys_addr); void vmptrld_error(struct vmcs *vmcs, u64 phys_addr); @@ -70,15 +72,28 @@ static __always_inline unsigned long __vmcs_readl(unsigned long field) asm volatile("1: vmread %2, %1\n\t" ".byte 0x3e\n\t" /* branch taken hint */ "ja 3f\n\t" - "mov %2, %%" _ASM_ARG1 "\n\t" - "xor %%" _ASM_ARG2 ", %%" _ASM_ARG2 "\n\t" - "2: call vmread_error\n\t" - "xor %k1, %k1\n\t" + + /* + * VMREAD failed. Push '0' for @fault, push the failing + * @field, and bounce through the trampoline to preserve + * volatile registers. + */ + "push $0\n\t" + "push %2\n\t" + "2:call vmread_error_trampoline\n\t" + + /* + * Unwind the stack. Note, the trampoline zeros out the + * memory for @fault so that the result is '0' on error. + */ + "pop %2\n\t" + "pop %1\n\t" "3:\n\t" + /* VMREAD faulted. As above, except push '1' for @fault. */ ".pushsection .fixup, \"ax\"\n\t" - "4: mov %2, %%" _ASM_ARG1 "\n\t" - "mov $1, %%" _ASM_ARG2 "\n\t" + "4: push $1\n\t" + "push %2\n\t" "jmp 2b\n\t" ".popsection\n\t" _ASM_EXTABLE(1b, 4b) |