diff options
| -rw-r--r-- | xen/arch/x86/x86_64/entry.S | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/xen/arch/x86/x86_64/entry.S b/xen/arch/x86/x86_64/entry.S index e6483f15db..f42630f2dc 100644 --- a/xen/arch/x86/x86_64/entry.S +++ b/xen/arch/x86/x86_64/entry.S @@ -51,6 +51,13 @@ restore_all_guest: testw $TRAP_syscall,4(%rsp) jz iret_exit_to_guest + /* Don't use SYSRET path if the return address is not canonical. */ + movq 8(%rsp),%rcx + sarq $47,%rcx + incl %ecx + cmpl $1,%ecx + ja .Lforce_iret + addq $8,%rsp popq %rcx # RIP popq %r11 # CS @@ -61,6 +68,10 @@ restore_all_guest: sysretq 1: sysretl +.Lforce_iret: + /* Mimic SYSRET behavior. */ + movq 8(%rsp),%rcx # RIP + movq 24(%rsp),%r11 # RFLAGS ALIGN /* No special register assumptions. */ iret_exit_to_guest: |