From 055a5d540b8a9f40be71fd52eacb39f0b3acf7b7 Mon Sep 17 00:00:00 2001 From: Andrew Cooper Date: Tue, 20 Oct 2020 14:54:12 +0200 Subject: [PATCH] x86/pv: Don't deliver #GP for a SYSENTER with NT set It is a matter of guest kernel policy what to do with offending userspace, and terminating said userspace may not be the action chosen. Linux explicitly tolerates this case. Reported-by: Andy Lutomirski Fixes: fdac951560 ("x86: clear EFLAGS.NT in SYSENTER entry path") Signed-off-by: Andrew Cooper Reviewed-by: Jan Beulich master commit: 61d4a04349895edc5a5868274b906ba61ef24f47 master date: 2020-09-24 21:02:35 +0100 --- xen/arch/x86/x86_64/entry.S | 1 - 1 file changed, 1 deletion(-) diff --git a/xen/arch/x86/x86_64/entry.S b/xen/arch/x86/x86_64/entry.S index 7850546749..6a5f8aaec3 100644 --- a/xen/arch/x86/x86_64/entry.S +++ b/xen/arch/x86/x86_64/entry.S @@ -296,7 +296,6 @@ UNLIKELY_START(nz, sysenter_nt_set) pushfq andl $~X86_EFLAGS_NT,(%rsp) popfq - xorl %eax,%eax UNLIKELY_END(sysenter_nt_set) testq %rax,%rax leal (,%rcx,TBF_INTERRUPT),%ecx