From a94b55a2986145ab5b357feb340f782d9d199d10 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Tue, 21 Apr 2020 10:51:42 +0200 Subject: [PATCH] x86emul: SYSRET must change CPL The special AMD behavior of leaving SS mostly alone wasn't really complete: We need to adjust CPL aka SS.DPL. Signed-off-by: Jan Beulich --- xen/arch/x86/x86_emulate/x86_emulate.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c b/xen/arch/x86/x86_emulate/x86_emulate.c index 3ed64c13ea..1959fc227a 100644 --- a/xen/arch/x86/x86_emulate/x86_emulate.c +++ b/xen/arch/x86/x86_emulate/x86_emulate.c @@ -6022,6 +6022,8 @@ x86_emulate( /* There's explicitly no RPL adjustment here. */ sreg.sel = (msr_val >> 48) + 8; + /* But DPL needs adjustment, for the new CPL to be correct. */ + sreg.dpl = 3; } #ifdef __x86_64__ -- 2.30.2