From a9638450cced05855cbb366fc6dd0792375a6611 Mon Sep 17 00:00:00 2001 From: Nadav Amit Date: Thu, 18 Sep 2014 22:39:43 +0300 Subject: [PATCH] KVM: x86: emulating descriptor load misses long-mode case MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit commit 040c8dc8a5afa7364bb8bb5b1b76c30007d6be14 upstream. In 64-bit mode a #GP should be delivered to the guest "if the code segment descriptor pointed to by the selector in the 64-bit gate doesn't have the L-bit set and the D-bit clear." - Intel SDM "Interrupt 13—General Protection Exception (#GP)". This patch fixes the behavior of CS loading emulation code. Although the comment says that segment loading is not supported in long mode, this function is executed in long mode, so the fix is necassary. Signed-off-by: Nadav Amit Signed-off-by: Paolo Bonzini Signed-off-by: Jiri Slaby --- arch/x86/kvm/emulate.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 987fdb379df64..d28104924255d 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -1533,6 +1533,15 @@ static int load_segment_descriptor(struct x86_emulate_ctxt *ctxt, if (rpl > cpl || dpl != cpl) goto exception; } + /* in long-mode d/b must be clear if l is set */ + if (seg_desc.d && seg_desc.l) { + u64 efer = 0; + + ctxt->ops->get_msr(ctxt, MSR_EFER, &efer); + if (efer & EFER_LMA) + goto exception; + } + /* CS(RPL) <- CPL */ selector = (selector & 0xfffc) | cpl; break; -- 2.47.3