From 040c8dc8a5afa7364bb8bb5b1b76c30007d6be14 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 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 --- 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 20d91873d831..a46207a05835 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -1504,6 +1504,15 @@ 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; -- 2.20.1