From 807c142595abcb99285746bd5512447bdf40b9b1 Mon Sep 17 00:00:00 2001 From: Nadav Amit Date: Sun, 2 Nov 2014 11:54:49 +0200 Subject: [PATCH] KVM: x86: SYSCALL cannot clear eflags[1] SYSCALL emulation currently clears in 64-bit mode eflags according to MSR_SYSCALL_MASK. However, on bare-metal eflags[1] which is fixed to one cannot be cleared, even if MSR_SYSCALL_MASK masks the bit. This wrong behavior may result in failed VM-entry, as VT disallows entry with eflags[1] cleared. This patch sets the bit after masking eflags on syscall. Signed-off-by: Nadav Amit Signed-off-by: Paolo Bonzini --- arch/x86/kvm/emulate.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 713295d913fd..e475cdff15e1 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -2306,6 +2306,7 @@ static int em_syscall(struct x86_emulate_ctxt *ctxt) ops->get_msr(ctxt, MSR_SYSCALL_MASK, &msr_data); ctxt->eflags &= ~msr_data; + ctxt->eflags |= EFLG_RESERVED_ONE_MASK; #endif } else { /* legacy mode */ -- 2.39.5