From 3a78a4f46302bfc83602a53dfa4dcbe76a7a1f5f Mon Sep 17 00:00:00 2001 From: Gleb Natapov Date: Thu, 20 Dec 2012 16:57:42 +0200 Subject: [PATCH] KVM: emulator: drop RPL check from linearize() function According to Intel SDM Vol3 Section 5.5 "Privilege Levels" and 5.6 "Privilege Level Checking When Accessing Data Segments" RPL checking is done during loading of a segment selector, not during data access. We already do checking during segment selector loading, so drop the check during data access. Checking RPL during data access triggers #GP if after transition from real mode to protected mode RPL bits in a segment selector are set. Signed-off-by: Gleb Natapov Signed-off-by: Marcelo Tosatti --- arch/x86/kvm/emulate.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index c7547b3..a3d31e3 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -665,7 +665,7 @@ static int __linearize(struct x86_emulate_ctxt *ctxt, ulong la; u32 lim; u16 sel; - unsigned cpl, rpl; + unsigned cpl; la = seg_base(ctxt, addr.seg) + addr.ea; switch (ctxt->mode) { @@ -699,11 +699,6 @@ static int __linearize(struct x86_emulate_ctxt *ctxt, goto bad; } cpl = ctxt->ops->cpl(ctxt); - if (ctxt->mode == X86EMUL_MODE_REAL) - rpl = 0; - else - rpl = sel & 3; - cpl = max(cpl, rpl); if (!(desc.type & 8)) { /* data segment */ if (cpl > desc.dpl) -- 2.7.4