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 <[email protected]> --- 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) -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
