Commit 9a4cfb27 authored Aug 18, 2014 by Paolo Bonzini

KVM: x86: do not check CS.DPL against RPL during task switch



This reverts the check added by commit 5045b468 (KVM: x86: check CS.DPL
against RPL during task switch, 2014-05-15).  Although the CS.DPL=CS.RPL
check is mentioned in table 7-1 of the SDM as causing a #TSS exception,
it is not mentioned in table 6-6 that lists "invalid TSS conditions"
which cause #TSS exceptions. In fact it causes some tests to fail, which
pass on bare-metal.

Keep the rest of the commit, since we will find new uses for it in 3.18.

Reported-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

parent 3a6095a0

arch/x86/kvm/emulate.c

+0 −3

Original line number	Original line	Diff line number	Diff line
	@@ -1491,9 +1491,6 @@ static int __load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
	goto exception;		goto exception;
	break;		break;
	case VCPU_SREG_CS:		case VCPU_SREG_CS:
	if (in_task_switch && rpl != dpl)
	goto exception;

	if (!(seg_desc.type & 8))		if (!(seg_desc.type & 8))
	goto exception;		goto exception;

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