Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 3a78a4f4 authored by Gleb Natapov's avatar Gleb Natapov Committed by Marcelo Tosatti
Browse files

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: default avatarGleb Natapov <gleb@redhat.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent 11393a07

arch/x86/kvm/emulate.c

+1 −6
Original line number Diff line number Diff line
@@ -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)