[PATCH 1/5] KVM: emulator: drop RPL check from linearize() function

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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 <gleb@xxxxxxxxxx>
---
 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

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