linux-kernel - [PATCH 2/3] KVM: x86: Set error code to segment selector on LLDT/LTR non-canonical #GP

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Message-Id: <20220711232750.1092012-3-seanjc@google.com>
Date:   Mon, 11 Jul 2022 23:27:49 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        syzbot+760a73552f47a8cd0fd9@...kaller.appspotmail.com,
        Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>,
        Hou Wenlong <houwenlong.hwl@...group.com>
Subject: [PATCH 2/3] KVM: x86: Set error code to segment selector on LLDT/LTR
 non-canonical #GP

When injecting a #GP on LLDT/LTR due to a non-canonical LDT/TSS base, set
the error code to the selector.  Intel SDM's says nothing about the #GP,
but AMD's APM explicitly states that both LLDT and LTR set the error code
to the selector, not zero.

Note, a non-canonical memory operand on LLDT/LTR does generate a #GP(0),
but the KVM code in question is specific to the base from the descriptor.

Fixes: e37a75a13cda ("KVM: x86: Emulator ignores LDTR/TR extended base on LLDT/LTR")
Cc: stable@...r.kernel.org
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/emulate.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 09e4b67b881f..bd9e9c5627d0 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1736,8 +1736,8 @@ static int __load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
 		if (ret != X86EMUL_CONTINUE)
 			return ret;
 		if (emul_is_noncanonical_address(get_desc_base(&seg_desc) |
-				((u64)base3 << 32), ctxt))
-			return emulate_gp(ctxt, 0);
+						 ((u64)base3 << 32), ctxt))
+			return emulate_gp(ctxt, err_code);
 	}
 
 	if (seg == VCPU_SREG_TR) {
-- 
2.37.0.144.g8ac04bfd2-goog