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From:   "Hou Wenlong" <houwenlong.hwl@antgroup.com>
To:     kvm@vger.kernel.org
Cc:     Sean Christopherson <seanjc@google.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org,
        "H. Peter Anvin" <hpa@zytor.com>, linux-kernel@vger.kernel.org
Subject: [PATCH] KVM: x86: Mark transfer type as X86_TRANSFER_RET when loading CS in iret emulation
Date:   Wed, 12 Oct 2022 17:11:13 +0800
Message-Id: <fcaf1408d2aaaa39b33cdd3b11bf06e7e935d11a.1665565774.git.houwenlong.hwl@antgroup.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

When loading code segment descriptor in iret instruction emulation, the
checks are same as far return instruction emulation, so transfer type
should be X86_TRANSFER_RET in __load_segment_descriptor(). Although,
only iret in real mode is implemented now, and no checks are actually
needed for real mode, it would still be better to mark transfer type as
X86_TRANSFER_RET.

No functional change intended.

Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com>
---
 arch/x86/kvm/emulate.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 3b27622d4642..5052eb480068 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2100,6 +2100,7 @@ static int emulate_iret_real(struct x86_emulate_ctxt *ctxt)
 			     X86_EFLAGS_FIXED;
 	unsigned long vm86_mask = X86_EFLAGS_VM | X86_EFLAGS_VIF |
 				  X86_EFLAGS_VIP;
+	u8 cpl = ctxt->ops->cpl(ctxt);
 
 	/* TODO: Add stack limit check */
 
@@ -2121,7 +2122,8 @@ static int emulate_iret_real(struct x86_emulate_ctxt *ctxt)
 	if (rc != X86EMUL_CONTINUE)
 		return rc;
 
-	rc = load_segment_descriptor(ctxt, (u16)cs, VCPU_SREG_CS);
+	rc = __load_segment_descriptor(ctxt, (u16)cs, VCPU_SREG_CS, cpl,
+				       X86_TRANSFER_RET, NULL);
 
 	if (rc != X86EMUL_CONTINUE)
 		return rc;
-- 
2.31.1