[PATCH] KVM: x86: Mark transfer type as X86_TRANSFER_RET when loading CS in iret emulation

Hou Wenlong
2022-10-12T09:11:23Z

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