[PATCH 4.14 020/229] KVM: x86: Set error code to segment selector on LLDT/LTR non-canonical #GP

Greg Kroah-Hartman
2022-08-23T09:29:58Z

From: Sean Christopherson <seanjc@google.com>

commit 2626206963ace9e8bf92b6eea5ff78dd674c555c upstream.

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@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Link: https://lore.kernel.org/r/20220711232750.1092012-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kvm/emulate.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1758,8 +1758,8 @@ static int __load_segment_descriptor(str
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) {