diff options
| author | Hou Wenlong | 2022-02-08 17:34:03 +0800 |
|---|---|---|
| committer | Paolo Bonzini | 2022-03-01 08:50:49 -0500 |
| commit | ca85f002258fdac3762c57d12d5e6e401b6a41af (patch) | |
| tree | ec1db110dafc9a400be658a186b748695307dc1f | |
| parent | 85c68eb429f7fc136b9bbb3646eb38a9e0e30fa2 (diff) | |
KVM: x86/emulator: Defer not-present segment check in __load_segment_descriptor()
Per Intel's SDM on the "Instruction Set Reference", when
loading segment descriptor, not-present segment check should
be after all type and privilege checks. But the emulator checks
it first, then #NP is triggered instead of #GP if privilege fails
and segment is not present. Put not-present segment check after
type and privilege checks in __load_segment_descriptor().
Fixes: 38ba30ba51a00 (KVM: x86 emulator: Emulate task switch in emulator.c)
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com>
Message-Id: <52573c01d369f506cadcf7233812427cf7db81a7.1644292363.git.houwenlong.hwl@antgroup.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | arch/x86/kvm/emulate.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index b7990defca9c..a6c54b8fdbc7 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -1608,11 +1608,6 @@ static int __load_segment_descriptor(struct x86_emulate_ctxt *ctxt, goto exception; } - if (!seg_desc.p) { - err_vec = (seg == VCPU_SREG_SS) ? SS_VECTOR : NP_VECTOR; - goto exception; - } - dpl = seg_desc.dpl; switch (seg) { @@ -1652,6 +1647,10 @@ static int __load_segment_descriptor(struct x86_emulate_ctxt *ctxt, case VCPU_SREG_TR: if (seg_desc.s || (seg_desc.type != 1 && seg_desc.type != 9)) goto exception; + if (!seg_desc.p) { + err_vec = NP_VECTOR; + goto exception; + } old_desc = seg_desc; seg_desc.type |= 2; /* busy */ ret = ctxt->ops->cmpxchg_emulated(ctxt, desc_addr, &old_desc, &seg_desc, @@ -1676,6 +1675,11 @@ static int __load_segment_descriptor(struct x86_emulate_ctxt *ctxt, break; } + if (!seg_desc.p) { + err_vec = (seg == VCPU_SREG_SS) ? SS_VECTOR : NP_VECTOR; + goto exception; + } + if (seg_desc.s) { /* mark segment as accessed */ if (!(seg_desc.type & 1)) { |