KVM: x86: Add an emulation flag for implicit system access

Add an emulation flag X86EMUL_F_IMPLICIT to identify implicit system access
in instruction emulation.  Don't bother wiring up any usage at this point,
as Linear Address Space Separation (LASS) will be the first "real" consumer
of the flag and LASS support will require dedicated hooks, i.e. there
aren't any existing calls where passing X86EMUL_F_IMPLICIT is meaningful.

Add the IMPLICIT flag even though there's no imminent usage so that
Linear Address Masking (LAM) support can reference the flag to document
that addresses for implicit accesses aren't untagged.

Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com>
Tested-by: Xuelian Guo <xuelian.guo@intel.com>
Link: https://lore.kernel.org/r/20230913124227.12574-4-binbin.wu@linux.intel.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/arch/x86/kvm/kvm_emulate.h b/arch/x86/kvm/kvm_emulate.h
index e24c8ac7b9304c2ab5d4cfea99a680bf33979454..65fc7ef5ca3da09061791bb081318c448e8f844a 100644 (file)
--- a/arch/x86/kvm/kvm_emulate.h
+++ b/arch/x86/kvm/kvm_emulate.h
@@ -91,6 +91,7 @@ struct x86_instruction_info {
 /* x86-specific emulation flags */
 #define X86EMUL_F_WRITE                        BIT(0)
 #define X86EMUL_F_FETCH                        BIT(1)
+#define X86EMUL_F_IMPLICIT             BIT(2)
 
 struct x86_emulate_ops {
        void (*vm_bugged)(struct x86_emulate_ctxt *ctxt);