KVM: nVMX: Let the compiler select the reg for holding HOST_RSP
authorSean Christopherson <sean.j.christopherson@intel.com>
Fri, 25 Jan 2019 15:41:01 +0000 (07:41 -0800)
committerPaolo Bonzini <pbonzini@redhat.com>
Tue, 12 Feb 2019 12:12:21 +0000 (13:12 +0100)
commitfbda0fd31a6d683637f848ba17956048dd0c7e48
tree07a35ae1335cd07a6ac1ce4c4d2edfe5eac3b070
parent74dfa2784e961fae66143b811f45105b43c63046
KVM: nVMX: Let the compiler select the reg for holding HOST_RSP

...and provide an explicit name for the constraint.  Naming the input
constraint makes the code self-documenting and also avoids the fragility
of numerically referring to constraints, e.g. %4 breaks badly whenever
the constraints are modified.

Explicitly using RDX was inherited from vCPU-run, i.e. completely
arbitrary.  Even vCPU-run doesn't truly need to explicitly use RDX, but
doing so is more robust as vCPU-run needs tight control over its
register usage.

Note that while the naming "conflict" between host_rsp and HOST_RSP
is slightly confusing, the former will be renamed slightly in a
future patch, at which point HOST_RSP is absolutely what is desired.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
arch/x86/kvm/vmx/nested.c