[bug report] KVM: x86: avoid incorrect writes to host MSR_IA32_SPEC_CTRL

[Dan Carpenter <dan.carpenter@xxxxxxxxxx>]

Hello Paolo Bonzini,

The patch e71ae535bc24: "KVM: x86: avoid incorrect writes to host
MSR_IA32_SPEC_CTRL" from Jan 20, 2020, leads to the following static
checker warning:

	arch/x86/kvm/vmx/vmx.c:2001 vmx_set_msr()
	warn: maybe use && instead of &

arch/x86/kvm/vmx/vmx.c
  1994                  vmx->msr_ia32_umwait_control = data;
  1995                  break;
  1996          case MSR_IA32_SPEC_CTRL:
  1997                  if (!msr_info->host_initiated &&
  1998                      !guest_cpuid_has(vcpu, X86_FEATURE_SPEC_CTRL))
  1999                          return 1;
  2000  
  2001                  if (data & ~kvm_spec_ctrl_valid_bits(vcpu))
                                   ^^^^^^^^^^^^^^^^^^^^^^^^^

This seems wrong.  kvm_spec_ctrl_valid_bits() returns a bool so this
is either 0xffffffff or 0xfffffffe.  data is a u64.

  2002                          return 1;
  2003  
  2004                  vmx->spec_ctrl = data;
  2005                  if (!data)
  2006                          break;
  2007  
  2008                  /*
  2009                   * For non-nested:

regards,
dan carpenter