MIME-Version: 1.0
In-Reply-To: <b542b08f-f190-6bd6-e124-51c57931345d@redhat.com>
References: <1479863680-117511-1-git-send-email-dmatlack@google.com>
 <1479863680-117511-2-git-send-email-dmatlack@google.com> <b542b08f-f190-6bd6-e124-51c57931345d@redhat.com>
From: David Matlack <dmatlack@google.com>
Date: Mon, 28 Nov 2016 13:11:55 -0800
Message-ID: <CALzav=cHZJcasS+aSYmuXv-RhO4AAUFTNOYDyViaoay19=rOeQ@mail.gmail.com>
Subject: Re: [PATCH 1/4] KVM: nVMX: support restore of VMX capability MSRs
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm list <kvm@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Jim Mattson <jmattson@google.com>,
        =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= <rkrcmar@redhat.com>
Content-Type: text/plain; charset=UTF-8
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1052
Lines: 22

On Wed, Nov 23, 2016 at 3:44 AM, Paolo Bonzini <pbonzini@redhat.com> wrote:
> On 23/11/2016 02:14, David Matlack wrote:
>>       switch (msr_index) {
>>       case MSR_IA32_VMX_BASIC:
>> +             return vmx_restore_vmx_basic(vmx, data);
>> +     case MSR_IA32_VMX_TRUE_PINBASED_CTLS:
>> +     case MSR_IA32_VMX_PINBASED_CTLS:
>> +     case MSR_IA32_VMX_TRUE_PROCBASED_CTLS:
>> +     case MSR_IA32_VMX_PROCBASED_CTLS:
>> +     case MSR_IA32_VMX_TRUE_EXIT_CTLS:
>> +     case MSR_IA32_VMX_EXIT_CTLS:
>> +     case MSR_IA32_VMX_TRUE_ENTRY_CTLS:
>> +     case MSR_IA32_VMX_ENTRY_CTLS:
>
> PINBASED_CTLS, PROCBASED_CTLS, EXIT_CTLS and ENTRY_CTLS can be derived
> from their "true" counterparts, so I think it's better to remove the
> "non-true" ones from struct nested_vmx (and/or add the "true" ones when
> missing) and make them entirely computed.  But it can be done on top.

Good point. And that would mean userspace does not need to restore the
non-true MSRs, right? KVM does not emulate MSR_IA32_VMX_BASIC[55]=0,
and will probably never want to.