Re: [PATCH v3 3/4] KVM: SVM: Fix CPL updates

[Kevin Wolf <kwolf@redhat.com>]

Am 05.02.2012 12:16, schrieb Gleb Natapov:
> On Fri, Feb 03, 2012 at 07:29:24PM +0100, Kevin Wolf wrote:
>> Keep CPL at 0 in real mode and at 3 in VM86. In protected/long mode, use
>> RPL rather than DPL of the code segment.
>>
>> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
>> ---
>>  arch/x86/kvm/svm.c |   19 ++++++++++++++++---
>>  1 files changed, 16 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
>> index 6a977c1..4124a7e 100644
>> --- a/arch/x86/kvm/svm.c
>> +++ b/arch/x86/kvm/svm.c
>> @@ -1263,6 +1263,21 @@ static void svm_vcpu_put(struct kvm_vcpu *vcpu)
>>  		wrmsrl(host_save_user_msrs[i], svm->host_user_msrs[i]);
>>  }
>>  
>> +static void svm_update_cpl(struct kvm_vcpu *vcpu)
>> +{
>> +	struct vcpu_svm *svm = to_svm(vcpu);
>> +	int cpl;
>> +
>> +	if (!is_protmode(vcpu))
>> +		cpl = 0;
>> +	else if (svm->vmcb->save.rflags & X86_EFLAGS_VM)
>> +		cpl = 3;
>> +	else
>> +		cpl = svm->vmcb->save.cs.selector & 0x3;
>> +
>> +	svm->vmcb->save.cpl = cpl;
>> +}
>> +
> As you probably know already I think cpl should be updated in
> svm_get_rflags() too. With current patch restoring CS segment
> register before rflags register after migration may cause cpl
> to get wrong value for instance.

I think you mean set_rflags rather than get_rflags?

Patch 4 adds this with the set_rflags emulator callback.

Kevin