Wincy Van wrote on 2015-01-28:
> On Wed, Jan 28, 2015 at 4:05 PM, Zhang, Yang Z <yang.z.zhang@xxxxxxxxx>
> wrote:
>>> @@ -8344,7 +8394,68 @@ static int
>>> nested_vmx_check_msr_bitmap_controls(struct kvm_vcpu *vcpu, static
>>> inline bool nested_vmx_merge_msr_bitmap(struct kvm_vcpu *vcpu,
>>> struct vmcs12
>>> *vmcs12) { - return false; + struct page *page; +
>>> unsigned long *msr_bitmap; + + if
>>> (!nested_cpu_has_virt_x2apic_mode(vmcs12)) + return
>>> false; + + page = nested_get_page(vcpu, vmcs12->msr_bitmap); +
>>> if (!page) { + WARN_ON(1); + return
>>> false; + } + msr_bitmap = (unsigned long *)kmap(page); +
>>> if (!msr_bitmap) { +
>>> nested_release_page_clean(page); + WARN_ON(1); +
>>> return false; + } + + memset(vmx_msr_bitmap_nested,
>>> 0xff, PAGE_SIZE); + + if
>>> (nested_cpu_has_virt_x2apic_mode(vmcs12)) + /* TPR is
>>> allowed */ +
>>> nested_vmx_disable_intercept_for_msr(msr_bitmap, +
>>> vmx_msr_bitmap_nested, +
>>> APIC_BASE_MSR + (APIC_TASKPRI >> 4), +
>>> MSR_TYPE_R | MSR_TYPE_W);
>>
>> I didn't understand what this function does? Per my understanding,
>> you only
> need to set the (vmx_msr_bitmap_nested = vmcs01->msr_bitmap |
> vmcs12->msr_bitmap) and inject the nested vmexit to L1 if the bit in
> vmcs12->msr_bitmap is setting. Am I missing some patches?
>
> In the beginning, I want to do "vmcs01->msr_bitmap |
> vmcs12->msr_bitmap", but I remember that there isn't a instruction to
> do a bit or operation in two pages effectively, so I do the bit or
> operation in nested_vmx_disable_intercept_for_msr. If the hardware do
> not support this, I think it is faster if we deal with the bits on demand.
> nested_vmx_merge_msr_bitmap is used to merge L0's and L1's bitmaps,
> any features can put their logic here.
You construct the nested_msr_bitmap based on vmcs12->msr_bitmap, what happens if vmcs01->msr_bitmap want to trap this msr?
>
> If there is a faster way, please teach me how to do it : )
You are right. Interception should be much faster.
>
> Thanks,
> Wincy
>
>
>>
>> Best regards,
>> Yang
>>
>>
Best regards,
Yang
��.n��������+%������w��{.n�����o�^n�r������&��z�ޗ�zf���h���~����������_��+v���)ߣ�
