On 07/09/2018 13:59, Wei Yang wrote:
> Here is the code path which shows kvm_mmu_setup() is invoked after
> kvm_mmu_create(). Since kvm_mmu_setup() is only invoked in this code path,
> this means the root_hpa and prev_roots are guaranteed to be invalid. And
> it is not necessary to reset it again.
>
> kvm_vm_ioctl_create_vcpu()
> kvm_arch_vcpu_create()
> vmx_create_vcpu()
> kvm_vcpu_init()
> kvm_arch_vcpu_init()
> kvm_mmu_create()
> kvm_arch_vcpu_setup()
> kvm_mmu_setup()
> kvm_init_mmu()
>
> This patch set reset_roots to false in kmv_mmu_setup().
>
> Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx>
> Reviewed-by: Liran Alon <liran.alon@xxxxxxxxxx>
>
> ---
> v3: add a comment in code based on Liran comment.
> v2: adjust changelog based on Sean Christopherson comment
> ---
> arch/x86/kvm/mmu.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index b2b88454b1d8..899c029cff0d 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -5413,7 +5413,12 @@ void kvm_mmu_setup(struct kvm_vcpu *vcpu)
> {
> MMU_WARN_ON(VALID_PAGE(vcpu->arch.mmu.root_hpa));
>
> - kvm_init_mmu(vcpu, true);
> + /*
> + * kvm_mmu_setup() is called only on vCPU initialization.
> + * Therefore, no need to reset mmu roots as they are not yet
> + * initialized.
> + */
> + kvm_init_mmu(vcpu, false);
> }
>
> static void kvm_mmu_invalidate_zap_pages_in_memslot(struct kvm *kvm,
>
Queued, thanks.
Paolo
