Re: [PATCH v7 043/102] KVM: x86/mmu: Focibly use TDP MMU for TDX

Yuan Yao
2022-07-11T05:48:54Z

On Mon, Jun 27, 2022 at 02:53:35PM -0700, isaku.yamahata@intel.com wrote:
> From: Isaku Yamahata <isaku.yamahata@intel.com>
>
> In this patch series, TDX supports only TDP MMU and doesn't support legacy
> MMU. Forcibly use TDP MMU for TDX irrelevant of kernel parameter to
> disable TDP MMU.
>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
> ---
> arch/x86/kvm/mmu/tdp_mmu.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
> index 82f1bfac7ee6..7eb41b176d1e 100644
> --- a/arch/x86/kvm/mmu/tdp_mmu.c
> +++ b/arch/x86/kvm/mmu/tdp_mmu.c
> @@ -18,8 +18,13 @@ int kvm_mmu_init_tdp_mmu(struct kvm *kvm)
> {
> struct workqueue_struct *wq;
>
> - if (!tdp_enabled || !READ_ONCE(tdp_mmu_enabled))
> - return 0;
> + /*
> + * Because TDX supports only TDP MMU, forcibly use TDP MMU in the case
> + * of TDX.
> + */
> + if (kvm->arch.vm_type != KVM_X86_TDX_VM &&
> + (!tdp_enabled || !READ_ONCE(tdp_mmu_enabled)))
> + return false;

Please return 0 here for int return value type.

>
> wq = alloc_workqueue("kvm", WQ_UNBOUND|WQ_MEM_RECLAIM|WQ_CPU_INTENSIVE, 0);
> if (!wq)
> --
> 2.25.1
>