On Thu, May 26, 2022, David Matlack wrote: > On Sat, May 21, 2022 at 09:16:50PM +0800, Lai Jiangshan wrote: > > From: Lai Jiangshan <jiangshan.ljs@xxxxxxxxxxxx> > > > > In some cases, local root pages are used for MMU. It is often using > > to_shadow_page(mmu->root.hpa) to check if local root pages are used. > > > > Add using_local_root_page() to directly check if local root pages are > > used or needed to be used even mmu->root.hpa is not set. > > > > Prepare for making to_shadow_page(mmu->root.hpa) returns non-NULL via > > using local shadow [root] pages. > > > > Signed-off-by: Lai Jiangshan <jiangshan.ljs@xxxxxxxxxxxx> > > --- > > arch/x86/kvm/mmu/mmu.c | 40 +++++++++++++++++++++++++++++++++++++--- > > 1 file changed, 37 insertions(+), 3 deletions(-) > > > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > > index efe5a3dca1e0..624b6d2473f7 100644 > > --- a/arch/x86/kvm/mmu/mmu.c > > +++ b/arch/x86/kvm/mmu/mmu.c > > @@ -1690,6 +1690,39 @@ static void drop_parent_pte(struct kvm_mmu_page *sp, > > mmu_spte_clear_no_track(parent_pte); > > } > > > > +/* > > + * KVM uses the VCPU's local root page (vcpu->mmu->pae_root) when either the > > + * shadow pagetable is using PAE paging or the host is shadowing nested NPT for > > + * 32bit L1 hypervisor. > > How about using the terms "private" and "shared" instead of "local" and > "non-local"? I think that more accurately conveys what is special about > these pages: they are private to the vCPU using them. And then "shared" > is more intuitive to understand than "non-local" (which is used > elsewhere in this series). Please avoid "private" and "shared". I haven't read the full context of the discussion, but those terms have already been claimed by confidential VMs. FWIW, I believe similar discussions happened around mm/ and kmap(), and they ended up with thread_local and kmap_local(). Maybe "vCPU local" and "common"?
