Messages in this thread | | | Subject | Re: [PATCH 09/10 RFC] KVM: x86: MMU: Move parent_pte handling from kvm_mmu_get_page() to link_shadow_page() | From | Paolo Bonzini <> | Date | Thu, 12 Nov 2015 15:27:26 +0100 |
| |
On 12/11/2015 12:56, Takuya Yoshikawa wrote: > diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h > index 9d21b44..f414ca6 100644 > --- a/arch/x86/kvm/paging_tmpl.h > +++ b/arch/x86/kvm/paging_tmpl.h > @@ -598,7 +598,7 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr, > goto out_gpte_changed; > > if (sp) > - link_shadow_page(it.sptep, sp, PT_GUEST_ACCESSED_MASK); > + link_shadow_page(vcpu, it.sptep, sp, PT_GUEST_ACCESSED_MASK); > } >
Here I think you can remove completely the
if (sp) kvm_mmu_put_page(sp, it.sptep);
later in FNAME(fetch). Apart from this nit, it's okay.
On to kvm_mmu_get_page...
if (!direct) { if (rmap_write_protect(vcpu, gfn)) kvm_flush_remote_tlbs(vcpu->kvm); if (level > PT_PAGE_TABLE_LEVEL && need_sync) kvm_sync_pages(vcpu, gfn);
This seems fishy.
need_sync is set if sp->unsync, but then the parents have not been unsynced yet.
On the other hand, all calls to kvm_mmu_get_page except for the roots are followed by link_shadow_page... Perhaps if parent_pte != NULL you can call link_shadow_page directly from kvm_mmu_get_page. The call would go before the "if (!direct)" and it would subsume all the existing calls.
We could probably also warn if
(parent_pte == NULL) != (level == vcpu->arch.mmu.root_level)
in kvm_mmu_get_page.
Paolo
| |