On Fri, Jan 27, 2023 at 11:36:52PM +0200, Zhi Wang <zhi.wang.linux@xxxxxxxxx> wrote: > On Wed, 25 Jan 2023 17:22:08 +0000 > Sean Christopherson <seanjc@xxxxxxxxxx> wrote: > > > On Wed, Jan 25, 2023, Zhi Wang wrote: > > > On Thu, 12 Jan 2023 08:31:38 -0800 > > > isaku.yamahata@xxxxxxxxx wrote: > > > > > > This refactor patch is quite hacky. > > > > > > Why not change the purpose of vcpu->arch.mmu_shadow_page.gfp_zero and let the > > > callers respect that the initial value of spte can be configurable? It will be > > > generic and not TDX-specific, then kvm_init_shadow_page() is not required, > > > mmu_topup_shadow_page_cache() can be left un-touched as the refactor can cover > > > other architectures. > > > > > > 1) Let it store the expected nonpresent value and rename it to nonpresent_spte. > > > > > > I agree that handling this in the common code would be cleaner, but repurposing > > gfp_zero gets kludgy because it would require a magic value to say "don't initialize > > the data", e.g. x86's mmu_shadowed_info_cache isn't pre-filled. > > > > And supporting a custom 64-bit init value for kmem_cache-backed caches would require > > restricting such caches to be a multiple of 8 bytes in size. > > > > How about this? Lightly tested. > > > > From: Sean Christopherson <seanjc@xxxxxxxxxx> > > Date: Wed, 25 Jan 2023 16:55:01 +0000 > > Subject: [PATCH] KVM: Allow page-sized MMU caches to be initialized with > > custom 64-bit values > > > > It looks good enough so far although it only supports 64bit init value. But > it can be extended in the future. > > Just want to make sure people are thinking the same: > > 1) Keep the changes of SHADOW_NONPRESENT_VALUE and REMOVED_SPTE in TDX patch. > init_value stays as a generic feature in the kvm mmu cache layer. It is *not* > going to replace SHADOW_NONPRESENT_VALUE. > > 2) TDX kvm_x86_vcpu_create sets the SHADOW_NONPRESENT value into init_value. > > 3) mmu cache topping up function initializes the page according to init_value > with Sean's patch. The patch worked for me. Included into v12 patch series. -- Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
