lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Wed, 10 Nov 2021 23:44:54 +0100 From: Paolo Bonzini <pbonzini@...hat.com> To: Ben Gardon <bgardon@...gle.com>, linux-kernel@...r.kernel.org, kvm@...r.kernel.org Cc: Peter Xu <peterx@...hat.com>, Sean Christopherson <seanjc@...gle.com>, Peter Shier <pshier@...gle.com>, David Matlack <dmatlack@...gle.com>, Mingwei Zhang <mizhang@...gle.com>, Yulei Zhang <yulei.kernel@...il.com>, Wanpeng Li <kernellwp@...il.com>, Xiao Guangrong <xiaoguangrong.eric@...il.com>, Kai Huang <kai.huang@...el.com>, Keqian Zhu <zhukeqian1@...wei.com>, David Hildenbrand <david@...hat.com> Subject: Re: [RFC 11/19] KVM: x86/mmu: Factor shadow_zero_check out of make_spte On 11/10/21 23:30, Ben Gardon wrote: > - WARN_ONCE(is_rsvd_spte(&vcpu->arch.mmu->shadow_zero_check, spte, level), > + WARN_ONCE(is_rsvd_spte(shadow_zero_check, spte, level), > "spte = 0x%llx, level = %d, rsvd bits = 0x%llx", spte, level, > - get_rsvd_bits(&vcpu->arch.mmu->shadow_zero_check, spte, level)); > + get_rsvd_bits(shadow_zero_check, spte, level)); Hmm, there is a deeper issue here, in that when using EPT/NPT (on either the legacy aka shadow or the TDP MMU) large parts of vcpu->arch.mmu are really the same for all vCPUs. The only thing that varies is those parts that actually depend on the guest's paging mode---the extended role, the reserved bits, etc. Those are needed by the emulator, but don't really belong in vcpu->arch.mmu when EPT/NPT is in use. I wonder if there's room for splitting kvm_mmu in two parts, such as kvm_mmu and kvm_guest_paging_context, and possibly change the walk_mmu pointer into a pointer to kvm_guest_paging_context. This way the EPT/NPT MMU (again either shadow or TDP) can be moved to kvm->arch. It should simplify this series and also David's work on eager page splitting. I'm not asking you to do this, of course, but perhaps I can trigger Sean's itch to refactor stuff. :) Paolo
Powered by blists - more mailing lists