Messages in this thread | | | Subject | Re: [PATCH 08/13] KVM: x86/mmu: Protect the tdp_mmu_roots list with RCU | From | Paolo Bonzini <> | Date | Thu, 1 Apr 2021 11:37:12 +0200 |
| |
On 31/03/21 23:08, Ben Gardon wrote: > Protect the contents of the TDP MMU roots list with RCU in preparation > for a future patch which will allow the iterator macro to be used under > the MMU lock in read mode. > > Signed-off-by: Ben Gardon<bgardon@google.com> > --- > arch/x86/kvm/mmu/tdp_mmu.c | 64 +++++++++++++++++++++----------------- > 1 file changed, 36 insertions(+), 28 deletions(-) > > diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c > + spin_lock(&kvm->arch.tdp_mmu_pages_lock); > + list_del_rcu(&root->link); > + spin_unlock(&kvm->arch.tdp_mmu_pages_lock);
Please update the comment above tdp_mmu_pages_lock in arch/x86/include/asm/kvm_host.h as well.
> /* Only safe under the MMU lock in write mode, without yielding. */ > #define for_each_tdp_mmu_root(_kvm, _root) \ > - list_for_each_entry(_root, &_kvm->arch.tdp_mmu_roots, link) > + list_for_each_entry_rcu(_root, &_kvm->arch.tdp_mmu_roots, link, \ > + lockdep_is_held_write(&kvm->mmu_lock))
This should also add "... || lockdep_is_help(&kvm->arch.tdp_mmu_pages_lock)", if only for documentation purposes.
Paolo
| |