From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f73.google.com (mail-pj1-f73.google.com [209.85.216.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BBE6A802 for ; Sat, 18 Jan 2025 01:05:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.73 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737162347; cv=none; b=hPvB7HKAeQBI6tzrAkPWT+tJotv5EnzikVZyanaA8fVwKY9EFtHJNrfkOeS/O6/yGZJmATjHTCAEm6tWr8vl8d7swoy8+Q036BZAwp56UQshcmW19deEqK9gw/vBBrv2N4TvREPqHhdcHuK13ZvqtuOluPe7rvjNNHkwzWflHR0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737162347; c=relaxed/simple; bh=Q/TINJUO8d2fOGe9JWbqFqDyKh7waSf5CJ+SpnwXEVA=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=NtZbOiruUyRYk3kxpa87gBnAjWZCjNWSp8wIGJp859MIoPyGyAdJaDlSfKJf3ISKlbWVi66ObNdzzF0vxXcJgmI6kfuYWI4TyEDYpHb88UdG58lzMiYiR5TS2XJwY1bOLhcR8EBEUK4GgDR1a8j4g/BxiUJo3gizHtkzxJ/aSqY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=3MXlWmws; arc=none smtp.client-ip=209.85.216.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="3MXlWmws" Received: by mail-pj1-f73.google.com with SMTP id 98e67ed59e1d1-2ef9dbeb848so5137737a91.0 for ; Fri, 17 Jan 2025 17:05:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1737162344; x=1737767144; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=wyh5C9zC3vuSZuTnGAGVYg2j9KLur0MVGQPHVsQm1yE=; b=3MXlWmwssOaHvn4JCKu93GpPsm2D2nCZCzMbk73lXzzZqGaOsfQf9g5KWEEJbB5ywY sF4ZjF33IkgDNZNSV3aeEc/hYa3YC/KWlDkoZUgQMT8z623PuKTbeV629aqEYQlW39ZJ BaTX4Ladv9Mo+ZTeibagZqmoc3cY1qIx1jMUmtTqKShrL2oBILeZ9ucmM0OUGah+TwRx 2fE4ACLv0zWZGmoVaXWUtNzx+vHqhNruGnbhv9Tmo34ac9QCc6zvlMtp+GvBomsJqioO 6RC8/cbDqd8BwxkDdQT7q0otDNbhl47+Fcs/82HlLXCd1WXOMh/FF3joOuGRVyuNQplW +Dlw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1737162344; x=1737767144; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=wyh5C9zC3vuSZuTnGAGVYg2j9KLur0MVGQPHVsQm1yE=; b=PZxPUiwxNQn59REpAey9hMv2zTJ4vNvyKaI7B+tPAkWmF1TOgpiCqIB6FSsfDGM29+ zmgn6yzSxF8ER+SjzXQVUOH8XiePgTc/pM0ZKL7qc0+4uttu4CzoD9CheG8YNcHLoTCj rZ/k9no++jGoOmGOFCaPdoJoF+DaXD3l3sCMk+wD4RtQxSwhaZXwOlc7GfXocPDAcvgX lxcOhfEL+5WY+3HSwJQZjKy64xuf19flqNh1PYa1krPBgJRupZ34cwH61PWWPAGi87Mg nPuGXt+VnxR+mGCIINDVyvAt8zgSS02eMVpx/P2sdYv0e5449J/1Sx2vrEyPO4ZpbXGn X7tQ== X-Gm-Message-State: AOJu0Yy51++XhaiAlgt3NACLRayzrGlEad8TJETht4kgCXUIG9rTDpRR Us3Y5XwN/Dt24Cz9OOazCwfnMrxLFkIqZDVL/tIn5R9YKJe3w1XY31pHbW49VWGmfY7ayCoyk6D oYw== X-Google-Smtp-Source: AGHT+IFbFqS0H7ctmQ/zosfCbMGK7ZNM4mMgLKLsDqrW5+LVcr2Y80YkNVAWyodcvOgfToaFg1wxh48u/HE= X-Received: from pjbsd15.prod.google.com ([2002:a17:90b:514f:b0:2ea:46ed:5d3b]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90a:e18f:b0:2ee:d7d3:3019 with SMTP id 98e67ed59e1d1-2f782c7a769mr8119864a91.12.1737162344033; Fri, 17 Jan 2025 17:05:44 -0800 (PST) Date: Fri, 17 Jan 2025 17:05:42 -0800 In-Reply-To: <20241222193445.349800-10-pbonzini@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20241222193445.349800-1-pbonzini@redhat.com> <20241222193445.349800-10-pbonzini@redhat.com> Message-ID: Subject: Re: [PATCH v6 09/18] KVM: x86/tdp_mmu: Extract root invalid check from tdx_mmu_next_root() From: Sean Christopherson To: Paolo Bonzini Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, yan.y.zhao@intel.com, isaku.yamahata@intel.com, binbin.wu@linux.intel.com, rick.p.edgecombe@intel.com Content-Type: text/plain; charset="us-ascii" On Sun, Dec 22, 2024, Paolo Bonzini wrote: > From: Isaku Yamahata > > Extract tdp_mmu_root_match() to check if the root has given types and use > it for the root page table iterator. It checks only_invalid now. > > TDX KVM operates on a shared page table only (Shared-EPT), a mirrored page > table only (Secure-EPT), or both based on the operation. KVM MMU notifier > operations only on shared page table. KVM guest_memfd invalidation > operations only on mirrored page table, and so on. Introduce a centralized > matching function instead of open coding matching logic in the iterator. > The next step is to extend the function to check whether the page is shared > or private > > Link: https://lore.kernel.org/kvm/ZivazWQw1oCU8VBC@google.com/ > Signed-off-by: Isaku Yamahata > Signed-off-by: Rick Edgecombe > Message-ID: <20240718211230.1492011-10-rick.p.edgecombe@intel.com> > Signed-off-by: Paolo Bonzini > --- > arch/x86/kvm/mmu/tdp_mmu.c | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c > index 5b01038ddce8..e0ccfdd4200b 100644 > --- a/arch/x86/kvm/mmu/tdp_mmu.c > +++ b/arch/x86/kvm/mmu/tdp_mmu.c > @@ -92,6 +92,14 @@ void kvm_tdp_mmu_put_root(struct kvm *kvm, struct kvm_mmu_page *root) > call_rcu(&root->rcu_head, tdp_mmu_free_sp_rcu_callback); > } > > +static bool tdp_mmu_root_match(struct kvm_mmu_page *root, bool only_valid) > +{ > + if (only_valid && root->role.invalid) > + return false; > + > + return true; Ugh, this is almost as bad as if (x) return true; return false; Just do return !only_valid || root->role.invalid; And I vote to drop the helper, "match" makes me think about things like roles and addresses, not just if a root is valid. > +} > + > /* > * Returns the next root after @prev_root (or the first root if @prev_root is > * NULL). A reference to the returned root is acquired, and the reference to > @@ -125,7 +133,7 @@ static struct kvm_mmu_page *tdp_mmu_next_root(struct kvm *kvm, > typeof(*next_root), link); > > while (next_root) { > - if ((!only_valid || !next_root->role.invalid) && > + if (tdp_mmu_root_match(next_root, only_valid) && E.g. this can just as easily be !only_valid || root->role.invalid && which is amusingly even fewer characters :-D > kvm_tdp_mmu_get_root(next_root)) > break; > > @@ -176,7 +184,7 @@ static struct kvm_mmu_page *tdp_mmu_next_root(struct kvm *kvm, > list_for_each_entry(_root, &_kvm->arch.tdp_mmu_roots, link) \ > if (kvm_lockdep_assert_mmu_lock_held(_kvm, false) && \ > ((_as_id >= 0 && kvm_mmu_page_as_id(_root) != _as_id) || \ > - ((_only_valid) && (_root)->role.invalid))) { \ > + !tdp_mmu_root_match((_root), (_only_valid)))) { \ > } else > > #define for_each_tdp_mmu_root(_kvm, _root, _as_id) \ > -- > 2.43.5 > >