From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f74.google.com (mail-ed1-f74.google.com [209.85.208.74]) (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 237942D9ED1 for ; Tue, 15 Jul 2025 09:34:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.74 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752572058; cv=none; b=rypNetArqoExLJWwGnafHSxnM+O7ZwvShqWh806B2flNFbT+EHupc5hMMs1RgKst0MSmifIB+BAx4FuShs8zJ+9wM0ChLcuaYNJYaKmXNuL+TSX/1AGtj+xY+EcXkOZAt8uZpqp2RI2Dg4rWGxTpXtUlVoi6cQhIF9tW3F/vgdY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752572058; c=relaxed/simple; bh=5SFcmIaZT18BqEoeZQIYRV1Aqypru/hVXQDtZkdpxP8=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=MLmyze9bdx8FTf43DkDnLRGOBftlqp2QaedQcMKBibu0VImdbXN0rsemTUmEQ8BY/8H23TACrlCSGJ64zivFtDVREZPXWv+Sn57tafKwZCBUfAyk6JDPyUCKr2vvBs5CeBo+zK1yZyoVz7U0k8y3Q+0//79Gm7yJMd8dhqQLo40= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--tabba.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=RPW3m2fB; arc=none smtp.client-ip=209.85.208.74 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--tabba.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="RPW3m2fB" Received: by mail-ed1-f74.google.com with SMTP id 4fb4d7f45d1cf-60995aa5417so4372870a12.1 for ; Tue, 15 Jul 2025 02:34:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1752572055; x=1753176855; 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=NswHrgkdcqxmOhQmg+I1ZftODzAqq/smUBNc/8jSsg0=; b=RPW3m2fBzSZtxB0J60H9AxPxtWjVFVEO74IHZ/kl2va8+WbU1+rMS4iTx5xaEKtfKI KHps8ja+lTRYvft86HkStdA4LDB51dhgxBOL6KUxBYE0rW+7TfvfVc8jH5o78kT5j4bE LU0Kh7Dukmeov7HBtpolJQ5i8ryOVZWmNnxYo/PysXrrGpuB1QrjlC332KdVcV77Fapz R3elF7FvLWbJURtCzHwFpsn5/S17LgD56tejLiaMRo+dNgNUCwoYgzgQQ8i10SP+wBdN wcmBjYogvmVeZJRTZh4luGyDO/Vtw//WzIOLMPBQYISlzXDfsz5uJ9dLfR5m0psnrk0K tpqw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1752572055; x=1753176855; 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=NswHrgkdcqxmOhQmg+I1ZftODzAqq/smUBNc/8jSsg0=; b=u+sNYoO4BOiGPIg1skwVt2iTIUaSzX8X4awAoCVEtBtX+qrgV1JpIPY1U0ADUr52n4 X8FADCPbX+LiSTc5nGdLHjSFyrI5ocLSAlqwKlIh8OuXhIrTH9AwKXH+FeGola1rmAOt eDddyojmKlLwDm1C3jBS+LIIqKDoLpuPcnOt4xmfOH7I4W6MMcJE0L4oXT8N5HucK/zw PcZbI+i/f+e5pd7ZiQKXlzPqUM88LdX9uo8QbW9q550pEpXxXn1QbLc9iJ9cB76AUbVz wDSrRo2K6N6VVWMYJ4zvOhms9FbwYTWcFh81a32EpQn+7KUD74YN6ZgRSIU52v8hKqYN EszA== X-Gm-Message-State: AOJu0YyOFriYNU0OBF+bQBSFbKNGyuNF+HhjGQP/j6KRAae3obh7ys2h b+CkGGEc+5CdgnUHkAHveua9RTP078OnxLsES+OhY74hywzkuRF/lT7b3uov6Y++MpFcM+Md6AZ fH0C4yXkIwHxA2/EwK1nV1FtjhVCcrT2g6Lzk0/8hPrEDsjAT4daRiUm+6nfHY4Q7WCkUIgmGPI D3+6KDyCfEmNtArEu7smH8C/xoKI4= X-Google-Smtp-Source: AGHT+IEDLe189qOiRgDedu5bKfhg6mmUJkhqiiy6MmhlJTVyAYMWtzw6N/Xpnr+zd4xHJ/TAYV4yM5jmtg== X-Received: from edbev26.prod.google.com ([2002:a05:6402:541a:b0:609:287d:ce97]) (user=tabba job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6402:22ba:b0:607:7de4:598b with SMTP id 4fb4d7f45d1cf-611e7636978mr9326687a12.9.1752572055050; Tue, 15 Jul 2025 02:34:15 -0700 (PDT) Date: Tue, 15 Jul 2025 10:33:40 +0100 In-Reply-To: <20250715093350.2584932-1-tabba@google.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250715093350.2584932-1-tabba@google.com> X-Mailer: git-send-email 2.50.0.727.gbf7dc18ff4-goog Message-ID: <20250715093350.2584932-12-tabba@google.com> Subject: [PATCH v14 11/21] KVM: x86/mmu: Allow NULL-able fault in kvm_max_private_mapping_level From: Fuad Tabba To: kvm@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-mm@kvack.org, kvmarm@lists.linux.dev Cc: pbonzini@redhat.com, chenhuacai@kernel.org, mpe@ellerman.id.au, anup@brainfault.org, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, seanjc@google.com, viro@zeniv.linux.org.uk, brauner@kernel.org, willy@infradead.org, akpm@linux-foundation.org, xiaoyao.li@intel.com, yilun.xu@intel.com, chao.p.peng@linux.intel.com, jarkko@kernel.org, amoorthy@google.com, dmatlack@google.com, isaku.yamahata@intel.com, mic@digikod.net, vbabka@suse.cz, vannapurve@google.com, ackerleytng@google.com, mail@maciej.szmigiero.name, david@redhat.com, michael.roth@amd.com, wei.w.wang@intel.com, liam.merwick@oracle.com, isaku.yamahata@gmail.com, kirill.shutemov@linux.intel.com, suzuki.poulose@arm.com, steven.price@arm.com, quic_eberman@quicinc.com, quic_mnalajal@quicinc.com, quic_tsoni@quicinc.com, quic_svaddagi@quicinc.com, quic_cvanscha@quicinc.com, quic_pderrin@quicinc.com, quic_pheragu@quicinc.com, catalin.marinas@arm.com, james.morse@arm.com, yuzenghui@huawei.com, oliver.upton@linux.dev, maz@kernel.org, will@kernel.org, qperret@google.com, keirf@google.com, roypat@amazon.co.uk, shuah@kernel.org, hch@infradead.org, jgg@nvidia.com, rientjes@google.com, jhubbard@nvidia.com, fvdl@google.com, hughd@google.com, jthoughton@google.com, peterx@redhat.com, pankaj.gupta@amd.com, ira.weiny@intel.com, tabba@google.com Content-Type: text/plain; charset="UTF-8" From: Ackerley Tng Refactor kvm_max_private_mapping_level() to accept a NULL kvm_page_fault pointer and rename it to kvm_gmem_max_mapping_level(). The max_mapping_level x86 operation (previously private_max_mapping_level) is designed to potentially be called without an active page fault, for instance, when kvm_mmu_max_mapping_level() is determining the maximum mapping level for a gfn proactively. Allow NULL fault pointer: Modify kvm_max_private_mapping_level() to safely handle a NULL fault argument. This aligns its interface with the kvm_x86_ops.max_mapping_level operation it wraps, which can also be called with NULL. Rename function to kvm_gmem_max_mapping_level(): This reinforces that the function's scope is for guest_memfd-backed memory, which can be either private or non-private, removing any remaining "private" connotation from its name. Optimize max_level checks: Introduce a check in the caller to skip querying for max_mapping_level if the current max_level is already PG_LEVEL_4K, as no further reduction is possible. Acked-by: David Hildenbrand Suggested-by: Sean Christoperson Signed-off-by: Ackerley Tng Signed-off-by: Fuad Tabba --- arch/x86/kvm/mmu/mmu.c | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index bb925994cbc5..6bd28fda0fd3 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -4467,17 +4467,13 @@ static inline u8 kvm_max_level_for_order(int order) return PG_LEVEL_4K; } -static u8 kvm_max_private_mapping_level(struct kvm *kvm, - struct kvm_page_fault *fault, - int gmem_order) +static u8 kvm_gmem_max_mapping_level(struct kvm *kvm, int order, + struct kvm_page_fault *fault) { - u8 max_level = fault->max_level; u8 req_max_level; + u8 max_level; - if (max_level == PG_LEVEL_4K) - return PG_LEVEL_4K; - - max_level = min(kvm_max_level_for_order(gmem_order), max_level); + max_level = kvm_max_level_for_order(order); if (max_level == PG_LEVEL_4K) return PG_LEVEL_4K; @@ -4513,7 +4509,9 @@ static int kvm_mmu_faultin_pfn_private(struct kvm_vcpu *vcpu, } fault->map_writable = !(fault->slot->flags & KVM_MEM_READONLY); - fault->max_level = kvm_max_private_mapping_level(vcpu->kvm, fault, max_order); + if (fault->max_level >= PG_LEVEL_4K) + fault->max_level = kvm_gmem_max_mapping_level(vcpu->kvm, + max_order, fault); return RET_PF_CONTINUE; } -- 2.50.0.727.gbf7dc18ff4-goog