From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f201.google.com (mail-pf1-f201.google.com [209.85.210.201]) (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 6E52942BEBA for ; Tue, 14 Jul 2026 23:10:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784070636; cv=none; b=k/30ynOmIzLeAkMH6TJxco8wxyuFPyD+mM1NaQT1xQx1IJnD0QFuUSnEOKqdOJG+xrDeHiypofcYPBWc6OgUcZohVvGUu57D4agITsops9JHdJL+zTWbPSXGu4CXCWmTGrPnfSKsRwhcDUW7bFf8hoXq0Ha1Sg2yHd9hF3sEDJg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784070636; c=relaxed/simple; bh=VS5kLf1YHr+hxUl/0CfBAnuEHDyMwEcyfjPnCxppJuE=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=EpXHDhdAQvcIJEkGceezlC9YJJvsKDuFunH08wuyLwCu44cW5h/spwedfxRlRADV+dfnrZhonYhK1w6P/RDrPZbjeyfQxCocAUAi/JOtORl7YDCeGX6nA4YnveLjHtiabH552jW29pApCTjhmW55m+mFAeqjzPVEBg0tkjW0J40= 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=ToLrMPnE; arc=none smtp.client-ip=209.85.210.201 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="ToLrMPnE" Received: by mail-pf1-f201.google.com with SMTP id d2e1a72fcca58-84859a64079so8613930b3a.3 for ; Tue, 14 Jul 2026 16:10:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1784070631; x=1784675431; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:reply-to:from:to:cc:subject:date:message-id :reply-to:content-type; bh=uQPpkuZ7+BAJNsSp57OZqehFLTzlDB+hdw9yVvivlTA=; b=ToLrMPnEQgrvy/6pElccCWUX7IDXos9ZdEmw9Z2zbpNnd/xvLiWZiigPIQUGhDTJXH x2U6xrz6GZCa9gg+X6ZQq0pqqn52YwibXqkrIqVkXURKNMNSxPxuXud+rxj/Kv8bo1bV wiGYrICOZoKcVv9GyofzkNit5CUN+Xm9v6AEPyEcOhD7Fc99GxNGk2WzDBia+x1tTuqv R0CHkxTGdy/iRJsXd+Bn15c1rW/au4hALMl5sNGBNuhs+oxMfi1eaGcd3Wg6rgMedcvQ u4Adj1M/W1RNf3XsQtD7dLQRltomPYan72DV1Foofno3NzhFadYW6EFRus5aveHx/nD1 m80w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1784070631; x=1784675431; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:reply-to:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to:content-type; bh=uQPpkuZ7+BAJNsSp57OZqehFLTzlDB+hdw9yVvivlTA=; b=LMVoBeMv1tbVMBpXLaVaHvmFB4aSqoeKk7kmPymls8WFq8rfUkjsnZYHCByZBiB9xN L7jSdbswjkhAtLJ4woBLpf9hycxCE01DX64o6HCiyAOtMqfuLSSqYlJYlD4InDMcMfGn rw5c6Go7cWijsJuWKDocFsjT51lO9XrXtZufRXN33sMmFkAE3piJ7ScilbeaOyZqNMkH U+zRMD8GBKyHVN6xuKCmEGDlVIi/vnZF3tACUzhUA7wqdIqfSeMFHHScvRH3AEnfH6Kq fBj0CVxi248ANqRun8ZucOlEi+wIM47Pud1GzmJTDolgvOffazKraM4jYJqhuS57pIxH HV+w== X-Forwarded-Encrypted: i=1; AHgh+RqIRpg1gczG9vyS26RcrPaPq1ngDfdoJf/jBITn4Dz5DLqsDbxReXoCOKWw2Drmse9e+TNAshJSvgcfqgY=@vger.kernel.org X-Gm-Message-State: AOJu0YzKBiUfV8b+6GhM+81nUiaLj11GdTlyrWAesAklUpWcdtlg2F8V Ysbe3VPrD3ZlWTNQxKPCd6hYAWboykZ7QLt1NcG/jfdUKOaJfH0Uwjq2ht2hgrOtt9EgUDwjID3 qBpmu4g== X-Received: from pfnx11.prod.google.com ([2002:aa7:84cb:0:b0:847:a522:7e85]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:3d55:b0:845:4fec:3f8f with SMTP id d2e1a72fcca58-84a55894653mr4282637b3a.40.1784070630545; Tue, 14 Jul 2026 16:10:30 -0700 (PDT) Reply-To: Sean Christopherson Date: Tue, 14 Jul 2026 16:10:12 -0700 In-Reply-To: <20260714231015.3337831-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260714231015.3337831-1-seanjc@google.com> X-Mailer: git-send-email 2.55.0.141.g00534a21ce-goog Message-ID: <20260714231015.3337831-5-seanjc@google.com> Subject: [PATCH v5 4/7] KVM: guest_memfd: Fold __kvm_gmem_prepare_folio() into its sole caller From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Fuad Tabba , Ackerley Tng Content-Type: text/plain; charset="UTF-8" Fold __kvm_gmem_prepare_folio() into kvm_gmem_prepare_folio() and extend the #ifdef guard to cover all of the kvm_gmem_prepare_folio(). Take care to align the gfn _before_ computing the index, otherwise KVM would end up with a mismatched gfn+pfn pair for folios larger than order-0 (this detail was subtly handled by recomputing gfn in the helper using the aligned pfn). Providing a single-use, ~2 line tail-call helper adds no value. In fact, due to having to reconstitute the gfn, *and* effectively hiding the alignment adjustment for hugepages, the separate helper is very arguably a net negative. Opportunistically convert the existing WARN in the prepare flow to a only fire once, e.g. so that a guest_memfd bug doesn't unintentionally Dos the kernel by spamming the log. No functional change intended. Signed-off-by: Sean Christopherson --- virt/kvm/guest_memfd.c | 24 ++++++++---------------- 1 file changed, 8 insertions(+), 16 deletions(-) diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c index 62c2c157f0c1..f9a1d6d64f6c 100644 --- a/virt/kvm/guest_memfd.c +++ b/virt/kvm/guest_memfd.c @@ -60,19 +60,6 @@ static pgoff_t kvm_gmem_get_index(struct kvm_memory_slot *slot, gfn_t gfn) return gfn - slot->base_gfn + slot->gmem.pgoff; } -static int __kvm_gmem_prepare_folio(struct kvm *kvm, struct kvm_memory_slot *slot, - pgoff_t index, struct folio *folio) -{ -#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_PREPARE - kvm_pfn_t pfn = folio_file_pfn(folio, index); - gfn_t gfn = slot->base_gfn + index - slot->gmem.pgoff; - - return kvm_arch_gmem_prepare(kvm, gfn, pfn, folio_order(folio)); -#else - return 0; -#endif -} - /* * Process @folio, which contains @gfn, so that the guest can use it. * The folio must be locked and the gfn must be contained in @slot. @@ -82,6 +69,7 @@ static int __kvm_gmem_prepare_folio(struct kvm *kvm, struct kvm_memory_slot *slo static int kvm_gmem_prepare_folio(struct kvm *kvm, struct kvm_memory_slot *slot, gfn_t gfn, struct folio *folio) { +#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_PREPARE pgoff_t index; /* @@ -97,11 +85,15 @@ static int kvm_gmem_prepare_folio(struct kvm *kvm, struct kvm_memory_slot *slot, * The order will be passed when creating the guest_memfd, and * checked when creating memslots. */ - WARN_ON(!IS_ALIGNED(slot->gmem.pgoff, folio_nr_pages(folio))); + WARN_ON_ONCE(!IS_ALIGNED(slot->gmem.pgoff, folio_nr_pages(folio))); + gfn = ALIGN_DOWN(gfn, folio_nr_pages(folio)); index = kvm_gmem_get_index(slot, gfn); - index = ALIGN_DOWN(index, folio_nr_pages(folio)); - return __kvm_gmem_prepare_folio(kvm, slot, index, folio); + return kvm_arch_gmem_prepare(kvm, gfn, folio_file_pfn(folio, index), + folio_order(folio)); +#else + return 0; +#endif } /* -- 2.55.0.141.g00534a21ce-goog