From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3710E22A1D4; Fri, 19 Jun 2026 00:31:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781829108; cv=none; b=QClCsRifJmbHt+4hS59Tv6tQCPPmK1xtPG0ZKuVqTMlQORKCIX0JDrBh7qIfKcM06unaDQAOHDz5ut7zE2KSRoycd4GNbZim4CQmciRNlD6nzdqByK+0fJgXmoT+kC1aySdQ7wDSItkm3MG95HQsmEAvWbHTlDE0YVA6wy6LFeM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781829108; c=relaxed/simple; bh=A9BWuh0zIJhcTYm8FbYh9REZtau55hLwvqXKIUHAvpg=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=u+LsNdgDPj8iW4dQ8oMbRPR1z8QWL+eUtLRI/drrbURFhKMJgaHMGNHtRZnXYvmMymj+BtqQGjNdOCoaIZHVc8hRRUe11V1q6j67xf8HBqd/tHV+TQLWkyyLkAs+OImNCbSyt2UIDIshxZE4u59/LTQR0Q8N8GOw+Hzu89XZS7U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=q9l837HS; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="q9l837HS" Received: by smtp.kernel.org (Postfix) with ESMTPS id DF23DC32781; Fri, 19 Jun 2026 00:31:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1781829107; bh=A9BWuh0zIJhcTYm8FbYh9REZtau55hLwvqXKIUHAvpg=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=q9l837HSAGanFVnkxhx5p4aqawHRhFurjdvN0l1MqljzPUXSJ57FbLIePoS7JXSQF W7MteyARADKvTMiEQG0t2mvGnWOd6vsnNcoJ1dJFQgsEYmoswPGVPc/dcpl4Tx1f7a zh5xSMPO16LuJKhZpyQTs1ChAchVJQWU7aO7EY0/5H2i4PD9kJoRTI5K+neNvMbeYE MMyHp5c8AH23d/mf/OmcfGRsfFSs82ZcTIHZBlY8fYpaCRVHZ+2kQpGBRKVpL3Aqwl 7jSDfam1cf6SGKlsAfqYZZtbS5W27hbrFcfl+LsikEytlE9WM06JPRbb9dc/RKS++H U6V0hb4v6/wkw== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id CDF06CD98F0; Fri, 19 Jun 2026 00:31:47 +0000 (UTC) From: Ackerley Tng via B4 Relay Date: Thu, 18 Jun 2026 17:31:49 -0700 Subject: [PATCH v8 12/46] KVM: guest_memfd: Only prepare folios for private pages Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260618-gmem-inplace-conversion-v8-12-9d2959357853@google.com> References: <20260618-gmem-inplace-conversion-v8-0-9d2959357853@google.com> In-Reply-To: <20260618-gmem-inplace-conversion-v8-0-9d2959357853@google.com> To: aik@amd.com, andrew.jones@linux.dev, binbin.wu@linux.intel.com, brauner@kernel.org, chao.p.peng@linux.intel.com, david@kernel.org, jmattson@google.com, jthoughton@google.com, michael.roth@amd.com, oupton@kernel.org, pankaj.gupta@amd.com, qperret@google.com, rick.p.edgecombe@intel.com, rientjes@google.com, shivankg@amd.com, steven.price@arm.com, tabba@google.com, willy@infradead.org, wyihan@google.com, yan.y.zhao@intel.com, forkloop@google.com, pratyush@kernel.org, suzuki.poulose@arm.com, aneesh.kumar@kernel.org, liam@infradead.org, Paolo Bonzini , Sean Christopherson , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Jonathan Corbet , Shuah Khan , Shuah Khan , Vishal Annapurve , Andrew Morton , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Youngjun Park , Qi Zheng , Shakeel Butt , Kiryl Shutsemau , Baoquan He , Jason Gunthorpe , Vlastimil Babka , Baoquan He Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, linux-coco@lists.linux.dev, Ackerley Tng X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1781829104; l=2293; i=ackerleytng@google.com; s=20260225; h=from:subject:message-id; bh=mLc3enLG08WtEKTF9ggxBdgxX6UxmOzxM2zY9AloEPg=; b=oZe/Yv8AmFIG+JqyaagwRcu5MeZw2HObrghbwkqyq3I/Gu/hckIe3WskdZS5xQYXmPWHN5vRC FNOBAuaXkL+AWJj4/aQuX0oAXi6c/BQJwVkXeI90j6dbh62iWW57ZYW X-Developer-Key: i=ackerleytng@google.com; a=ed25519; pk=sAZDYXdm6Iz8FHitpHeFlCMXwabodTm7p8/3/8xUxuU= X-Endpoint-Received: by B4 Relay for ackerleytng@google.com/20260225 with auth_id=649 X-Original-From: Ackerley Tng Reply-To: ackerleytng@google.com From: Ackerley Tng All-shared guest_memfd used to be only supported for non-CoCo VMs where preparation doesn't apply. INIT_SHARED is about to be supported for CoCo VMs in a later patch in this series. In addition, KVM_SET_MEMORY_ATTRIBUTES2 is about to be supported in guest_memfd in a later patch in this series. This means that the kvm fault handler may now call kvm_gmem_get_pfn() on a shared folio for a CoCo VM where preparation applies. Add a check to make sure that preparation is only performed for private folios. Preparation will be undone on freeing (see kvm_gmem_free_folio()) and on conversion to shared. Suggested-by: Michael Roth Reviewed-by: Fuad Tabba Signed-off-by: Ackerley Tng --- virt/kvm/guest_memfd.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c index e0e544ef47d69..65ce795c090d9 100644 --- a/virt/kvm/guest_memfd.c +++ b/virt/kvm/guest_memfd.c @@ -890,6 +890,7 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, int *max_order) { pgoff_t index = kvm_gmem_get_index(slot, gfn); + struct inode *inode; struct folio *folio; int r = 0; @@ -897,7 +898,8 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, if (!file) return -EFAULT; - filemap_invalidate_lock_shared(file_inode(file)->i_mapping); + inode = file_inode(file); + filemap_invalidate_lock_shared(inode->i_mapping); folio = __kvm_gmem_get_pfn(file, slot, index, pfn, max_order); if (IS_ERR(folio)) { @@ -910,7 +912,8 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, folio_mark_uptodate(folio); } - r = kvm_gmem_prepare_folio(kvm, slot, gfn, folio); + if (kvm_gmem_is_private_mem(inode, index)) + r = kvm_gmem_prepare_folio(kvm, slot, gfn, folio); folio_unlock(folio); @@ -920,7 +923,7 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, folio_put(folio); out: - filemap_invalidate_unlock_shared(file_inode(file)->i_mapping); + filemap_invalidate_unlock_shared(inode->i_mapping); return r; } EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_gmem_get_pfn); -- 2.55.0.rc0.738.g0c8ab3ebcc-goog