From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.223.130]) (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 396EB2DE6F9 for ; Mon, 8 Dec 2025 08:43:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.135.223.130 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765183420; cv=none; b=ffxbWbl5ULjh+NNkhZBFK1kcoXWrJ/549FqhgskkoIjHw5nAMw7gMH6/un3D42p9V9+uQO0x2BukCpT767orLJ+4Cl7+byuPCQogHivxHrYcxwpkmJGtMw+Pywerobafuxyz0F0Z1pdhdQF05Cb6tJSBNHBPphPP64uB71vx1DU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765183420; c=relaxed/simple; bh=076RMy8CdAJS0PoTtdDoiDHyMv0EW+niqNeftGLuu1g=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=sDcxS56eyqlMfLxfV4/sWQLyz5oJi/iFtp54doMUrwfB4svwX2z0AyvrJCRUx414HyksuzzHF0X8dRU0n6chcrf44q5lJ746/js+3uSFFtuRJ51VucvL2vzBij5bFVrzL27NgiZFlBTM88/p+734OVIds/BVnES2v9Xt+ljTaDY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz; spf=pass smtp.mailfrom=suse.cz; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b=xPqIkeq4; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b=pDZVdYJW; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b=xPqIkeq4; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b=pDZVdYJW; arc=none smtp.client-ip=195.135.223.130 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.cz Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b="xPqIkeq4"; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b="pDZVdYJW"; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b="xPqIkeq4"; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b="pDZVdYJW" Received: from imap1.dmz-prg2.suse.org (unknown [10.150.64.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 86BBD33849; Mon, 8 Dec 2025 08:43:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1765183416; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=yK0/tInIe5Sj2qH3JVl2XBHL+xgUUc9R4ncCoNXnSU0=; b=xPqIkeq4/TtH5fjRyHywquhhlnSg8/Fxy8bZr03pv8viiAevOyMnIom8WgbWbH++TEt9AZ kYvI5EyjSuKAijyjXk/MgCiEEyl8pOfjiVaNv1g/vsk335KF8sHFbpuOzJ+wl3K8sX4TLk AV28/reQBE63us3h8C0JRTEGOD9OzQ0= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1765183416; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=yK0/tInIe5Sj2qH3JVl2XBHL+xgUUc9R4ncCoNXnSU0=; b=pDZVdYJWDRQRqzbSZUgWu3LKhzmU9zU1tMR0Qwxcv2fVahBPz8vqRlnpcJfxtFHbRANHwg xQFrBUj3ApRtNuDQ== Authentication-Results: smtp-out1.suse.de; none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1765183416; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=yK0/tInIe5Sj2qH3JVl2XBHL+xgUUc9R4ncCoNXnSU0=; b=xPqIkeq4/TtH5fjRyHywquhhlnSg8/Fxy8bZr03pv8viiAevOyMnIom8WgbWbH++TEt9AZ kYvI5EyjSuKAijyjXk/MgCiEEyl8pOfjiVaNv1g/vsk335KF8sHFbpuOzJ+wl3K8sX4TLk AV28/reQBE63us3h8C0JRTEGOD9OzQ0= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1765183416; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=yK0/tInIe5Sj2qH3JVl2XBHL+xgUUc9R4ncCoNXnSU0=; b=pDZVdYJWDRQRqzbSZUgWu3LKhzmU9zU1tMR0Qwxcv2fVahBPz8vqRlnpcJfxtFHbRANHwg xQFrBUj3ApRtNuDQ== Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id EE7B53EA63; Mon, 8 Dec 2025 08:43:35 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id Kf67ObePNmkjcAAAD6G6ig (envelope-from ); Mon, 08 Dec 2025 08:43:35 +0000 Message-ID: Date: Mon, 8 Dec 2025 09:43:35 +0100 Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v8 05/13] KVM: guest_memfd: Add flag to remove from direct map To: "Kalyazin, Nikita" , "kvm@vger.kernel.org" , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "kvmarm@lists.linux.dev" , "linux-fsdevel@vger.kernel.org" , "linux-mm@kvack.org" , "bpf@vger.kernel.org" , "linux-kselftest@vger.kernel.org" Cc: "pbonzini@redhat.com" , "corbet@lwn.net" , "maz@kernel.org" , "oupton@kernel.org" , "joey.gouly@arm.com" , "suzuki.poulose@arm.com" , "yuzenghui@huawei.com" , "catalin.marinas@arm.com" , "will@kernel.org" , "seanjc@google.com" , "tglx@linutronix.de" , "mingo@redhat.com" , "bp@alien8.de" , "dave.hansen@linux.intel.com" , "x86@kernel.org" , "hpa@zytor.com" , "luto@kernel.org" , "peterz@infradead.org" , "willy@infradead.org" , "akpm@linux-foundation.org" , "david@kernel.org" , "lorenzo.stoakes@oracle.com" , "Liam.Howlett@oracle.com" , "rppt@kernel.org" , "surenb@google.com" , "mhocko@suse.com" , "ast@kernel.org" , "daniel@iogearbox.net" , "andrii@kernel.org" , "martin.lau@linux.dev" , "eddyz87@gmail.com" , "song@kernel.org" , "yonghong.song@linux.dev" , "john.fastabend@gmail.com" , "kpsingh@kernel.org" , "sdf@fomichev.me" , "haoluo@google.com" , "jolsa@kernel.org" , "jgg@ziepe.ca" , "jhubbard@nvidia.com" , "peterx@redhat.com" , "jannh@google.com" , "pfalcato@suse.de" , "shuah@kernel.org" , "riel@surriel.com" , "baohua@kernel.org" , "ryan.roberts@arm.com" , "jgross@suse.com" , "yu-cheng.yu@intel.com" , "kas@kernel.org" , "coxu@redhat.com" , "kevin.brodsky@arm.com" , "ackerleytng@google.com" , "maobibo@loongson.cn" , "prsampat@amd.com" , "mlevitsk@redhat.com" , "isaku.yamahata@intel.com" , "jmattson@google.com" , "jthoughton@google.com" , "linux-arm-kernel@lists.infradead.org" , "vannapurve@google.com" , "jackmanb@google.com" , "aneesh.kumar@kernel.org" , "patrick.roy@linux.dev" , "Thomson, Jack" , "Itazuri, Takahiro" , "Manwaring, Derek" , "Cali, Marco" References: <20251205165743.9341-1-kalyazin@amazon.com> <20251205165743.9341-6-kalyazin@amazon.com> Content-Language: en-US From: Vlastimil Babka Autocrypt: addr=vbabka@suse.cz; keydata= xsFNBFZdmxYBEADsw/SiUSjB0dM+vSh95UkgcHjzEVBlby/Fg+g42O7LAEkCYXi/vvq31JTB KxRWDHX0R2tgpFDXHnzZcQywawu8eSq0LxzxFNYMvtB7sV1pxYwej2qx9B75qW2plBs+7+YB 87tMFA+u+L4Z5xAzIimfLD5EKC56kJ1CsXlM8S/LHcmdD9Ctkn3trYDNnat0eoAcfPIP2OZ+ 9oe9IF/R28zmh0ifLXyJQQz5ofdj4bPf8ecEW0rhcqHfTD8k4yK0xxt3xW+6Exqp9n9bydiy tcSAw/TahjW6yrA+6JhSBv1v2tIm+itQc073zjSX8OFL51qQVzRFr7H2UQG33lw2QrvHRXqD Ot7ViKam7v0Ho9wEWiQOOZlHItOOXFphWb2yq3nzrKe45oWoSgkxKb97MVsQ+q2SYjJRBBH4 8qKhphADYxkIP6yut/eaj9ImvRUZZRi0DTc8xfnvHGTjKbJzC2xpFcY0DQbZzuwsIZ8OPJCc LM4S7mT25NE5kUTG/TKQCk922vRdGVMoLA7dIQrgXnRXtyT61sg8PG4wcfOnuWf8577aXP1x 6mzw3/jh3F+oSBHb/GcLC7mvWreJifUL2gEdssGfXhGWBo6zLS3qhgtwjay0Jl+kza1lo+Cv BB2T79D4WGdDuVa4eOrQ02TxqGN7G0Biz5ZLRSFzQSQwLn8fbwARAQABzSBWbGFzdGltaWwg QmFia2EgPHZiYWJrYUBzdXNlLmN6PsLBlAQTAQoAPgIbAwULCQgHAwUVCgkICwUWAgMBAAIe AQIXgBYhBKlA1DSZLC6OmRA9UCJPp+fMgqZkBQJnyBr8BQka0IFQAAoJECJPp+fMgqZkqmMQ AIbGN95ptUMUvo6aAdhxaOCHXp1DfIBuIOK/zpx8ylY4pOwu3GRe4dQ8u4XS9gaZ96Gj4bC+ jwWcSmn+TjtKW3rH1dRKopvC07tSJIGGVyw7ieV/5cbFffA8NL0ILowzVg8w1ipnz1VTkWDr 2zcfslxJsJ6vhXw5/npcY0ldeC1E8f6UUoa4eyoskd70vO0wOAoGd02ZkJoox3F5ODM0kjHu Y97VLOa3GG66lh+ZEelVZEujHfKceCw9G3PMvEzyLFbXvSOigZQMdKzQ8D/OChwqig8wFBmV QCPS4yDdmZP3oeDHRjJ9jvMUKoYODiNKsl2F+xXwyRM2qoKRqFlhCn4usVd1+wmv9iLV8nPs 2Db1ZIa49fJet3Sk3PN4bV1rAPuWvtbuTBN39Q/6MgkLTYHb84HyFKw14Rqe5YorrBLbF3rl M51Dpf6Egu1yTJDHCTEwePWug4XI11FT8lK0LNnHNpbhTCYRjX73iWOnFraJNcURld1jL1nV r/LRD+/e2gNtSTPK0Qkon6HcOBZnxRoqtazTU6YQRmGlT0v+rukj/cn5sToYibWLn+RoV1CE Qj6tApOiHBkpEsCzHGu+iDQ1WT0Idtdynst738f/uCeCMkdRu4WMZjteQaqvARFwCy3P/jpK uvzMtves5HvZw33ZwOtMCgbpce00DaET4y/UzsBNBFsZNTUBCACfQfpSsWJZyi+SHoRdVyX5 J6rI7okc4+b571a7RXD5UhS9dlVRVVAtrU9ANSLqPTQKGVxHrqD39XSw8hxK61pw8p90pg4G /N3iuWEvyt+t0SxDDkClnGsDyRhlUyEWYFEoBrrCizbmahOUwqkJbNMfzj5Y7n7OIJOxNRkB IBOjPdF26dMP69BwePQao1M8Acrrex9sAHYjQGyVmReRjVEtv9iG4DoTsnIR3amKVk6si4Ea X/mrapJqSCcBUVYUFH8M7bsm4CSxier5ofy8jTEa/CfvkqpKThTMCQPNZKY7hke5qEq1CBk2 wxhX48ZrJEFf1v3NuV3OimgsF2odzieNABEBAAHCwXwEGAEKACYCGwwWIQSpQNQ0mSwujpkQ PVAiT6fnzIKmZAUCZ8gcVAUJFhTonwAKCRAiT6fnzIKmZLY8D/9uo3Ut9yi2YCuASWxr7QQZ lJCViArjymbxYB5NdOeC50/0gnhK4pgdHlE2MdwF6o34x7TPFGpjNFvycZqccSQPJ/gibwNA zx3q9vJT4Vw+YbiyS53iSBLXMweeVV1Jd9IjAoL+EqB0cbxoFXvnjkvP1foiiF5r73jCd4PR rD+GoX5BZ7AZmFYmuJYBm28STM2NA6LhT0X+2su16f/HtummENKcMwom0hNu3MBNPUOrujtW khQrWcJNAAsy4yMoJ2Lw51T/5X5Hc7jQ9da9fyqu+phqlVtn70qpPvgWy4HRhr25fCAEXZDp xG4RNmTm+pqorHOqhBkI7wA7P/nyPo7ZEc3L+ZkQ37u0nlOyrjbNUniPGxPxv1imVq8IyycG AN5FaFxtiELK22gvudghLJaDiRBhn8/AhXc642/Z/yIpizE2xG4KU4AXzb6C+o7LX/WmmsWP Ly6jamSg6tvrdo4/e87lUedEqCtrp2o1xpn5zongf6cQkaLZKQcBQnPmgHO5OG8+50u88D9I rywqgzTUhHFKKF6/9L/lYtrNcHU8Z6Y4Ju/MLUiNYkmtrGIMnkjKCiRqlRrZE/v5YFHbayRD dJKXobXTtCBYpLJM4ZYRpGZXne/FAtWNe4KbNJJqxMvrTOrnIatPj8NhBVI0RSJRsbilh6TE m6M14QORSWTLRg== In-Reply-To: <20251205165743.9341-6-kalyazin@amazon.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Spamd-Result: default: False [-2.80 / 50.00]; BAYES_HAM(-3.00)[100.00%]; SUSPICIOUS_RECIPS(1.50)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-0.996]; MIME_GOOD(-0.10)[text/plain]; RCVD_VIA_SMTP_AUTH(0.00)[]; FUZZY_RATELIMITED(0.00)[rspamd.com]; ARC_NA(0.00)[]; RCVD_TLS_ALL(0.00)[]; MIME_TRACE(0.00)[0:+]; TO_DN_EQ_ADDR_SOME(0.00)[]; URIBL_BLOCKED(0.00)[imap1.dmz-prg2.suse.org:helo,suse.cz:mid]; TO_DN_SOME(0.00)[]; TAGGED_RCPT(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; DKIM_SIGNED(0.00)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; FROM_HAS_DN(0.00)[]; FREEMAIL_CC(0.00)[redhat.com,lwn.net,kernel.org,arm.com,huawei.com,google.com,linutronix.de,alien8.de,linux.intel.com,zytor.com,infradead.org,linux-foundation.org,oracle.com,suse.com,iogearbox.net,linux.dev,gmail.com,fomichev.me,ziepe.ca,nvidia.com,suse.de,surriel.com,intel.com,loongson.cn,amd.com,lists.infradead.org,amazon.co.uk,amazon.com]; R_RATELIMIT(0.00)[to_ip_from(RLwob6p4ge6yi5tbqokujz9zu4)]; FROM_EQ_ENVFROM(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_SOME(0.00)[]; RCPT_COUNT_GT_50(0.00)[77]; DBL_BLOCKED_OPENRESOLVER(0.00)[imap1.dmz-prg2.suse.org:helo,suse.cz:mid] X-Spam-Level: X-Spam-Flag: NO X-Spam-Score: -2.80 On 12/5/25 17:58, Kalyazin, Nikita wrote: > +static int kvm_gmem_folio_zap_direct_map(struct folio *folio) > +{ > + int r = 0; > + unsigned long addr = (unsigned long) folio_address(folio); > + u64 gmem_flags = GMEM_I(folio_inode(folio))->flags; > + > + if (kvm_gmem_folio_no_direct_map(folio) || !(gmem_flags & GUEST_MEMFD_FLAG_NO_DIRECT_MAP)) > + goto out; > + > + r = set_direct_map_valid_noflush(folio_page(folio, 0), folio_nr_pages(folio), > + false); > + > + if (r) > + goto out; > + > + folio->private = (void *) KVM_GMEM_FOLIO_NO_DIRECT_MAP; With Dave's suggestion on patch 1/13 to have folio_zap_direct_map(), setting this folio->private flag wouldn't be possible between the zap and tlb flush, but it's not an issue to set it before the zap, right? > + flush_tlb_kernel_range(addr, addr + folio_size(folio)); > + > +out: > + return r; > +} > + > +static void kvm_gmem_folio_restore_direct_map(struct folio *folio) > +{ > + /* > + * Direct map restoration cannot fail, as the only error condition > + * for direct map manipulation is failure to allocate page tables > + * when splitting huge pages, but this split would have already > + * happened in set_direct_map_invalid_noflush() in kvm_gmem_folio_zap_direct_map(). > + * Thus set_direct_map_valid_noflush() here only updates prot bits. > + */ > + if (kvm_gmem_folio_no_direct_map(folio)) > + set_direct_map_valid_noflush(folio_page(folio, 0), folio_nr_pages(folio), > + true); I think you're missing here clearing KVM_GMEM_FOLIO_NO_DIRECT_MAP from folio->private, which means if there's another kvm_gmem_folio_zap_direct_map() call on it in the future, it will do nothing? > +} > + > static inline void kvm_gmem_mark_prepared(struct folio *folio) > { > folio_mark_uptodate(folio); > @@ -398,6 +444,7 @@ static vm_fault_t kvm_gmem_fault_user_mapping(struct vm_fault *vmf) > struct inode *inode = file_inode(vmf->vma->vm_file); > struct folio *folio; > vm_fault_t ret = VM_FAULT_LOCKED; > + int err; > > if (((loff_t)vmf->pgoff << PAGE_SHIFT) >= i_size_read(inode)) > return VM_FAULT_SIGBUS; > @@ -423,6 +470,12 @@ static vm_fault_t kvm_gmem_fault_user_mapping(struct vm_fault *vmf) > kvm_gmem_mark_prepared(folio); > } > > + err = kvm_gmem_folio_zap_direct_map(folio); > + if (err) { > + ret = vmf_error(err); > + goto out_folio; > + } > + > vmf->page = folio_file_page(folio, vmf->pgoff); > > out_folio: > @@ -533,6 +586,8 @@ static void kvm_gmem_free_folio(struct folio *folio) > kvm_pfn_t pfn = page_to_pfn(page); > int order = folio_order(folio); > > + kvm_gmem_folio_restore_direct_map(folio); > + > kvm_arch_gmem_invalidate(pfn, pfn + (1ul << order)); > } > > @@ -596,6 +651,9 @@ static int __kvm_gmem_create(struct kvm *kvm, loff_t size, u64 flags) > /* Unmovable mappings are supposed to be marked unevictable as well. */ > WARN_ON_ONCE(!mapping_unevictable(inode->i_mapping)); > > + if (flags & GUEST_MEMFD_FLAG_NO_DIRECT_MAP) > + mapping_set_no_direct_map(inode->i_mapping); > + > GMEM_I(inode)->flags = flags; > > file = alloc_file_pseudo(inode, kvm_gmem_mnt, name, O_RDWR, &kvm_gmem_fops); > @@ -807,6 +865,8 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, > if (!is_prepared) > r = kvm_gmem_prepare_folio(kvm, slot, gfn, folio); > > + kvm_gmem_folio_zap_direct_map(folio); > + > folio_unlock(folio); > > if (!r)