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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 9737A2116B X-Spam-Score: -3.01 X-Rspamd-Action: no action X-Spamd-Result: default: False [-3.01 / 50.00]; BAYES_HAM(-3.00)[100.00%]; SUSPICIOUS_RECIPS(1.50)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; R_DKIM_ALLOW(-0.20)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; FUZZY_BLOCKED(0.00)[rspamd.com]; ARC_NA(0.00)[]; DKIM_SIGNED(0.00)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; RCPT_COUNT_TWELVE(0.00)[38]; MIME_TRACE(0.00)[0:+]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; RCVD_TLS_ALL(0.00)[]; TO_DN_SOME(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; FREEMAIL_CC(0.00)[redhat.com,lwn.net,infradead.org,linux-foundation.org,kernel.org,iogearbox.net,linux.dev,gmail.com,fomichev.me,google.com,oracle.com,vger.kernel.org,kvack.org,amazon.com]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; TAGGED_RCPT(0.00)[]; DKIM_TRACE(0.00)[suse.cz:+]; R_RATELIMIT(0.00)[to_ip_from(RLo3k5aap4ysuunujcz1d3qjj5)]; DBL_BLOCKED_OPENRESOLVER(0.00)[imap1.dmz-prg2.suse.org:rdns,imap1.dmz-prg2.suse.org:helo] X-Rspamd-Server: rspamd1.dmz-prg2.suse.org X-Spam-Flag: NO X-Spam-Level: On 2/25/25 17:52, David Hildenbrand wrote: > On 21.02.25 17:07, Patrick Roy wrote: >> Add AS_NO_DIRECT_MAP for mappings where direct map entries of folios are >> set to not present . Currently, mappings that match this description are >> secretmem mappings (memfd_secret()). Later, some guest_memfd >> configurations will also fall into this category. >> >> Reject this new type of mappings in all locations that currently reject >> secretmem mappings, on the assumption that if secretmem mappings are >> rejected somewhere, it is precisely because of an inability to deal with >> folios without direct map entries. >> >> Use a new flag instead of overloading AS_INACCESSIBLE (which is already >> set by guest_memfd) because not all guest_memfd mappings will end up >> being direct map removed (e.g. in pKVM setups, parts of guest_memfd that >> can be mapped to userspace should also be GUP-able, and generally not >> have restrictions on who can access it). >> >> Signed-off-by: Patrick Roy >> --- > > ... > >> static inline gfp_t mapping_gfp_mask(struct address_space * mapping) >> { >> return mapping->gfp_mask; >> diff --git a/lib/buildid.c b/lib/buildid.c >> index c4b0f376fb34..80b5d805067f 100644 >> --- a/lib/buildid.c >> +++ b/lib/buildid.c >> @@ -65,8 +65,8 @@ static int freader_get_folio(struct freader *r, loff_t file_off) >> >> freader_put_folio(r); >> >> - /* reject secretmem folios created with memfd_secret() */ >> - if (secretmem_mapping(r->file->f_mapping)) >> + /* reject secretmem folios created with memfd_secret() or guest_memfd() */ >> + if (secretmem_mapping(r->file->f_mapping) || mapping_no_direct_map(r->file->f_mapping)) >> return -EFAULT; > > Maybe I'm missing it, but why do we have to special-case secretmem with > that at all anymore? > > Couldn't we just let secretmem set AS_NO_DIRECT_MAP as well, and convert > all/most secretmem specific stuff to check AS_NO_DIRECT_MAP as well? That's done in patch 02. But yeah, squashing them together would reduce some churn. I guess because it removes some !IS_ENABLED(CONFIG_SECRETMEM) optimizations, a separate change for review was preferred.