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Howlett" , Suren Baghdasaryan , Michal Hocko , Johannes Weiner , Zi Yan , Axel Rasmussen , Yuanchu Xie , Roman Gushchin Cc: peterz@infradead.org, bp@alien8.de, dave.hansen@linux.intel.com, mingo@redhat.com, tglx@linutronix.de, akpm@linux-foundation.org, david@redhat.com, derkling@google.com, junaids@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, reijiw@google.com, rientjes@google.com, rppt@kernel.org, vbabka@suse.cz, x86@kernel.org, yosry.ahmed@linux.dev Content-Type: text/plain; charset="utf-8" X-Rspamd-Queue-Id: 702561A0016 X-Stat-Signature: q4uqmpd4x96jzbdxbbgckwc98rkermsy X-Rspam-User: X-Rspamd-Server: rspam09 X-HE-Tag: 1758726023-104172 X-HE-Meta: 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 ScO5dW0S 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Different usecases for the CPA code have different needs for the behaviour when encountering an unmapped address. Currently this is encoded by using the presence of the .pgd as a side-channel. Subsequent ASI changes won't get the correct behaviour based on this side-channel, so add an explicit enum to request the different behaviours that might be needed. Note this is now making explicit a couple of causes that populate the pagetables when encountering holes, until now this was implicit: 1. kernel_unmap_pages_in_pgd() Calling this function without a corresponding kernel_map_pages_in_pgd() seems like a bug, so the "correct" behaviour here might actually be CPA_FAULT_ERROR. 2. Ditto for __set_memory_enc_pgtable(). It seems the comment in __cpa_process_fault() (deleted in this patch) may have been stale with regard to the coco usecases here (including point 2). Anyway, if these need to be updated that will be a separate patch, no functional change is intended with this one. Signed-off-by: Brendan Jackman --- arch/x86/mm/pat/set_memory.c | 27 ++++++++++++++++++++------- 1 file changed, 20 insertions(+), 7 deletions(-) diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c index 53c3ac0ba55d6b6992db6f6761ffdfbd52bf3688..2a50844515e81913fed32d5b6d1ec19e8e249533 100644 --- a/arch/x86/mm/pat/set_memory.c +++ b/arch/x86/mm/pat/set_memory.c @@ -36,6 +36,16 @@ #include "../mm_internal.h" +/* What should CPA do if encountering an unmapped address? */ +enum cpa_fault { + /* Default depending on address. */ + CPA_FAULT_DEFAULT = 0, + /* Populate cpa_data.pgd using cpa_data.pfn. */ + CPA_FAULT_POPULATE, + /* Warn and return an error. */ + CPA_FAULT_ERROR, +}; + /* * The current flushing context - we pass it instead of 5 arguments: */ @@ -51,6 +61,7 @@ struct cpa_data { unsigned int force_split : 1, force_static_prot : 1, force_flush_all : 1; + enum cpa_fault on_fault : 2; struct page **pages; }; @@ -1790,14 +1801,13 @@ static inline bool is_direct_map(unsigned long vaddr) static int __cpa_process_fault(struct cpa_data *cpa, unsigned long vaddr, int primary) { - if (cpa->pgd) { - /* - * Right now, we only execute this code path when mapping - * the EFI virtual memory map regions, no other users - * provide a ->pgd value. This may change in the future. - */ + if (cpa->on_fault == CPA_FAULT_POPULATE) return populate_pgd(cpa, vaddr); - } + + if (WARN_ON(cpa->on_fault == CPA_FAULT_ERROR)) + return -EFAULT; + + /* CPA_FAULT_DEFAULT: */ /* * Ignore all non primary paths. @@ -2417,6 +2427,7 @@ static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc) cpa.mask_set = enc ? pgprot_encrypted(empty) : pgprot_decrypted(empty); cpa.mask_clr = enc ? pgprot_decrypted(empty) : pgprot_encrypted(empty); cpa.pgd = init_mm.pgd; + cpa.on_fault = CPA_FAULT_POPULATE; /* Must avoid aliasing mappings in the highmem code */ kmap_flush_unused(); @@ -2743,6 +2754,7 @@ int __init kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address, .mask_set = __pgprot(0), .mask_clr = __pgprot(~page_flags & (_PAGE_NX|_PAGE_RW|_PAGE_DIRTY)), .flags = CPA_NO_CHECK_ALIAS, + .on_fault = CPA_FAULT_POPULATE, }; WARN_ONCE(num_online_cpus() > 1, "Don't call after initializing SMP"); @@ -2786,6 +2798,7 @@ int __init kernel_unmap_pages_in_pgd(pgd_t *pgd, unsigned long address, .mask_set = __pgprot(0), .mask_clr = __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY), .flags = CPA_NO_CHECK_ALIAS, + .on_fault = CPA_FAULT_POPULATE, }; WARN_ONCE(num_online_cpus() > 1, "Don't call after initializing SMP"); -- 2.50.1