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Tue, 13 Aug 2024 13:42:11 +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 E+DcMrNiu2bUGQAAD6G6ig (envelope-from ); Tue, 13 Aug 2024 13:42:11 +0000 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: d813d5c8-5979-11ef-8776-851b0ebba9a2 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1723556532; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=mSPiqOW7akL0nRnyX8VpLZ5Z1GRvi01pTr8QTeeTzVI=; b=IMcdZoJ2H/dtByOc/sPV/fLdIor8zw/ZlNS0Drsh1zShfE85oWIC3Ase3eGraVcMxTpNu1 5JW0P2J1KSzJJ2l9GI1qLTz/Y5ihm9o//Lgyk2AztbZJYdXqDpOUuaRMtOgCUe/tKpCV// zQP2bWdRQ1v8YA6VmVMO4/CDJv2gDD0= Authentication-Results: smtp-out2.suse.de; dkim=pass header.d=suse.com header.s=susede1 header.b=IMcdZoJ2 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1723556532; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=mSPiqOW7akL0nRnyX8VpLZ5Z1GRvi01pTr8QTeeTzVI=; b=IMcdZoJ2H/dtByOc/sPV/fLdIor8zw/ZlNS0Drsh1zShfE85oWIC3Ase3eGraVcMxTpNu1 5JW0P2J1KSzJJ2l9GI1qLTz/Y5ihm9o//Lgyk2AztbZJYdXqDpOUuaRMtOgCUe/tKpCV// zQP2bWdRQ1v8YA6VmVMO4/CDJv2gDD0= From: Juergen Gross To: minios-devel@lists.xenproject.org, xen-devel@lists.xenproject.org Cc: samuel.thibault@ens-lyon.org, Juergen Gross Subject: [PATCH v2 2/3] mini-os: mm: switch need_pgt() to use walk_pt() Date: Tue, 13 Aug 2024 15:41:57 +0200 Message-ID: <20240813134158.580-3-jgross@suse.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240813134158.580-1-jgross@suse.com> References: <20240813134158.580-1-jgross@suse.com> MIME-Version: 1.0 X-Rspamd-Queue-Id: 0E7B0203B9 X-Spamd-Result: default: False [-3.01 / 50.00]; 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Signed-off-by: Juergen Gross Reviewed-by: Samuel Thibault --- V2: - add comment and ASSERT() (Samuel Thibault) --- arch/x86/mm.c | 72 +++++++++++++++++++++------------------------------ 1 file changed, 30 insertions(+), 42 deletions(-) diff --git a/arch/x86/mm.c b/arch/x86/mm.c index 9849b985..84a6d7f0 100644 --- a/arch/x86/mm.c +++ b/arch/x86/mm.c @@ -523,57 +523,45 @@ static pgentry_t *get_pgt(unsigned long va) * return a valid PTE for a given virtual address. If PTE does not exist, * allocate page-table pages. */ -pgentry_t *need_pgt(unsigned long va) +static int need_pgt_func(unsigned long va, unsigned int lvl, bool is_leaf, + pgentry_t *pte, void *par) { + pgentry_t **result = par; unsigned long pt_mfn; - pgentry_t *tab; unsigned long pt_pfn; - unsigned offset; + unsigned int idx; - tab = pt_base; - pt_mfn = virt_to_mfn(pt_base); + if ( !is_leaf ) + return 0; -#if defined(__x86_64__) - offset = l4_table_offset(va); - if ( !(tab[offset] & _PAGE_PRESENT) ) - { - pt_pfn = virt_to_pfn(alloc_page()); - if ( !pt_pfn ) - return NULL; - new_pt_frame(&pt_pfn, pt_mfn, offset, L3_FRAME); - } - ASSERT(tab[offset] & _PAGE_PRESENT); - pt_mfn = pte_to_mfn(tab[offset]); - tab = mfn_to_virt(pt_mfn); -#endif - offset = l3_table_offset(va); - if ( !(tab[offset] & _PAGE_PRESENT) ) - { - pt_pfn = virt_to_pfn(alloc_page()); - if ( !pt_pfn ) - return NULL; - new_pt_frame(&pt_pfn, pt_mfn, offset, L2_FRAME); - } - ASSERT(tab[offset] & _PAGE_PRESENT); - pt_mfn = pte_to_mfn(tab[offset]); - tab = mfn_to_virt(pt_mfn); - offset = l2_table_offset(va); - if ( !(tab[offset] & _PAGE_PRESENT) ) + if ( lvl == L1_FRAME || (*pte & _PAGE_PRESENT) ) { - pt_pfn = virt_to_pfn(alloc_page()); - if ( !pt_pfn ) - return NULL; - new_pt_frame(&pt_pfn, pt_mfn, offset, L1_FRAME); + /* + * The PTE is not addressing a page table (is_leaf is true). If we are + * either at the lowest level or we have a valid large page, we don't + * need to allocate a page table. + */ + ASSERT(lvl == L1_FRAME || (*pte & _PAGE_PSE)); + *result = pte; + return 1; } - ASSERT(tab[offset] & _PAGE_PRESENT); - if ( tab[offset] & _PAGE_PSE ) - return &tab[offset]; - pt_mfn = pte_to_mfn(tab[offset]); - tab = mfn_to_virt(pt_mfn); + pt_mfn = virt_to_mfn(pte); + pt_pfn = virt_to_pfn(alloc_page()); + if ( !pt_pfn ) + return -1; + idx = idx_from_va_lvl(va, lvl); + new_pt_frame(&pt_pfn, pt_mfn, idx, lvl - 1); - offset = l1_table_offset(va); - return &tab[offset]; + return 0; +} + +pgentry_t *need_pgt(unsigned long va) +{ + pgentry_t *tab = NULL; + + walk_pt(va, va, need_pgt_func, &tab); + return tab; } EXPORT_SYMBOL(need_pgt);