From patchwork Mon May 13 11:11:16 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Elias El Yandouzi X-Patchwork-Id: 13663348 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 10F7DC25B7A for ; Mon, 13 May 2024 11:12:17 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.720823.1123870 (Exim 4.92) (envelope-from ) id 1s6TbF-0007iu-5f; Mon, 13 May 2024 11:12:09 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 720823.1123870; Mon, 13 May 2024 11:12:08 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1s6TbE-0007c5-3u; Mon, 13 May 2024 11:12:08 +0000 Received: by outflank-mailman (input) for mailman id 720823; Mon, 13 May 2024 11:12:06 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1s6TbC-0003MC-BK for xen-devel@lists.xenproject.org; Mon, 13 May 2024 11:12:06 +0000 Received: from smtp-fw-80008.amazon.com (smtp-fw-80008.amazon.com [99.78.197.219]) by se1-gles-sth1.inumbo.com (Halon) with ESMTPS id 9f6b2f0d-1119-11ef-909d-e314d9c70b13; Mon, 13 May 2024 13:12:03 +0200 (CEST) Received: from pdx4-co-svc-p1-lb2-vlan3.amazon.com (HELO smtpout.prod.us-east-1.prod.farcaster.email.amazon.dev) ([10.25.36.214]) by smtp-border-fw-80008.pdx80.corp.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 May 2024 11:12:00 +0000 Received: from EX19MTAUEB002.ant.amazon.com [10.0.29.78:51808] by smtpin.naws.us-east-1.prod.farcaster.email.amazon.dev [10.0.61.78:2525] with esmtp (Farcaster) id 41b2d30f-ddb1-4efb-88b6-74e78337e70b; Mon, 13 May 2024 11:11:59 +0000 (UTC) Received: from EX19D008UEA004.ant.amazon.com (10.252.134.191) by EX19MTAUEB002.ant.amazon.com (10.252.135.47) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1258.28; Mon, 13 May 2024 11:11:59 +0000 Received: from EX19MTAUWB001.ant.amazon.com (10.250.64.248) by EX19D008UEA004.ant.amazon.com (10.252.134.191) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1258.28; Mon, 13 May 2024 11:11:59 +0000 Received: from dev-dsk-eliasely-1a-fd74790f.eu-west-1.amazon.com (10.253.91.118) by mail-relay.amazon.com (10.250.64.254) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1258.28 via Frontend Transport; Mon, 13 May 2024 11:11:58 +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: 9f6b2f0d-1119-11ef-909d-e314d9c70b13 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1715598723; x=1747134723; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=Xrly80bM9b4Iylo4MumX8GuIMjwgPtJngKOUTgszWKw=; b=NNSZ4aiOHDISjYhEmI2cPwno0y4heS2Sv78NGsBVFBfKshrdXdegk25/ jFeoToBxM9IYr8oiVqy2jJy+CRdvZW61ffpElN8a1I17RqejfY/jHuRPP i0xRkm08MkGArh19vdAuFS303PKiqA1DMOnqTx0WmlnG70rJUDpZDiiu+ s=; X-IronPort-AV: E=Sophos;i="6.08,158,1712620800"; d="scan'208";a="88736903" X-Farcaster-Flow-ID: 41b2d30f-ddb1-4efb-88b6-74e78337e70b From: Elias El Yandouzi To: CC: , , , Julien Grall , Elias El Yandouzi Subject: [PATCH V3 18/19] xen/arm64: Implement a mapcache for arm64 Date: Mon, 13 May 2024 11:11:16 +0000 Message-ID: <20240513111117.68828-19-eliasely@amazon.com> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20240513111117.68828-1-eliasely@amazon.com> References: <20240513111117.68828-1-eliasely@amazon.com> MIME-Version: 1.0 From: Julien Grall At the moment, on arm64, map_domain_page() is implemented using virt_to_mfn(). Therefore it is relying on the directmap. In a follow-up patch, we will allow the admin to remove the directmap. Therefore we want to implement a mapcache. Thanksfully there is already one for arm32. So select ARCH_ARM_DOMAIN_PAGE and add the necessary boiler plate to support 64-bit: - The page-table start at level 0, so we need to allocate the level 1 page-table - map_domain_page() should check if the page is in the directmap. If yes, then use virt_to_mfn() to limit the performance impact when the directmap is still enabled (this will be selectable on the command line). Take the opportunity to replace first_table_offset(...) with offsets[...]. Note that, so far, arch_mfns_in_directmap() always return true on arm64. So the mapcache is not yet used. This will change in a follow-up patch. Signed-off-by: Julien Grall Signed-off-by: Elias El Yandouzi ---- There are a few TODOs: - It is becoming more critical to fix the mapcache implementation (this is not compliant with the Arm Arm) - Evaluate the performance diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig index 21d03d9f44..0462960fc7 100644 --- a/xen/arch/arm/Kconfig +++ b/xen/arch/arm/Kconfig @@ -1,7 +1,6 @@ config ARM_32 def_bool y depends on "$(ARCH)" = "arm32" - select ARCH_MAP_DOMAIN_PAGE config ARM_64 def_bool y diff --git a/xen/arch/arm/arm64/mmu/mm.c b/xen/arch/arm/arm64/mmu/mm.c index 2ec1ffe1dc..826864d25d 100644 --- a/xen/arch/arm/arm64/mmu/mm.c +++ b/xen/arch/arm/arm64/mmu/mm.c @@ -4,6 +4,7 @@ #include #include +#include #include #include #include @@ -237,6 +238,14 @@ void __init setup_mm(void) setup_frametable_mappings(ram_start, ram_end); max_page = PFN_DOWN(ram_end); + /* + * The allocators may need to use map_domain_page() (such as for + * scrubbing pages). So we need to prepare the domheap area first. + */ + if ( !init_domheap_mappings(smp_processor_id()) ) + panic("CPU%u: Unable to prepare the domheap page-tables\n", + smp_processor_id()); + init_staticmem_pages(); init_sharedmem_pages(); } diff --git a/xen/arch/arm/domain_page.c b/xen/arch/arm/domain_page.c index ac2a6d0332..0f6ba48892 100644 --- a/xen/arch/arm/domain_page.c +++ b/xen/arch/arm/domain_page.c @@ -1,4 +1,5 @@ /* SPDX-License-Identifier: GPL-2.0-or-later */ +#include #include #include #include @@ -8,6 +9,8 @@ /* Override macros from asm/page.h to make them work with mfn_t */ #undef virt_to_mfn #define virt_to_mfn(va) _mfn(__virt_to_mfn(va)) +#undef mfn_to_virt +#define mfn_to_virt(va) __mfn_to_virt(mfn_x(mfn)) /* cpu0's domheap page tables */ static DEFINE_PAGE_TABLES(cpu0_dommap, DOMHEAP_SECOND_PAGES); @@ -31,13 +34,30 @@ bool init_domheap_mappings(unsigned int cpu) { unsigned int order = get_order_from_pages(DOMHEAP_SECOND_PAGES); lpae_t *root = per_cpu(xen_pgtable, cpu); + lpae_t *first; unsigned int i, first_idx; lpae_t *domheap; mfn_t mfn; + /* Convenience aliases */ + DECLARE_OFFSETS(offsets, DOMHEAP_VIRT_START); + ASSERT(root); ASSERT(!per_cpu(xen_dommap, cpu)); + /* + * On Arm64, the root is at level 0. Therefore we need an extra step + * to allocate the first level page-table. + */ +#ifdef CONFIG_ARM_64 + if ( create_xen_table(&root[offsets[0]]) ) + return false; + + first = xen_map_table(lpae_get_mfn(root[offsets[0]])); +#else + first = root; +#endif + /* * The domheap for cpu0 is initialized before the heap is initialized. * So we need to use pre-allocated pages. @@ -58,16 +78,20 @@ bool init_domheap_mappings(unsigned int cpu) * domheap mapping pages. */ mfn = virt_to_mfn(domheap); - first_idx = first_table_offset(DOMHEAP_VIRT_START); + first_idx = offsets[1]; for ( i = 0; i < DOMHEAP_SECOND_PAGES; i++ ) { lpae_t pte = mfn_to_xen_entry(mfn_add(mfn, i), MT_NORMAL); pte.pt.table = 1; - write_pte(&root[first_idx + i], pte); + write_pte(&first[first_idx + i], pte); } per_cpu(xen_dommap, cpu) = domheap; +#ifdef CONFIG_ARM_64 + xen_unmap_table(first); +#endif + return true; } @@ -91,6 +115,10 @@ void *map_domain_page(mfn_t mfn) lpae_t pte; int i, slot; + /* Bypass the mapcache if the page is in the directmap */ + if ( arch_mfns_in_directmap(mfn_x(mfn), 1) ) + return mfn_to_virt(mfn); + local_irq_save(flags); /* The map is laid out as an open-addressed hash table where each @@ -153,13 +181,25 @@ void *map_domain_page(mfn_t mfn) /* Release a mapping taken with map_domain_page() */ void unmap_domain_page(const void *ptr) { + unsigned long va = (unsigned long)ptr; unsigned long flags; lpae_t *map = this_cpu(xen_dommap); - int slot = ((unsigned long)ptr - DOMHEAP_VIRT_START) >> SECOND_SHIFT; + unsigned int slot; + + /* Below we assume that the domheap area doesn't start at 0 */ + BUILD_BUG_ON(DOMHEAP_VIRT_START == 0); - if ( !ptr ) + /* + * map_domain_page() may not have mapped anything if the address + * is part of the directmap. So ignore anything outside of the + * domheap. + */ + if ( (va < DOMHEAP_VIRT_START) || + ((va - DOMHEAP_VIRT_START) >= DOMHEAP_VIRT_SIZE) ) return; + slot = (va - DOMHEAP_VIRT_START) >> SECOND_SHIFT; + local_irq_save(flags); ASSERT(slot >= 0 && slot < DOMHEAP_ENTRIES); diff --git a/xen/arch/arm/include/asm/mm.h b/xen/arch/arm/include/asm/mm.h index 60e0122cba..610dfa0466 100644 --- a/xen/arch/arm/include/asm/mm.h +++ b/xen/arch/arm/include/asm/mm.h @@ -432,6 +432,11 @@ static inline void page_set_xenheap_gfn(struct page_info *p, gfn_t gfn) } while ( (y = cmpxchg(&p->u.inuse.type_info, x, nx)) != x ); } +/* Helpers to allocate, map and unmap a Xen page-table */ +int create_xen_table(lpae_t *entry); +lpae_t *xen_map_table(mfn_t mfn); +void xen_unmap_table(const lpae_t *table); + #endif /* __ARCH_ARM_MM__ */ /* * Local variables: diff --git a/xen/arch/arm/include/asm/mmu/layout.h b/xen/arch/arm/include/asm/mmu/layout.h index a3b546465b..c549420e8b 100644 --- a/xen/arch/arm/include/asm/mmu/layout.h +++ b/xen/arch/arm/include/asm/mmu/layout.h @@ -35,9 +35,13 @@ * * 32G - 64G Frametable: 56 bytes per page for 2TB of RAM * - * 0x00000a8000000000 - 0x00007fffffffffff (512GB+117TB, L0 slots [21..255]) + * 0x00000a8000000000 - 0x00007f7fffffffff (117TB, L0 slots [21..254]) * Unused * + * 0x00007f8000000000 - 0x00007fffffffffff (512GB, L0 slot [255]) + * (Relative offsets) + * 0 - 2G Domheap: on-demand-mapped + * * 0x0000800000000000 - 0x000084ffffffffff (5TB, L0 slots [256..265]) * 1:1 mapping of RAM * @@ -130,6 +134,13 @@ #define FRAMETABLE_SIZE GB(32) #define FRAMETABLE_NR (FRAMETABLE_SIZE / sizeof(*frame_table)) +#define DOMHEAP_VIRT_START SLOT0(255) +#define DOMHEAP_VIRT_SIZE GB(2) + +#define DOMHEAP_ENTRIES 1024 /* 1024 2MB mapping slots */ +/* Number of domheap pagetable pages required at the second level (2MB mappings) */ +#define DOMHEAP_SECOND_PAGES (DOMHEAP_VIRT_SIZE >> FIRST_SHIFT) + #define DIRECTMAP_VIRT_START SLOT0(256) #define DIRECTMAP_SIZE (SLOT0_ENTRY_SIZE * (266 - 256)) #define DIRECTMAP_VIRT_END (DIRECTMAP_VIRT_START + DIRECTMAP_SIZE - 1) diff --git a/xen/arch/arm/mmu/pt.c b/xen/arch/arm/mmu/pt.c index 1ed1a53ab1..da33c6c52e 100644 --- a/xen/arch/arm/mmu/pt.c +++ b/xen/arch/arm/mmu/pt.c @@ -33,7 +33,7 @@ mm_printk(const char *fmt, ...) {} #define HYP_PT_ROOT_LEVEL 1 #endif -static lpae_t *xen_map_table(mfn_t mfn) +lpae_t *xen_map_table(mfn_t mfn) { /* * During early boot, map_domain_page() may be unusable. Use the @@ -45,7 +45,7 @@ static lpae_t *xen_map_table(mfn_t mfn) return map_domain_page(mfn); } -static void xen_unmap_table(const lpae_t *table) +void xen_unmap_table(const lpae_t *table) { /* * During early boot, xen_map_table() will not use map_domain_page() @@ -228,7 +228,7 @@ void *ioremap(paddr_t pa, size_t len) return ioremap_attr(pa, len, PAGE_HYPERVISOR_NOCACHE); } -static int create_xen_table(lpae_t *entry) +int create_xen_table(lpae_t *entry) { mfn_t mfn; void *p;