From patchwork Fri Oct 14 08:09:17 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Henry Wang X-Patchwork-Id: 13006761 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 02CC6C433FE for ; Fri, 14 Oct 2022 08:09:49 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.422523.668600 (Exim 4.92) (envelope-from ) id 1ojFlA-0008RF-8x; Fri, 14 Oct 2022 08:09:36 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 422523.668600; Fri, 14 Oct 2022 08:09:36 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1ojFlA-0008R8-6E; Fri, 14 Oct 2022 08:09:36 +0000 Received: by outflank-mailman (input) for mailman id 422523; Fri, 14 Oct 2022 08:09:34 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1ojFl8-0008R1-RC for xen-devel@lists.xenproject.org; Fri, 14 Oct 2022 08:09:34 +0000 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by se1-gles-flk1.inumbo.com (Halon) with ESMTP id 887923b6-4b97-11ed-8fd0-01056ac49cbb; Fri, 14 Oct 2022 10:09:32 +0200 (CEST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id CBFFD1424; Fri, 14 Oct 2022 01:09:37 -0700 (PDT) Received: from entos-skylake.shanghai.arm.com (entos-skylake.shanghai.arm.com [10.169.212.207]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 4A78E3F67D; Fri, 14 Oct 2022 01:09:29 -0700 (PDT) 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: 887923b6-4b97-11ed-8fd0-01056ac49cbb From: Henry Wang To: xen-devel@lists.xenproject.org Cc: Henry Wang , Stefano Stabellini , Julien Grall , Bertrand Marquis , Wei Chen , Volodymyr Babchuk Subject: [PATCH v2] xen/arm: p2m: Populate pages for GICv2 mapping in arch_domain_create() Date: Fri, 14 Oct 2022 08:09:17 +0000 Message-Id: <20221014080917.14980-1-Henry.Wang@arm.com> X-Mailer: git-send-email 2.17.1 Hardware using GICv2 needs to create a P2M mapping of 8KB GICv2 area when the domain is created. Considering the worst case of page tables which requires 6 P2M pages as the two pages will be consecutive but not necessarily in the same L3 page table and keep a buffer, populate 16 pages as the default value to the P2M pages pool in arch_domain_create() at the domain creation stage to satisfy the GICv2 requirement. For GICv3, the above-mentioned P2M mapping is not necessary, but since the allocated 16 pages here would not be lost, hence populate these pages unconditionally. With the default 16 P2M pages populated, there would be a case that failures would happen in the domain creation with P2M pages already in use. To properly free the P2M for this case, firstly support the optionally preemption of p2m_teardown(), then call p2m_teardown() and p2m_set_allocation(d, 0, NULL) in p2m_final_teardown() if needed. Fixes: cbea5a1149ca ("xen/arm: Allocate and free P2M pages from the P2M pool") Suggested-by: Julien Grall Signed-off-by: Henry Wang --- This should also be backported to 4.13, 4.14, 4.15 and 4.16. v2 changes: - Move the p2m_set_allocation(d, 0, NULL); to p2m_final_teardown(). - Support optionally preemption of p2m_teardown(), and make the calling of p2m_teardown() preemptively when relinquish the resources, non-preemptively in p2m_final_teardown(). - Refactor the error handling to make the code use less spin_unlock. - Explain the worst case of page tables and the unconditional population of pages in commit message. - Mention the unconditional population of pages in in-code comment. --- xen/arch/arm/domain.c | 16 +++++++++++++++- xen/arch/arm/include/asm/p2m.h | 11 +++++++---- xen/arch/arm/p2m.c | 15 +++++++++++++-- 3 files changed, 35 insertions(+), 7 deletions(-) diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c index 2c84e6dbbb..831e248ad7 100644 --- a/xen/arch/arm/domain.c +++ b/xen/arch/arm/domain.c @@ -740,6 +740,20 @@ int arch_domain_create(struct domain *d, BUG(); } + /* + * Hardware using GICv2 needs to create a P2M mapping of 8KB GICv2 area + * when the domain is created. Considering the worst case for page + * tables and keep a buffer, populate 16 pages to the P2M pages pool here. + * For GICv3, the above-mentioned P2M mapping is not necessary, but since + * the allocated 16 pages here would not be lost, hence populate these + * pages unconditionally. + */ + spin_lock(&d->arch.paging.lock); + rc = p2m_set_allocation(d, 16, NULL); + spin_unlock(&d->arch.paging.lock); + if ( rc != 0 ) + goto fail; + if ( (rc = domain_vgic_register(d, &count)) != 0 ) goto fail; @@ -1064,7 +1078,7 @@ int domain_relinquish_resources(struct domain *d) return ret; PROGRESS(p2m): - ret = p2m_teardown(d); + ret = p2m_teardown(d, true); if ( ret ) return ret; diff --git a/xen/arch/arm/include/asm/p2m.h b/xen/arch/arm/include/asm/p2m.h index 42bfd548c4..480d65e95e 100644 --- a/xen/arch/arm/include/asm/p2m.h +++ b/xen/arch/arm/include/asm/p2m.h @@ -194,14 +194,17 @@ int p2m_init(struct domain *d); /* * The P2M resources are freed in two parts: - * - p2m_teardown() will be called when relinquish the resources. It - * will free large resources (e.g. intermediate page-tables) that - * requires preemption. + * - p2m_teardown() will be called preemptively when relinquish the + * resources, in which case it will free large resources (e.g. intermediate + * page-tables) that requires preemption. * - p2m_final_teardown() will be called when domain struct is been * freed. This *cannot* be preempted and therefore one small * resources should be freed here. + * Note that p2m_final_teardown() will also call p2m_teardown(), to properly + * free the P2M when failures happen in the domain creation with P2M pages + * already in use. In this case p2m_teardown() is called non-preemptively. */ -int p2m_teardown(struct domain *d); +int p2m_teardown(struct domain *d, bool allow_preemption); void p2m_final_teardown(struct domain *d); /* diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c index f17500ddf3..707bd3e2e3 100644 --- a/xen/arch/arm/p2m.c +++ b/xen/arch/arm/p2m.c @@ -1685,7 +1685,7 @@ static void p2m_free_vmid(struct domain *d) spin_unlock(&vmid_alloc_lock); } -int p2m_teardown(struct domain *d) +int p2m_teardown(struct domain *d, bool allow_preemption) { struct p2m_domain *p2m = p2m_get_hostp2m(d); unsigned long count = 0; @@ -1716,7 +1716,7 @@ int p2m_teardown(struct domain *d) p2m_free_page(p2m->domain, pg); count++; /* Arbitrarily preempt every 512 iterations */ - if ( !(count % 512) && hypercall_preempt_check() ) + if ( allow_preemption && !(count % 512) && hypercall_preempt_check() ) { rc = -ERESTART; break; @@ -1736,6 +1736,17 @@ void p2m_final_teardown(struct domain *d) if ( !p2m->domain ) return; + if ( !page_list_empty(&p2m->pages) ) + p2m_teardown(d, false); + + if ( d->arch.paging.p2m_total_pages != 0 ) + { + spin_lock(&d->arch.paging.lock); + p2m_set_allocation(d, 0, NULL); + spin_unlock(&d->arch.paging.lock); + ASSERT(d->arch.paging.p2m_total_pages == 0); + } + ASSERT(page_list_empty(&p2m->pages)); ASSERT(page_list_empty(&d->arch.paging.p2m_freelist));