From patchwork Fri Dec 10 17:54:47 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Robin Murphy X-Patchwork-Id: 12670531 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 02AD2C433EF for ; Fri, 10 Dec 2021 17:58:24 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id F3C316B007D; Fri, 10 Dec 2021 12:55:24 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id EEBB16B007E; Fri, 10 Dec 2021 12:55:24 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DB39C6B0080; Fri, 10 Dec 2021 12:55:24 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0005.hostedemail.com [216.40.44.5]) by kanga.kvack.org (Postfix) with ESMTP id CCA486B007D for ; Fri, 10 Dec 2021 12:55:24 -0500 (EST) Received: from smtpin10.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 91CA187C8B for ; Fri, 10 Dec 2021 17:55:14 +0000 (UTC) X-FDA: 78902636148.10.B35B0C5 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf22.hostedemail.com (Postfix) with ESMTP id 02963C0007 for ; Fri, 10 Dec 2021 17:55:13 +0000 (UTC) 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 089A5142F; Fri, 10 Dec 2021 09:55:13 -0800 (PST) Received: from e121345-lin.cambridge.arm.com (e121345-lin.cambridge.arm.com [10.1.196.40]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id C3F863F73B; Fri, 10 Dec 2021 09:55:11 -0800 (PST) From: Robin Murphy To: joro@8bytes.org, will@kernel.org Cc: iommu@lists.linux-foundation.org, suravee.suthikulpanit@amd.com, baolu.lu@linux.intel.com, willy@infradead.org, linux-kernel@vger.kernel.org, john.garry@huawei.com, linux-mm@kvack.org Subject: [PATCH v2 06/11] iommu/amd: Simplify pagetable freeing Date: Fri, 10 Dec 2021 17:54:47 +0000 Message-Id: X-Mailer: git-send-email 2.28.0.dirty In-Reply-To: References: MIME-Version: 1.0 X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 02963C0007 X-Stat-Signature: fseg55hc48d3w98mtczmndjujg19jwrb Authentication-Results: imf22.hostedemail.com; dkim=none; spf=pass (imf22.hostedemail.com: domain of robin.murphy@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=robin.murphy@arm.com; dmarc=pass (policy=none) header.from=arm.com X-HE-Tag: 1639158913-408012 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: For reasons unclear, pagetable freeing is an effectively recursive method implemented via an elaborate system of templated functions that turns out to account for 25% of the object file size. Implementing it using regular straightforward recursion makes the code simpler, and seems like a good thing to do before we work on it further. As part of that, also fix the types to avoid all the needless casting back and forth which just gets in the way. Signed-off-by: Robin Murphy --- v2: Comment the (pre-existing) level 2 optimisation logic drivers/iommu/amd/io_pgtable.c | 82 ++++++++++++++-------------------- 1 file changed, 34 insertions(+), 48 deletions(-) diff --git a/drivers/iommu/amd/io_pgtable.c b/drivers/iommu/amd/io_pgtable.c index 182c93a43efd..4165e1372b6e 100644 --- a/drivers/iommu/amd/io_pgtable.c +++ b/drivers/iommu/amd/io_pgtable.c @@ -84,49 +84,45 @@ static void free_page_list(struct page *freelist) } } -static struct page *free_pt_page(unsigned long pt, struct page *freelist) +static struct page *free_pt_page(u64 *pt, struct page *freelist) { - struct page *p = virt_to_page((void *)pt); + struct page *p = virt_to_page(pt); p->freelist = freelist; return p; } -#define DEFINE_FREE_PT_FN(LVL, FN) \ -static struct page *free_pt_##LVL (unsigned long __pt, struct page *freelist) \ -{ \ - unsigned long p; \ - u64 *pt; \ - int i; \ - \ - pt = (u64 *)__pt; \ - \ - for (i = 0; i < 512; ++i) { \ - /* PTE present? */ \ - if (!IOMMU_PTE_PRESENT(pt[i])) \ - continue; \ - \ - /* Large PTE? */ \ - if (PM_PTE_LEVEL(pt[i]) == 0 || \ - PM_PTE_LEVEL(pt[i]) == 7) \ - continue; \ - \ - p = (unsigned long)IOMMU_PTE_PAGE(pt[i]); \ - freelist = FN(p, freelist); \ - } \ - \ - return free_pt_page((unsigned long)pt, freelist); \ +static struct page *free_pt_lvl(u64 *pt, struct page *freelist, int lvl) +{ + u64 *p; + int i; + + for (i = 0; i < 512; ++i) { + /* PTE present? */ + if (!IOMMU_PTE_PRESENT(pt[i])) + continue; + + /* Large PTE? */ + if (PM_PTE_LEVEL(pt[i]) == 0 || + PM_PTE_LEVEL(pt[i]) == 7) + continue; + + /* + * Free the next level. No need to look at l1 tables here since + * they can only contain leaf PTEs; just free them directly. + */ + p = IOMMU_PTE_PAGE(pt[i]); + if (lvl > 2) + freelist = free_pt_lvl(p, freelist, lvl - 1); + else + freelist = free_pt_page(p, freelist); + } + + return free_pt_page(pt, freelist); } -DEFINE_FREE_PT_FN(l2, free_pt_page) -DEFINE_FREE_PT_FN(l3, free_pt_l2) -DEFINE_FREE_PT_FN(l4, free_pt_l3) -DEFINE_FREE_PT_FN(l5, free_pt_l4) -DEFINE_FREE_PT_FN(l6, free_pt_l5) - -static struct page *free_sub_pt(unsigned long root, int mode, - struct page *freelist) +static struct page *free_sub_pt(u64 *root, int mode, struct page *freelist) { switch (mode) { case PAGE_MODE_NONE: @@ -136,19 +132,11 @@ static struct page *free_sub_pt(unsigned long root, int mode, freelist = free_pt_page(root, freelist); break; case PAGE_MODE_2_LEVEL: - freelist = free_pt_l2(root, freelist); - break; case PAGE_MODE_3_LEVEL: - freelist = free_pt_l3(root, freelist); - break; case PAGE_MODE_4_LEVEL: - freelist = free_pt_l4(root, freelist); - break; case PAGE_MODE_5_LEVEL: - freelist = free_pt_l5(root, freelist); - break; case PAGE_MODE_6_LEVEL: - freelist = free_pt_l6(root, freelist); + free_pt_lvl(root, freelist, mode); break; default: BUG(); @@ -364,7 +352,7 @@ static u64 *fetch_pte(struct amd_io_pgtable *pgtable, static struct page *free_clear_pte(u64 *pte, u64 pteval, struct page *freelist) { - unsigned long pt; + u64 *pt; int mode; while (cmpxchg64(pte, pteval, 0) != pteval) { @@ -375,7 +363,7 @@ static struct page *free_clear_pte(u64 *pte, u64 pteval, struct page *freelist) if (!IOMMU_PTE_PRESENT(pteval)) return freelist; - pt = (unsigned long)IOMMU_PTE_PAGE(pteval); + pt = IOMMU_PTE_PAGE(pteval); mode = IOMMU_PTE_MODE(pteval); return free_sub_pt(pt, mode, freelist); @@ -512,7 +500,6 @@ static void v1_free_pgtable(struct io_pgtable *iop) struct amd_io_pgtable *pgtable = container_of(iop, struct amd_io_pgtable, iop); struct protection_domain *dom; struct page *freelist = NULL; - unsigned long root; if (pgtable->mode == PAGE_MODE_NONE) return; @@ -529,8 +516,7 @@ static void v1_free_pgtable(struct io_pgtable *iop) BUG_ON(pgtable->mode < PAGE_MODE_NONE || pgtable->mode > PAGE_MODE_6_LEVEL); - root = (unsigned long)pgtable->root; - freelist = free_sub_pt(root, pgtable->mode, freelist); + freelist = free_sub_pt(pgtable->root, pgtable->mode, freelist); free_page_list(freelist); }