From mboxrd@z Thu Jan 1 00:00:00 1970 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 037B3C53200 for ; Wed, 29 Jul 2026 10:47:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=pcAuYsu0755M/LuA8SWzj9uvfmRzNP6x4Boe1U5Dos0=; b=rxUjakSNd5KPDpvUXFgerNySZO Y7IivxxfyNx+Zq76WuFfOTXI3CdVSze3Y7LSLSs/B7XBnoRwOOQP2mdmwSIiGcU7KtqQCuhPNjWAm fm8+ilZkrlQWMu2grvI6Ja0lGerUzPpoGEy6LHc8dANS6ULuu1/VW8OKSNw242JNc8pURwBRjd8vo XIQkGZeeVSLyzMB/eTLNjIDuiCENooqCKgcb/ylMbH9RRGvYODA76CeJs8x1//bq7I2Q6nQh6rg+N DCaFpw9g/p6mcMM5qrbdQiih3YZmhBMhJ1TijdDmSUHkcCTgQAJU10C27Cu/zHnkO0zhcSnCzEK1T Z/eI0Zeg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wp1oP-00000007aVM-1xx1; Wed, 29 Jul 2026 10:46:57 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wp1oH-00000007aPD-00u2 for linux-arm-kernel@lists.infradead.org; Wed, 29 Jul 2026 10:46:50 +0000 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 8DB7F202C; Wed, 29 Jul 2026 03:46:43 -0700 (PDT) Received: from LeoBrasDK.cambridge.arm.com (LeoBrasDK.cambridge.arm.com [10.2.212.21]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id CE0183F66F; Wed, 29 Jul 2026 03:46:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1785322007; bh=ixb/OphbVvSlJT0SHXkOzrFLDyYiSyXRPu+hqyd0RzQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kSmc8s/RTdHvHQr3CJPgIkV9yYejP995Mbp6z8hIW6SR3nAh8saksnYlZoQ0gKFXg gYGzYrl8Jz0pRi7f6XFksW1FDr5armllNEE7R/0Am4czeDXvWTII9PQ1htvMcia0MN eVcQRrkWBvAppABZw/ydIeAhb3IwBg45y/8OPSmw= From: Leonardo Bras To: Catalin Marinas , Will Deacon , Marc Zyngier , Oliver Upton , Fuad Tabba , Joey Gouly , Steffen Eiden , Suzuki K Poulose , Zenghui Yu , Paolo Bonzini , James Morse , Leonardo Bras , Yang Shi , mrigendrachaubey , Thomas Huth , Zeng Heng , Ryan Roberts , Mark Brown , Sascha Bischoff , Yicong Yang , Kevin Brodsky , James Clark , Raghavendra Rao Ananta , Yeoreum Yun , Mark Rutland , Anshuman Khandual , Tian Zheng Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev, kvm@vger.kernel.org Subject: [PATCH v3 07/11] KVM: arm64: Dirty-bitmap: avoid splitting previously split blocks Date: Wed, 29 Jul 2026 11:45:42 +0100 Message-ID: <20260729104548.3439958-8-leo.bras@arm.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260729104548.3439958-1-leo.bras@arm.com> References: <20260729104548.3439958-1-leo.bras@arm.com> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2203; i=leo.bras@arm.com; h=from:subject; bh=ixb/OphbVvSlJT0SHXkOzrFLDyYiSyXRPu+hqyd0RzQ=; b=owGbwMvMwCX2pizjszvTwvWMp9WSGLIyb17beorjxT2HxuDzKg3uP6PXnU6+qnB3X1eUY0JRd peXu3lbRykLgxgXg6yYIovso/mreL5PyThy5ccCmDmsTCBDGLg4BWAi838zMjQyuTGb9W084fdh 44Y5WzcrlHnM3LX58MWKa70ftXu2v5nJyLBIqe9gg/yM/b6zYvl6dpZodnEc7zrPlDrVpkrhhMk UbQYA X-Developer-Key: i=leo.bras@arm.com; a=openpgp; fpr=36E6C95AE0F111CC5B6F4D2E688C33F8A0C5B0C5 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260729_034649_131555_0CC8B010 X-CRM114-Status: GOOD ( 12.51 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org If previous dirty-clean already split a block, then avoid calling the split helper on that block again. Signed-off-by: Leonardo Bras --- arch/arm64/kvm/dirty_bit.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/arch/arm64/kvm/dirty_bit.c b/arch/arm64/kvm/dirty_bit.c index 5a6266205295..d7e624f9b630 100644 --- a/arch/arm64/kvm/dirty_bit.c +++ b/arch/arm64/kvm/dirty_bit.c @@ -244,20 +244,21 @@ int __kvm_arch_dirty_log_clear(struct kvm *kvm, bool *flush) { int ret = 0; int idx = 0; unsigned long *dirty_bitmap = memslot->dirty_bitmap; u64 *hw_entries; const int entries_sz = PAGE_SIZE / sizeof(*hw_entries); u64 ttwl; u64 start, end; gfn_t base_gfn; + gpa_t last_split = 0; hw_entries = kmalloc_objs(u64, entries_sz, GFP_KERNEL); if (!hw_entries) return -ENOMEM; ttwl = HDBSS_ENTRY_TTWL(KVM_PGTABLE_LAST_LEVEL); if (log) { start = log->first_page / BITS_PER_LONG; end = start + DIV_ROUND_UP(log->num_pages, BITS_PER_LONG); @@ -288,24 +289,29 @@ int __kvm_arch_dirty_log_clear(struct kvm *kvm, mask = xchg(&dirty_bitmap[i], 0); bitmap[i] = mask; } if (!mask) continue; offset = base_gfn + i * BITS_PER_LONG; - if (kvm_dirty_log_manual_protect_and_init_set(kvm)) - kvm_mmu_split_huge_pages(kvm, - gfn_to_gpa(offset + __ffs(mask)), - gfn_to_gpa(offset + __fls(mask) + 1)); + if (kvm_dirty_log_manual_protect_and_init_set(kvm)) { + gpa_t split_start = gfn_to_gpa(offset + __ffs(mask)); + gpa_t split_end = gfn_to_gpa(offset + __fls(mask) + 1); + + if (split_end > last_split) { + kvm_mmu_split_huge_pages(kvm, split_start, split_end); + last_split = ALIGN_DOWN(split_end - 1, PMD_SIZE) + PMD_SIZE; + } + } do { idx = mask_to_hdbss(&mask, hw_entries, offset, ttwl, idx, entries_sz); if (idx >= entries_sz) { ret = dirty_bit_clear(kvm, hw_entries, idx); *flush = *flush || ret > 0; if (ret != idx) { /* Restore mask as before processing */ atomic_long_or(mask, (atomic_long_t *)&dirty_bitmap[i]); end = i + 1; -- 2.55.0