From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id C8F6044E67C; Wed, 29 Jul 2026 10:46:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785322020; cv=none; b=tWQTRKCeAwrMz2//hXil6A9pkjWP/0eyb7Iv2kLkwaWXr+P6KZuyXluh9PlWTF8iLfkwk7zRvlTztCt1w+Wd6yqDxkpuPLDtFm2jbB1kdSsYScBZ9YUKYmk5aa2dXr0O5zLIkSot4GnTghTvrQYN2wbNYgSwtGCV2iLjvuB6kgc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785322020; c=relaxed/simple; bh=4khYqylUpukD41WfoeMeH0nQNHvx+xJKbgU5VMe1emQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Ij+ThBVpzpg2nVq1YyVE3svbzZHoSzbTjfkxDRG3owkilo/XcAktMsp7L8SjVFEiiffaNceRow+VTcsCeQw8fNfQG6RcpkroQS4aGarwUV7DlTOdwVczzLlSiRc45LUVuM2pOYB1SZIsj8dY71faaeAe1rP5Go1uuALOBvPUUsE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=NGfhb8Sq; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="NGfhb8Sq" 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 0A0711688; Wed, 29 Jul 2026 03:46:54 -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 486A43F66F; Wed, 29 Jul 2026 03:46:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1785322018; bh=4khYqylUpukD41WfoeMeH0nQNHvx+xJKbgU5VMe1emQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NGfhb8SqKa01Lyjr90afa+7XRefGzvSrDnoztEcplS5uwYPXICaueFrkpcMy9ezZu TIO3i0FRFd5wDmvIiTG9nGADTL6Kh+fjgz1ncTB4y3TzsUU7AaLQ/8NLI1jnyvAbFy QUpCs3iifGNKpY9CDLCK2We3ac2xcqKxq9ldbcVU= 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 09/11] kvm/dirty_ring: Add arch-generic interface for hw-accelerated dirty-ring cleaning Date: Wed, 29 Jul 2026 11:45:44 +0100 Message-ID: <20260729104548.3439958-10-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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3599; i=leo.bras@arm.com; h=from:subject; bh=4khYqylUpukD41WfoeMeH0nQNHvx+xJKbgU5VMe1emQ=; b=owGbwMvMwCX2pizjszvTwvWMp9WSGLIyb16rKFdYF7PxckjHp+sT5AU99kw+LP/j+jGuPsNLm QbT2WKFOkpZGMS4GGTFFFlkH81fxfN9SsaRKz8WwMxhZQIZwsDFKQATqb3P8L+ycyXHxU8/TW4t blARepFqVNZ+3/n3rStS14LFJfSrLuYxMlxOlV/X2fHiySG153Ud55gMipuf/3P9NGPpj40SMx6 ujmMBAA== X-Developer-Key: i=leo.bras@arm.com; a=openpgp; fpr=36E6C95AE0F111CC5B6F4D2E688C33F8A0C5B0C5 Content-Transfer-Encoding: 8bit Introduce kvm_arch_dirty_ring_clear() that allow implementation of arch-specific hardware-accelerated dirty-ring routines. A call to that is added on kvm_dirty_ring_reset() and will fall back to software version if not implemented, or any error was detected in the arch-specific routine. For an arch to implement this function, it's required to provide it in a asm/kvm_dirty_bit.h and have CONFIG_HAVE_KVM_HW_DIRTY_BIT=y on building. If the arch does not implement it, and thus lack above config, the introduced snippet is expected to be compiled-out and have zero impact at runtime. Signed-off-by: Leonardo Bras --- include/linux/kvm_dirty_bit.h | 7 +++++++ virt/kvm/dirty_ring.c | 5 +++++ 2 files changed, 12 insertions(+) diff --git a/include/linux/kvm_dirty_bit.h b/include/linux/kvm_dirty_bit.h index fa4f6b67b623..8492979d694e 100644 --- a/include/linux/kvm_dirty_bit.h +++ b/include/linux/kvm_dirty_bit.h @@ -11,17 +11,24 @@ static inline int kvm_arch_dirty_log_clear(struct kvm *kvm, struct kvm_memory_slot *memslot, struct kvm_clear_dirty_log *log, unsigned long *bitmap, bool *flush) { return -ENXIO; } +static inline int kvm_arch_dirty_ring_clear(struct kvm *kvm, + struct kvm_dirty_ring *ring, + int *nr_entries_reset) +{ + return -ENXIO; +} + #else /* CONFIG_HAVE_KVM_HW_DIRTY_BIT */ #include #endif /* CONFIG_HAVE_KVM_HW_DIRTY_BIT */ #endif /* __KVM_DIRTY_BIT_H__ */ diff --git a/virt/kvm/dirty_ring.c b/virt/kvm/dirty_ring.c index 807c45fb1fc7..3fa62894f3d2 100644 --- a/virt/kvm/dirty_ring.c +++ b/virt/kvm/dirty_ring.c @@ -1,20 +1,21 @@ // SPDX-License-Identifier: GPL-2.0-only /* * KVM dirty ring implementation * * Copyright 2019 Red Hat, Inc. */ #include #include #include #include +#include #include #include "kvm_mm.h" int __weak kvm_cpu_dirty_log_size(struct kvm *kvm) { return 0; } u32 kvm_dirty_ring_get_rsvd_entries(struct kvm *kvm) { @@ -126,20 +127,23 @@ int kvm_dirty_ring_reset(struct kvm *kvm, struct kvm_dirty_ring *ring, struct kvm_dirty_gfn *entry; /* * Ensure concurrent calls to KVM_RESET_DIRTY_RINGS are serialized, * e.g. so that KVM fully resets all entries processed by a given call * before returning to userspace. Holding slots_lock also protects * the various memslot accesses. */ lockdep_assert_held(&kvm->slots_lock); + if (kvm_arch_dirty_ring_clear(kvm, ring, nr_entries_reset) >= 0) + goto out; + while (likely((*nr_entries_reset) < INT_MAX)) { if (signal_pending(current)) return -EINTR; entry = &ring->dirty_gfns[ring->reset_index & (ring->size - 1)]; if (!kvm_dirty_gfn_harvested(entry)) break; next_slot = READ_ONCE(entry->slot); @@ -206,20 +210,21 @@ int kvm_dirty_ring_reset(struct kvm *kvm, struct kvm_dirty_ring *ring, * always be left pending. */ if (mask) kvm_reset_dirty_gfn(kvm, cur_slot, cur_offset, mask); /* * The request KVM_REQ_DIRTY_RING_SOFT_FULL will be cleared * by the VCPU thread next time when it enters the guest. */ +out: trace_kvm_dirty_ring_reset(ring); return 0; } void kvm_dirty_ring_push(struct kvm_vcpu *vcpu, u32 slot, u64 offset) { struct kvm_dirty_ring *ring = &vcpu->dirty_ring; struct kvm_dirty_gfn *entry; -- 2.55.0