From patchwork Tue Jun 4 12:15:02 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: maobibo X-Patchwork-Id: 13685109 Received: from mail.loongson.cn (mail.loongson.cn [114.242.206.163]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 6489B145FF6; Tue, 4 Jun 2024 12:15:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=114.242.206.163 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717503307; cv=none; b=K5aqyTpAFLcMjhGRNshWsZ6FrbTdUHDphcg/E6fXacHcbAM0x/92aAeyK3Fthu8j2YNd+8+ZwDh1FDPK071Eoe71z2BrfpZw5gWtEmEYzY8I3bzw5lERXe4GJhtCvmojGJaEoCMRcxySlF8iG9wiFpwVKToHeVqwvxgUrZlzEuM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717503307; c=relaxed/simple; bh=WFVQjWH0ZoiMDGK+S3K+zIY7KmR/jPZqZ71uWqigK70=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=fW2+FXujkGYgRXKEEJQAlVYsShIBfA1d4QpvYe2vTVzU9SGdsRz9DQiG+kK01v9IbcjekghhKc0Hb4HLo/qLc9wknuYxrkFAW1SFxIji/dlKMN5/eAjSmuYpEk8zNBqrfVEu1pKswmbI0ou53jbSau/CdQFzmKGkQYFNybFdN3U= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn; spf=pass smtp.mailfrom=loongson.cn; arc=none smtp.client-ip=114.242.206.163 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=loongson.cn Received: from loongson.cn (unknown [10.2.5.213]) by gateway (Coremail) with SMTP id _____8DxSupGBV9mXmEDAA--.14543S3; Tue, 04 Jun 2024 20:15:02 +0800 (CST) Received: from localhost.localdomain (unknown [10.2.5.213]) by localhost.localdomain (Coremail) with SMTP id AQAAf8AxDMdGBV9mFzkUAA--.50896S2; Tue, 04 Jun 2024 20:15:02 +0800 (CST) From: Bibo Mao To: Tianrui Zhao , Huacai Chen Cc: WANG Xuerui , kvm@vger.kernel.org, loongarch@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH] LoongArch: KVM: Discard dirty page tracking on readonly memslot Date: Tue, 4 Jun 2024 20:15:02 +0800 Message-Id: <20240604121502.1985410-1-maobibo@loongson.cn> X-Mailer: git-send-email 2.39.3 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: AQAAf8AxDMdGBV9mFzkUAA--.50896S2 X-CM-SenderInfo: xpdruxter6z05rqj20fqof0/ X-Coremail-Antispam: 1Uk129KBjDUn29KB7ZKAUJUUUUU529EdanIXcx71UUUUU7KY7 ZEXasCq-sGcSsGvfJ3UbIjqfuFe4nvWSU5nxnvy29KBjDU0xBIdaVrnUUvcSsGvfC2Kfnx nUUI43ZEXa7xR_UUUUUUUUU== For readonly memslot such as UEFI bios or UEFI var space, guest can not write this memory space directly. So it is not necessary to track dirty pages for readonly memslot. Here there is such optimization in function kvm_arch_commit_memory_region(). Signed-off-by: Bibo Mao --- arch/loongarch/kvm/mmu.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) base-commit: 2ab79514109578fc4b6df90633d500cf281eb689 diff --git a/arch/loongarch/kvm/mmu.c b/arch/loongarch/kvm/mmu.c index 98883aa23ab8..ec8c43aad724 100644 --- a/arch/loongarch/kvm/mmu.c +++ b/arch/loongarch/kvm/mmu.c @@ -444,6 +444,17 @@ void kvm_arch_commit_memory_region(struct kvm *kvm, enum kvm_mr_change change) { int needs_flush; + u32 old_flags = old ? old->flags : 0; + u32 new_flags = new ? new->flags : 0; + bool log_dirty_pages = new_flags & KVM_MEM_LOG_DIRTY_PAGES; + + /* only track memslot flags changed */ + if (change != KVM_MR_FLAGS_ONLY) + return; + + /* Discard dirty page tracking on readonly memslot */ + if ((old_flags & new_flags) & KVM_MEM_READONLY) + return; /* * If dirty page logging is enabled, write protect all pages in the slot @@ -454,9 +465,7 @@ void kvm_arch_commit_memory_region(struct kvm *kvm, * MOVE/DELETE: The old mappings will already have been cleaned up by * kvm_arch_flush_shadow_memslot() */ - if (change == KVM_MR_FLAGS_ONLY && - (!(old->flags & KVM_MEM_LOG_DIRTY_PAGES) && - new->flags & KVM_MEM_LOG_DIRTY_PAGES)) { + if (!(old_flags & KVM_MEM_LOG_DIRTY_PAGES) && log_dirty_pages) { spin_lock(&kvm->mmu_lock); /* Write protect GPA page table entries */ needs_flush = kvm_mkclean_gpa_pt(kvm, new->base_gfn,