From patchwork Fri Sep 16 04:51:35 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gavin Shan X-Patchwork-Id: 12978128 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BD76BECAAD8 for ; Fri, 16 Sep 2022 04:53:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229952AbiIPExC (ORCPT ); Fri, 16 Sep 2022 00:53:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49108 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229948AbiIPEwk (ORCPT ); Fri, 16 Sep 2022 00:52:40 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1D2C3A1D53 for ; Thu, 15 Sep 2022 21:52:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1663303949; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=dsE8NdyhX5qef8QVsrNnndpCLaTRMlO/gHKVyL+LIsw=; b=CjNC76sJ8LLPjUFQ4VDpD8sSFUTFCOC9kLTyC1Jij48X02PhN5iG3plzHzAmJAbH9x77Ck GaqE6ZeHg7b+57hpXft8g62RPztn54fqX1JLloKBlR1p2FMiUOIMZgT6qTwhhPWnmslw6P 9OCPnHWutORKW7S52dnWthWzzNxbx0g= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-475-OvCHZnSlO5Ct-YwtnDc50w-1; Fri, 16 Sep 2022 00:52:25 -0400 X-MC-Unique: OvCHZnSlO5Ct-YwtnDc50w-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id B7CED85A59D; Fri, 16 Sep 2022 04:52:24 +0000 (UTC) Received: from gshan.redhat.com (vpn2-54-126.bne.redhat.com [10.64.54.126]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 903BE140EBF3; Fri, 16 Sep 2022 04:52:18 +0000 (UTC) From: Gavin Shan To: kvmarm@lists.cs.columbia.edu Cc: kvm@vger.kernel.org, linux-doc@vger.kernel.org, catalin.marinas@arm.com, linux-kselftest@vger.kernel.org, bgardon@google.com, shuah@kernel.org, corbet@lwn.net, maz@kernel.org, drjones@redhat.com, will@kernel.org, zhenyzha@redhat.com, dmatlack@google.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, pbonzini@redhat.com, peterx@redhat.com, oliver.upton@linux.dev, shan.gavin@gmail.com Subject: [PATCH v2 5/5] KVM: selftests: Automate choosing dirty ring size in dirty_log_test Date: Fri, 16 Sep 2022 12:51:35 +0800 Message-Id: <20220916045135.154505-6-gshan@redhat.com> In-Reply-To: <20220916045135.154505-1-gshan@redhat.com> References: <20220916045135.154505-1-gshan@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org In the dirty ring case, we rely on vcpu exit due to full dirty ring state. On ARM64 system, there are 4096 host pages when the host page size is 64KB. In this case, the vcpu never exits due to the full dirty ring state. The similar case is 4KB page size on host and 64KB page size on guest. The vcpu corrupts same set of host pages, but the dirty page information isn't collected in the main thread. This leads to infinite loop as the following log shows. # ./dirty_log_test -M dirty-ring -c 65536 -m 5 Setting log mode to: 'dirty-ring' Test iterations: 32, interval: 10 (ms) Testing guest mode: PA-bits:40, VA-bits:48, 4K pages guest physical test memory offset: 0xffbffe0000 vcpu stops because vcpu is kicked out... Notifying vcpu to continue vcpu continues now. Iteration 1 collected 576 pages Fix the issue by automatically choosing the best dirty ring size, to ensure vcpu exit due to full dirty ring state. The option '-c' becomes a hint to the dirty ring count, instead of the value of it. Signed-off-by: Gavin Shan --- tools/testing/selftests/kvm/dirty_log_test.c | 26 +++++++++++++++++--- 1 file changed, 22 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/kvm/dirty_log_test.c b/tools/testing/selftests/kvm/dirty_log_test.c index 7d91df7e036f..47ac2c719ade 100644 --- a/tools/testing/selftests/kvm/dirty_log_test.c +++ b/tools/testing/selftests/kvm/dirty_log_test.c @@ -23,6 +23,9 @@ #include "guest_modes.h" #include "processor.h" +#define DIRTY_MEM_BITS 30 /* 1G */ +#define PAGE_SHIFT_4K 12 + /* The memory slot index to track dirty pages */ #define TEST_MEM_SLOT_INDEX 1 @@ -271,6 +274,24 @@ static bool dirty_ring_supported(void) static void dirty_ring_create_vm_done(struct kvm_vm *vm) { + uint64_t pages; + uint32_t limit; + + /* + * We rely on vcpu exit due to full dirty ring state. Adjust + * the ring buffer size to ensure we're able to reach the + * full dirty ring state. + */ + pages = (1ul << (DIRTY_MEM_BITS - vm->page_shift)) + 3; + pages = vm_adjust_num_guest_pages(vm->mode, pages); + if (vm->page_size < getpagesize()) + pages = vm_num_host_pages(vm->mode, pages); + + limit = 1 << (31 - __builtin_clz(pages)); + test_dirty_ring_count = 1 << (31 - __builtin_clz(test_dirty_ring_count)); + test_dirty_ring_count = min(limit, test_dirty_ring_count); + pr_info("dirty ring count: 0x%x\n", test_dirty_ring_count); + /* * Switch to dirty ring mode after VM creation but before any * of the vcpu creation. @@ -683,9 +704,6 @@ static struct kvm_vm *create_vm(enum vm_guest_mode mode, struct kvm_vcpu **vcpu, return vm; } -#define DIRTY_MEM_BITS 30 /* 1G */ -#define PAGE_SHIFT_4K 12 - struct test_params { unsigned long iterations; unsigned long interval; @@ -828,7 +846,7 @@ static void help(char *name) printf("usage: %s [-h] [-i iterations] [-I interval] " "[-p offset] [-m mode]\n", name); puts(""); - printf(" -c: specify dirty ring size, in number of entries\n"); + printf(" -c: hint to dirty ring size, in number of entries\n"); printf(" (only useful for dirty-ring test; default: %"PRIu32")\n", TEST_DIRTY_RING_COUNT); printf(" -i: specify iteration counts (default: %"PRIu64")\n",