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 A0DB036C5B4; Mon, 29 Jun 2026 11:00:11 +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=1782730814; cv=none; b=dHbF2XnmvdVOT1e02DK2CoN/KJY1S9xVf6JZMWwJvBUF2u9X8JT5w2G011iV4TLhmc38eJJClba2OnZ2WvcNRf2W5UVSNeZP7RTNGGXyKLnexLUbvr60RMAVPypt7T7RreiHp0NrlN++LZnU4ndBKiwkoZp/l/+n3jbhg/vm3e4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782730814; c=relaxed/simple; bh=rXl6YfMXYvYDSdPsMQ629hiSvMKFL5QOqwUVLE4GpL0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=k2MQk+iwoPKqx4mburpQwSbgD3dNrR6sbBjcen0XnH/L86YrbOoegVpY56n8gZdnXMwjp4TI6os+iV9TmGR90mQ4L/5U+oKhsw0+NLlZDV0cHHWeMMvJ8gN2Ob3Mcs6zC9UiAm3boLEg7GBni0ZLGhz6KCAM/beP+c6Gsf/SZXY= 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=AxnlOi2m; 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="AxnlOi2m" 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 9710B25DE; Mon, 29 Jun 2026 04:00:06 -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 629393F836; Mon, 29 Jun 2026 04:00:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1782730811; bh=rXl6YfMXYvYDSdPsMQ629hiSvMKFL5QOqwUVLE4GpL0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AxnlOi2mucr3nV254zg9UhnNOMD8s2k3/9LQ+vuGdDjMqd9DKECKyZP5OGQFwH6zd epkHJkiKNcm6E+HujFne0NzqqNnHWnTk6AHjFQuUBv8J7+4jhd6gS5t6cFKtdK9DFr 7tNknbcynqkNTMTZzVGZnVrmS0rbciH4vTDx/uZY= From: Leonardo Bras To: Paolo Bonzini , Shuah Khan , Sean Christopherson , David Matlack , Leonardo Bras , Ackerley Tng , Oliver Upton , Marc Zyngier , Wu Fei , Steffen Eiden , Claudio Imbrenda Cc: kvm@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [RFC PATCH v2 2/3] KVM: selftests: Check dirty-ring size before enabling Date: Mon, 29 Jun 2026 11:59:41 +0100 Message-ID: <20260629105950.1790259-3-leo.bras@arm.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260629105950.1790259-1-leo.bras@arm.com> References: <20260629105950.1790259-1-leo.bras@arm.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2030; i=leo.bras@arm.com; h=from:subject; bh=rXl6YfMXYvYDSdPsMQ629hiSvMKFL5QOqwUVLE4GpL0=; b=owGbwMvMwCX2pizjszvTwvWMp9WSGLKc/Cs6dhxSS6pJkv3Oc8FsC4tdX+T8QmfVlS4ZK+zst 5s7nZvdUcrCIMbFICumyCL7aP4qnu9TMo5c+bEAZg4rE8gQBi5OAZjIZAOG/3Gl89f5beROEe74 OHHbgtnvPfgvlT5d1973I/nfMRNffkWGv/KiIoKux8JNeZZM7O45sOPV/fJp4a1G3KFrowSP3+n axQIA X-Developer-Key: i=leo.bras@arm.com; a=openpgp; fpr=36E6C95AE0F111CC5B6F4D2E688C33F8A0C5B0C5 Content-Transfer-Encoding: 8bit As of today, trying to enable dirty-ring with a size bigger than the maximum will return an "argument list too long" error. Change vm_enable_dirty_ring() to get the maximum size, then compare it to the desired size before enabling. If the value is invalid, print a more precise error message. Signed-off-by: Leonardo Bras --- tools/testing/selftests/kvm/lib/kvm_util.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c index 195f3fdae1e3..4ae27ad9f947 100644 --- a/tools/testing/selftests/kvm/lib/kvm_util.c +++ b/tools/testing/selftests/kvm/lib/kvm_util.c @@ -160,24 +160,35 @@ unsigned int kvm_check_cap(long cap) ret = __kvm_ioctl(kvm_fd, KVM_CHECK_EXTENSION, (void *)cap); TEST_ASSERT(ret >= 0, KVM_IOCTL_ERROR(KVM_CHECK_EXTENSION, ret)); kvm_free_fd(kvm_fd); return (unsigned int)ret; } void vm_enable_dirty_ring(struct kvm_vm *vm, u32 ring_size) { - if (vm_check_cap(vm, KVM_CAP_DIRTY_LOG_RING_ACQ_REL)) - vm_enable_cap(vm, KVM_CAP_DIRTY_LOG_RING_ACQ_REL, ring_size); - else - vm_enable_cap(vm, KVM_CAP_DIRTY_LOG_RING, ring_size); + long cap = KVM_CAP_DIRTY_LOG_RING_ACQ_REL; + int max_size = vm_check_cap(vm, cap); + + if (!max_size) { + cap = KVM_CAP_DIRTY_LOG_RING; + max_size = vm_check_cap(vm, cap); + } + + TEST_ASSERT(max_size > 0, "Dirty-ring not supported in this kernel\n"); + TEST_ASSERT(ring_size <= max_size && is_power_of_2(ring_size), + "Invalid dirty-ring size: Should be a power of two " + "<= %lu entries\n", + max_size / sizeof(struct kvm_dirty_gfn)); + + vm_enable_cap(vm, cap, ring_size); vm->dirty_ring_size = ring_size; } static void vm_open(struct kvm_vm *vm) { vm->kvm_fd = _open_kvm_dev_path_or_exit(O_RDWR); TEST_REQUIRE(kvm_has_cap(KVM_CAP_IMMEDIATE_EXIT)); vm->fd = __kvm_ioctl(vm->kvm_fd, KVM_CREATE_VM, (void *)vm->type); -- 2.54.0