From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C6A5962818 for ; Tue, 19 Mar 2024 15:34:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710862442; cv=none; b=eUogsePGKSMdDgR5jgo9bI7hLwb3o/JggWSBa4L+1hjWMqeDY1aIR6vSSIAiFUncP12q0aywFVou1TeUfPuFt42p3yqoWz5DpUd1lR8z688+2VFcutwzdTbNgTFxy0spKpSvh9A52eG4oKyYfJRa5RwvXqfmKM6rOh0dKTFSwcw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710862442; c=relaxed/simple; bh=rrQSAAEQCgctnBTxLRZaF5NpLsX/foa8mFUz552bLlo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=XFL7C8DO2i+XuAQeIFkyP4I/oUd6OlT6jxhhwzVQo6VbGuNw2tifqOLZO0ahP9cSfgSbugbX9WTm99Q0EGp3rTRhbyh8ZDI8QJ0xTc0ETVG88ovunFC5RpqomeiHEVLCwUwU84UBLaCfTF8jdbUJyOn0VSvwdTg4/24lGG2RSG0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=YY+tFMXj; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="YY+tFMXj" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1710862439; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=LTv0c9gBsGx2cGoLzFXhFtEOz/PUb4iNz/cutnWVCfY=; b=YY+tFMXjJu1Bae/EA9qG8BfuN6FmiBa2aAoFEtGOpzlWBEOlpH6rV77qsk1Y/obGlKbxc5 v5beO0zk3uGje5zodSEa8RiIW5gqbibG5kY0s77tBMVnHHiajViOqCJRi/5VfqmGOv5+1d 8xU1sMts+QKrDr+Z8zCefnu4ReNNe0Y= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-571-cHXfH-IXM4GpTBHYlzoxHg-1; Tue, 19 Mar 2024 11:33:51 -0400 X-MC-Unique: cHXfH-IXM4GpTBHYlzoxHg-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 84F6D1C2CDE6; Tue, 19 Mar 2024 15:33:51 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.88]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3698F492BD1; Tue, 19 Mar 2024 15:33:50 +0000 (UTC) Date: Tue, 19 Mar 2024 15:33:44 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Shaoqin Huang Cc: qemu-arm@nongnu.org, Eric Auger , Sebastian Ott , Peter Maydell , Paolo Bonzini , qemu-devel@nongnu.org, kvm@vger.kernel.org Subject: Re: [PATCH v7] arm/kvm: Enable support for KVM_ARM_VCPU_PMU_V3_FILTER Message-ID: Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= References: <20240221063431.76992-1-shahuang@redhat.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20240221063431.76992-1-shahuang@redhat.com> User-Agent: Mutt/2.2.12 (2023-09-09) X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.10 On Wed, Feb 21, 2024 at 01:34:31AM -0500, Shaoqin Huang wrote: > diff --git a/docs/system/arm/cpu-features.rst b/docs/system/arm/cpu-features.rst > index a5fb929243..7c8f6a60ef 100644 > --- a/docs/system/arm/cpu-features.rst > +++ b/docs/system/arm/cpu-features.rst > @@ -204,6 +204,29 @@ the list of KVM VCPU features and their descriptions. > the guest scheduler behavior and/or be exposed to the guest > userspace. > > +``kvm-pmu-filter`` > + By default kvm-pmu-filter is disabled. This means that by default all pmu > + events will be exposed to guest. > + > + KVM implements PMU Event Filtering to prevent a guest from being able to > + sample certain events. It depends on the KVM_ARM_VCPU_PMU_V3_FILTER > + attribute supported in KVM. It has the following format: > + > + kvm-pmu-filter="{A,D}:start-end[;{A,D}:start-end...]" > + > + The A means "allow" and D means "deny", start is the first event of the > + range and the end is the last one. The first registered range defines > + the global policy(global ALLOW if the first @action is DENY, global DENY > + if the first @action is ALLOW). The start and end only support hexadecimal > + format. For example: > + > + kvm-pmu-filter="A:0x11-0x11;A:0x23-0x3a;D:0x30-0x30" > + > + Since the first action is allow, we have a global deny policy. It > + will allow event 0x11 (The cycle counter), events 0x23 to 0x3a are > + also allowed except the event 0x30 which is denied, and all the other > + events are denied. Can you document whether the policy evaluation stops at the first matching range, or checks all ranges ie, if you have kvm-pmu-filter="A:0x1-0x9;D=0x7-0x7" will an input of '0x7' be allowed (because it matches the first range and stops), or denied (because the second range overrides the result of the first) With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|