From mboxrd@z Thu Jan 1 00:00:00 1970 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 ws5-mx01.kavi.com (ws5-mx01.kavi.com [34.193.7.191]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 27E89C76196 for ; Mon, 10 Apr 2023 07:17:01 +0000 (UTC) Received: from lists.oasis-open.org (oasis.ws5.connectedcommunity.org [10.110.1.242]) by ws5-mx01.kavi.com (Postfix) with ESMTP id 3E94F2B021 for ; Mon, 10 Apr 2023 07:17:01 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 16B719863D8 for ; Mon, 10 Apr 2023 07:17:01 +0000 (UTC) Received: from host09.ws5.connectedcommunity.org (host09.ws5.connectedcommunity.org [10.110.1.97]) by lists.oasis-open.org (Postfix) with QMQP id E6BF49862A5; Mon, 10 Apr 2023 07:17:00 +0000 (UTC) Mailing-List: contact virtio-dev-help@lists.oasis-open.org; run by ezmlm List-ID: Sender: Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id D4F7D98631E for ; Mon, 10 Apr 2023 07:17:00 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-MC-Unique: xLrWdhu0OiS_hmm-yvreOw-1 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1681111018; x=1683703018; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=xCASe/31PQJgcYquO7k8UZlc3OUApt7X6Arw2QuZGaI=; b=K3YCY1woAWdmC2MH+efoDyiXXyVITnMkdHQi9ZBolWYkYaTHxy6Chsc9Dk54/+5ydo 4O9Bq7l+UCsd4wejiddw/jJYSICpoj65CJyJ59WqtA4PS7M6t5FZ1DZU1JOXRKJwYWXK BUi0A/gRfGNaq57E3NBTMAqqKQKgYcIToG+cg0RN8xOldikVB78CPWvBWqqN3esCBfLR T0gSV/qw/KtY3O20E3vJ9EILgMex5JUn39A0WQRHpDUF9Iz2SdVZGtVq6ymPT549f76x 5tuZlYyL+rOzbNeKSFUdRYFJemq035XjT2x9c0hef7BvpH32X9K8mPyudeuE/Gj1Jo+A yHaw== X-Gm-Message-State: AAQBX9d0G2N1fJR0RZe7ky1+zxzkY6kdypfn9QvT/zcX+edImIBBThAV jnbHxiqzUWyXFTiDwfSkMMEK1pKrhMtDeCfa5dVJDnIn+ZInYUTUoEkii1cwqo9eC2oMc6J1kDA ZsD3ni5xGfMSF4MwdeF89i/l/+0vciCdV8+KUfi+AhTJG X-Received: by 2002:a05:6808:3307:b0:383:fef9:6cac with SMTP id ca7-20020a056808330700b00383fef96cacmr2559408oib.9.1681111017795; Mon, 10 Apr 2023 00:16:57 -0700 (PDT) X-Google-Smtp-Source: AKy350ZovcXYKe7SHE5v/MAr73WhBk/8T+MNkULlMe06/6WhnKBFoq8FhLzH3/5tS7IX+dMqD66kgHQXIUnf05xVcys= X-Received: by 2002:a05:6808:3307:b0:383:fef9:6cac with SMTP id ca7-20020a056808330700b00383fef96cacmr2559403oib.9.1681111017550; Mon, 10 Apr 2023 00:16:57 -0700 (PDT) MIME-Version: 1.0 References: <20230330225834.506969-1-parav@nvidia.com> <20230330225834.506969-9-parav@nvidia.com> <20230410021619-mutt-send-email-mst@kernel.org> In-Reply-To: <20230410021619-mutt-send-email-mst@kernel.org> From: Jason Wang Date: Mon, 10 Apr 2023 15:16:46 +0800 Message-ID: To: "Michael S. Tsirkin" Cc: Parav Pandit , virtio-dev@lists.oasis-open.org, cohuck@redhat.com, virtio-comment@lists.oasis-open.org, shahafs@nvidia.com, Satananda Burla X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Subject: Re: [virtio-dev] [PATCH 08/11] transport-pci: Introduce virtio extended capability On Mon, Apr 10, 2023 at 2:24=E2=80=AFPM Michael S. Tsirkin = wrote: > > On Mon, Apr 10, 2023 at 09:36:17AM +0800, Jason Wang wrote: > > On Fri, Mar 31, 2023 at 7:00=E2=80=AFAM Parav Pandit = wrote: > > > > > > PCI device configuration space for capabilities is limited to only 19= 2 > > > bytes shared by many PCI capabilities of generic PCI device and virti= o > > > specific. > > > > > > Hence, introduce virtio extended capability that uses PCI Express > > > extended capability. > > > Subsequent patch uses this virtio extended capability. > > > > > > Co-developed-by: Satananda Burla > > > Signed-off-by: Parav Pandit > > > > Can you explain the differences compared to what I've used to propose? > > > > https://www.mail-archive.com/virtio-dev@lists.oasis-open.org/msg08078.h= tml > > > > This can save time for everybody. > > > > Thanks > > BTW another advantage of extended capabilities is - these are actually > cheaper to access from a VM than classic config space. Config space/BAR is allowed by both of the proposals or anything I missed? > > > Several points > - I don't like it that yours is 32 bit. We do not need 2 variants just > make it all 64 bit That's fine. > - We need to document that if driver does not scan extended capbilities i= t will not find them. This is implicit since I remember we don't have such documentation for pci capability, anything makes pcie special? > And existing drivers do not scan them. So what is safe > to put there? vendor specific? extra access types? For PASID at least, since it's a PCI-E feature, vendor specific should be fine. Not sure about legacy MMIO then. > Can we make scanning these mandatory in future drivers? future devices? > I guess we can add a feature bit to flag that. For PASID, it doesn't need this, otherwise we may duplicate transport specific features. > Is accessing these possible from bios? Not at least for the two use cases now PASID or legacy MMIO. > > So I like this one better as a basis - care reviewing it and adding > stuff? There are very few differences and I will have a look. Thanks > > -- > MST > --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org