From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) (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 7F69C7E576 for ; Wed, 24 Jan 2024 16:58:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.176.79.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706115503; cv=none; b=O3V+PSCK/XrhJrLFA0jBwQgT1RcOhZjAPcfhwU3Lj06GwQOfX1Ox5T67NxegnwvwtKDgpANOeMOkR/M2T10lDbUDC/GBf0HXGWnxxFwe+PN3PWa6p3s0QLL1GbH1q/2XnalUhgfKbx3e9mmqNDOr3wt0BDV3Av0QURjtYfAg5ko= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706115503; c=relaxed/simple; bh=unF6iGryB/Zw/IktTiIQ88/87xyyVKjhrLZzf/bKQh8=; h=Date:From:To:CC:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=uxJlzzoa9nU0prlCInFXX8lH88TpOJ2I1o06d5fgelcfOCzTuIKnc5u1lWTqHJXp4AFR4RnNe25w/Y2JCx8D8RSg8Y1DRKnKlcxRD2YvBnwFrJosqJrsSLKDCu48CgTrPvCnte8iCjB7WJPT0rzYoL9YJmI/0AlUmfUWISIZfNA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=Huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=185.176.79.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=Huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.18.186.216]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4TKqnw3CR7z6J9jy; Thu, 25 Jan 2024 00:55:16 +0800 (CST) Received: from lhrpeml500005.china.huawei.com (unknown [7.191.163.240]) by mail.maildlp.com (Postfix) with ESMTPS id D70131400D3; Thu, 25 Jan 2024 00:58:16 +0800 (CST) Received: from localhost (10.202.227.76) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.35; Wed, 24 Jan 2024 16:58:16 +0000 Date: Wed, 24 Jan 2024 16:58:15 +0000 From: Jonathan Cameron To: CC: , , , , , , , , , "Fan Ni" Subject: Re: [PATCH v3 9/9] hw/mem/cxl_type3: Add dpa range validation for accesses to dc regions Message-ID: <20240124165815.00007e46@Huawei.com> In-Reply-To: <20231107180907.553451-10-nifan.cxl@gmail.com> References: <20231107180907.553451-1-nifan.cxl@gmail.com> <20231107180907.553451-10-nifan.cxl@gmail.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: lhrpeml500001.china.huawei.com (7.191.163.213) To lhrpeml500005.china.huawei.com (7.191.163.240) On Tue, 7 Nov 2023 10:07:13 -0800 nifan.cxl@gmail.com wrote: > From: Fan Ni >=20 > Not all dpa range in the dc regions is valid to access until an extent DPA ... DC etc > covering the range has been added. Add a bitmap for each region to > record whether a dc block in the region has been backed by dc extent. > For the bitmap, a bit in the bitmap represents a dc block. When a dc > extent is added, all the bits of the blocks in the extent will be set, > which will be cleared when the extent is released. >=20 > Signed-off-by: Fan Ni Hi Fan, one query inline and a few comments. Jonathan >=20 > -- > JC changes: > - Rebase on what will be next gitlab.com/jic23/qemu CXL staging tree. > - Drop unnecessary handling of failed bitmap allocations. In common with > most QEMU allocations they fail hard anyway. > - Use previously factored out cxl_find_region() helper > - Minor editorial stuff in comments such as spec version references > according to the standard form I'm trying to push through the code. > Picked up J=F8rgen's fix: > https://lore.kernel.org/qemu-devel/d0d7ca1d-81bc-19b3-4904-d60046ded844@w= dc.com/T/#u > --- > hw/cxl/cxl-mailbox-utils.c | 31 +++++++++------ > hw/mem/cxl_type3.c | 78 +++++++++++++++++++++++++++++++++++++ > include/hw/cxl/cxl_device.h | 15 +++++-- > 3 files changed, 109 insertions(+), 15 deletions(-) >=20 > diff --git a/hw/cxl/cxl-mailbox-utils.c b/hw/cxl/cxl-mailbox-utils.c > index 8e6a98753a..6be92fb5ba 100644 > --- a/hw/cxl/cxl-mailbox-utils.c > +++ b/hw/cxl/cxl-mailbox-utils.c > @@ -1401,10 +1401,9 @@ CXLDCDRegion *cxl_find_dc_region(CXLType3Dev *ct3d= , uint64_t dpa, uint64_t len) > } > =20 > void cxl_insert_extent_to_extent_list(CXLDCDExtentList *list, > - uint64_t dpa, > - uint64_t len, > - uint8_t *tag, > - uint16_t shared_seq) > + uint64_t dpa, uint64_t len, > + uint8_t *tag, > + uint16_t shared_seq) avoid noisy whitespace changes like this. > diff --git a/hw/mem/cxl_type3.c b/hw/mem/cxl_type3.c > index 43cea3d818..4ec65a751a 100644 > --- a/hw/mem/cxl_type3.c > +++ b/hw/mem/cxl_type3.c > +/* > + * Check whether a DPA range [dpa, dpa + len) has been backed with DC ex= tents. > + * Used when validating read/write to dc regions > + */ > +bool ct3_test_region_block_backed(CXLType3Dev *ct3d, uint64_t dpa, > + uint64_t len) > +{ > + CXLDCDRegion *region; > + uint64_t nbits; > + long nr; > + > + region =3D cxl_find_dc_region(ct3d, dpa, len); > + if (!region) { > + return false; > + } > + > + nr =3D (dpa - region->base) / region->block_size; > + nbits =3D DIV_ROUND_UP(len, region->block_size); > + return find_next_zero_bit(region->blk_bitmap, nr + nbits, nr) =3D=3D= nr + nbits; I'm not sure how this works... Is it taking a size or an end point? Linux equivalent takes size, so I'd expect return find_next_zero_bit(region->blk_bitmap, nbits, nr); Perhaps a comment would avoid any future confusion on this. > +} > + > +/* > + * Mark the DPA range [dpa, dap + len) to be unbacked and inaccessible. = This > + * happens when a dc extent is return by the host. > + */ > +void ct3_clear_region_block_backed(CXLType3Dev *ct3d, uint64_t dpa, > + uint64_t len) > +{ > + CXLDCDRegion *region; > + uint64_t nbits; > + long nr; > + > + region =3D cxl_find_dc_region(ct3d, dpa, len); > + if (!region) { > + return; > + } > + > + nr =3D (dpa - region->base) / region->block_size; > + nbits =3D len / region->block_size; > + bitmap_clear(region->blk_bitmap, nr, nbits); > +} > +