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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Wed, 26 Feb 2020 00:29:19 -0000 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06avi18878370.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 01Q0TI8544302718 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 26 Feb 2020 00:29:18 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1F6735204F; Wed, 26 Feb 2020 00:29:18 +0000 (GMT) Received: from ozlabs.au.ibm.com (unknown [9.192.253.14]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id 73E275204E; Wed, 26 Feb 2020 00:29:17 +0000 (GMT) Received: from adsilva.ozlabs.ibm.com (haven.au.ibm.com [9.192.254.114]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.au.ibm.com (Postfix) with ESMTPSA id C7E00A00F1; Wed, 26 Feb 2020 11:29:12 +1100 (AEDT) Subject: Re: [PATCH v3 06/27] ocxl: Tally up the LPC memory on a link & allow it to be mapped From: "Alastair D'Silva" To: Frederic Barrat Cc: "Aneesh Kumar K . V" , "Oliver O'Halloran" , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Andrew Donnellan , Arnd Bergmann , Greg Kroah-Hartman , Dan Williams , Vishal Verma , Dave Jiang , Ira Weiny , Andrew Morton , Mauro Carvalho Chehab , "David S. Miller" , Rob Herring , Anton Blanchard , Krzysztof Kozlowski , Mahesh Salgaonkar , Madhavan Srinivasan , =?ISO-8859-1?Q?C=E9dric?= Le Goater , Anju T Sudhakar , Hari Bathini , Thomas Gleixner , Greg Kurz , Nicholas Piggin , Masahiro Yamada , Alexey Kardashevskiy , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-nvdimm@lists.01.org, linux-mm@kvack.org Date: Wed, 26 Feb 2020 11:29:16 +1100 In-Reply-To: <4c8f704b-5607-5ca0-c00e-01e412117f6b@linux.ibm.com> References: <20200221032720.33893-1-alastair@au1.ibm.com> <20200221032720.33893-7-alastair@au1.ibm.com> <4c8f704b-5607-5ca0-c00e-01e412117f6b@linux.ibm.com> Organization: IBM Australia Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.34.3 (3.34.3-1.fc31) MIME-Version: 1.0 X-TM-AS-GCONF: 00 x-cbid: 20022600-0028-0000-0000-000003DDFA10 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 20022600-0029-0000-0000-000024A31410 Message-Id: <7833545b1c276ac62651c598af27728b8cacabed.camel@au1.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138,18.0.572 definitions=2020-02-25_09:2020-02-25,2020-02-25 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 phishscore=0 spamscore=0 bulkscore=0 mlxlogscore=999 adultscore=0 suspectscore=2 malwarescore=0 priorityscore=1501 lowpriorityscore=0 clxscore=1015 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2001150001 definitions=main-2002260000 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, 2020-02-25 at 17:30 +0100, Frederic Barrat wrote: >=20 > Le 21/02/2020 =C3=A0 04:26, Alastair D'Silva a =C3=A9crit : > > From: Alastair D'Silva > >=20 > > Tally up the LPC memory on an OpenCAPI link & allow it to be mapped > >=20 > > Signed-off-by: Alastair D'Silva > > --- > > drivers/misc/ocxl/core.c | 10 ++++++ > > drivers/misc/ocxl/link.c | 53 > > +++++++++++++++++++++++++++++++ > > drivers/misc/ocxl/ocxl_internal.h | 33 +++++++++++++++++++ > > 3 files changed, 96 insertions(+) > >=20 > > diff --git a/drivers/misc/ocxl/core.c b/drivers/misc/ocxl/core.c > > index b7a09b21ab36..2531c6cf19a0 100644 > > --- a/drivers/misc/ocxl/core.c > > +++ b/drivers/misc/ocxl/core.c > > @@ -230,8 +230,18 @@ static int configure_afu(struct ocxl_afu *afu, > > u8 afu_idx, struct pci_dev *dev) > > if (rc) > > goto err_free_pasid; > > =20 > > + if (afu->config.lpc_mem_size || afu- > > >config.special_purpose_mem_size) { > > + rc =3D ocxl_link_add_lpc_mem(afu->fn->link, afu- > > >config.lpc_mem_offset, > > + afu->config.lpc_mem_size + > > + afu- > > >config.special_purpose_mem_size); > > + if (rc) > > + goto err_free_mmio; > > + } > > + > > return 0; > > =20 > > +err_free_mmio: > > + unmap_mmio_areas(afu); > > err_free_pasid: > > reclaim_afu_pasid(afu); > > err_free_actag: > > diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c > > index 58d111afd9f6..1e039cc5ebe5 100644 > > --- a/drivers/misc/ocxl/link.c > > +++ b/drivers/misc/ocxl/link.c > > @@ -84,6 +84,11 @@ struct ocxl_link { > > int dev; > > atomic_t irq_available; > > struct spa *spa; > > + struct mutex lpc_mem_lock; /* protects lpc_mem & lpc_mem_sz */ > > + u64 lpc_mem_sz; /* Total amount of LPC memory presented on the > > link */ > > + u64 lpc_mem; > > + int lpc_consumers; > > + > > void *platform_data; > > }; > > static struct list_head links_list =3D LIST_HEAD_INIT(links_list); > > @@ -396,6 +401,8 @@ static int alloc_link(struct pci_dev *dev, int > > PE_mask, struct ocxl_link **out_l > > if (rc) > > goto err_spa; > > =20 > > + mutex_init(&link->lpc_mem_lock); > > + > > /* platform specific hook */ > > rc =3D pnv_ocxl_spa_setup(dev, link->spa->spa_mem, PE_mask, > > &link->platform_data); > > @@ -711,3 +718,49 @@ void ocxl_link_free_irq(void *link_handle, int > > hw_irq) > > atomic_inc(&link->irq_available); > > } > > EXPORT_SYMBOL_GPL(ocxl_link_free_irq); > > + > > +int ocxl_link_add_lpc_mem(void *link_handle, u64 offset, u64 size) > > +{ > > + struct ocxl_link *link =3D (struct ocxl_link *) link_handle; > > + > > + // Check for overflow > > + if (offset > (offset + size)) > > + return -EINVAL; > > + > > + mutex_lock(&link->lpc_mem_lock); > > + link->lpc_mem_sz =3D max(link->lpc_mem_sz, offset + size); > > + > > + mutex_unlock(&link->lpc_mem_lock); > > + > > + return 0; > > +} > > + > > +u64 ocxl_link_lpc_map(void *link_handle, struct pci_dev *pdev) > > +{ > > + struct ocxl_link *link =3D (struct ocxl_link *) link_handle; > > + > > + mutex_lock(&link->lpc_mem_lock); > > + > > + if(!link->lpc_mem) > > + link->lpc_mem =3D pnv_ocxl_platform_lpc_setup(pdev, link- > > >lpc_mem_sz); > > + > > + if(link->lpc_mem) > > + link->lpc_consumers++; > > + mutex_unlock(&link->lpc_mem_lock); > > + > > + return link->lpc_mem; > > +} > > + > > +void ocxl_link_lpc_release(void *link_handle, struct pci_dev > > *pdev) > > +{ > > + struct ocxl_link *link =3D (struct ocxl_link *) link_handle; > > + > > + mutex_lock(&link->lpc_mem_lock); > > + WARN_ON(--link->lpc_consumers < 0); >=20 > Here, we always decrement the lpc_consumers count. However, it was > only=20 > incremented if the mapping was setup correctly in opal. >=20 > We could arguably claim that ocxl_link_lpc_release() should only be=20 > called if ocxl_link_lpc_map() succeeded, but it would make error > path=20 > handling easier if we only decrement the lpc_consumers count if=20 > link->lpc_mem is set. So that we can just call > ocxl_link_lpc_release()=20 > in error paths without having to worry about triggering the WARN_ON > message. >=20 > Fred >=20 >=20 Ok, this makes sense. >=20 > > + if (link->lpc_consumers =3D=3D 0) { > > + pnv_ocxl_platform_lpc_release(pdev); > > + link->lpc_mem =3D 0; > > + } > > + > > + mutex_unlock(&link->lpc_mem_lock); > > +} > > diff --git a/drivers/misc/ocxl/ocxl_internal.h > > b/drivers/misc/ocxl/ocxl_internal.h > > index 198e4e4bc51d..d0c8c4838f42 100644 > > --- a/drivers/misc/ocxl/ocxl_internal.h > > +++ b/drivers/misc/ocxl/ocxl_internal.h > > @@ -142,4 +142,37 @@ int ocxl_irq_offset_to_id(struct ocxl_context > > *ctx, u64 offset); > > u64 ocxl_irq_id_to_offset(struct ocxl_context *ctx, int irq_id); > > void ocxl_afu_irq_free_all(struct ocxl_context *ctx); > > =20 > > +/** > > + * ocxl_link_add_lpc_mem() - Increment the amount of memory > > required by an OpenCAPI link > > + * > > + * @link_handle: The OpenCAPI link handle > > + * @offset: The offset of the memory to add > > + * @size: The amount of memory to increment by > > + * > > + * Returns 0 on success, negative on overflow > > + */ > > +int ocxl_link_add_lpc_mem(void *link_handle, u64 offset, u64 > > size); > > + > > +/** > > + * ocxl_link_lpc_map() - Map the LPC memory for an OpenCAPI device > > + * Since LPC memory belongs to a link, the whole LPC memory > > available > > + * on the link must be mapped in order to make it accessible to a > > device. > > + * @link_handle: The OpenCAPI link handle > > + * @pdev: A device that is on the link > > + * > > + * Returns the address of the mapped LPC memory, or 0 on error > > + */ > > +u64 ocxl_link_lpc_map(void *link_handle, struct pci_dev *pdev); > > + > > +/** > > + * ocxl_link_lpc_release() - Release the LPC memory device for an > > OpenCAPI device > > + * > > + * Offlines LPC memory on an OpenCAPI link for a device. If this > > is the > > + * last device on the link to release the memory, unmap it from > > the link. > > + * > > + * @link_handle: The OpenCAPI link handle > > + * @pdev: A device that is on the link > > + */ > > +void ocxl_link_lpc_release(void *link_handle, struct pci_dev > > *pdev); > > + > > #endif /* _OCXL_INTERNAL_H_ */ > >=20 --=20 Alastair D'Silva Open Source Developer Linux Technology Centre, IBM Australia mob: 0423 762 819