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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Tue, 25 Feb 2020 16:30:55 -0000 Received: from d06av24.portsmouth.uk.ibm.com (d06av24.portsmouth.uk.ibm.com [9.149.105.60]) by b06avi18878370.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 01PGUsai37683538 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 25 Feb 2020 16:30:54 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3A49542041; Tue, 25 Feb 2020 16:30:54 +0000 (GMT) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 0F8E34204B; Tue, 25 Feb 2020 16:30:53 +0000 (GMT) Received: from bali.tlslab.ibm.com (unknown [9.101.4.17]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTP; Tue, 25 Feb 2020 16:30:52 +0000 (GMT) Subject: Re: [PATCH v3 06/27] ocxl: Tally up the LPC memory on a link & allow it to be mapped To: "Alastair D'Silva" , alastair@d-silva.org 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 , =?UTF-8?Q?C=c3=a9dric_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 References: <20200221032720.33893-1-alastair@au1.ibm.com> <20200221032720.33893-7-alastair@au1.ibm.com> From: Frederic Barrat Date: Tue, 25 Feb 2020 17:30:52 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200221032720.33893-7-alastair@au1.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US X-TM-AS-GCONF: 00 x-cbid: 20022516-4275-0000-0000-000003A56068 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 20022516-4276-0000-0000-000038B976B1 Message-Id: <4c8f704b-5607-5ca0-c00e-01e412117f6b@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138,18.0.572 definitions=2020-02-25_05:2020-02-21,2020-02-25 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 adultscore=0 spamscore=0 mlxlogscore=999 mlxscore=0 priorityscore=1501 bulkscore=0 malwarescore=0 phishscore=0 clxscore=1015 suspectscore=2 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2001150001 definitions=main-2002250124 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: Le 21/02/2020 =C3=A0 04:26, Alastair D'Silva a =C3=A9crit=C2=A0: > 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_offs= et, > + 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_m= ask, 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); Here, we always decrement the lpc_consumers count. However, it was only=20 incremented if the mapping was setup correctly in opal. 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 messa= ge. Fred > + 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 b= y 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 devi= ce. > + * @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 Open= CAPI device > + * > + * Offlines LPC memory on an OpenCAPI link for a device. If this is th= e > + * last device on the link to release the memory, unmap it from the li= nk. > + * > + * @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