From: Florian Fainelli <f.fainelli@gmail.com> To: linux-kernel@vger.kernel.org, Christoph Hellwig <hch@lst.de> Cc: opendmb@gmail.com, Jonathan Corbet <corbet@lwn.net>, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>, Marek Szyprowski <m.szyprowski@samsung.com>, Robin Murphy <robin.murphy@arm.com>, "Paul E. McKenney" <paulmck@kernel.org>, Randy Dunlap <rdunlap@infradead.org>, Andrew Morton <akpm@linux-foundation.org>, Thomas Gleixner <tglx@linutronix.de>, Mauro Carvalho Chehab <mchehab+huawei@kernel.org>, Viresh Kumar <viresh.kumar@linaro.org>, Mike Kravetz <mike.kravetz@oracle.com>, Peter Zijlstra <peterz@infradead.org>, "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>, "open list:SWIOTLB SUBSYSTEM" <iommu@lists.linux-foundation.org> Subject: Re: [PATCH] swiotlb: Add swiotlb=off to disable SWIOTLB Date: Thu, 18 Mar 2021 12:22:13 -0700 [thread overview] Message-ID: <bbd44c42-cedc-7bd6-a443-c991fd080298@gmail.com> (raw) In-Reply-To: <20210318191816.4185226-1-f.fainelli@gmail.com> On 3/18/2021 12:18 PM, Florian Fainelli wrote: > It may be useful to disable the SWIOTLB completely for testing or when a > platform is known not to have any DRAM addressing limitations what so > ever. > > Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Christoph, in addition to this change, how would you feel if we qualified the swiotlb_init() in arch/arm/mm/init.c with a: if (memblock_end_of_DRAM() >= SZ_4G) swiotlb_init(1) right now this is made unconditional whenever ARM_LPAE is enabled which is the case for the platforms I maintain (ARCH_BRCMSTB) however we do not really need a SWIOTLB so long as the largest DRAM physical address does not exceed 4GB AFAICT. Thanks! > --- > Documentation/admin-guide/kernel-parameters.txt | 1 + > include/linux/swiotlb.h | 1 + > kernel/dma/swiotlb.c | 9 +++++++++ > 3 files changed, 11 insertions(+) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index 04545725f187..b0223e48921e 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -5278,6 +5278,7 @@ > force -- force using of bounce buffers even if they > wouldn't be automatically used by the kernel > noforce -- Never use bounce buffers (for debugging) > + off -- Completely disable SWIOTLB > > switches= [HW,M68k] > > diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h > index 5857a937c637..23f86243defe 100644 > --- a/include/linux/swiotlb.h > +++ b/include/linux/swiotlb.h > @@ -15,6 +15,7 @@ enum swiotlb_force { > SWIOTLB_NORMAL, /* Default - depending on HW DMA mask etc. */ > SWIOTLB_FORCE, /* swiotlb=force */ > SWIOTLB_NO_FORCE, /* swiotlb=noforce */ > + SWIOTLB_OFF, /* swiotlb=off */ > }; > > /* > diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c > index c10e855a03bc..d7a4a789c7d3 100644 > --- a/kernel/dma/swiotlb.c > +++ b/kernel/dma/swiotlb.c > @@ -126,6 +126,8 @@ setup_io_tlb_npages(char *str) > } else if (!strcmp(str, "noforce")) { > swiotlb_force = SWIOTLB_NO_FORCE; > io_tlb_nslabs = 1; > + } else if (!strcmp(str, "off")) { > + swiotlb_force = SWIOTLB_OFF; > } > > return 0; > @@ -229,6 +231,9 @@ int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose) > unsigned long i, bytes; > size_t alloc_size; > > + if (swiotlb_force == SWIOTLB_OFF) > + return 0; > + > bytes = nslabs << IO_TLB_SHIFT; > > io_tlb_nslabs = nslabs; > @@ -284,6 +289,9 @@ swiotlb_init(int verbose) > unsigned char *vstart; > unsigned long bytes; > > + if (swiotlb_force == SWIOTLB_OFF) > + goto out; > + > if (!io_tlb_nslabs) { > io_tlb_nslabs = (default_size >> IO_TLB_SHIFT); > io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE); > @@ -302,6 +310,7 @@ swiotlb_init(int verbose) > io_tlb_start = 0; > } > pr_warn("Cannot allocate buffer"); > +out: > no_iotlb_memory = true; > } > > -- Florian
WARNING: multiple messages have this Message-ID (diff)
From: Florian Fainelli <f.fainelli@gmail.com> To: linux-kernel@vger.kernel.org, Christoph Hellwig <hch@lst.de> Cc: opendmb@gmail.com, "Paul E. McKenney" <paulmck@kernel.org>, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>, Mauro Carvalho Chehab <mchehab+huawei@kernel.org>, Viresh Kumar <viresh.kumar@linaro.org>, Jonathan Corbet <corbet@lwn.net>, "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>, Peter Zijlstra <peterz@infradead.org>, "open list:SWIOTLB SUBSYSTEM" <iommu@lists.linux-foundation.org>, Randy Dunlap <rdunlap@infradead.org>, Andrew Morton <akpm@linux-foundation.org>, Mike Kravetz <mike.kravetz@oracle.com>, Robin Murphy <robin.murphy@arm.com>, Thomas Gleixner <tglx@linutronix.de> Subject: Re: [PATCH] swiotlb: Add swiotlb=off to disable SWIOTLB Date: Thu, 18 Mar 2021 12:22:13 -0700 [thread overview] Message-ID: <bbd44c42-cedc-7bd6-a443-c991fd080298@gmail.com> (raw) In-Reply-To: <20210318191816.4185226-1-f.fainelli@gmail.com> On 3/18/2021 12:18 PM, Florian Fainelli wrote: > It may be useful to disable the SWIOTLB completely for testing or when a > platform is known not to have any DRAM addressing limitations what so > ever. > > Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Christoph, in addition to this change, how would you feel if we qualified the swiotlb_init() in arch/arm/mm/init.c with a: if (memblock_end_of_DRAM() >= SZ_4G) swiotlb_init(1) right now this is made unconditional whenever ARM_LPAE is enabled which is the case for the platforms I maintain (ARCH_BRCMSTB) however we do not really need a SWIOTLB so long as the largest DRAM physical address does not exceed 4GB AFAICT. Thanks! > --- > Documentation/admin-guide/kernel-parameters.txt | 1 + > include/linux/swiotlb.h | 1 + > kernel/dma/swiotlb.c | 9 +++++++++ > 3 files changed, 11 insertions(+) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index 04545725f187..b0223e48921e 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -5278,6 +5278,7 @@ > force -- force using of bounce buffers even if they > wouldn't be automatically used by the kernel > noforce -- Never use bounce buffers (for debugging) > + off -- Completely disable SWIOTLB > > switches= [HW,M68k] > > diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h > index 5857a937c637..23f86243defe 100644 > --- a/include/linux/swiotlb.h > +++ b/include/linux/swiotlb.h > @@ -15,6 +15,7 @@ enum swiotlb_force { > SWIOTLB_NORMAL, /* Default - depending on HW DMA mask etc. */ > SWIOTLB_FORCE, /* swiotlb=force */ > SWIOTLB_NO_FORCE, /* swiotlb=noforce */ > + SWIOTLB_OFF, /* swiotlb=off */ > }; > > /* > diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c > index c10e855a03bc..d7a4a789c7d3 100644 > --- a/kernel/dma/swiotlb.c > +++ b/kernel/dma/swiotlb.c > @@ -126,6 +126,8 @@ setup_io_tlb_npages(char *str) > } else if (!strcmp(str, "noforce")) { > swiotlb_force = SWIOTLB_NO_FORCE; > io_tlb_nslabs = 1; > + } else if (!strcmp(str, "off")) { > + swiotlb_force = SWIOTLB_OFF; > } > > return 0; > @@ -229,6 +231,9 @@ int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose) > unsigned long i, bytes; > size_t alloc_size; > > + if (swiotlb_force == SWIOTLB_OFF) > + return 0; > + > bytes = nslabs << IO_TLB_SHIFT; > > io_tlb_nslabs = nslabs; > @@ -284,6 +289,9 @@ swiotlb_init(int verbose) > unsigned char *vstart; > unsigned long bytes; > > + if (swiotlb_force == SWIOTLB_OFF) > + goto out; > + > if (!io_tlb_nslabs) { > io_tlb_nslabs = (default_size >> IO_TLB_SHIFT); > io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE); > @@ -302,6 +310,7 @@ swiotlb_init(int verbose) > io_tlb_start = 0; > } > pr_warn("Cannot allocate buffer"); > +out: > no_iotlb_memory = true; > } > > -- Florian _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2021-03-18 19:22 UTC|newest] Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-03-18 19:18 [PATCH] swiotlb: Add swiotlb=off to disable SWIOTLB Florian Fainelli 2021-03-18 19:18 ` Florian Fainelli 2021-03-18 19:22 ` Florian Fainelli [this message] 2021-03-18 19:22 ` Florian Fainelli 2021-03-18 19:34 ` Robin Murphy 2021-03-18 19:34 ` Robin Murphy 2021-03-18 19:43 ` Florian Fainelli 2021-03-18 19:43 ` Florian Fainelli 2021-03-18 19:53 ` Robin Murphy 2021-03-18 19:53 ` Robin Murphy 2021-03-18 21:31 ` Florian Fainelli 2021-03-18 21:31 ` Florian Fainelli 2021-03-18 23:35 ` Robin Murphy 2021-03-18 23:35 ` Robin Murphy 2021-03-19 0:48 ` Florian Fainelli 2021-03-19 0:48 ` Florian Fainelli 2021-03-19 2:34 ` Konrad Rzeszutek Wilk 2021-03-19 2:34 ` Konrad Rzeszutek Wilk 2021-03-19 4:00 ` [PATCH] swiotlb: Make SWIOTLB_NO_FORCE perform no allocation Florian Fainelli 2021-03-19 4:00 ` Florian Fainelli 2021-03-19 5:01 ` Konrad Rzeszutek Wilk 2021-03-19 5:01 ` Konrad Rzeszutek Wilk 2021-03-21 3:37 ` [PATCH v2] " Florian Fainelli 2021-03-21 3:37 ` Florian Fainelli 2021-03-22 7:46 ` Christoph Hellwig 2021-03-22 7:46 ` Christoph Hellwig 2021-03-23 1:53 ` [PATCH v3] " Florian Fainelli 2021-03-23 1:53 ` Florian Fainelli 2021-03-24 8:42 ` Christoph Hellwig 2021-03-24 8:42 ` Christoph Hellwig 2021-04-09 3:13 ` Florian Fainelli 2021-04-09 3:13 ` Florian Fainelli 2021-04-09 19:32 ` Konrad Rzeszutek Wilk 2021-04-09 19:32 ` Konrad Rzeszutek Wilk 2021-04-09 20:33 ` Florian Fainelli 2021-04-09 20:33 ` Florian Fainelli
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=bbd44c42-cedc-7bd6-a443-c991fd080298@gmail.com \ --to=f.fainelli@gmail.com \ --cc=akpm@linux-foundation.org \ --cc=corbet@lwn.net \ --cc=hch@lst.de \ --cc=iommu@lists.linux-foundation.org \ --cc=konrad.wilk@oracle.com \ --cc=linux-doc@vger.kernel.org \ --cc=linux-kernel@vger.kernel.org \ --cc=m.szyprowski@samsung.com \ --cc=mchehab+huawei@kernel.org \ --cc=mike.kravetz@oracle.com \ --cc=opendmb@gmail.com \ --cc=paulmck@kernel.org \ --cc=peterz@infradead.org \ --cc=rdunlap@infradead.org \ --cc=robin.murphy@arm.com \ --cc=tglx@linutronix.de \ --cc=viresh.kumar@linaro.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.