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Date: Sun, 21 Sep 2008 11:05:50 +0200 From: Joerg Roedel <joro@...tes.org> To: "Keshavamurthy, Anil S" <anil.s.keshavamurthy@...el.com> Cc: "Raj, Ashok" <ashok.raj@...el.com>, "Li, Shaohua" <shaohua.li@...el.com>, muli@...ibm.com, "Woodhouse, David" <david.woodhouse@...el.com>, Joerg Roedel <joerg.roedel@....com>, FUJITA Tomonori <fujita.tomonori@....ntt.co.jp>, iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...e.hu> Subject: Re: [PATCH 03/23] AMD IOMMU: implement lazy IO/TLB flushing Hey David, can you add an entry to the MAINTAINERs file for Intel IOMMU? I found it difficult to find the responsible person for this thread. Joerg On Fri, Sep 19, 2008 at 11:48:50AM -0700, Keshavamurthy, Anil S wrote: > > Adding David Wookhouse who is now the official maintainer for intel VT-d > driver. > -----Original Message----- > From: Keshavamurthy, Anil S > Sent: Friday, September 19, 2008 11:47 AM > To: 'Joerg Roedel'; Raj, Ashok; Li, Shaohua; muli@...ibm.com > Cc: Joerg Roedel; FUJITA Tomonori; iommu@...ts.linux-foundation.org; > linux-kernel@...r.kernel.org; Ingo Molnar > Subject: RE: [PATCH 03/23] AMD IOMMU: implement lazy IO/TLB flushing > > > > -----Original Message----- > From: Joerg Roedel [mailto:joro@...tes.org] > Sent: Friday, September 19, 2008 10:44 AM > To: Raj, Ashok; Li, Shaohua; Keshavamurthy, Anil S; muli@...ibm.com > Cc: Joerg Roedel; FUJITA Tomonori; iommu@...ts.linux-foundation.org; > linux-kernel@...r.kernel.org; Ingo Molnar > Subject: Re: [PATCH 03/23] AMD IOMMU: implement lazy IO/TLB flushing > > Hi All, > > FUJITA mentioned that I forgot to discuss this patch with you guys, the > implementers and maintainers for Intel VT-d and Calgary IOMMU drivers. I > would like to hear your opinion on that patch. He is right with that. > The patch is already in tip/iommu but can easily be reverted if there > are fundamental objections. > The patch basically moves the iommu=fullflush and iommu=nofullflush > option from the GART code to pci-dma.c. So we can use these parameters > in other IOMMU implementations too. Since Intel VT-d is implementing > also lazy IO/TLB flushing it would benefit from this generic parameter > too. I am not so sure about Calgary, but we have other parameters for > iommu= which doesn't affect all hardware IOMMUs. > > Joerg > > On Thu, Sep 18, 2008 at 04:03:50PM +0200, Joerg Roedel wrote: > > On Thu, Sep 18, 2008 at 10:29:24AM +0900, FUJITA Tomonori wrote: > > > On Wed, 17 Sep 2008 21:28:27 +0200 > > > Joerg Roedel <joro@...tes.org> wrote: > > > > > > > On Thu, Sep 18, 2008 at 04:20:18AM +0900, FUJITA Tomonori wrote: > > > > > On Wed, 17 Sep 2008 18:52:37 +0200 > > > > > Joerg Roedel <joerg.roedel@....com> wrote: > > > > > > > > > > > The IO/TLB flushing on every unmaping operation is the most > expensive > > > > > > part there and not strictly necessary. It is sufficient to do > the flush > > > > > > before any entries are reused. This is patch implements lazy > IO/TLB > > > > > > flushing which does exactly this. > > > > > > > > > > > > Signed-off-by: Joerg Roedel <joerg.roedel@....com> > > > > > > --- > > > > > > Documentation/kernel-parameters.txt | 5 +++++ > > > > > > arch/x86/kernel/amd_iommu.c | 26 > ++++++++++++++++++++++---- > > > > > > arch/x86/kernel/amd_iommu_init.c | 10 +++++++++- > > > > > > include/asm-x86/amd_iommu_types.h | 9 +++++++++ > > > > > > 4 files changed, 45 insertions(+), 5 deletions(-) > > > > > > > > > > > > diff --git a/Documentation/kernel-parameters.txt > b/Documentation/kernel-parameters.txt > > > > > > index c2e00ee..5f0aefe 100644 > > > > > > --- a/Documentation/kernel-parameters.txt > > > > > > +++ b/Documentation/kernel-parameters.txt > > > > > > @@ -284,6 +284,11 @@ and is between 256 and 4096 characters. > It is defined in the file > > > > > > isolate - enable device isolation (each > device, as far > > > > > > as possible, will get its own > protection > > > > > > domain) > > > > > > + unmap_flush - enable flushing of IO/TLB > entries when > > > > > > + they are unmapped. > Otherwise they are > > > > > > + flushed before they will > be reused, which > > > > > > + is a lot of faster > > > > > > + > > > > > > > > > > Would it be nice to have consistency of IOMMU parameters? > > > > > > > > True. We should merge common parameters across IOMMUs into the > > > > iommu= parameter some time in the future, I think. It would also > be the > > > > place for the IOMMU size parameter. > > > > > > Hmm, now is better than the future? I think that now you can add > > > something like 'disable_batching_flush' as a common parameter and > > > change AMD IOMMU to use it. > > > > Ok, I queued the following patch in the AMD IOMMU updates and changed > > this patch to use iommu_fullflush instead. Is this patch ok? It > changes > > the behavior of GART to use lazy flushing by default. But I don't > think > > that this is a problem. > > > > commit 9769771290fddcfc0362c5d30242151d4eb1cc46 > > Author: Joerg Roedel <joerg.roedel@....com> > > Date: Thu Sep 18 15:23:43 2008 +0200 > > > > x86: move GART TLB flushing options to generic code > > > > The GART currently implements the iommu=[no]fullflush command line > > parameters which influence its IO/TLB flushing strategy. This > patch > > makes these parameters generic so that they can be used by the AMD > IOMMU > > too. > > > > Signed-off-by: Joerg Roedel <joerg.roedel@....com> > > > > diff --git a/Documentation/kernel-parameters.txt > b/Documentation/kernel-parameters.txt > > index c2e00ee..569527e 100644 > > --- a/Documentation/kernel-parameters.txt > > +++ b/Documentation/kernel-parameters.txt > > @@ -888,6 +888,10 @@ and is between 256 and 4096 characters. It is > defined in the file > > nomerge > > forcesac > > soft > > + fullflush > > + Flush IO/TLB at every deallocation > > + nofullflush > > + Flush IO/TLB only when addresses are reused > (default) > > > > > > intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option > > diff --git a/Documentation/x86/x86_64/boot-options.txt > b/Documentation/x86/x86_64/boot-options.txt > > index 72ffb53..42c887b 100644 > > --- a/Documentation/x86/x86_64/boot-options.txt > > +++ b/Documentation/x86/x86_64/boot-options.txt > > @@ -229,8 +229,6 @@ IOMMU (input/output memory management unit) > > iommu options only relevant to the AMD GART hardware IOMMU: > > <size> Set the size of the remapping area in bytes. > > allowed Overwrite iommu off workarounds for specific > chipsets. > > - fullflush Flush IOMMU on each allocation (default). > > - nofullflush Don't use IOMMU fullflush. > > leak Turn on simple iommu leak tracing (only when > > CONFIG_IOMMU_LEAK is on). Default number of > leak pages > > is 20. > > diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c > > index 23882c4..6dae123 100644 > > --- a/arch/x86/kernel/pci-dma.c > > +++ b/arch/x86/kernel/pci-dma.c > > @@ -16,6 +16,15 @@ EXPORT_SYMBOL(dma_ops); > > > > static int iommu_sac_force __read_mostly; > > > > +/* > > + * If this is disabled the IOMMU will use an optimized flushing > strategy > > + * of only flushing when an mapping is reused. With it true the GART > is > > + * flushed for every mapping. Problem is that doing the lazy flush > seems > > + * to trigger bugs with some popular PCI cards, in particular 3ware > (but > > + * has been also also seen with Qlogic at least). > > + */ > > +int iommu_fullflush; > > + > > #ifdef CONFIG_IOMMU_DEBUG > > int panic_on_overflow __read_mostly = 1; > > int force_iommu __read_mostly = 1; > > @@ -171,6 +180,10 @@ static __init int iommu_setup(char *p) > > } > > if (!strncmp(p, "nomerge", 7)) > > iommu_merge = 0; > > + if (!strncmp(p, "fullflush", 8)) > > + iommu_fullflush = 1; > > + if (!strncmp(p, "nofullflush", 11)) > > + iommu_fullflush = 0; > > if (!strncmp(p, "forcesac", 8)) > > iommu_sac_force = 1; > > if (!strncmp(p, "allowdac", 8)) > > diff --git a/arch/x86/kernel/pci-gart_64.c > b/arch/x86/kernel/pci-gart_64.c > > index 9739d56..508ef47 100644 > > --- a/arch/x86/kernel/pci-gart_64.c > > +++ b/arch/x86/kernel/pci-gart_64.c > > @@ -45,15 +45,6 @@ static unsigned long iommu_pages; /* .. and in > pages */ > > > > static u32 *iommu_gatt_base; /* Remapping table */ > > > > -/* > > - * If this is disabled the IOMMU will use an optimized flushing > strategy > > - * of only flushing when an mapping is reused. With it true the GART > is > > - * flushed for every mapping. Problem is that doing the lazy flush > seems > > - * to trigger bugs with some popular PCI cards, in particular 3ware > (but > > - * has been also also seen with Qlogic at least). > > - */ > > -int iommu_fullflush = 1; > > - > > /* Allocation bitmap for the remapping area: */ > > static DEFINE_SPINLOCK(iommu_bitmap_lock); > > /* Guarded by iommu_bitmap_lock: */ > > @@ -901,10 +892,6 @@ void __init gart_parse_options(char *p) > > #endif > > if (isdigit(*p) && get_option(&p, &arg)) > > iommu_size = arg; > > - if (!strncmp(p, "fullflush", 8)) > > - iommu_fullflush = 1; > > - if (!strncmp(p, "nofullflush", 11)) > > - iommu_fullflush = 0; > > if (!strncmp(p, "noagp", 5)) > > no_agp = 1; > > if (!strncmp(p, "noaperture", 10)) > > diff --git a/include/asm-x86/iommu.h b/include/asm-x86/iommu.h > > index 546ad31..bcebc37 100644 > > --- a/include/asm-x86/iommu.h > > +++ b/include/asm-x86/iommu.h > > @@ -7,6 +7,7 @@ extern struct dma_mapping_ops nommu_dma_ops; > > extern int force_iommu, no_iommu; > > extern int iommu_detected; > > extern int dmar_disabled; > > +extern int iommu_fullflush; > > > > extern unsigned long iommu_num_pages(unsigned long addr, unsigned > long len); > > > > > > -- > > | AMD Saxony Limited Liability Company & Co. KG > > Operating | Wilschdorfer Landstr. 101, 01109 Dresden, Germany > > System | Register Court Dresden: HRA 4896 > > Research | General Partner authorized to represent: > > Center | AMD Saxony LLC (Wilmington, Delaware, US) > > | General Manager of AMD Saxony LLC: Dr. Hans-R. Deppe, > Thomas McCoy > > > > -- > > To unsubscribe from this list: send the line "unsubscribe > linux-kernel" in > > the body of a message to majordomo@...r.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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