From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [PATCH 1/1] arch/x86: Add CONFIG_IOMMU_DEFAULT_PT for iommu=pt Date: Thu, 29 Sep 2016 14:11:51 -0400 Message-ID: <20160929181150.GC9432@localhost.localdomain> References: <2ebef311-b346-f3ed-2fca-ce4715b84c9d@brocade.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <2ebef311-b346-f3ed-2fca-ce4715b84c9d-43mecJUBy8ZBDgjK7y7TUQ@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Glenn Serre Cc: iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org List-Id: iommu@lists.linux-foundation.org On Thu, Sep 29, 2016 at 09:58:55AM -0700, Glenn Serre wrote: > Add CONFIG_IOMMU_DEFAULT_PT for iommu=pt > > Allow default to iommu=pt without adding to command line. > Add iommu=nopt to turn off default. What's the reason / use-case for it? > > Signed-off-by: Glenn Serre > --- > Documentation/kernel-parameters.txt | 3 ++- > arch/x86/Kconfig | 7 +++++++ > arch/x86/kernel/pci-dma.c | 6 ++++++ > 3 files changed, 15 insertions(+), 1 deletion(-) > > --- a/Documentation/kernel-parameters.txt > +++ b/Documentation/kernel-parameters.txt > @@ -1607,7 +1607,8 @@ > nomerge > forcesac > soft > - pt [x86, IA-64] > + pt [x86] > + nopt [x86] > nobypass [PPC/POWERNV] > Disable IOMMU bypass, using IOMMU for PCI devices. > > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -845,6 +845,15 @@ > def_bool y > depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU > > +config IOMMU_DEFAULT_PT > + int "Default iommu pt value (0-1)" > + range 0 1 > + default "0" > + prompt "Set to 1 to default to iommu=pt" > + help > + Setting this option to 1 will set iommu passthrough (iommu=pt) > + by default. Use iommu=nopt to override. > + > config MAXSMP > bool "Enable Maximum number of SMP Processors and NUMA Nodes" > depends on X86_64 && SMP && DEBUG_KERNEL > --- a/arch/x86/kernel/pci-dma.c > +++ b/arch/x86/kernel/pci-dma.c > @@ -43,7 +43,7 @@ > * useful if a user wants to use an IOMMU only for KVM device assignment to > * guests and not for driver dma translation. > */ > -int iommu_pass_through __read_mostly; > +int iommu_pass_through __read_mostly = CONFIG_IOMMU_DEFAULT_PT; > > extern struct iommu_table_entry __iommu_table[], __iommu_table_end[]; > > @@ -196,6 +196,8 @@ > #endif > if (!strncmp(p, "pt", 2)) > iommu_pass_through = 1; > + if (!strncmp(p, "nopt", 4)) > + iommu_pass_through = 0; > > gart_parse_options(p); > > _______________________________________________ > iommu mailing list > iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org > https://lists.linuxfoundation.org/mailman/listinfo/iommu