From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> To: Lu Baolu <baolu.lu@linux.intel.com> Cc: David Woodhouse <dwmw2@infradead.org>, Joerg Roedel <joro@8bytes.org>, Bjorn Helgaas <bhelgaas@google.com>, Christoph Hellwig <hch@lst.de>, ashok.raj@intel.com, jacob.jun.pan@intel.com, alan.cox@intel.com, kevin.tian@intel.com, mika.westerberg@linux.intel.com, Ingo Molnar <mingo@redhat.com>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, pengfei.xu@intel.com, Marek Szyprowski <m.szyprowski@samsung.com>, Robin Murphy <robin.murphy@arm.com>, Jonathan Corbet <corbet@lwn.net>, Boris Ostrovsky <boris.ostrovsky@oracle.com>, Juergen Gross <jgross@suse.com>, Stefano Stabellini <sstabellini@kernel.org>, Steven Rostedt <rostedt@goodmis.org>, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Jacob Pan <jacob.jun.pan@linux.intel.com> Subject: Re: [PATCH v4 6/9] iommu/vt-d: Check whether device requires bounce buffer Date: Mon, 10 Jun 2019 12:08:03 -0400 [thread overview] Message-ID: <20190610160802.GX28796@char.us.oracle.com> (raw) In-Reply-To: <20190603011620.31999-7-baolu.lu@linux.intel.com> On Mon, Jun 03, 2019 at 09:16:17AM +0800, Lu Baolu wrote: > This adds a helper to check whether a device needs to > use bounce buffer. It also provides a boot time option > to disable the bounce buffer. Users can use this to > prevent the iommu driver from using the bounce buffer > for performance gain. > > Cc: Ashok Raj <ashok.raj@intel.com> > Cc: Jacob Pan <jacob.jun.pan@linux.intel.com> > Cc: Kevin Tian <kevin.tian@intel.com> > Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> > Tested-by: Xu Pengfei <pengfei.xu@intel.com> > Tested-by: Mika Westerberg <mika.westerberg@intel.com> > --- > Documentation/admin-guide/kernel-parameters.txt | 5 +++++ > drivers/iommu/intel-iommu.c | 6 ++++++ > 2 files changed, 11 insertions(+) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index 138f6664b2e2..65685c6e53e4 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -1728,6 +1728,11 @@ > Note that using this option lowers the security > provided by tboot because it makes the system > vulnerable to DMA attacks. > + nobounce [Default off] > + Do not use the bounce buffer for untrusted devices like > + the Thunderbolt devices. This will treat the untrusted My brain has sometimes a hard time parsing 'Not' and 'un'. Could this be: Disable bounce buffer for unstrusted devices ..? And perhaps call it 'noswiotlb' ? Not everyone knows that SWIOTLB = bounce buffer. > + devices as the trusted ones, hence might expose security > + risks of DMA attacks. > > intel_idle.max_cstate= [KNL,HW,ACPI,X86] > 0 disables intel_idle and fall back on acpi_idle. > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c > index 235837c50719..41439647f75d 100644 > --- a/drivers/iommu/intel-iommu.c > +++ b/drivers/iommu/intel-iommu.c > @@ -371,6 +371,7 @@ static int dmar_forcedac; > static int intel_iommu_strict; > static int intel_iommu_superpage = 1; > static int iommu_identity_mapping; > +static int intel_no_bounce; intel_swiotlb_on = 1 ? > > #define IDENTMAP_ALL 1 > #define IDENTMAP_GFX 2 > @@ -384,6 +385,8 @@ EXPORT_SYMBOL_GPL(intel_iommu_gfx_mapped); > static DEFINE_SPINLOCK(device_domain_lock); > static LIST_HEAD(device_domain_list); > > +#define device_needs_bounce(d) (!intel_no_bounce && dev_is_untrusted(d)) > + > /* > * Iterate over elements in device_domain_list and call the specified > * callback @fn against each element. > @@ -466,6 +469,9 @@ static int __init intel_iommu_setup(char *str) > printk(KERN_INFO > "Intel-IOMMU: not forcing on after tboot. This could expose security risk for tboot\n"); > intel_iommu_tboot_noforce = 1; > + } else if (!strncmp(str, "nobounce", 8)) { > + pr_info("Intel-IOMMU: No bounce buffer. This could expose security risks of DMA attacks\n"); Again, Intel-IOMMU: No SWIOTLB. T.. blah blah' Asking for this as doing 'dmesg | grep SWIOTLB' will expose nicely all the SWIOTLB invocations.. > + intel_no_bounce = 1; > } > > str += strcspn(str, ","); > -- > 2.17.1 >
WARNING: multiple messages have this Message-ID (diff)
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> To: Lu Baolu <baolu.lu@linux.intel.com> Cc: alan.cox@intel.com, Christoph Hellwig <hch@lst.de>, Stefano Stabellini <sstabellini@kernel.org>, ashok.raj@intel.com, Jonathan Corbet <corbet@lwn.net>, pengfei.xu@intel.com, Ingo Molnar <mingo@redhat.com>, David Woodhouse <dwmw2@infradead.org>, kevin.tian@intel.com, Steven Rostedt <rostedt@goodmis.org>, Bjorn Helgaas <bhelgaas@google.com>, Boris Ostrovsky <boris.ostrovsky@oracle.com>, mika.westerberg@linux.intel.com, Juergen Gross <jgross@suse.com>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, jacob.jun.pan@intel.com, Robin Murphy <robin.murphy@arm.com> Subject: Re: [PATCH v4 6/9] iommu/vt-d: Check whether device requires bounce buffer Date: Mon, 10 Jun 2019 12:08:03 -0400 [thread overview] Message-ID: <20190610160802.GX28796@char.us.oracle.com> (raw) In-Reply-To: <20190603011620.31999-7-baolu.lu@linux.intel.com> On Mon, Jun 03, 2019 at 09:16:17AM +0800, Lu Baolu wrote: > This adds a helper to check whether a device needs to > use bounce buffer. It also provides a boot time option > to disable the bounce buffer. Users can use this to > prevent the iommu driver from using the bounce buffer > for performance gain. > > Cc: Ashok Raj <ashok.raj@intel.com> > Cc: Jacob Pan <jacob.jun.pan@linux.intel.com> > Cc: Kevin Tian <kevin.tian@intel.com> > Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> > Tested-by: Xu Pengfei <pengfei.xu@intel.com> > Tested-by: Mika Westerberg <mika.westerberg@intel.com> > --- > Documentation/admin-guide/kernel-parameters.txt | 5 +++++ > drivers/iommu/intel-iommu.c | 6 ++++++ > 2 files changed, 11 insertions(+) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index 138f6664b2e2..65685c6e53e4 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -1728,6 +1728,11 @@ > Note that using this option lowers the security > provided by tboot because it makes the system > vulnerable to DMA attacks. > + nobounce [Default off] > + Do not use the bounce buffer for untrusted devices like > + the Thunderbolt devices. This will treat the untrusted My brain has sometimes a hard time parsing 'Not' and 'un'. Could this be: Disable bounce buffer for unstrusted devices ..? And perhaps call it 'noswiotlb' ? Not everyone knows that SWIOTLB = bounce buffer. > + devices as the trusted ones, hence might expose security > + risks of DMA attacks. > > intel_idle.max_cstate= [KNL,HW,ACPI,X86] > 0 disables intel_idle and fall back on acpi_idle. > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c > index 235837c50719..41439647f75d 100644 > --- a/drivers/iommu/intel-iommu.c > +++ b/drivers/iommu/intel-iommu.c > @@ -371,6 +371,7 @@ static int dmar_forcedac; > static int intel_iommu_strict; > static int intel_iommu_superpage = 1; > static int iommu_identity_mapping; > +static int intel_no_bounce; intel_swiotlb_on = 1 ? > > #define IDENTMAP_ALL 1 > #define IDENTMAP_GFX 2 > @@ -384,6 +385,8 @@ EXPORT_SYMBOL_GPL(intel_iommu_gfx_mapped); > static DEFINE_SPINLOCK(device_domain_lock); > static LIST_HEAD(device_domain_list); > > +#define device_needs_bounce(d) (!intel_no_bounce && dev_is_untrusted(d)) > + > /* > * Iterate over elements in device_domain_list and call the specified > * callback @fn against each element. > @@ -466,6 +469,9 @@ static int __init intel_iommu_setup(char *str) > printk(KERN_INFO > "Intel-IOMMU: not forcing on after tboot. This could expose security risk for tboot\n"); > intel_iommu_tboot_noforce = 1; > + } else if (!strncmp(str, "nobounce", 8)) { > + pr_info("Intel-IOMMU: No bounce buffer. This could expose security risks of DMA attacks\n"); Again, Intel-IOMMU: No SWIOTLB. T.. blah blah' Asking for this as doing 'dmesg | grep SWIOTLB' will expose nicely all the SWIOTLB invocations.. > + intel_no_bounce = 1; > } > > str += strcspn(str, ","); > -- > 2.17.1 > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2019-06-10 16:07 UTC|newest] Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-06-03 1:16 [PATCH v4 0/9] iommu: Bounce page for untrusted devices Lu Baolu 2019-06-03 1:16 ` Lu Baolu 2019-06-03 1:16 ` [PATCH v4 1/9] PCI: Add dev_is_untrusted helper Lu Baolu 2019-06-03 1:16 ` Lu Baolu 2019-06-03 1:16 ` [PATCH v4 2/9] swiotlb: Split size parameter to map/unmap APIs Lu Baolu 2019-06-03 1:16 ` Lu Baolu 2019-06-03 1:16 ` [PATCH v4 3/9] swiotlb: Zero out bounce buffer for untrusted device Lu Baolu 2019-06-03 1:16 ` Lu Baolu 2019-06-10 15:45 ` Konrad Rzeszutek Wilk 2019-06-10 15:45 ` Konrad Rzeszutek Wilk 2019-06-12 0:43 ` Lu Baolu 2019-06-12 0:43 ` Lu Baolu 2019-06-12 1:05 ` Konrad Rzeszutek Wilk 2019-06-12 1:05 ` Konrad Rzeszutek Wilk 2019-06-12 3:08 ` Lu Baolu 2019-06-12 3:08 ` Lu Baolu 2019-06-03 1:16 ` [PATCH v4 4/9] iommu: Add bounce page APIs Lu Baolu 2019-06-03 1:16 ` Lu Baolu 2019-06-10 15:56 ` Konrad Rzeszutek Wilk 2019-06-10 15:56 ` Konrad Rzeszutek Wilk 2019-06-12 0:45 ` Lu Baolu 2019-06-12 0:45 ` Lu Baolu 2019-06-11 12:10 ` Pavel Begunkov 2019-06-11 12:10 ` Pavel Begunkov 2019-06-12 0:52 ` Lu Baolu 2019-06-12 0:52 ` Lu Baolu 2019-06-03 1:16 ` [PATCH v4 5/9] iommu/vt-d: Don't switch off swiotlb if use direct dma Lu Baolu 2019-06-03 1:16 ` Lu Baolu 2019-06-10 15:54 ` Konrad Rzeszutek Wilk 2019-06-10 15:54 ` Konrad Rzeszutek Wilk 2019-06-12 2:03 ` Lu Baolu 2019-06-12 2:03 ` Lu Baolu 2019-06-03 1:16 ` [PATCH v4 6/9] iommu/vt-d: Check whether device requires bounce buffer Lu Baolu 2019-06-03 1:16 ` Lu Baolu 2019-06-10 16:08 ` Konrad Rzeszutek Wilk [this message] 2019-06-10 16:08 ` Konrad Rzeszutek Wilk 2019-06-12 2:22 ` Lu Baolu 2019-06-12 2:22 ` Lu Baolu 2019-06-03 1:16 ` [PATCH v4 7/9] iommu/vt-d: Add trace events for domain map/unmap Lu Baolu 2019-06-03 1:16 ` Lu Baolu 2019-06-04 9:01 ` Steven Rostedt 2019-06-04 9:01 ` Steven Rostedt 2019-06-05 6:48 ` Lu Baolu 2019-06-05 6:48 ` Lu Baolu 2019-06-10 16:08 ` Konrad Rzeszutek Wilk 2019-06-10 16:08 ` Konrad Rzeszutek Wilk 2019-06-12 2:31 ` Lu Baolu 2019-06-12 2:31 ` Lu Baolu 2019-06-03 1:16 ` [PATCH v4 8/9] iommu/vt-d: Code refactoring for bounce map and unmap Lu Baolu 2019-06-03 1:16 ` Lu Baolu 2019-06-03 1:16 ` [PATCH v4 9/9] iommu/vt-d: Use bounce buffer for untrusted devices Lu Baolu 2019-06-03 1:16 ` Lu Baolu 2019-06-10 15:42 ` [PATCH v4 0/9] iommu: Bounce page " Konrad Rzeszutek Wilk 2019-06-10 15:42 ` Konrad Rzeszutek Wilk 2019-06-12 3:00 ` Lu Baolu 2019-06-12 3:00 ` Lu Baolu 2019-06-12 6:22 ` Mika Westerberg 2019-06-12 6:22 ` Mika Westerberg 2019-06-10 16:10 ` Konrad Rzeszutek Wilk 2019-06-10 16:10 ` Konrad Rzeszutek Wilk 2019-06-12 3:04 ` Lu Baolu 2019-06-12 3:04 ` Lu Baolu
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