From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:36000) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UhMym-0005HK-W6 for qemu-devel@nongnu.org; Tue, 28 May 2013 12:42:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UhMyd-00086C-S1 for qemu-devel@nongnu.org; Tue, 28 May 2013 12:42:32 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:47659) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UhMyd-00085u-Lw for qemu-devel@nongnu.org; Tue, 28 May 2013 12:42:23 -0400 Date: Tue, 28 May 2013 12:42:14 -0400 From: Konrad Rzeszutek Wilk Message-ID: <20130528164214.GC6073@phenom.dumpdata.com> References: <20130524171613.14229.84050.stgit@bling.home> <20130528162637.28848.76733.stgit@bling.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130528162637.28848.76733.stgit@bling.home> Subject: Re: [Qemu-devel] [PATCH 3/2] vfio: Provide module option to disable vfio_iommu_type1 hugepage support List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alex Williamson Cc: iommu@lists.linux-foundation.org, chegu_vinod@hp.com, qemu-devel@nongnu.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org On Tue, May 28, 2013 at 10:27:52AM -0600, Alex Williamson wrote: > Add a module option to vfio_iommu_type1 to disable IOMMU hugepage > support. This causes iommu_map to only be called with single page > mappings, disabling the IOMMU driver's ability to use hugepages. > This option can be enabled by loading vfio_iommu_type1 with > disable_hugepages=1 or dynamically through sysfs. If enabled > dynamically, only new mappings are restricted. > > Signed-off-by: Alex Williamson Reviewed-by: Konrad Rzeszutek Wilk > --- > > As suggested by Konrad. This is cleaner to add as a follow-on > > drivers/vfio/vfio_iommu_type1.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c > index 6654a7e..8a2be4e 100644 > --- a/drivers/vfio/vfio_iommu_type1.c > +++ b/drivers/vfio/vfio_iommu_type1.c > @@ -48,6 +48,12 @@ module_param_named(allow_unsafe_interrupts, > MODULE_PARM_DESC(allow_unsafe_interrupts, > "Enable VFIO IOMMU support for on platforms without interrupt remapping support."); > > +static bool disable_hugepages; > +module_param_named(disable_hugepages, > + disable_hugepages, bool, S_IRUGO | S_IWUSR); > +MODULE_PARM_DESC(disable_hugepages, > + "Disable VFIO IOMMU support for IOMMU hugepages."); > + > struct vfio_iommu { > struct iommu_domain *domain; > struct mutex lock; > @@ -270,6 +276,11 @@ static long vfio_pin_pages(unsigned long vaddr, long npage, > return -ENOMEM; > } > > + if (unlikely(disable_hugepages)) { > + vfio_lock_acct(1); > + return 1; > + } > + > /* Lock all the consecutive pages from pfn_base */ > for (i = 1, vaddr += PAGE_SIZE; i < npage; i++, vaddr += PAGE_SIZE) { > unsigned long pfn = 0; >