Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932603AbbBPKLG (ORCPT ); Mon, 16 Feb 2015 05:11:06 -0500 Received: from e23smtp08.au.ibm.com ([202.81.31.141]:56813 "EHLO e23smtp08.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932354AbbBPKHw (ORCPT ); Mon, 16 Feb 2015 05:07:52 -0500 From: Alexey Kardashevskiy To: linuxppc-dev@lists.ozlabs.org Cc: Alexey Kardashevskiy , Benjamin Herrenschmidt , Paul Mackerras , Alex Williamson , Gavin Shan , Alexander Graf , linux-kernel@vger.kernel.org Subject: [PATCH v4 13/28] powerpc/iommu: Fix IOMMU ownership control functions Date: Mon, 16 Feb 2015 21:06:05 +1100 Message-Id: <1424081180-4494-14-git-send-email-aik@ozlabs.ru> X-Mailer: git-send-email 2.0.0 In-Reply-To: <1424081180-4494-1-git-send-email-aik@ozlabs.ru> References: <1424081180-4494-1-git-send-email-aik@ozlabs.ru> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15021610-0029-0000-0000-0000012230A1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3176 Lines: 104 This adds missing locks in iommu_take_ownership()/ iommu_release_ownership(). This marks all pages busy in iommu_table::it_map in order to catch errors if there is an attempt to use this table while ownership over it is taken. This only clears TCE content if there is no page marked busy in it_map. Clearing must be done outside of the table locks as iommu_clear_tce() called from iommu_clear_tces_and_put_pages() does this. Signed-off-by: Alexey Kardashevskiy --- Note: we might want to get rid of it as this patchset removes it_map from tables passed to VFIO. Changes: v5: * do not store bit#0 value, it has to be set for zero-based table anyway * removed test_and_clear_bit * only disable bypass if succeeded --- arch/powerpc/kernel/iommu.c | 31 +++++++++++++++++++++++++------ 1 file changed, 25 insertions(+), 6 deletions(-) diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c index 952939f..407d0d6 100644 --- a/arch/powerpc/kernel/iommu.c +++ b/arch/powerpc/kernel/iommu.c @@ -1024,33 +1024,48 @@ EXPORT_SYMBOL_GPL(iommu_tce_build); int iommu_take_ownership(struct iommu_table *tbl) { - unsigned long sz = (tbl->it_size + 7) >> 3; + unsigned long flags, i, sz = (tbl->it_size + 7) >> 3; + int ret = 0; + + spin_lock_irqsave(&tbl->large_pool.lock, flags); + for (i = 0; i < tbl->nr_pools; i++) + spin_lock(&tbl->pools[i].lock); if (tbl->it_offset == 0) clear_bit(0, tbl->it_map); if (!bitmap_empty(tbl->it_map, tbl->it_size)) { pr_err("iommu_tce: it_map is not empty"); - return -EBUSY; + ret = -EBUSY; + if (tbl->it_offset == 0) + set_bit(0, tbl->it_map); + } else { + memset(tbl->it_map, 0xff, sz); } - memset(tbl->it_map, 0xff, sz); + for (i = 0; i < tbl->nr_pools; i++) + spin_unlock(&tbl->pools[i].lock); + spin_unlock_irqrestore(&tbl->large_pool.lock, flags); /* * Disable iommu bypass, otherwise the user can DMA to all of * our physical memory via the bypass window instead of just * the pages that has been explicitly mapped into the iommu */ - if (tbl->set_bypass) + if (!ret && tbl->set_bypass) tbl->set_bypass(tbl, false); - return 0; + return ret; } EXPORT_SYMBOL_GPL(iommu_take_ownership); void iommu_release_ownership(struct iommu_table *tbl) { - unsigned long sz = (tbl->it_size + 7) >> 3; + unsigned long flags, i, sz = (tbl->it_size + 7) >> 3; + + spin_lock_irqsave(&tbl->large_pool.lock, flags); + for (i = 0; i < tbl->nr_pools; i++) + spin_lock(&tbl->pools[i].lock); memset(tbl->it_map, 0, sz); @@ -1058,6 +1073,10 @@ void iommu_release_ownership(struct iommu_table *tbl) if (tbl->it_offset == 0) set_bit(0, tbl->it_map); + for (i = 0; i < tbl->nr_pools; i++) + spin_unlock(&tbl->pools[i].lock); + spin_unlock_irqrestore(&tbl->large_pool.lock, flags); + /* The kernel owns the device now, we can restore the iommu bypass */ if (tbl->set_bypass) tbl->set_bypass(tbl, true); -- 2.0.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/