Commit c5a5dc4c authored by Lu Baolu's avatar Lu Baolu Committed by Joerg Roedel
Browse files

iommu/vt-d: Don't switch off swiotlb if bounce page is used 



The bounce page implementation depends on swiotlb. Hence, don't
switch off swiotlb if the system has untrusted devices or could
potentially be hot-added with any untrusted devices.

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: default avatarLu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent e5e04d05

drivers/iommu/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -182,6 +182,7 @@ config INTEL_IOMMU 
	select IOMMU_IOVA

	select NEED_DMA_MAP_STATE

	select DMAR_TABLE

	select SWIOTLB

	help

	  DMA remapping (DMAR) devices support enables independent address

	  translations for Direct Memory Access (DMA) from devices.

drivers/iommu/intel-iommu.c

+17 −15
Original line number Diff line number Diff line
@@ -4547,22 +4547,20 @@ const struct attribute_group *intel_iommu_groups[] = { 
	NULL,

};



static int __init platform_optin_force_iommu(void)

static inline bool has_untrusted_dev(void)

{

	struct pci_dev *pdev = NULL;

	bool has_untrusted_dev = false;



	if (!dmar_platform_optin() || no_platform_optin)

		return 0;

	for_each_pci_dev(pdev)

		if (pdev->untrusted)

			return true;



	for_each_pci_dev(pdev) {

		if (pdev->untrusted) {

			has_untrusted_dev = true;

			break;

		}

	return false;

}



	if (!has_untrusted_dev)

static int __init platform_optin_force_iommu(void)

{

	if (!dmar_platform_optin() || no_platform_optin || !has_untrusted_dev())

		return 0;



	if (no_iommu || dmar_disabled)
@@ -4576,9 +4574,6 @@ static int __init platform_optin_force_iommu(void) 
		iommu_identity_mapping |= IDENTMAP_ALL;



	dmar_disabled = 0;

#if defined(CONFIG_X86) && defined(CONFIG_SWIOTLB)

	swiotlb = 0;

#endif

	no_iommu = 0;



	return 1;
@@ -4718,6 +4713,13 @@ int __init intel_iommu_init(void) 
	up_write(&dmar_global_lock);



#if defined(CONFIG_X86) && defined(CONFIG_SWIOTLB)

	/*

	 * If the system has no untrusted device or the user has decided

	 * to disable the bounce page mechanisms, we don't need swiotlb.

	 * Mark this and the pre-allocated bounce pages will be released

	 * later.

	 */

	if (!has_untrusted_dev() || intel_no_bounce)

		swiotlb = 0;

#endif

	dma_ops = &intel_dma_ops;

CRA Git | Maintained and supported by SUSTech CRA and CCSE