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Commit bd60b735 authored by Joerg Roedel's avatar Joerg Roedel Committed by Ingo Molnar
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AMD IOMMU: don't assign preallocated protection domains to devices 



In isolation mode the protection domains for the devices are
preallocated and preassigned. This is bad if a device should be passed
to a virtualization guest because the IOMMU code does not know if it is
in use by a driver. This patch changes the code to assign the device to
the preallocated domain only if there are dma mapping requests for it.

Signed-off-by: default avatarJoerg Roedel <joerg.roedel@amd.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent b39ba6ad

arch/x86/kernel/amd_iommu.c

+38 −5
Original line number Original line Diff line number Diff line
@@ -33,6 +33,10 @@ 




static DEFINE_RWLOCK(amd_iommu_devtable_lock);

static DEFINE_RWLOCK(amd_iommu_devtable_lock);





/* A list of preallocated protection domains */

static LIST_HEAD(iommu_pd_list);

static DEFINE_SPINLOCK(iommu_pd_list_lock);



/*

/*

 * general struct to manage commands send to an IOMMU

 * general struct to manage commands send to an IOMMU

 */

 */
@@ -663,6 +667,7 @@ static struct dma_ops_domain *dma_ops_domain_alloc(struct amd_iommu *iommu, 
	dma_dom->next_bit = 0;

	dma_dom->next_bit = 0;





	dma_dom->need_flush = false;

	dma_dom->need_flush = false;

	dma_dom->target_dev = 0xffff;





	/* Intialize the exclusion range if necessary */

	/* Intialize the exclusion range if necessary */

	if (iommu->exclusion_start &&

	if (iommu->exclusion_start &&
@@ -768,6 +773,33 @@ static bool check_device(struct device *dev) 
	return true;

	return true;

}

}





/*

 * In this function the list of preallocated protection domains is traversed to

 * find the domain for a specific device

 */

static struct dma_ops_domain *find_protection_domain(u16 devid)

{

	struct dma_ops_domain *entry, *ret = NULL;

	unsigned long flags;



	if (list_empty(&iommu_pd_list))

		return NULL;



	spin_lock_irqsave(&iommu_pd_list_lock, flags);



	list_for_each_entry(entry, &iommu_pd_list, list) {

		if (entry->target_dev == devid) {

			ret = entry;

			list_del(&ret->list);

			break;

		}

	}



	spin_unlock_irqrestore(&iommu_pd_list_lock, flags);



	return ret;

}



/*

/*

 * In the dma_ops path we only have the struct device. This function

 * In the dma_ops path we only have the struct device. This function

 * finds the corresponding IOMMU, the protection domain and the

 * finds the corresponding IOMMU, the protection domain and the
@@ -803,9 +835,11 @@ static int get_device_resources(struct device *dev, 
	*iommu = amd_iommu_rlookup_table[*bdf];

	*iommu = amd_iommu_rlookup_table[*bdf];

	if (*iommu == NULL)

	if (*iommu == NULL)

		return 0;

		return 0;

	dma_dom = (*iommu)->default_dom;

	*domain = domain_for_device(*bdf);

	*domain = domain_for_device(*bdf);

	if (*domain == NULL) {

	if (*domain == NULL) {

		dma_dom = find_protection_domain(*bdf);

		if (!dma_dom)

			dma_dom = (*iommu)->default_dom;

		*domain = &dma_dom->domain;

		*domain = &dma_dom->domain;

		set_device_domain(*iommu, *domain, *bdf);

		set_device_domain(*iommu, *domain, *bdf);

		printk(KERN_INFO "AMD IOMMU: Using protection domain %d for "

		printk(KERN_INFO "AMD IOMMU: Using protection domain %d for "
@@ -1257,10 +1291,9 @@ void prealloc_protection_domains(void) 
		if (!dma_dom)

		if (!dma_dom)

			continue;

			continue;

		init_unity_mappings_for_device(dma_dom, devid);

		init_unity_mappings_for_device(dma_dom, devid);

		set_device_domain(iommu, &dma_dom->domain, devid);

		dma_dom->target_dev = devid;

		printk(KERN_INFO "AMD IOMMU: Allocated domain %d for device ",



		       dma_dom->domain.id);

		list_add_tail(&dma_dom->list, &iommu_pd_list);

		print_devid(devid, 1);

	}

	}

}

}

include/asm-x86/amd_iommu_types.h

+6 −0
Original line number Original line Diff line number Diff line
@@ -227,6 +227,12 @@ struct dma_ops_domain { 




	/* This will be set to true when TLB needs to be flushed */

	/* This will be set to true when TLB needs to be flushed */

	bool need_flush;

	bool need_flush;



	/*

	 * if this is a preallocated domain, keep the device for which it was

	 * preallocated in this variable

	 */

	u16 target_dev;

};

};





/*

/*