[PATCH v9 08/10] iommu/vt-d: assign new page table for dma_map

Li, Zhen-Hua
2015-03-19T05:37:55Z

When a device driver issues the first dma_map command for a device, we
assign a new and empty page-table, thus removing all mappings from the
old kernel for the device.

Signed-off-by: Li, Zhen-Hua <zhen-hual@hp.com>
---
drivers/iommu/intel-iommu.c | 54 ++++++++++++++++++++++++++++++++++++++-------
1 file changed, 46 insertions(+), 8 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 312f06b..6b691d4 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -44,6 +44,7 @@
#include <asm/irq_remapping.h>
#include <asm/cacheflush.h>
#include <asm/iommu.h>
+#include <linux/dma-mapping.h>

#include "irq_remapping.h"

@@ -3121,14 +3122,30 @@ static struct dmar_domain *__get_valid_domain_for_dev(struct device *dev)
return NULL;
}

- /* make sure context mapping is ok */
- if (unlikely(!domain_context_mapped(dev))) {
- ret = domain_context_mapping(domain, dev, CONTEXT_TT_MULTI_LEVEL);
- if (ret) {
- printk(KERN_ERR "Domain context map for %s failed",
- dev_name(dev));
- return NULL;
- }
+ /* if in kdump kernel, we need to unmap the mapped dma pages,
+ * detach this device first.
+ */
+ if (likely(domain_context_mapped(dev))) {
+#ifdef CONFIG_CRASH_DUMP
+ if (is_kdump_kernel()) {
+ unmap_device_dma(domain, dev);
+ domain = get_domain_for_dev(dev,
+ DEFAULT_DOMAIN_ADDRESS_WIDTH);
+ if (!domain) {
+ pr_err("Allocating domain for %s failed",
+ dev_name(dev));
+ return NULL;
+ }
+ } else
+#endif
+ return domain;
+ }
+
+ ret = domain_context_mapping(domain, dev, CONTEXT_TT_MULTI_LEVEL);
+ if (ret) {
+ pr_err("Domain context map for %s failed",
+ dev_name(dev));
+ return NULL;
}

return domain;
@@ -5177,4 +5194,25 @@ static int intel_iommu_load_translation_tables(struct dmar_drhd_unit *drhd)
return ret;
}

+static void unmap_device_dma(struct dmar_domain *domain, struct device *dev)
+{
+ struct intel_iommu *iommu;
+ struct context_entry *ce;
+ struct iova *iova;
+ u8 bus, devfn;
+ phys_addr_t phys_addr;
+ dma_addr_t dev_addr;
+
+ iommu = device_to_iommu(dev, &bus, &devfn);
+ ce = device_to_context_entry(iommu, bus, devfn);
+ phys_addr = context_address_root(ce) << VTD_PAGE_SHIFT;
+ dev_addr = phys_to_dma(dev, phys_addr);
+
+ iova = find_iova(&domain->iovad, IOVA_PFN(dev_addr));
+ if (iova)
+ intel_unmap(dev, dev_addr);
+
+ domain_remove_one_dev_info(domain, dev);
+}
+
#endif /* CONFIG_CRASH_DUMP */
--
2.0.0-rc0