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From: Joerg Roedel on 7 Apr 2010 09:00
This patch introduces a mutex to lock page table updates in
the IOMMU-API path. We can't use the spin_lock here because
this patch might sleep.

Signed-off-by: Joerg Roedel <joerg.roedel(a)amd.com>
---
arch/x86/include/asm/amd_iommu_types.h | 2 ++
arch/x86/kernel/amd_iommu.c | 9 +++++++++
2 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/arch/x86/include/asm/amd_iommu_types.h b/arch/x86/include/asm/amd_iommu_types.h
index ba19ad4..5e46e78 100644
--- a/arch/x86/include/asm/amd_iommu_types.h
+++ b/arch/x86/include/asm/amd_iommu_types.h
@@ -21,6 +21,7 @@
#define _ASM_X86_AMD_IOMMU_TYPES_H

#include <linux/types.h>
+#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/spinlock.h>

@@ -237,6 +238,7 @@ struct protection_domain {
struct list_head list; /* for list of all protection domains */
struct list_head dev_list; /* List of all devices in this domain */
spinlock_t lock; /* mostly used to lock the page table*/
+ struct mutex api_lock; /* protect page tables in the iommu-api path */
u16 id; /* the domain id written to the device table */
int mode; /* paging mode (0-6 levels) */
u64 *pt_root; /* page table root pointer */
diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 2c4a501..b97f2f1 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -2327,6 +2327,7 @@ static struct protection_domain *protection_domain_alloc(void)
return NULL;

spin_lock_init(&domain->lock);
+ mutex_init(&domain->api_lock);
domain->id = domain_id_alloc();
if (!domain->id)
goto out_err;
@@ -2456,6 +2457,8 @@ static int amd_iommu_map_range(struct iommu_domain *dom,
iova &= PAGE_MASK;
paddr &= PAGE_MASK;

+ mutex_lock(&domain->api_lock);
+
for (i = 0; i < npages; ++i) {
ret = iommu_map_page(domain, iova, paddr, prot, PM_MAP_4k);
if (ret)
@@ -2465,6 +2468,8 @@ static int amd_iommu_map_range(struct iommu_domain *dom,
paddr += PAGE_SIZE;
}

+ mutex_unlock(&domain->api_lock);
+
return 0;
}

@@ -2477,12 +2482,16 @@ static void amd_iommu_unmap_range(struct iommu_domain *dom,

iova &= PAGE_MASK;

+ mutex_lock(&domain->api_lock);
+
for (i = 0; i < npages; ++i) {
iommu_unmap_page(domain, iova, PM_MAP_4k);
iova += PAGE_SIZE;
}

iommu_flush_tlb_pde(domain);
+
+ mutex_unlock(&domain->api_lock);
}

static phys_addr_t amd_iommu_iova_to_phys(struct iommu_domain *dom,
--
1.7.0.4


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Prev: [PATCH 12/12] x86/gart: Disable GART explicitly before initialization
Next: [PATCH] btusb: Raw mode and ACL/SCO data