[PATCH] intel_iommu,dmar: reserve mmio of IOMMU registers

[PATCH] intel_iommu,dmar: reserve mmio of IOMMU registers

[Donald Dutile]

Intel-iommu initialization doesn't currently reserve the memory used
for the IOMMU registers. This can allow the pci resource allocator
to assign a device BAR to the same address as the IOMMU registers.
This can cause some not so nice side affects when the driver
ioremap's that region.

Signed-off-by: Donald Dutile <ddutile-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
---
 drivers/iommu/dmar.c |   18 ++++++++++++++++--
 1 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index 35c1e17..1fcbd96 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -599,10 +599,16 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
 	iommu->seq_id = iommu_allocated++;
 	sprintf (iommu->name, "dmar%d", iommu->seq_id);
 
+	map_size = VTD_PAGE_SIZE;
+	if (!request_mem_region(drhd->reg_base_addr, map_size, iommu->name)) {
+		printk(KERN_ERR "IOMMU: can't reserve memory\n");
+		goto error;
+	}
+
 	iommu->reg = ioremap(drhd->reg_base_addr, VTD_PAGE_SIZE);
 	if (!iommu->reg) {
 		printk(KERN_ERR "IOMMU: can't map the region\n");
-		goto error;
+		goto err_release;
 	}
 	iommu->cap = dmar_readq(iommu->reg + DMAR_CAP_REG);
 	iommu->ecap = dmar_readq(iommu->reg + DMAR_ECAP_REG);
@@ -637,10 +643,16 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
 	map_size = VTD_PAGE_ALIGN(map_size);
 	if (map_size > VTD_PAGE_SIZE) {
 		iounmap(iommu->reg);
+		release_mem_region(drhd->reg_base_addr, VTD_PAGE_SIZE);
+		if (!request_mem_region(drhd->reg_base_addr, map_size, 
+					iommu->name)) {
+			printk(KERN_ERR "IOMMU: can't reserve memory\n");
+			goto error;
+		}
 		iommu->reg = ioremap(drhd->reg_base_addr, map_size);
 		if (!iommu->reg) {
 			printk(KERN_ERR "IOMMU: can't map the region\n");
-			goto error;
+			goto err_release;
 		}
 	}
 
@@ -659,6 +671,8 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
 
  err_unmap:
 	iounmap(iommu->reg);
+ err_release:
+	release_mem_region(drhd->reg_base_addr, VTD_PAGE_SIZE);
  error:
 	kfree(iommu);
 	return -1;
-- 
1.7.1

Re: [PATCH] intel_iommu,dmar: reserve mmio of IOMMU registers

[Don Dutile]

self-nak.
Found an iounmap() with a  missing release_mem_region();
will post V2 shortly.

On 03/08/2012 06:51 PM, Donald Dutile wrote:
> Intel-iommu initialization doesn't currently reserve the memory used
> for the IOMMU registers. This can allow the pci resource allocator
> to assign a device BAR to the same address as the IOMMU registers.
> This can cause some not so nice side affects when the driver
> ioremap's that region.
>
> Signed-off-by: Donald Dutile<ddutile-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> ---
>   drivers/iommu/dmar.c |   18 ++++++++++++++++--
>   1 files changed, 16 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
> index 35c1e17..1fcbd96 100644
> --- a/drivers/iommu/dmar.c
> +++ b/drivers/iommu/dmar.c
> @@ -599,10 +599,16 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
>   	iommu->seq_id = iommu_allocated++;
>   	sprintf (iommu->name, "dmar%d", iommu->seq_id);
>
> +	map_size = VTD_PAGE_SIZE;
> +	if (!request_mem_region(drhd->reg_base_addr, map_size, iommu->name)) {
> +		printk(KERN_ERR "IOMMU: can't reserve memory\n");
> +		goto error;
> +	}
> +
>   	iommu->reg = ioremap(drhd->reg_base_addr, VTD_PAGE_SIZE);
>   	if (!iommu->reg) {
>   		printk(KERN_ERR "IOMMU: can't map the region\n");
> -		goto error;
> +		goto err_release;
>   	}
>   	iommu->cap = dmar_readq(iommu->reg + DMAR_CAP_REG);
>   	iommu->ecap = dmar_readq(iommu->reg + DMAR_ECAP_REG);
> @@ -637,10 +643,16 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
>   	map_size = VTD_PAGE_ALIGN(map_size);
>   	if (map_size>  VTD_PAGE_SIZE) {
>   		iounmap(iommu->reg);
> +		release_mem_region(drhd->reg_base_addr, VTD_PAGE_SIZE);
> +		if (!request_mem_region(drhd->reg_base_addr, map_size,
> +					iommu->name)) {
> +			printk(KERN_ERR "IOMMU: can't reserve memory\n");
> +			goto error;
> +		}
>   		iommu->reg = ioremap(drhd->reg_base_addr, map_size);
>   		if (!iommu->reg) {
>   			printk(KERN_ERR "IOMMU: can't map the region\n");
> -			goto error;
> +			goto err_release;
>   		}
>   	}
>
> @@ -659,6 +671,8 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
>
>    err_unmap:
>   	iounmap(iommu->reg);
> + err_release:
> +	release_mem_region(drhd->reg_base_addr, VTD_PAGE_SIZE);
>    error:
>   	kfree(iommu);
>   	return -1;