On Mon, Sep 12, 2011 at 1:17 PM, Don Dutile <ddutile@xxxxxxxxxx> wrote:
> John,
>
> Could you refresh this patch, since the file has changed locations,
> and make some repairs based on feedback below?
> attached a patch that could be possible update...
>
> - Don
Jordan, please refresh and repost if this is still important.
Thanks,
Bjorn
> On 07/28/2011 05:13 PM, jharg93@xxxxxxxxx wrote:
>>
>> The DMAR driver currently doesn't reserve the memory used for the IOMMU
>> registers. On one specific combination of cards on our system, the kernel
>> pci resource allocator was assigning a BAR to the same address as the
>> IOMMU.
>> When the other driver did an ioremap, suddenly the IOMMU registers were no
>> longer valid.
>>
>> Signed-off-by: Jordan Hargrave<Jordan_Hargrave@xxxxxxxx>
>> ---
>> drivers/pci/dmar.c | 9 +++++++++
>> 1 files changed, 9 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/pci/dmar.c b/drivers/pci/dmar.c
>> index 12e02bf..9650b9b 100644
>> --- a/drivers/pci/dmar.c
>> +++ b/drivers/pci/dmar.c
>> @@ -750,6 +750,10 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
>> iommu->seq_id = iommu_allocated++;
>> sprintf (iommu->name, "dmar%d", iommu->seq_id);
>>
>> + if (!request_mem_region(drhd->reg_base_addr, VTD_PAGE_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");
>
> probably want to introduce an err_release: at bottom of function that
> does release_mem_region(), and set map_size to VTD_PAGE_SIZE here,
> so it can be used in both ioremap() error checks in this function.
>
>> @@ -789,7 +793,12 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
>> cap_max_fault_reg_offset(iommu->cap));
>> map_size = VTD_PAGE_ALIGN(map_size);
>> if (map_size> VTD_PAGE_SIZE) {
>> + release_mem_region(drhd->reg_base_addr, VTD_PAGE_SIZE);
>
> need to do release after iounmap() below, not before it.
>
>> iounmap(iommu->reg);
>> + 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");
>
> this is where you need an err_release goto as well
>
>
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