On Tue, May 20, 2014 at 08:37:48PM +0800, Yijing Wang wrote:
> Move up the no_iommu and dmar_disabled check, avoid the
> useless initialization for dmar.
>
> Signed-off-by: Yijing Wang <[email protected]>
> ---
> drivers/iommu/intel-iommu.c | 6 +++---
> 1 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index e020dcf..6b71608 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -3948,6 +3948,9 @@ int __init intel_iommu_init(void)
> /* VT-d is required for a TXT/tboot launch, so enforce that */
> force_on = tboot_force_iommu();
>
> + if (no_iommu || dmar_disabled)
> + return ret;
> +
> if (iommu_init_mempool()) {
> if (force_on)
> panic("tboot: Failed to initialize iommu memory\n");
> @@ -3974,9 +3977,6 @@ int __init intel_iommu_init(void)
> goto out_free_dmar;
> }
>
> - if (no_iommu || dmar_disabled)
> - goto out_free_dmar;
> -
> if (list_empty(&dmar_rmrr_units))
> printk(KERN_INFO "DMAR: No RMRR found\n");
This breaks the kexec case were the old kernel had VT-d enabled and the
new one disabled. In this case the new kernel might need to disable the
IOMMUs.
Joerg
>> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
>> index e020dcf..6b71608 100644
>> --- a/drivers/iommu/intel-iommu.c
>> +++ b/drivers/iommu/intel-iommu.c
>> @@ -3948,6 +3948,9 @@ int __init intel_iommu_init(void)
>> /* VT-d is required for a TXT/tboot launch, so enforce that */
>> force_on = tboot_force_iommu();
>>
>> + if (no_iommu || dmar_disabled)
>> + return ret;
>> +
>> if (iommu_init_mempool()) {
>> if (force_on)
>> panic("tboot: Failed to initialize iommu memory\n");
>> @@ -3974,9 +3977,6 @@ int __init intel_iommu_init(void)
>> goto out_free_dmar;
>> }
>>
>> - if (no_iommu || dmar_disabled)
>> - goto out_free_dmar;
>> -
>> if (list_empty(&dmar_rmrr_units))
>> printk(KERN_INFO "DMAR: No RMRR found\n");
>
> This breaks the kexec case were the old kernel had VT-d enabled and the
> new one disabled. In this case the new kernel might need to disable the
> IOMMUs.
Hi Joerg,
Thanks for your review and comments! You are right, I didn't consider the kexec case,
I will drop this patch.
Thanks!
Yijing.
>
>
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--
Thanks!
Yijing