diff mbox

[v11,05/10] iommu/vt-d: Add functions to load and save old re

Message ID 1431337974-545-6-git-send-email-zhen-hual@hp.com (mailing list archive)
State New, archived
Headers show

Commit Message

Li, Zhen-Hua May 11, 2015, 9:52 a.m. UTC
Add functions to load root entry table from old kernel, and to save updated
root entry table.
Add two member in struct intel_iommu, to store the RTA in old kernel, and
the mapped virt address of it.

We use the old RTA in dump kernel, and when the iommu->root_entry is used as
a cache in kdump kernel, its phys address will not be save to RTA register,
but when its data is changed, we will save the new data to old root entry table.

Li, Zhen-hua:
    The functions and logics.

Takao Indoh:
    Add __iommu_flush_cache.

Signed-off-by: Li, Zhen-Hua <zhen-hual@hp.com>
Signed-off-by: Takao Indoh <indou.takao@jp.fujitsu.com>
---
 drivers/iommu/intel-iommu.c | 54 ++++++++++++++++++++++++++++++++++++++++++++-
 include/linux/intel-iommu.h |  3 +++
 2 files changed, 56 insertions(+), 1 deletion(-)

Comments

Dave Young May 12, 2015, 8:37 a.m. UTC | #1
Seems the subject was truncated? Maybe "re" means root entry? Then please fix it

On 05/11/15 at 05:52pm, Li, Zhen-Hua wrote:
> Add functions to load root entry table from old kernel, and to save updated
> root entry table.
> Add two member in struct intel_iommu, to store the RTA in old kernel, and
> the mapped virt address of it.

Please explain a bit what is "RTA" in patch log, it is unclear to most of people
who do not know iommu details.

> 
> We use the old RTA in dump kernel, and when the iommu->root_entry is used as
> a cache in kdump kernel, its phys address will not be save to RTA register,
> but when its data is changed, we will save the new data to old root entry table.
> 
> Li, Zhen-hua:
>     The functions and logics.
> 
> Takao Indoh:
>     Add __iommu_flush_cache.
> 
> Signed-off-by: Li, Zhen-Hua <zhen-hual@hp.com>
> Signed-off-by: Takao Indoh <indou.takao@jp.fujitsu.com>
> ---
>  drivers/iommu/intel-iommu.c | 54 ++++++++++++++++++++++++++++++++++++++++++++-
>  include/linux/intel-iommu.h |  3 +++
>  2 files changed, 56 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index 0b97c15..3a5d446 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -371,6 +371,10 @@ static struct context_entry *device_to_existing_context_entry(
>  				struct intel_iommu *iommu,
>  				u8 bus, u8 devfn);
>  
> +static void __iommu_load_old_root_entry(struct intel_iommu *iommu);
> +
> +static void __iommu_update_old_root_entry(struct intel_iommu *iommu, int index);
> +
>  /*
>   * A structure used to store the address allocated by ioremap();
>   * The we need to call iounmap() to free them out of spin_lock_irqsave/unlock;
> @@ -382,7 +386,6 @@ struct iommu_remapped_entry {
>  static LIST_HEAD(__iommu_remapped_mem);
>  static DEFINE_MUTEX(__iommu_mem_list_lock);
>  
> -
>  /*
>   * This domain is a statically identity mapping domain.
>   *	1. This domain creats a static 1:1 mapping to all usable memory.
> @@ -4935,3 +4938,52 @@ int __iommu_free_mapped_mem(void)
>  	return 0;
>  }
>  
> +/*
> + * Load the old root entry table to new root entry table.
> + */
> +static void __iommu_load_old_root_entry(struct intel_iommu *iommu)
> +{
> +	if ((!iommu)
> +		|| (!iommu->root_entry)
> +		|| (!iommu->root_entry_old_virt)
> +		|| (!iommu->root_entry_old_phys))
> +		return;
> +	memcpy(iommu->root_entry, iommu->root_entry_old_virt, PAGE_SIZE);
> +
> +	__iommu_flush_cache(iommu, iommu->root_entry, PAGE_SIZE);
> +}
> +
> +/*
> + * When the data in new root entry table is changed, this function
> + * must be called to save the updated data to old root entry table.
> + */
> +static void __iommu_update_old_root_entry(struct intel_iommu *iommu, int index)
> +{
> +	u8 start;
> +	unsigned long size;
> +	void __iomem *to;
> +	void *from;
> +
> +	if ((!iommu)
> +		|| (!iommu->root_entry)
> +		|| (!iommu->root_entry_old_virt)
> +		|| (!iommu->root_entry_old_phys))
> +		return;
> +
> +	if (index < -1 || index >= ROOT_ENTRY_NR)
> +		return;
> +
> +	if (index == -1) {
> +		start = 0;
> +		size = ROOT_ENTRY_NR * sizeof(struct root_entry);
> +	} else {
> +		start = index * sizeof(struct root_entry);
> +		size = sizeof(struct root_entry);
> +	}
> +	to = iommu->root_entry_old_virt;
> +	from = iommu->root_entry;
> +	memcpy(to + start, from + start, size);
> +
> +	__iommu_flush_cache(iommu, to + start, size);
> +}
> +
> diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
> index ced1fac..e7cac12 100644
> --- a/include/linux/intel-iommu.h
> +++ b/include/linux/intel-iommu.h
> @@ -340,6 +340,9 @@ struct intel_iommu {
>  	spinlock_t	lock; /* protect context, domain ids */
>  	struct root_entry *root_entry; /* virtual address */
>  
> +	void __iomem	*root_entry_old_virt; /* mapped from old root entry */
> +	unsigned long	root_entry_old_phys; /* root entry in old kernel */
> +
>  	struct iommu_flush flush;
>  #endif
>  	struct q_inval  *qi;            /* Queued invalidation info */
> -- 
> 2.0.0-rc0
> 
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Li, Zhen-Hua May 13, 2015, 1:47 a.m. UTC | #2
On 05/12/2015 04:37 PM, Dave Young wrote:
> Seems the subject was truncated? Maybe "re" means root entry? Then please fix it
>
> On 05/11/15 at 05:52pm, Li, Zhen-Hua wrote:
>> Add functions to load root entry table from old kernel, and to save updated
>> root entry table.
>> Add two member in struct intel_iommu, to store the RTA in old kernel, and
>> the mapped virt address of it.
>
> Please explain a bit what is "RTA" in patch log, it is unclear to most of people
> who do not know iommu details.
>
>>

If people want to understand this patchset, I assume they have read the 
vt-d specs. RTA is defined clearly in this spec.

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Dave Young May 13, 2015, 8:49 a.m. UTC | #3
On 05/13/15 at 09:47am, Li, ZhenHua wrote:
> On 05/12/2015 04:37 PM, Dave Young wrote:
> >Seems the subject was truncated? Maybe "re" means root entry? Then please fix it
> >
> >On 05/11/15 at 05:52pm, Li, Zhen-Hua wrote:
> >>Add functions to load root entry table from old kernel, and to save updated
> >>root entry table.
> >>Add two member in struct intel_iommu, to store the RTA in old kernel, and
> >>the mapped virt address of it.
> >
> >Please explain a bit what is "RTA" in patch log, it is unclear to most of people
> >who do not know iommu details.
> >
> >>
> 
> If people want to understand this patchset, I assume they have read the vt-d
> specs. RTA is defined clearly in this spec.
> 

I think explain a bit is better, it will be easier for review, RTA is defined in spec,
right, but if you refer to it in kernel source code, describe the meaning will help
people to understand your code.

I would not stick on this 'RTA', but a descriptive subject and patch log is still
important, please check the logs, not only for this patch.

Thanks
Dave
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diff mbox

Patch

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 0b97c15..3a5d446 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -371,6 +371,10 @@  static struct context_entry *device_to_existing_context_entry(
 				struct intel_iommu *iommu,
 				u8 bus, u8 devfn);
 
+static void __iommu_load_old_root_entry(struct intel_iommu *iommu);
+
+static void __iommu_update_old_root_entry(struct intel_iommu *iommu, int index);
+
 /*
  * A structure used to store the address allocated by ioremap();
  * The we need to call iounmap() to free them out of spin_lock_irqsave/unlock;
@@ -382,7 +386,6 @@  struct iommu_remapped_entry {
 static LIST_HEAD(__iommu_remapped_mem);
 static DEFINE_MUTEX(__iommu_mem_list_lock);
 
-
 /*
  * This domain is a statically identity mapping domain.
  *	1. This domain creats a static 1:1 mapping to all usable memory.
@@ -4935,3 +4938,52 @@  int __iommu_free_mapped_mem(void)
 	return 0;
 }
 
+/*
+ * Load the old root entry table to new root entry table.
+ */
+static void __iommu_load_old_root_entry(struct intel_iommu *iommu)
+{
+	if ((!iommu)
+		|| (!iommu->root_entry)
+		|| (!iommu->root_entry_old_virt)
+		|| (!iommu->root_entry_old_phys))
+		return;
+	memcpy(iommu->root_entry, iommu->root_entry_old_virt, PAGE_SIZE);
+
+	__iommu_flush_cache(iommu, iommu->root_entry, PAGE_SIZE);
+}
+
+/*
+ * When the data in new root entry table is changed, this function
+ * must be called to save the updated data to old root entry table.
+ */
+static void __iommu_update_old_root_entry(struct intel_iommu *iommu, int index)
+{
+	u8 start;
+	unsigned long size;
+	void __iomem *to;
+	void *from;
+
+	if ((!iommu)
+		|| (!iommu->root_entry)
+		|| (!iommu->root_entry_old_virt)
+		|| (!iommu->root_entry_old_phys))
+		return;
+
+	if (index < -1 || index >= ROOT_ENTRY_NR)
+		return;
+
+	if (index == -1) {
+		start = 0;
+		size = ROOT_ENTRY_NR * sizeof(struct root_entry);
+	} else {
+		start = index * sizeof(struct root_entry);
+		size = sizeof(struct root_entry);
+	}
+	to = iommu->root_entry_old_virt;
+	from = iommu->root_entry;
+	memcpy(to + start, from + start, size);
+
+	__iommu_flush_cache(iommu, to + start, size);
+}
+
diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index ced1fac..e7cac12 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -340,6 +340,9 @@  struct intel_iommu {
 	spinlock_t	lock; /* protect context, domain ids */
 	struct root_entry *root_entry; /* virtual address */
 
+	void __iomem	*root_entry_old_virt; /* mapped from old root entry */
+	unsigned long	root_entry_old_phys; /* root entry in old kernel */
+
 	struct iommu_flush flush;
 #endif
 	struct q_inval  *qi;            /* Queued invalidation info */