Re: [PATCH v10 04/10] iommu/vt-d: functions to copy data from old mem

[Li, ZhenHua]

It is called in
static int copy_root_entry_table(struct intel_iommu *iommu);


On 05/07/2015 03:49 PM, Baoquan He wrote:
> On 04/10/15 at 04:42pm, Li, Zhen-Hua wrote:
> > Add some functions to copy the data from old kernel.
> > These functions are used to copy context tables and page tables.
> >
> > To avoid calling iounmap between spin_lock_irqsave and spin_unlock_irqrestore,
> > use a link here, store the pointers , and then use iounmap to free them in
> > another place.
> >
> > Li, Zhen-hua:
> >      The functions and logics.
> >
> > Takao Indoh:
> >      Check if pfn is ram:
> >          if (page_is_ram(pfn))
> >
> > Signed-off-by: Li, Zhen-Hua <zhen-hual@xxxxxx>
> > Signed-off-by: Takao Indoh <indou.takao@xxxxxxxxxxxxxx>
> > ---
> >   drivers/iommu/intel-iommu.c | 102 ++++++++++++++++++++++++++++++++++++++++++++
> >   include/linux/intel-iommu.h |   6 +++
> >   2 files changed, 108 insertions(+)
> >
> > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> > index ff5ac04..5ba403a 100644
> > --- a/drivers/iommu/intel-iommu.c
> > +++ b/drivers/iommu/intel-iommu.c
> > @@ -373,6 +373,17 @@ static struct context_entry *device_to_existing_context_entry(
> >   				struct intel_iommu *iommu,
> >   				u8 bus, u8 devfn);
> >
> > +/*
> > + * 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;
> > + */
> > +struct iommu_remapped_entry {
> > +	struct list_head list;
> > +	void __iomem *mem;
> > +};
> > +static LIST_HEAD(__iommu_remapped_mem);
> > +static DEFINE_MUTEX(__iommu_mem_list_lock);
> > +
> >
> >   /*
> >    * This domain is a statically identity mapping domain.
> > @@ -4817,3 +4828,94 @@ static struct context_entry *device_to_existing_context_entry(
> >   	return ret;
> >   }
> >
> > +/*
> > + * Copy memory from a physically-addressed area into a virtually-addressed area
> > + */
>
> I don't find where __iommu_load_from_oldmem is called. Obsolete code of
> this patch?
>
> > +int __iommu_load_from_oldmem(void *to, unsigned long from, unsigned long size)
> > +{
> > +	unsigned long pfn;		/* Page Frame Number */
> > +	size_t csize = (size_t)size;	/* Num(bytes to copy) */
> > +	unsigned long offset;		/* Lower 12 bits of to */
> > +	void __iomem *virt_mem;
> > +	struct iommu_remapped_entry *mapped;
> > +
> > +	pfn = from >> VTD_PAGE_SHIFT;
> > +	offset = from & (~VTD_PAGE_MASK);
> > +
> > +	if (page_is_ram(pfn)) {
> > +		memcpy(to, pfn_to_kaddr(pfn) + offset, csize);
> > +	} else{
> > +
> > +		mapped = kzalloc(sizeof(struct iommu_remapped_entry),
> > +				GFP_KERNEL);
> > +		if (!mapped)
> > +			return -ENOMEM;
> > +
> > +		virt_mem = ioremap_cache((unsigned long)from, size);
> > +		if (!virt_mem) {
> > +			kfree(mapped);
> > +			return -ENOMEM;
> > +		}
> > +		memcpy(to, virt_mem, size);
> > +
> > +		mutex_lock(&__iommu_mem_list_lock);
> > +		mapped->mem = virt_mem;
> > +		list_add_tail(&mapped->list, &__iommu_remapped_mem);
> > +		mutex_unlock(&__iommu_mem_list_lock);
> > +	}
> > +	return size;
> > +}
> > +
> > +/*
> > + * Copy memory from a virtually-addressed area into a physically-addressed area
> > + */
> > +int __iommu_save_to_oldmem(unsigned long to, void *from, unsigned long size)
> > +{
> > +	unsigned long pfn;		/* Page Frame Number */
> > +	size_t csize = (size_t)size;	/* Num(bytes to copy) */
> > +	unsigned long offset;		/* Lower 12 bits of to */
> > +	void __iomem *virt_mem;
> > +	struct iommu_remapped_entry *mapped;
> > +
> > +	pfn = to >> VTD_PAGE_SHIFT;
> > +	offset = to & (~VTD_PAGE_MASK);
> > +
> > +	if (page_is_ram(pfn)) {
> > +		memcpy(pfn_to_kaddr(pfn) + offset, from, csize);
> > +	} else{
> > +		mapped = kzalloc(sizeof(struct iommu_remapped_entry),
> > +				GFP_KERNEL);
> > +		if (!mapped)
> > +			return -ENOMEM;
> > +
> > +		virt_mem = ioremap_cache((unsigned long)to, size);
> > +		if (!virt_mem) {
> > +			kfree(mapped);
> > +			return -ENOMEM;
> > +		}
> > +		memcpy(virt_mem, from, size);
> > +		mutex_lock(&__iommu_mem_list_lock);
> > +		mapped->mem = virt_mem;
> > +		list_add_tail(&mapped->list, &__iommu_remapped_mem);
> > +		mutex_unlock(&__iommu_mem_list_lock);
> > +	}
> > +	return size;
> > +}
> > +
> > +/*
> > + * Free the mapped memory for ioremap;
> > + */
> > +int __iommu_free_mapped_mem(void)
> > +{
> > +	struct iommu_remapped_entry *mem_entry, *tmp;
> > +
> > +	mutex_lock(&__iommu_mem_list_lock);
> > +	list_for_each_entry_safe(mem_entry, tmp, &__iommu_remapped_mem, list) {
> > +		iounmap(mem_entry->mem);
> > +		list_del(&mem_entry->list);
> > +		kfree(mem_entry);
> > +	}
> > +	mutex_unlock(&__iommu_mem_list_lock);
> > +	return 0;
> > +}
> > +
> > diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
> > index a65208a..4bca7b5 100644
> > --- a/include/linux/intel-iommu.h
> > +++ b/include/linux/intel-iommu.h
> > @@ -368,4 +368,10 @@ extern int dmar_ir_support(void);
> >
> >   extern const struct attribute_group *intel_iommu_groups[];
> >
> > +extern int __iommu_load_from_oldmem(void *to, unsigned long from,
> > +					unsigned long size);
> > +extern int __iommu_save_to_oldmem(unsigned long to, void *from,
> > +					unsigned long size);
> > +extern int __iommu_free_mapped_mem(void);
> > +
> >   #endif
> > --
> > 2.0.0-rc0

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