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Date: Tue, 12 May 2015 16:29:54 +0800
From: Dave Young <dyoung@...hat.com>
To: "Li, Zhen-Hua" <zhen-hual@...com>
Cc: dwmw2@...radead.org, indou.takao@...fujitsu.com, bhe@...hat.com,
joro@...tes.org, vgoyal@...hat.com,
iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
linux-pci@...r.kernel.org, kexec@...ts.infradead.org,
alex.williamson@...hat.com, ddutile@...hat.com,
ishii.hironobu@...fujitsu.com, bhelgaas@...gle.com,
doug.hatch@...com, jerry.hoemann@...com, tom.vaden@...com,
li.zhang6@...com, lisa.mitchell@...com, billsumnerlinux@...il.com,
rwright@...com
Subject: Re: [PATCH v11 04/10] iommu/vt-d: functions to copy data from old mem
On 05/11/15 at 05:52pm, 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@...com>
> Signed-off-by: Takao Indoh <indou.takao@...fujitsu.com>
> ---
> 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 07e6118..0b97c15 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -371,6 +371,17 @@ 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.
> @@ -4833,3 +4844,94 @@ static struct context_entry *device_to_existing_context_entry(
> return ret;
> }
>
> +/*
> + * Copy memory from a physically-addressed area into a virtually-addressed area
> + */
> +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 */
comment for above variable are unnecessary, they are clear enough.
BTW, use size_t size in function argument is better.
> + 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);
csize or size? as previous comment use size_t in argument it will be ok here.
> +
> + 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;
type mismatch?
> +}
> +
> +/*
> + * 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 */
Ditto about data type and comments..
> + 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;
> +}
Above two functions looks duplicate, can they be merged as one function and
add a argument about direction?
> +
> +/*
> + * 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 796ef96..ced1fac 100644
> --- a/include/linux/intel-iommu.h
> +++ b/include/linux/intel-iommu.h
> @@ -380,4 +380,10 @@ 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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