Re: [PATCH 5/6] xen: arm: implement remap interfaces needed forprivcmd mappings.

[Stefano Stabellini]

On Wed, 17 Oct 2012, Ian Campbell wrote:
> We use XENMEM_add_to_physmap_range which is the preferred interface
> for foreign mappings.
> 
> Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>

It looks OK but there are few code style issues, please run the patch
through checkpatch.


>  arch/arm/include/asm/xen/interface.h |    1 +
>  arch/arm/xen/enlighten.c             |  100 +++++++++++++++++++++++++++++++++-
>  arch/x86/include/asm/xen/interface.h |    1 +
>  include/xen/interface/memory.h       |   18 ++++++
>  4 files changed, 117 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm/include/asm/xen/interface.h b/arch/arm/include/asm/xen/interface.h
> index 1d6ef9c..007e6da 100644
> --- a/arch/arm/include/asm/xen/interface.h
> +++ b/arch/arm/include/asm/xen/interface.h
> @@ -43,6 +43,7 @@ DEFINE_GUEST_HANDLE(void);
>  DEFINE_GUEST_HANDLE(uint64_t);
>  DEFINE_GUEST_HANDLE(uint32_t);
>  DEFINE_GUEST_HANDLE(xen_pfn_t);
> +DEFINE_GUEST_HANDLE(xen_ulong_t);
>  
>  /* Maximum number of virtual CPUs in multi-processor guests. */
>  #define MAX_VIRT_CPUS 1
> diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
> index ba5cc13..6bb4630 100644
> --- a/arch/arm/xen/enlighten.c
> +++ b/arch/arm/xen/enlighten.c
> @@ -9,6 +9,7 @@
>  #include <xen/platform_pci.h>
>  #include <xen/xenbus.h>
>  #include <xen/page.h>
> +#include <xen/xen-ops.h>
>  #include <asm/xen/hypervisor.h>
>  #include <asm/xen/hypercall.h>
>  #include <linux/interrupt.h>
> @@ -18,6 +19,8 @@
>  #include <linux/of_irq.h>
>  #include <linux/of_address.h>
>  
> +#include <linux/mm.h>
> +
>  struct start_info _xen_start_info;
>  struct start_info *xen_start_info = &_xen_start_info;
>  EXPORT_SYMBOL_GPL(xen_start_info);
> @@ -43,15 +46,106 @@ EXPORT_SYMBOL_GPL(xen_platform_pci_unplug);
>  
>  static __read_mostly int xen_events_irq = -1;
>  
> +/* map fgmfn of domid to lpfn in the current domain */
> +static int map_foreign_page(unsigned long lpfn, unsigned long fgmfn,
> +			    unsigned int domid)
> +{
> +	int rc;
> +	struct xen_add_to_physmap_range xatp = {
> +		.domid = DOMID_SELF,
> +		.foreign_domid = domid,
> +		.size = 1,
> +		.space = XENMAPSPACE_gmfn_foreign,
> +	};
> +	xen_ulong_t idx = fgmfn;
> +	xen_pfn_t gpfn = lpfn;
> +
> +	set_xen_guest_handle(xatp.idxs, &idx);
> +	set_xen_guest_handle(xatp.gpfns, &gpfn);
> +
> +	rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap_range, &xatp);
> +	if (rc) {
> +		pr_warn("Failed to map pfn to mfn rc:%d pfn:%lx mfn:%lx\n",
> +			rc, lpfn, fgmfn);
> +		return 1;
> +	}
> +	return 0;
> +}
> +
> +struct remap_data {
> +	xen_pfn_t fgmfn; /* foreign domain's gmfn */
> +	pgprot_t prot;
> +	domid_t  domid;
> +	struct vm_area_struct *vma;
> +	int index;
> +	struct page **pages;
> +	struct xen_remap_mfn_info *info;
> +};
> +
> +static int remap_pte_fn(pte_t *ptep, pgtable_t token, unsigned long addr,
> +			void *data)
> +{
> +	struct remap_data *info = data;
> +	struct page *page = info->pages[info->index++];
> +	unsigned long pfn = page_to_pfn(page);
> +	pte_t pte = pfn_pte(pfn, info->prot);
> +
> +	if (map_foreign_page(pfn, info->fgmfn, info->domid))
> +		return -EFAULT;
> +	set_pte_at(info->vma->vm_mm, addr, ptep, pte);
> +
> +	return 0;
> +}
> +
>  int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
>  			       unsigned long addr,
> -			       unsigned long mfn, int nr,
> -			       pgprot_t prot, unsigned domid)
> +			       xen_pfn_t mfn, int nr,
> +			       pgprot_t prot, unsigned domid,
> +			       struct page **pages)
>  {
> -	return -ENOSYS;
> +	int err;
> +	struct remap_data data;
> +
> +	/* TBD: Batching, current sole caller only does page at a time */
> +	if (nr > 1)
> +		return -EINVAL;
> +
> +	data.fgmfn = mfn;
> +	data.prot = prot;
> +	data.domid = domid;
> +	data.vma = vma;
> +	data.index = 0;
> +	data.pages = pages;
> +	err = apply_to_page_range(vma->vm_mm, addr, nr << PAGE_SHIFT,
> +				  remap_pte_fn, &data);
> +	return err;
>  }
>  EXPORT_SYMBOL_GPL(xen_remap_domain_mfn_range);
>  
> +int xen_unmap_domain_mfn_range(struct vm_area_struct *vma,
> +			       struct page **pages, int nr)
> +{
> +	int i;
> +
> +	for (i=0; i<nr; i++) {
> +		struct xen_remove_from_physmap xrp;
> +		unsigned long rc, pfn;
> +
> +		pfn = page_to_pfn(pages[i]);
> +
> +		xrp.domid = DOMID_SELF;
> +		xrp.gpfn = pfn;
> +		rc = HYPERVISOR_memory_op(XENMEM_remove_from_physmap, &xrp);
> +		if (rc) {
> +			pr_warn("Failed to unmap pfn:%lx rc:%ld\n",
> +				pfn, rc);
> +			return rc;
> +		}
> +	}
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(xen_unmap_domain_mfn_range);
> +
>  /*
>   * see Documentation/devicetree/bindings/arm/xen.txt for the
>   * documentation of the Xen Device Tree format.
> diff --git a/arch/x86/include/asm/xen/interface.h b/arch/x86/include/asm/xen/interface.h
> index 25669c3..6246d80 100644
> --- a/arch/x86/include/asm/xen/interface.h
> +++ b/arch/x86/include/asm/xen/interface.h
> @@ -63,6 +63,7 @@ DEFINE_GUEST_HANDLE(void);
>  DEFINE_GUEST_HANDLE(uint64_t);
>  DEFINE_GUEST_HANDLE(uint32_t);
>  DEFINE_GUEST_HANDLE(xen_pfn_t);
> +DEFINE_GUEST_HANDLE(xen_ulong_t);
>  #endif
>  
>  #ifndef HYPERVISOR_VIRT_START
> diff --git a/include/xen/interface/memory.h b/include/xen/interface/memory.h
> index 91bdc2a..eb2d3e5 100644
> --- a/include/xen/interface/memory.h
> +++ b/include/xen/interface/memory.h
> @@ -190,6 +190,24 @@ DEFINE_GUEST_HANDLE_STRUCT(xen_add_to_physmap);
>  /*** REMOVED ***/
>  /*#define XENMEM_translate_gpfn_list  8*/
>  
> +#define XENMEM_add_to_physmap_range 23
> +struct xen_add_to_physmap_range {
> +    /* Which domain to change the mapping for. */
> +    domid_t domid;
> +    uint16_t space; /* => enum phys_map_space */
> +
> +    /* Number of pages to go through */
> +    uint16_t size;
> +    domid_t foreign_domid; /* IFF gmfn_foreign */
> +
> +    /* Indexes into space being mapped. */
> +    GUEST_HANDLE(xen_ulong_t) idxs;
> +
> +    /* GPFN in domid where the source mapping page should appear. */
> +    GUEST_HANDLE(xen_pfn_t) gpfns;
> +};
> +DEFINE_GUEST_HANDLE_STRUCT(xen_add_to_physmap_range);
> +
>  /*
>   * Returns the pseudo-physical memory map as it was when the domain
>   * was started (specified by XENMEM_set_memory_map).
> -- 
> 1.7.2.5
> 
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