Re: [PATCH v2 23/23] [HACK] xen/arm: implement xen_remap_domain_mfn_range

Konrad Rzeszutek Wilk
2012-08-07T18:49:23Z

On Mon, Aug 06, 2012 at 03:27:26PM +0100, Stefano Stabellini wrote:
> From: Ian Campbell <Ian.Campbell@citrix.com>
>
> Do not apply!

OK.
>
> This is a simple, hacky implementation of xen_remap_domain_mfn_range,
> using XENMAPSPACE_gmfn_foreign.
>
> It should use same interface as hybrid x86.

Yeah, Mukesh - can you share your patch here please?
>
> Changes in v2:
>
> - retain binary compatibility in xen_add_to_physmap: use a union.
>
> Signed-off-by: Ian Campbell <Ian.Campbell@citrix.com>
> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> ---
> arch/arm/xen/enlighten.c | 79 +++++++++++++++++++++++++++++++++++++++-
> drivers/xen/privcmd.c | 16 +++++----
> drivers/xen/xenfs/super.c | 7 ++++
> include/xen/interface/memory.h | 15 ++++++--
> 4 files changed, 105 insertions(+), 12 deletions(-)
>
> diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
> index c244583..20ca1e4 100644
> --- a/arch/arm/xen/enlighten.c
> +++ b/arch/arm/xen/enlighten.c
> @@ -16,6 +16,10 @@
> #include <linux/of.h>
> #include <linux/of_irq.h>
> #include <linux/of_address.h>
> +#include <linux/mm.h>
> +#include <linux/ioport.h>
> +
> +#include <asm/pgtable.h>
>
> struct start_info _xen_start_info;
> struct start_info *xen_start_info = &_xen_start_info;
> @@ -38,12 +42,85 @@ EXPORT_SYMBOL_GPL(xen_platform_pci_unplug);
>
> static __read_mostly int xen_events_irq = -1;
>
> +#define FOREIGN_MAP_BUFFER 0x90000000UL
> +#define FOREIGN_MAP_BUFFER_SIZE 0x10000000UL
> +struct resource foreign_map_resource = {
> + .start = FOREIGN_MAP_BUFFER,
> + .end = FOREIGN_MAP_BUFFER + FOREIGN_MAP_BUFFER_SIZE,
> + .name = "Xen foreign map buffer",
> + .flags = 0,
> +};
> +
> +static unsigned long foreign_map_buffer_pfn = FOREIGN_MAP_BUFFER >> PAGE_SHIFT;
> +
> +struct remap_data {
> + struct mm_struct *mm;
> + unsigned long mfn;
> + pgprot_t prot;
> +};
> +
> +static int remap_area_mfn_pte_fn(pte_t *ptep, pgtable_t token,
> + unsigned long addr, void *data)
> +{
> + struct remap_data *rmd = data;
> + pte_t pte = pfn_pte(rmd->mfn, rmd->prot);
> +
> + if (rmd->mfn < 0x90010)
> + pr_crit("%s: ptep %p addr %#lx => %#x / %#lx\n",
> + __func__, ptep, addr, pte_val(pte), rmd->mfn);
> +
> + set_pte_at(rmd->mm, addr, ptep, pte);
> +
> + rmd->mfn++;
> + 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)
> {
> - return -ENOSYS;
> + int i, rc = 0;
> + struct remap_data rmd = {
> + .mm = vma->vm_mm,
> + .prot = prot,
> + };
> + struct xen_add_to_physmap xatp = {
> + .domid = DOMID_SELF,
> + .space = XENMAPSPACE_gmfn_foreign,
> +
> + .foreign_domid = domid,
> + };
> +
> + if (foreign_map_buffer_pfn + nr > ((FOREIGN_MAP_BUFFER +
> + FOREIGN_MAP_BUFFER_SIZE)>>PAGE_SHIFT)) {
> + pr_crit("RAM out of foreign map buffers...\n");
> + return -EBUSY;
> + }
> +
> + for (i = 0; i < nr; i++) {
> + xatp.idx = mfn + i;
> + xatp.gpfn = foreign_map_buffer_pfn + i;
> + rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
> + if (rc != 0) {
> + pr_crit("foreign map add_to_physmap failed, err=%d\n", rc);
> + goto out;
> + }
> + }
> +
> + rmd.mfn = foreign_map_buffer_pfn;
> + rc = apply_to_page_range(vma->vm_mm,
> + addr,
> + (unsigned long)nr << PAGE_SHIFT,
> + remap_area_mfn_pte_fn, &rmd);
> + if (rc != 0) {
> + pr_crit("apply_to_page_range failed rc=%d\n", rc);
> + goto out;
> + }
> +
> + foreign_map_buffer_pfn += nr;
> +out:
> + return rc;
> }
> EXPORT_SYMBOL_GPL(xen_remap_domain_mfn_range);
>
> diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
> index 85226cb..3e15c22 100644
> --- a/drivers/xen/privcmd.c
> +++ b/drivers/xen/privcmd.c
> @@ -20,6 +20,8 @@
> #include <linux/pagemap.h>
> #include <linux/seq_file.h>
> #include <linux/miscdevice.h>
> +#include <linux/resource.h>
> +#include <linux/ioport.h>
>
> #include <asm/pgalloc.h>
> #include <asm/pgtable.h>
> @@ -196,9 +198,6 @@ static long privcmd_ioctl_mmap(void __user *udata)
> LIST_HEAD(pagelist);
> struct mmap_mfn_state state;
>
> - if (!xen_initial_domain())
> - return -EPERM;
> -
> if (copy_from_user(&mmapcmd, udata, sizeof(mmapcmd)))
> return -EFAULT;
>
> @@ -286,9 +285,6 @@ static long privcmd_ioctl_mmap_batch(void __user *udata)
> LIST_HEAD(pagelist);
> struct mmap_batch_state state;
>
> - if (!xen_initial_domain())
> - return -EPERM;
> -
> if (copy_from_user(&m, udata, sizeof(m)))
> return -EFAULT;
>
> @@ -365,6 +361,11 @@ static long privcmd_ioctl(struct file *file,
> return ret;
> }
>
> +static void privcmd_close(struct vm_area_struct *vma)
> +{
> + /* TODO: unmap VMA */
> +}
> +
> static int privcmd_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
> {
> printk(KERN_DEBUG "privcmd_fault: vma=%p %lx-%lx, pgoff=%lx, uv=%p\n",
> @@ -375,7 +376,8 @@ static int privcmd_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
> }
>
> static struct vm_operations_struct privcmd_vm_ops = {
> - .fault = privcmd_fault
> + .fault = privcmd_fault,
> + .close = privcmd_close,
> };
>
> static int privcmd_mmap(struct file *file, struct vm_area_struct *vma)
> diff --git a/drivers/xen/xenfs/super.c b/drivers/xen/xenfs/super.c
> index a84b53c..edbe22f 100644
> --- a/drivers/xen/xenfs/super.c
> +++ b/drivers/xen/xenfs/super.c
> @@ -12,6 +12,7 @@
> #include <linux/module.h>
> #include <linux/fs.h>
> #include <linux/magic.h>
> +#include <linux/ioport.h>
>
> #include <xen/xen.h>
>
> @@ -80,6 +81,8 @@ static const struct file_operations capabilities_file_ops = {
> .llseek = default_llseek,
> };
>
> +extern struct resource foreign_map_resource;
> +
> static int xenfs_fill_super(struct super_block *sb, void *data, int silent)
> {
> static struct tree_descr xenfs_files[] = {
> @@ -100,6 +103,10 @@ static int xenfs_fill_super(struct super_block *sb, void *data, int silent)
> &xsd_kva_file_ops, NULL, S_IRUSR|S_IWUSR);
> xenfs_create_file(sb, sb->s_root, "xsd_port",
> &xsd_port_file_ops, NULL, S_IRUSR|S_IWUSR);
> + rc = request_resource(&iomem_resource, &foreign_map_resource);
> + if (rc < 0)
> + pr_crit("failed to register foreign map resource\n");
> + rc = 0; /* ignore */
> }
>
> return rc;
> diff --git a/include/xen/interface/memory.h b/include/xen/interface/memory.h
> index b66d04c..dd2ffe0 100644
> --- a/include/xen/interface/memory.h
> +++ b/include/xen/interface/memory.h
> @@ -163,12 +163,19 @@ struct xen_add_to_physmap {
> /* Which domain to change the mapping for. */
> domid_t domid;
>
> - /* Number of pages to go through for gmfn_range */
> - uint16_t size;
> + union {
> + /* Number of pages to go through for gmfn_range */
> + uint16_t size;
> + /* IFF gmfn_foreign */
> + domid_t foreign_domid;
> + };
>
> /* Source mapping space. */
> -#define XENMAPSPACE_shared_info 0 /* shared info page */
> -#define XENMAPSPACE_grant_table 1 /* grant table page */
> +#define XENMAPSPACE_shared_info 0 /* shared info page */
> +#define XENMAPSPACE_grant_table 1 /* grant table page */
> +#define XENMAPSPACE_gmfn 2 /* GMFN */
> +#define XENMAPSPACE_gmfn_range 3 /* GMFN range */
> +#define XENMAPSPACE_gmfn_foreign 4 /* GMFN from another guest */
> unsigned int space;
>
> /* Index into source mapping space. */
> --
> 1.7.2.5