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

Stefano Stabellini
2012-08-06T14:56:55Z

From: Ian Campbell <Ian.Campbell@citrix.com>

Do not apply!

This is a simple, hacky implementation of xen_remap_domain_mfn_range,
using XENMAPSPACE_gmfn_foreign.

It should use same interface as hybrid x86.

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