[PATCH v3 3/5] xen, common: add the XEN_DOMCTL_memory_mapping hypercall

[Arianna Avanzini <avanzini.arianna@gmail.com>]

This commit introduces a first attempt of implementation of the
XEN_DOMCTL_memory_mapping hypercall for ARM. As the implementation
would have been almost identical to the one for x86, this code has
been made common to both the architectures. The only difference
between the two procedures lies in the arch-specific implementation
of the map_mmio_regions() and unmap_mmio_regions() functions.

Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
Cc: Dario Faggioli <dario.faggioli@citrix.com>
Cc: Paolo Valente <paolo.valente@unimore.it>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Julien Grall <julien.grall@citrix.com>
Cc: Ian Campbell <Ian.Campbell@eu.citrix.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Keir Fraser <keir@xen.org>
Cc: Tim Deegan <tim@xen.org>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Keir Fraser <keir@xen.org>
Cc: Tim Deegan <tim@xen.org>
Cc: Ian Jackson <Ian.Jackson@eu.citrix.com>
Cc: Eric Trudeau <etrudeau@broadcom.com>
Cc: Viktor Kleinik <viktor.kleinik@globallogic.com>

---

    v3:
        - Move code to xen/common/domctl.c; abstract out differences between
          the x86 and ARM code:
          . add map_mmio_regions() and unmap_mmio_regions() functions for x86;
          . add a paddr_bits variable for ARM.
        - Use pfn as parameters to the unmap_mmio_regions() function.
        - Compute gfn + nr_mfns and mfn + nr_mfns only once.

    v2:
        - Move code to xen/arm/domctl.c.
        - Use the already-defined PADDR_BITS constant in the new DOMCTL.
        - Use paddr_t as arguments to the map_mmio_regions() function.
        - Page-align addresses given as arguments to map_mmio_regions() and
          unmap_mmio_regions().

---
 xen/arch/arm/cpu.c              |  2 ++
 xen/arch/arm/p2m.c              | 12 +++++++
 xen/arch/x86/domctl.c           | 70 -----------------------------------------
 xen/arch/x86/mm/p2m.c           | 39 +++++++++++++++++++++++
 xen/common/domctl.c             | 69 ++++++++++++++++++++++++++++++++++++++++
 xen/include/asm-arm/p2m.h       |  4 +++
 xen/include/asm-arm/processor.h |  2 ++
 xen/include/asm-x86/p2m.h       | 10 ++++++
 8 files changed, 138 insertions(+), 70 deletions(-)

diff --git a/xen/arch/arm/cpu.c b/xen/arch/arm/cpu.c
index afc564f..28f2611 100644
--- a/xen/arch/arm/cpu.c
+++ b/xen/arch/arm/cpu.c
@@ -17,6 +17,8 @@
 
 #include <asm/processor.h>
 
+unsigned int paddr_bits __read_mostly = 40;
+
 void __cpuinit identify_cpu(struct cpuinfo_arm *c)
 {
         c->midr.bits = READ_SYSREG32(MIDR_EL1);
diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index 47bf154..6c4c318 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -490,6 +490,18 @@ int map_mmio_regions(struct domain *d,
                              maddr, MATTR_DEV, p2m_mmio_direct);
 }
 
+int unmap_mmio_regions(struct domain *d,
+                       unsigned long start_gfn,
+                       unsigned long end_gfn,
+                       unsigned long mfn)
+{
+    return apply_p2m_changes(d, REMOVE,
+                             pfn_to_paddr(start_gfn),
+                             pfn_to_paddr(end_gfn),
+                             pfn_to_paddr(mfn),
+                             MATTR_DEV, p2m_mmio_direct);
+}
+
 int guest_physmap_add_entry(struct domain *d,
                             unsigned long gpfn,
                             unsigned long mfn,
diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c
index 26635ff..69a7fbf 100644
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -639,76 +639,6 @@ long arch_do_domctl(
     }
     break;
 
-    case XEN_DOMCTL_memory_mapping:
-    {
-        unsigned long gfn = domctl->u.memory_mapping.first_gfn;
-        unsigned long mfn = domctl->u.memory_mapping.first_mfn;
-        unsigned long nr_mfns = domctl->u.memory_mapping.nr_mfns;
-        int add = domctl->u.memory_mapping.add_mapping;
-        unsigned long i;
-
-        ret = -EINVAL;
-        if ( (mfn + nr_mfns - 1) < mfn || /* wrap? */
-             ((mfn | (mfn + nr_mfns - 1)) >> (paddr_bits - PAGE_SHIFT)) ||
-             (gfn + nr_mfns - 1) < gfn ) /* wrap? */
-            break;
-
-        ret = -EPERM;
-        if ( !iomem_access_permitted(current->domain, mfn, mfn + nr_mfns - 1) )
-            break;
-
-        ret = xsm_iomem_mapping(XSM_HOOK, d, mfn, mfn + nr_mfns - 1, add);
-        if ( ret )
-            break;
-
-        if ( add )
-        {
-            printk(XENLOG_G_INFO
-                   "memory_map:add: dom%d gfn=%lx mfn=%lx nr=%lx\n",
-                   d->domain_id, gfn, mfn, nr_mfns);
-
-            ret = iomem_permit_access(d, mfn, mfn + nr_mfns - 1);
-            if ( !ret && paging_mode_translate(d) )
-            {
-                for ( i = 0; !ret && i < nr_mfns; i++ )
-                    if ( !set_mmio_p2m_entry(d, gfn + i, _mfn(mfn + i)) )
-                        ret = -EIO;
-                if ( ret )
-                {
-                    printk(XENLOG_G_WARNING
-                           "memory_map:fail: dom%d gfn=%lx mfn=%lx\n",
-                           d->domain_id, gfn + i, mfn + i);
-                    while ( i-- )
-                        clear_mmio_p2m_entry(d, gfn + i);
-                    if ( iomem_deny_access(d, mfn, mfn + nr_mfns - 1) &&
-                         is_hardware_domain(current->domain) )
-                        printk(XENLOG_ERR
-                               "memory_map: failed to deny dom%d access to [%lx,%lx]\n",
-                               d->domain_id, mfn, mfn + nr_mfns - 1);
-                }
-            }
-        }
-        else
-        {
-            printk(XENLOG_G_INFO
-                   "memory_map:remove: dom%d gfn=%lx mfn=%lx nr=%lx\n",
-                   d->domain_id, gfn, mfn, nr_mfns);
-
-            if ( paging_mode_translate(d) )
-                for ( i = 0; i < nr_mfns; i++ )
-                    add |= !clear_mmio_p2m_entry(d, gfn + i);
-            ret = iomem_deny_access(d, mfn, mfn + nr_mfns - 1);
-            if ( !ret && add )
-                ret = -EIO;
-            if ( ret && is_hardware_domain(current->domain) )
-                printk(XENLOG_ERR
-                       "memory_map: error %ld %s dom%d access to [%lx,%lx]\n",
-                       ret, add ? "removing" : "denying", d->domain_id,
-                       mfn, mfn + nr_mfns - 1);
-        }
-    }
-    break;
-
     case XEN_DOMCTL_ioport_mapping:
     {
 #define MAX_IOPORTS    0x10000
diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
index c0ddef0..f4951b1 100644
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -1591,6 +1591,45 @@ unsigned long paging_gva_to_gfn(struct vcpu *v,
     return hostmode->gva_to_gfn(v, hostp2m, va, pfec);
 }
 
+int map_mmio_regions(struct domain *d,
+                     paddr_t start_gaddr,
+                     paddr_t end_gaddr,
+                     paddr_t maddr)
+{
+    int i, ret = 0;
+    unsigned long gfn = paddr_to_pfn(start_gaddr);
+    unsigned long nr_mfns = paddr_to_pfn(end_gaddr) - paddr_to_pfn(start_gaddr);
+    unsigned long mfn = paddr_to_pfn(maddr);
+
+    if ( !paging_mode_translate(d) )
+        return 0;
+
+    for ( i = 0; !ret && i < nr_mfns; i++ )
+        if ( !set_mmio_p2m_entry(d, gfn + i, _mfn(mfn + i)) )
+            ret = -EIO;
+    while ( i-- )
+        clear_mmio_p2m_entry(d, gfn + i);
+
+    return ret;
+}
+
+int unmap_mmio_regions(struct domain *d,
+                       unsigned long start_gfn,
+                       unsigned long end_gfn,
+                       unsigned long mfn)
+{
+    unsigned long nr_mfns = end_gfn - start_gfn;
+    int i, ret = 0;
+
+    if ( !paging_mode_translate(d) )
+        return 0;
+
+    for ( i = 0; i < nr_mfns; i++ )
+        ret |= !clear_mmio_p2m_entry(d, start_gfn + i);
+
+    return ret;
+}
+
 /*** Audit ***/
 
 #if P2M_AUDIT
diff --git a/xen/common/domctl.c b/xen/common/domctl.c
index 7cf610a..b18fd46 100644
--- a/xen/common/domctl.c
+++ b/xen/common/domctl.c
@@ -818,6 +818,75 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl)
     }
     break;
 
+    case XEN_DOMCTL_memory_mapping:
+    {
+        unsigned long gfn = op->u.memory_mapping.first_gfn;
+        unsigned long mfn = op->u.memory_mapping.first_mfn;
+        unsigned long nr_mfns = op->u.memory_mapping.nr_mfns;
+        unsigned long mfn_end = mfn + nr_mfns;
+        unsigned long gfn_end = gfn + nr_mfns;
+        int add = op->u.memory_mapping.add_mapping;
+        long int ret;
+
+        ret = -EINVAL;
+        if ( (mfn_end - 1) < mfn || /* wrap? */
+             ((mfn | (mfn_end - 1)) >> (paddr_bits - PAGE_SHIFT)) ||
+             (gfn_end - 1) < gfn ) /* wrap? */
+            return ret;
+
+        ret = -EPERM;
+        if ( !iomem_access_permitted(current->domain, mfn, mfn_end - 1) )
+            return ret;
+
+        ret = xsm_iomem_mapping(XSM_HOOK, d, mfn, mfn_end - 1, add);
+        if ( ret )
+            return ret;
+
+        if ( add )
+        {
+            printk(XENLOG_G_INFO
+                   "memory_map: add: dom%d gfn=%lx mfn=%lx nr=%lx\n",
+                   d->domain_id, gfn, mfn, nr_mfns);
+            ret = iomem_permit_access(d, mfn, mfn_end - 1);
+            if ( !ret )
+            {
+                ret = map_mmio_regions(d, PAGE_ALIGN(pfn_to_paddr(gfn)),
+                                       PAGE_ALIGN(
+                                           pfn_to_paddr(gfn_end)) - 1,
+                                       PAGE_ALIGN(pfn_to_paddr(mfn)));
+                if ( ret )
+                {
+                    printk(XENLOG_G_WARNING
+                           "memory_map: fail: dom%d gfn=%lx mfn=%lx\n",
+                           d->domain_id, gfn, mfn);
+                    if ( iomem_deny_access(d, mfn, mfn_end - 1) &&
+                         is_hardware_domain(current->domain) )
+                        printk(XENLOG_ERR
+                               "memory_map: failed to deny dom%d access "
+                               "to [%lx,%lx]\n",
+                               d->domain_id, mfn, mfn_end - 1);
+                }
+            }
+        }
+	else
+        {
+            printk(XENLOG_G_INFO
+                   "memory_map: remove: dom%d gfn=%lx mfn=%lx nr=%lx\n",
+                   d->domain_id, gfn, mfn, nr_mfns);
+
+            add = unmap_mmio_regions(d, gfn, gfn_end - 1, mfn);
+            ret = iomem_deny_access(d, mfn, mfn_end - 1);
+            if ( ret && add )
+                ret = -EIO;
+            if ( ret && is_hardware_domain(current->domain) )
+                printk(XENLOG_ERR
+                       "memory_map: error %ld %s dom%d access to [%lx,%lx]\n",
+                       ret, add ? "removing" : "denying", d->domain_id,
+                       mfn, mfn_end - 1);
+	}
+    }
+    break;
+
     case XEN_DOMCTL_settimeoffset:
     {
         domain_set_time_offset(d, op->u.settimeoffset.time_offset_seconds);
diff --git a/xen/include/asm-arm/p2m.h b/xen/include/asm-arm/p2m.h
index 3b39c45..00e3bba 100644
--- a/xen/include/asm-arm/p2m.h
+++ b/xen/include/asm-arm/p2m.h
@@ -88,6 +88,10 @@ int p2m_populate_ram(struct domain *d, paddr_t start, paddr_t end);
  * address maddr. */
 int map_mmio_regions(struct domain *d, paddr_t start_gaddr,
                      paddr_t end_gaddr, paddr_t maddr);
+int unmap_mmio_regions(struct domain *d,
+                       unsigned long start_gfn,
+                       unsigned long end_gfn,
+                       unsigned long mfn);
 
 int guest_physmap_add_entry(struct domain *d,
                             unsigned long gfn,
diff --git a/xen/include/asm-arm/processor.h b/xen/include/asm-arm/processor.h
index 06e638f..4869a75 100644
--- a/xen/include/asm-arm/processor.h
+++ b/xen/include/asm-arm/processor.h
@@ -119,6 +119,8 @@
 
 #include <xen/types.h>
 
+extern unsigned int paddr_bits;
+
 struct cpuinfo_arm {
     union {
         uint32_t bits;
diff --git a/xen/include/asm-x86/p2m.h b/xen/include/asm-x86/p2m.h
index f4e7253..91ef110 100644
--- a/xen/include/asm-x86/p2m.h
+++ b/xen/include/asm-x86/p2m.h
@@ -657,6 +657,16 @@ void p2m_flush(struct vcpu *v, struct p2m_domain *p2m);
 /* Flushes all nested p2m tables */
 void p2m_flush_nestedp2m(struct domain *d);
 
+/* Map MMIO regions in the p2m: start_gaddr and end_gaddr is the range
+ * in the guest physical address space to map, starting from the machine
+ * address maddr. */
+int map_mmio_regions(struct domain *d, paddr_t start_gaddr,
+                     paddr_t end_gaddr, paddr_t maddr);
+int unmap_mmio_regions(struct domain *d,
+                       unsigned long start_gfn,
+                       unsigned long end_gfn,
+                       unsigned long mfn);
+
 void nestedp2m_write_p2m_entry(struct p2m_domain *p2m, unsigned long gfn,
     l1_pgentry_t *p, mfn_t table_mfn, l1_pgentry_t new, unsigned int level);
 
-- 
1.9.0