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[Xen-devel] [PATCH v2 04/10] xen/arm: Store p2m type in each page of the guest



Use the field 'avail' to store the type of the page. Rename it to 'p2mt' for
convenience.
The information stored in this field will be retrieved in a future patch to
hange the behaviour when the page is removed.

Also introduce guest_physmap_add_entry to map and set a specific p2m type for
a page.

Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>

---
    Changes in v2:
        - Rename 'avail' field to 'p2mt' in the p2m structure
        - Add BUILD_BUG_ON to check if the enum value will fit in the field
        - Implement grant mapping type
---
 xen/arch/arm/p2m.c         |   58 ++++++++++++++++++++++++++++++++------------
 xen/include/asm-arm/p2m.h  |   18 +++++++++++---
 xen/include/asm-arm/page.h |    2 +-
 3 files changed, 58 insertions(+), 20 deletions(-)

diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index 8f8b47e..e43804c 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -124,7 +124,8 @@ int p2m_pod_decrease_reservation(struct domain *d,
     return -ENOSYS;
 }
 
-static lpae_t mfn_to_p2m_entry(unsigned long mfn, unsigned int mattr)
+static lpae_t mfn_to_p2m_entry(unsigned long mfn, unsigned int mattr,
+                               p2m_type_t t)
 {
     paddr_t pa = ((paddr_t) mfn) << PAGE_SHIFT;
     lpae_t e = (lpae_t) {
@@ -132,12 +133,34 @@ static lpae_t mfn_to_p2m_entry(unsigned long mfn, 
unsigned int mattr)
         .p2m.af = 1,
         .p2m.sh = LPAE_SH_OUTER,
         .p2m.read = 1,
-        .p2m.write = 1,
         .p2m.mattr = mattr,
         .p2m.table = 1,
         .p2m.valid = 1,
+        .p2m.p2mt = t,
     };
 
+    BUILD_BUG_ON(p2m_max_real_type > (2 << 4));
+
+    switch (t)
+    {
+    case p2m_grant_map_rw:
+        e.p2m.xn = 1;
+        /* Fallthrough */
+    case p2m_ram_rw:
+    case p2m_mmio_direct:
+    case p2m_map_foreign:
+        e.p2m.write = 1;
+        break;
+
+    case p2m_grant_map_ro:
+        e.p2m.xn = 1;
+        /* Fallthrough */
+    case p2m_invalid:
+    case p2m_ram_ro:
+    default:
+        e.p2m.write = 0;
+    }
+
     ASSERT(!(pa & ~PAGE_MASK));
     ASSERT(!(pa & ~PADDR_MASK));
 
@@ -167,7 +190,7 @@ static int p2m_create_table(struct domain *d,
     clear_page(p);
     unmap_domain_page(p);
 
-    pte = mfn_to_p2m_entry(page_to_mfn(page), MATTR_MEM);
+    pte = mfn_to_p2m_entry(page_to_mfn(page), MATTR_MEM, p2m_invalid);
 
     write_pte(entry, pte);
 
@@ -185,7 +208,8 @@ static int create_p2m_entries(struct domain *d,
                      paddr_t start_gpaddr,
                      paddr_t end_gpaddr,
                      paddr_t maddr,
-                     int mattr)
+                     int mattr,
+                     p2m_type_t t)
 {
     int rc, flush;
     struct p2m_domain *p2m = &d->arch.p2m;
@@ -260,14 +284,15 @@ static int create_p2m_entries(struct domain *d,
                         goto out;
                     }
 
-                    pte = mfn_to_p2m_entry(page_to_mfn(page), mattr);
+                    pte = mfn_to_p2m_entry(page_to_mfn(page), mattr, t);
 
                     write_pte(&third[third_table_offset(addr)], pte);
                 }
                 break;
             case INSERT:
                 {
-                    lpae_t pte = mfn_to_p2m_entry(maddr >> PAGE_SHIFT, mattr);
+                    lpae_t pte = mfn_to_p2m_entry(maddr >> PAGE_SHIFT,
+                                                  mattr, t);
                     write_pte(&third[third_table_offset(addr)], pte);
                     maddr += PAGE_SIZE;
                 }
@@ -302,7 +327,8 @@ int p2m_populate_ram(struct domain *d,
                      paddr_t start,
                      paddr_t end)
 {
-    return create_p2m_entries(d, ALLOCATE, start, end, 0, MATTR_MEM);
+    return create_p2m_entries(d, ALLOCATE, start, end,
+                              0, MATTR_MEM, p2m_ram_rw);
 }
 
 int map_mmio_regions(struct domain *d,
@@ -310,18 +336,20 @@ int map_mmio_regions(struct domain *d,
                      paddr_t end_gaddr,
                      paddr_t maddr)
 {
-    return create_p2m_entries(d, INSERT, start_gaddr, end_gaddr, maddr, 
MATTR_DEV);
+    return create_p2m_entries(d, INSERT, start_gaddr, end_gaddr,
+                              maddr, MATTR_DEV, p2m_mmio_direct);
 }
 
-int guest_physmap_add_page(struct domain *d,
-                           unsigned long gpfn,
-                           unsigned long mfn,
-                           unsigned int page_order)
+int guest_physmap_add_entry(struct domain *d,
+                            unsigned long gpfn,
+                            unsigned long mfn,
+                            unsigned long page_order,
+                            p2m_type_t t)
 {
     return create_p2m_entries(d, INSERT,
                               pfn_to_paddr(gpfn),
-                              pfn_to_paddr(gpfn + (1<<page_order)),
-                              pfn_to_paddr(mfn), MATTR_MEM);
+                              pfn_to_paddr(gpfn + (1 << page_order)),
+                              pfn_to_paddr(mfn), MATTR_MEM, t);
 }
 
 void guest_physmap_remove_page(struct domain *d,
@@ -331,7 +359,7 @@ void guest_physmap_remove_page(struct domain *d,
     create_p2m_entries(d, REMOVE,
                        pfn_to_paddr(gpfn),
                        pfn_to_paddr(gpfn + (1<<page_order)),
-                       pfn_to_paddr(mfn), MATTR_MEM);
+                       pfn_to_paddr(mfn), MATTR_MEM, p2m_invalid);
 }
 
 int p2m_alloc_table(struct domain *d)
diff --git a/xen/include/asm-arm/p2m.h b/xen/include/asm-arm/p2m.h
index f621d15..56bbf4d 100644
--- a/xen/include/asm-arm/p2m.h
+++ b/xen/include/asm-arm/p2m.h
@@ -68,11 +68,21 @@ int p2m_populate_ram(struct domain *d, paddr_t start, 
paddr_t end);
 int map_mmio_regions(struct domain *d, paddr_t start_gaddr,
                      paddr_t end_gaddr, paddr_t maddr);
 
+int guest_physmap_add_entry(struct domain *d,
+                            unsigned long gfn,
+                            unsigned long mfn,
+                            unsigned long page_order,
+                            p2m_type_t t);
+
 /* Untyped version for RAM only, for compatibility */
-int guest_physmap_add_page(struct domain *d,
-                           unsigned long gfn,
-                           unsigned long mfn,
-                           unsigned int page_order);
+static inline int guest_physmap_add_page(struct domain *d,
+                                         unsigned long gfn,
+                                         unsigned long mfn,
+                                         unsigned int page_order)
+{
+    return guest_physmap_add_entry(d, gfn, mfn, page_order, p2m_ram_rw);
+}
+
 void guest_physmap_remove_page(struct domain *d,
                                unsigned long gpfn,
                                unsigned long mfn, unsigned int page_order);
diff --git a/xen/include/asm-arm/page.h b/xen/include/asm-arm/page.h
index 0625464..a363a62 100644
--- a/xen/include/asm-arm/page.h
+++ b/xen/include/asm-arm/page.h
@@ -153,7 +153,7 @@ typedef struct {
     unsigned long contig:1;     /* In a block of 16 contiguous entries */
     unsigned long sbz2:1;
     unsigned long xn:1;         /* eXecute-Never */
-    unsigned long avail:4;      /* Ignored by hardware */
+    unsigned long p2mt:4;       /* Ignore by hardware. Used to store p2m types 
*/
 
     unsigned long sbz1:5;
 } __attribute__((__packed__)) lpae_p2m_t;
-- 
1.7.10.4


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