xen/arm: introduce allocate_static_memory

This commit introduces a new function allocate_static_memory to allocate
static memory as guest RAM for domains on Static Allocation.

It uses acquire_domstatic_pages to acquire pre-configured static memory
for the domain, and uses guest_physmap_add_pages to set up the P2M table.
These pre-defined static memory banks shall be mapped to the usual guest
memory addresses (GUEST_RAM0_BASE, GUEST_RAM1_BASE) defined by
xen/include/public/arch-arm.h.

In order to deal with the trouble of count-to-order conversion when page number
is not in a power-of-two, this commit exports p2m_insert_mapping and introduce
a new function guest_physmap_add_pages to cope with adding guest RAM p2m
mapping with nr_pages.

Signed-off-by: Penny Zheng <penny.zheng@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

xen/arch/arm/domain_build.c

@@ -480,6 +480,162 @@ fail:
           (unsigned long)kinfo->unassigned_mem >> 10);
 }
 
+#ifdef CONFIG_STATIC_MEMORY
+static bool __init append_static_memory_to_bank(struct domain *d,
+                                                struct membank *bank,
+                                                mfn_t smfn,
+                                                paddr_t size)
+{
+    int res;
+    unsigned int nr_pages = PFN_DOWN(size);
+    /* Infer next GFN. */
+    gfn_t sgfn = gaddr_to_gfn(bank->start + bank->size);
+
+    res = guest_physmap_add_pages(d, sgfn, smfn, nr_pages);
+    if ( res )
+    {
+        dprintk(XENLOG_ERR, "Failed to map pages to DOMU: %d", res);
+        return false;
+    }
+
+    bank->size = bank->size + size;
+
+    return true;
+}
+
+/* Allocate memory from static memory as RAM for one specific domain d. */
+static void __init allocate_static_memory(struct domain *d,
+                                          struct kernel_info *kinfo,
+                                          const struct dt_device_node *node)
+{
+    const struct dt_property *prop;
+    u32 addr_cells, size_cells, reg_cells;
+    unsigned int nr_banks, gbank, bank = 0;
+    const uint64_t rambase[] = GUEST_RAM_BANK_BASES;
+    const uint64_t ramsize[] = GUEST_RAM_BANK_SIZES;
+    const __be32 *cell;
+    u64 tot_size = 0;
+    paddr_t pbase, psize, gsize;
+    mfn_t smfn;
+    int res;
+
+    prop = dt_find_property(node, "xen,static-mem", NULL);
+    if ( !dt_property_read_u32(node, "#xen,static-mem-address-cells",
+                               &addr_cells) )
+    {
+        printk(XENLOG_ERR
+               "%pd: failed to read \"#xen,static-mem-address-cells\".\n", d);
+        goto fail;
+    }
+
+    if ( !dt_property_read_u32(node, "#xen,static-mem-size-cells",
+                               &size_cells) )
+    {
+        printk(XENLOG_ERR
+               "%pd: failed to read \"#xen,static-mem-size-cells\".\n", d);
+        goto fail;
+    }
+    reg_cells = addr_cells + size_cells;
+
+    /*
+     * The static memory will be mapped in the guest at the usual guest memory
+     * addresses (GUEST_RAM0_BASE, GUEST_RAM1_BASE) defined by
+     * xen/include/public/arch-arm.h.
+     */
+    gbank = 0;
+    gsize = ramsize[gbank];
+    kinfo->mem.bank[gbank].start = rambase[gbank];
+
+    cell = (const __be32 *)prop->value;
+    nr_banks = (prop->length) / (reg_cells * sizeof (u32));
+
+    for ( ; bank < nr_banks; bank++ )
+    {
+        device_tree_get_reg(&cell, addr_cells, size_cells, &pbase, &psize);
+        ASSERT(IS_ALIGNED(pbase, PAGE_SIZE) && IS_ALIGNED(psize, PAGE_SIZE));
+
+        smfn = maddr_to_mfn(pbase);
+        res = acquire_domstatic_pages(d, smfn, PFN_DOWN(psize), 0);
+        if ( res )
+        {
+            printk(XENLOG_ERR
+                   "%pd: failed to acquire static memory: %d.\n", d, res);
+            goto fail;
+        }
+
+        printk(XENLOG_INFO "%pd: STATIC BANK[%u] %#"PRIpaddr"-%#"PRIpaddr"\n",
+               d, bank, pbase, pbase + psize);
+
+        while ( 1 )
+        {
+            /* Map as much as possible the static range to the guest bank */
+            if ( !append_static_memory_to_bank(d, &kinfo->mem.bank[gbank], smfn,
+                                               min(psize, gsize)) )
+                goto fail;
+
+            /*
+             * The current physical bank is fully mapped.
+             * Handle the next physical bank.
+             */
+            if ( gsize >= psize )
+            {
+                gsize = gsize - psize;
+                break;
+            }
+            /*
+             * When current guest bank is not enough to map, exhaust
+             * the current one and seek to the next.
+             * Before seeking to the next, check if we still have available
+             * guest bank.
+             */
+            else if ( (gbank + 1) >= GUEST_RAM_BANKS )
+            {
+                printk(XENLOG_ERR "Exhausted all possible guest banks.\n");
+                goto fail;
+            }
+            else
+            {
+                psize = psize - gsize;
+                smfn = mfn_add(smfn, gsize >> PAGE_SHIFT);
+                /* Update to the next guest bank. */
+                gbank++;
+                gsize = ramsize[gbank];
+                kinfo->mem.bank[gbank].start = rambase[gbank];
+            }
+        }
+
+        tot_size += psize;
+    }
+
+    kinfo->mem.nr_banks = ++gbank;
+
+    kinfo->unassigned_mem -= tot_size;
+    /*
+     * The property 'memory' should match the amount of memory given to the
+     * guest.
+     * Currently, it is only possible to either acquire static memory or let
+     * Xen allocate. *Mixing* is not supported.
+     */
+    if ( kinfo->unassigned_mem )
+    {
+        printk(XENLOG_ERR
+               "Size of \"memory\" property doesn't match up with the sum-up of \"xen,static-mem\". Unsupported configuration.\n");
+        goto fail;
+    }
+
+    return;
+
+ fail:
+    panic("Failed to allocate requested static memory for domain %pd.", d);
+}
+#else
+static void __init allocate_static_memory(struct domain *d,
+                                          struct kernel_info *kinfo,
+                                          const struct dt_device_node *node)
+{
+}
+#endif
+
 static int __init write_properties(struct domain *d, struct kernel_info *kinfo,
                                    const struct dt_device_node *node)
 {
@@ -2453,7 +2609,10 @@ static int __init construct_domU(struct domain *d,
     /* type must be set before allocate memory */
     d->arch.type = kinfo.type;
 #endif
+    if ( !dt_find_property(node, "xen,static-mem", NULL) )
         allocate_memory(d, &kinfo);
+    else
+        allocate_static_memory(d, &kinfo, node);
 
     rc = prepare_dtb_domU(d, &kinfo);
     if ( rc < 0 )

xen/arch/arm/p2m.c

@@ -1293,11 +1293,8 @@ out:
     return resolved;
 }
 
-static inline int p2m_insert_mapping(struct domain *d,
-                                     gfn_t start_gfn,
-                                     unsigned long nr,
-                                     mfn_t mfn,
-                                     p2m_type_t t)
+int p2m_insert_mapping(struct domain *d, gfn_t start_gfn, unsigned long nr,
+                       mfn_t mfn, p2m_type_t t)
 {
     struct p2m_domain *p2m = p2m_get_hostp2m(d);
     int rc;

xen/include/asm-arm/p2m.h

@@ -300,6 +300,9 @@ int map_dev_mmio_region(struct domain *d,
                         unsigned long nr,
                         mfn_t mfn);
 
+int p2m_insert_mapping(struct domain *d, gfn_t start_gfn, unsigned long nr,
+                       mfn_t mfn, p2m_type_t t);
+
 int guest_physmap_add_entry(struct domain *d,
                             gfn_t gfn,
                             mfn_t mfn,
@@ -315,6 +318,14 @@ static inline int guest_physmap_add_page(struct domain *d,
     return guest_physmap_add_entry(d, gfn, mfn, page_order, p2m_ram_rw);
 }
 
+static inline int guest_physmap_add_pages(struct domain *d,
+                                          gfn_t gfn,
+                                          mfn_t mfn,
+                                          unsigned int nr_pages)
+{
+    return p2m_insert_mapping(d, gfn, nr_pages, mfn, p2m_ram_rw);
+}
+
 mfn_t gfn_to_mfn(struct domain *d, gfn_t gfn);
 
 /* Look up a GFN and take a reference count on the backing page. */