xen/arm: remove shm holes from extended regions

Static shared memory acts as reserved memory in guest, so it shall be
excluded from extended regions.

Extended regions are taken care of under three different scenarios:
normal DomU, direct-map domain with iommu on, and direct-map domain
with iommu off.

For normal DomU, we create a new function "remove_shm_holes_for_domU",
to firstly transfer original outputs into the format of
"struct rangeset", then use "remove_shm_from_rangeset" to remove static
shm from them.

For direct-map domain with iommu on, after we get guest shm info from "kinfo",
we use "remove_shm_from_rangeset" to remove static shm.

For direct-map domain with iommu off, as static shm has already been taken
care of through find_unallocated_memory, we do nothing.

Signed-off-by: Penny Zheng <penny.zheng@arm.com>
Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>
Reviewed-by: Michal Orzel <michal.orzel@amd.com>

xen/arch/arm/domain_build.c

@@ -816,8 +816,8 @@ int __init make_memory_node(const struct domain *d,
     return res;
 }
 
-static int __init add_ext_regions(unsigned long s_gfn, unsigned long e_gfn,
-                                  void *data)
+int __init add_ext_regions(unsigned long s_gfn, unsigned long e_gfn,
+                           void *data)
 {
     struct membanks *ext_regions = data;
     paddr_t start, size;
@@ -990,6 +990,8 @@ static int __init handle_pci_range(const struct dt_device_node *dev,
  * - MMIO
  * - Host RAM
  * - PCI aperture
+ * - Static shared memory regions, which are described by special property
+ *   "xen,shared-mem"
  */
 static int __init find_memory_holes(const struct kernel_info *kinfo,
                                     struct membanks *ext_regions)
@@ -1017,6 +1019,11 @@ static int __init find_memory_holes(const struct kernel_info *kinfo,
         goto out;
     }
 
+    /* Remove static shared memory regions */
+    res = remove_shm_from_rangeset(kinfo, mem_holes);
+    if ( res )
+        goto out;
+
     /*
      * Remove regions described by "reg" and "ranges" properties where
      * the memory is addressable (MMIO, RAM, PCI BAR, etc).
@@ -1109,7 +1116,10 @@ static int __init find_domU_holes(const struct kernel_info *kinfo,
         res = 0;
     }
 
-    return res;
+    if ( res )
+        return res;
+
+    return remove_shm_holes_for_domU(kinfo, ext_regions);
 }
 
 int __init make_hypervisor_node(struct domain *d,

xen/arch/arm/include/asm/domain_build.h

@@ -51,6 +51,8 @@ static inline int prepare_acpi(struct domain *d, struct kernel_info *kinfo)
 int prepare_acpi(struct domain *d, struct kernel_info *kinfo);
 #endif
 
+int add_ext_regions(unsigned long s_gfn, unsigned long e_gfn, void *data);
+
 #endif
 
 /*

xen/arch/arm/include/asm/static-shmem.h

@@ -28,6 +28,12 @@ void early_print_info_shmem(void);
 
 void init_sharedmem_pages(void);
 
+int remove_shm_from_rangeset(const struct kernel_info *kinfo,
+                             struct rangeset *rangeset);
+
+int remove_shm_holes_for_domU(const struct kernel_info *kinfo,
+                              struct membanks *ext_regions);
+
 #else /* !CONFIG_STATIC_SHM */
 
 static inline int make_resv_memory_node(const struct kernel_info *kinfo,
@@ -59,6 +65,18 @@ static inline void early_print_info_shmem(void) {};
 
 static inline void init_sharedmem_pages(void) {};
 
+static inline int remove_shm_from_rangeset(const struct kernel_info *kinfo,
+                                           struct rangeset *rangeset)
+{
+    return 0;
+}
+
+static inline int remove_shm_holes_for_domU(const struct kernel_info *kinfo,
+                                            struct membanks *ext_regions)
+{
+    return 0;
+}
+
 #endif /* CONFIG_STATIC_SHM */
 
 #endif /* __ASM_STATIC_SHMEM_H_ */

xen/arch/arm/static-shmem.c

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
 #include <xen/libfdt/libfdt.h>
+#include <xen/rangeset.h>
 #include <xen/sched.h>
 
 #include <asm/domain_build.h>
@@ -574,6 +575,99 @@ void __init init_sharedmem_pages(void)
         init_staticmem_bank(&shmem->bank[bank]);
 }
 
+int __init remove_shm_from_rangeset(const struct kernel_info *kinfo,
+                                    struct rangeset *rangeset)
+{
+    const struct membanks *shm_mem = &kinfo->shm_mem.common;
+    unsigned int i;
+
+    /* Remove static shared memory regions */
+    for ( i = 0; i < shm_mem->nr_banks; i++ )
+    {
+        paddr_t start, end;
+        int res;
+
+        start = shm_mem->bank[i].start;
+        end = shm_mem->bank[i].start + shm_mem->bank[i].size;
+        res = rangeset_remove_range(rangeset, PFN_DOWN(start),
+                                    PFN_DOWN(end - 1));
+        if ( res )
+        {
+            printk(XENLOG_ERR
+                   "Failed to remove: %#"PRIpaddr"->%#"PRIpaddr", error: %d\n",
+                   start, end, res);
+            return -EINVAL;
+        }
+    }
+
+    return 0;
+}
+
+int __init remove_shm_holes_for_domU(const struct kernel_info *kinfo,
+                                     struct membanks *ext_regions)
+{
+    const struct membanks *shm_mem = &kinfo->shm_mem.common;
+    struct rangeset *guest_holes;
+    unsigned int i;
+    paddr_t start;
+    paddr_t end;
+    int res;
+
+    /* No static shared memory region. */
+    if ( shm_mem->nr_banks == 0 )
+        return 0;
+
+    dt_dprintk("Remove static shared memory holes from extended regions of DomU\n");
+
+    guest_holes = rangeset_new(NULL, NULL, 0);
+    if ( !guest_holes )
+        return -ENOMEM;
+
+    /* Copy extended regions sets into the rangeset */
+    for ( i = 0; i < ext_regions->nr_banks; i++ )
+    {
+        start = ext_regions->bank[i].start;
+        end = start + ext_regions->bank[i].size;
+
+        res = rangeset_add_range(guest_holes, PFN_DOWN(start),
+                                 PFN_DOWN(end - 1));
+        if ( res )
+        {
+            printk(XENLOG_ERR
+                   "Failed to add: %#"PRIpaddr"->%#"PRIpaddr", error: %d\n",
+                   start, end, res);
+            goto out;
+        }
+    }
+
+    /* Remove static shared memory regions */
+    res = remove_shm_from_rangeset(kinfo, guest_holes);
+    if ( res )
+        goto out;
+
+    /*
+     * Take the interval of memory starting from the first extended region bank
+     * start address and ending to the end of the last extended region bank.
+     */
+    i = ext_regions->nr_banks - 1;
+    start = ext_regions->bank[0].start;
+    end = ext_regions->bank[i].start + ext_regions->bank[i].size - 1;
+
+    /* Reset original extended regions to hold new value */
+    ext_regions->nr_banks = 0;
+    res = rangeset_report_ranges(guest_holes, PFN_DOWN(start), PFN_DOWN(end),
+                                 add_ext_regions, ext_regions);
+    if ( res )
+        ext_regions->nr_banks = 0;
+    else if ( !ext_regions->nr_banks )
+        res = -ENOENT;
+
+ out:
+    rangeset_destroy(guest_holes);
+
+    return res;
+}
+
 /*
  * Local variables:
  * mode: C