[PATCH v4 16/16] tools/tests: Enable xen-access on ARM

[Tamas K Lengyel <tklengyel@sec.in.tum.de>]

On ARM the guest memory doesn't start from 0 and has multiple banks
of memory, thus we adjust the setting/unsetting routines accordingly.
We also define the ARM specific test_and_set_bit function.

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
---
v4: - Take into account multiple guest ram banks on ARM.
    - Move HAS_MEM_ACCESS definition into config/*.mk and only compile
      xen-access when it is defined.
    - Pass CONFIG_X86/CONFIG_ARM flags during compilation in xen-access
      Makefile.
---
 config/arm32.mk                     |  1 +
 config/arm64.mk                     |  1 +
 config/x86_32.mk                    |  2 +
 config/x86_64.mk                    |  2 +
 tools/tests/xen-access/Makefile     |  9 +++-
 tools/tests/xen-access/xen-access.c | 94 +++++++++++++++++++++++++++++++++----
 xen/arch/arm/Rules.mk               |  1 -
 xen/arch/x86/Rules.mk               |  1 -
 8 files changed, 97 insertions(+), 14 deletions(-)

diff --git a/config/arm32.mk b/config/arm32.mk
index aa79d22..4a7c259 100644
--- a/config/arm32.mk
+++ b/config/arm32.mk
@@ -13,6 +13,7 @@ HAS_PL011 := y
 HAS_EXYNOS4210 := y
 HAS_OMAP := y
 HAS_NS16550 := y
+HAS_MEM_ACCESS := y
 
 # Use only if calling $(LD) directly.
 LDFLAGS_DIRECT += -EL
diff --git a/config/arm64.mk b/config/arm64.mk
index 15b57a4..ea6558d 100644
--- a/config/arm64.mk
+++ b/config/arm64.mk
@@ -8,6 +8,7 @@ CFLAGS += #-marm -march= -mcpu= etc
 
 HAS_PL011 := y
 HAS_NS16550 := y
+HAS_MEM_ACCESS := y
 
 # Use only if calling $(LD) directly.
 LDFLAGS_DIRECT += -EL
diff --git a/config/x86_32.mk b/config/x86_32.mk
index 7f76b25..5906e60 100644
--- a/config/x86_32.mk
+++ b/config/x86_32.mk
@@ -6,6 +6,8 @@ CONFIG_HVM := y
 CONFIG_MIGRATE := y
 CONFIG_XCUTILS := y
 
+HAS_MEM_ACCESS := y
+
 CFLAGS += -m32 -march=i686
 
 # Use only if calling $(LD) directly.
diff --git a/config/x86_64.mk b/config/x86_64.mk
index 11104bd..b000c4e 100644
--- a/config/x86_64.mk
+++ b/config/x86_64.mk
@@ -7,6 +7,8 @@ CONFIG_HVM := y
 CONFIG_MIGRATE := y
 CONFIG_XCUTILS := y
 
+HAS_MEM_ACCESS := y
+
 CONFIG_XEN_INSTALL_SUFFIX := .gz
 
 CFLAGS += -m64
diff --git a/tools/tests/xen-access/Makefile b/tools/tests/xen-access/Makefile
index 65eef99..5056972 100644
--- a/tools/tests/xen-access/Makefile
+++ b/tools/tests/xen-access/Makefile
@@ -7,8 +7,13 @@ CFLAGS += $(CFLAGS_libxenctrl)
 CFLAGS += $(CFLAGS_libxenguest)
 CFLAGS += $(CFLAGS_xeninclude)
 
-TARGETS-y := 
-TARGETS-$(CONFIG_X86) += xen-access
+CFLAGS-y :=
+CFLAGS-$(CONFIG_X86) := -DCONFIG_X86
+CFLAGS-$(CONFIG_ARM) := -DCONFIG_ARM
+CFLAGS += $(CFLAGS-y)
+
+TARGETS-y :=
+TARGETS-$(HAS_MEM_ACCESS) := xen-access
 TARGETS := $(TARGETS-y)
 
 .PHONY: all
diff --git a/tools/tests/xen-access/xen-access.c b/tools/tests/xen-access/xen-access.c
index 090df5f..e122ef8 100644
--- a/tools/tests/xen-access/xen-access.c
+++ b/tools/tests/xen-access/xen-access.c
@@ -41,22 +41,15 @@
 #include <xenctrl.h>
 #include <xen/mem_event.h>
 
-#define DPRINTF(a, b...) fprintf(stderr, a, ## b)
-#define ERROR(a, b...) fprintf(stderr, a "\n", ## b)
-#define PERROR(a, b...) fprintf(stderr, a ": %s\n", ## b, strerror(errno))
-
-/* Spinlock and mem event definitions */
-
-#define SPIN_LOCK_UNLOCKED 0
+#ifdef CONFIG_X86
 
 #define ADDR (*(volatile long *) addr)
+
 /**
  * test_and_set_bit - Set a bit and return its old value
  * @nr: Bit to set
  * @addr: Address to count from
  *
- * This operation is atomic and cannot be reordered.
- * It also implies a memory barrier.
  */
 static inline int test_and_set_bit(int nr, volatile void *addr)
 {
@@ -69,6 +62,44 @@ static inline int test_and_set_bit(int nr, volatile void *addr)
     return oldbit;
 }
 
+#elif CONFIG_ARM
+
+#include <xen/arch-arm.h>
+
+#define PAGE_SHIFT              12
+#define GUEST_RAM0_4K_PAGES     GUEST_RAM0_SIZE / (1ull<<PAGE_SHIFT)
+#define GUEST_RAM1_4K_PAGES     GUEST_RAM1_SIZE / (1ull<<PAGE_SHIFT)
+#define BITS_PER_WORD           32
+#define BIT_MASK(nr)            (1UL << ((nr) % BITS_PER_WORD))
+#define BIT_WORD(nr)            ((nr) / BITS_PER_WORD)
+
+/**
+ * test_and_set_bit - Set a bit and return its old value
+ * @nr: Bit to set
+ * @addr: Address to count from
+ *
+ */
+static inline int test_and_set_bit(int nr, volatile void *addr)
+{
+        unsigned int mask = BIT_MASK(nr);
+        volatile unsigned int *p =
+                ((volatile unsigned int *)addr) + BIT_WORD(nr);
+        unsigned int old = *p;
+
+        *p = old | mask;
+        return (old & mask) != 0;
+}
+
+#endif
+
+#define DPRINTF(a, b...) fprintf(stderr, a, ## b)
+#define ERROR(a, b...) fprintf(stderr, a "\n", ## b)
+#define PERROR(a, b...) fprintf(stderr, a ": %s\n", ## b, strerror(errno))
+
+/* Spinlock and mem event definitions */
+
+#define SPIN_LOCK_UNLOCKED 0
+
 typedef int spinlock_t;
 
 static inline void spin_lock(spinlock_t *lock)
@@ -403,7 +434,7 @@ int main(int argc, char *argv[])
     mem_event_request_t req;
     mem_event_response_t rsp;
     int rc = -1;
-    int rc1;
+    int rc1, rc2;
     xc_interface *xch;
     xenmem_access_t default_access = XENMEM_access_rwx;
     xenmem_access_t after_first_access = XENMEM_access_rwx;
@@ -492,8 +523,30 @@ int main(int argc, char *argv[])
         goto exit;
     }
 
+#ifdef CONFIG_X86
     rc = xc_set_mem_access(xch, domain_id, default_access, 0,
                            xenaccess->domain_info->max_pages);
+#elif CONFIG_ARM
+    /* On ARM the guest memory is mapped with a gap after the first 3GB. */
+    if ( xenaccess->domain_info->max_pages <= GUEST_RAM0_4K_PAGES )
+    {
+        rc = xc_set_mem_access(xch, domain_id, default_access,
+                               GUEST_RAM0_BASE >> PAGE_SHIFT,
+                               xenaccess->domain_info->max_pages);
+    }
+    else
+    {
+        rc1 = xc_set_mem_access(xch, domain_id, default_access,
+                                GUEST_RAM0_BASE >> PAGE_SHIFT,
+                                GUEST_RAM0_4K_PAGES);
+        rc2 = xc_set_mem_access(xch, domain_id, default_access,
+                                GUEST_RAM1_BASE >> PAGE_SHIFT,
+                                xenaccess->domain_info->max_pages
+                                 - GUEST_RAM0_4K_PAGES);
+        rc = rc1 < 0 ? rc1 : (rc2 < 0 ? rc2 : 0);
+    }
+#endif
+
     if ( rc < 0 )
     {
         ERROR("Error %d setting all memory to access type %d\n", rc,
@@ -520,8 +573,29 @@ int main(int argc, char *argv[])
 
             /* Unregister for every event */
             rc = xc_set_mem_access(xch, domain_id, XENMEM_access_rwx, ~0ull, 0);
+#ifdef CONFIG_X86
             rc = xc_set_mem_access(xch, domain_id, XENMEM_access_rwx, 0,
                                    xenaccess->domain_info->max_pages);
+#elif CONFIG_ARM
+            /* On ARM the guest memory is mapped with a gap after the first 3GB. */
+            if ( xenaccess->domain_info->max_pages <= GUEST_RAM0_4K_PAGES )
+            {
+                rc = xc_set_mem_access(xch, domain_id, XENMEM_access_rwx,
+                                       GUEST_RAM0_BASE >> PAGE_SHIFT,
+                                       xenaccess->domain_info->max_pages);
+            }
+            else
+            {
+                rc = xc_set_mem_access(xch, domain_id, XENMEM_access_rwx,
+                                       GUEST_RAM0_BASE >> PAGE_SHIFT,
+                                       GUEST_RAM0_4K_PAGES);
+                rc = xc_set_mem_access(xch, domain_id, XENMEM_access_rwx,
+                                       GUEST_RAM1_BASE >> PAGE_SHIFT,
+                                       xenaccess->domain_info->max_pages
+                                        - GUEST_RAM0_4K_PAGES);
+            }
+#endif
+
             rc = xc_hvm_param_set(xch, domain_id, HVM_PARAM_MEMORY_EVENT_INT3, HVMPME_mode_disabled);
 
             shutting_down = 1;
diff --git a/xen/arch/arm/Rules.mk b/xen/arch/arm/Rules.mk
index f6781b5..8658176 100644
--- a/xen/arch/arm/Rules.mk
+++ b/xen/arch/arm/Rules.mk
@@ -10,7 +10,6 @@ HAS_DEVICE_TREE := y
 HAS_VIDEO := y
 HAS_ARM_HDLCD := y
 HAS_PASSTHROUGH := y
-HAS_MEM_ACCESS := y
 
 CFLAGS += -I$(BASEDIR)/include
 
diff --git a/xen/arch/x86/Rules.mk b/xen/arch/x86/Rules.mk
index bd4e342..576985e 100644
--- a/xen/arch/x86/Rules.mk
+++ b/xen/arch/x86/Rules.mk
@@ -12,7 +12,6 @@ HAS_NS16550 := y
 HAS_EHCI := y
 HAS_KEXEC := y
 HAS_GDBSX := y
-HAS_MEM_ACCESS := y
 xenoprof := y
 
 #
-- 
2.1.0