[PATCH linux v3] arm: xen: implement multicall hypercall support.

[Ian Campbell <ian.campbell@citrix.com>]

As part of this make the usual change to xen_ulong_t in place of unsigned long.
This change has no impact on x86.

The Linux definition of struct multicall_entry.result differs from the Xen
definition, I think for good reasons, and used a long rather than an unsigned
long. Therefore introduce a xen_long_t, which is a long on x86 architectures
and a signed 64-bit integer on ARM.

Use uint32_t nr_calls on x86 for consistency with the ARM definition.

Build tested on amd64 and i386 builds. Runtime tested on ARM.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
---
v3: - Add for arm64 too
v2: - Typo in commit message.
    - Update x86 prototype for HYPERCALL_multicall for consistency (nr_calls
      is a uint32_t).

Tested on ARM and arm64 with a stupid patch:
	diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
	index b96723e..8b1dc7a 100644
	--- a/arch/arm/xen/enlighten.c
	+++ b/arch/arm/xen/enlighten.c
	@@ -339,6 +339,63 @@ static int __init xen_pm_init(void)
	 }
	 late_initcall(xen_pm_init);

	+static int __init multicall_test(void)
	+{
	+	struct multicall_entry templ[3];
	+	struct multicall_entry call[3];
	+	const char *str0 = "This is the first debug string\n";
	+	const char *str1 = "This is the second debug string\n";
	+	const char *str2 = "This is the third debug string\n";
	+	int ret;
	+
	+	templ[0] = (struct multicall_entry) {
	+		.op = __HYPERVISOR_console_io,
	+		.args[0] = CONSOLEIO_write,
	+		.args[1] = strlen(str0),
	+		.args[2] = (uintptr_t)str0
	+	};
	+	templ[1] = (struct multicall_entry) {
	+		.op = __HYPERVISOR_console_io,
	+		.args[0] = CONSOLEIO_write,
	+		.args[1] = strlen(str1),
	+		.args[2] = (uintptr_t)str1
	+	};
	+	templ[2] = (struct multicall_entry) {
	+		.op = __HYPERVISOR_console_io,
	+		.args[0] = CONSOLEIO_write,
	+		.args[1] = strlen(str2),
	+		.args[2] = (uintptr_t)str2
	+	};
	+
	+	memcpy(call, templ, sizeof(templ));
	+
	+	ret = HYPERVISOR_multicall(call, ARRAY_SIZE(call));
	+	printk("1st MULTICALL returned %d\n", ret);
	+	if (ret == 0) {
	+		printk("call[0].result = %"PRI_xen_long"\n", call[0].result);
	+		printk("call[1].result = %"PRI_xen_long"\n", call[1].result);
	+		printk("call[2].result = %"PRI_xen_long"\n", call[2].result);
	+	}
	+
	+	memcpy(call, templ, sizeof(templ));
	+	call[1].args[0] |= 0xf000000000000000ULL;
	+
	+	/*
	+         * On arm: should die after printing first string, shouldn't print third
	+         * On arm64: should print all three.
	+         */
	+	ret = HYPERVISOR_multicall(call, ARRAY_SIZE(call));
	+	printk("2nd MULTICALL returned %d\n", ret);
	+	if (ret == 0) {
	+		printk("call[0].result = %"PRI_xen_long"\n", call[0].result);
	+		printk("call[1].result = %"PRI_xen_long"\n", call[1].result);
	+		printk("call[2].result = %"PRI_xen_long"\n", call[2].result);
	+	}
	+
	+	return 0;
	+}
	+late_initcall(multicall_test);
	+
	 /* In the hypervisor.S file. */
	 EXPORT_SYMBOL_GPL(HYPERVISOR_event_channel_op);
	 EXPORT_SYMBOL_GPL(HYPERVISOR_grant_table_op);
---
 arch/arm/include/asm/xen/hypercall.h |    6 +-----
 arch/arm/include/asm/xen/interface.h |    2 ++
 arch/arm/xen/hypercall.S             |    1 +
 arch/arm64/xen/hypercall.S           |    1 +
 arch/x86/include/asm/xen/hypercall.h |    2 +-
 arch/x86/include/asm/xen/interface.h |    3 +++
 include/xen/interface/xen.h          |    6 +++---
 7 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/arch/arm/include/asm/xen/hypercall.h b/arch/arm/include/asm/xen/hypercall.h
index 7704e28..7658150 100644
--- a/arch/arm/include/asm/xen/hypercall.h
+++ b/arch/arm/include/asm/xen/hypercall.h
@@ -48,6 +48,7 @@ int HYPERVISOR_memory_op(unsigned int cmd, void *arg);
 int HYPERVISOR_physdev_op(int cmd, void *arg);
 int HYPERVISOR_vcpu_op(int cmd, int vcpuid, void *extra_args);
 int HYPERVISOR_tmem_op(void *arg);
+int HYPERVISOR_multicall(struct multicall_entry *calls, uint32_t nr);
 
 static inline void
 MULTI_update_va_mapping(struct multicall_entry *mcl, unsigned long va,
@@ -63,9 +64,4 @@ MULTI_mmu_update(struct multicall_entry *mcl, struct mmu_update *req,
 	BUG();
 }
 
-static inline int
-HYPERVISOR_multicall(void *call_list, int nr_calls)
-{
-	BUG();
-}
 #endif /* _ASM_ARM_XEN_HYPERCALL_H */
diff --git a/arch/arm/include/asm/xen/interface.h b/arch/arm/include/asm/xen/interface.h
index 1151188..5006600 100644
--- a/arch/arm/include/asm/xen/interface.h
+++ b/arch/arm/include/asm/xen/interface.h
@@ -40,6 +40,8 @@ typedef uint64_t xen_pfn_t;
 #define PRI_xen_pfn "llx"
 typedef uint64_t xen_ulong_t;
 #define PRI_xen_ulong "llx"
+typedef int64_t xen_long_t;
+#define PRI_xen_long "llx"
 /* Guest handles for primitive C types. */
 __DEFINE_GUEST_HANDLE(uchar, unsigned char);
 __DEFINE_GUEST_HANDLE(uint,  unsigned int);
diff --git a/arch/arm/xen/hypercall.S b/arch/arm/xen/hypercall.S
index d1cf7b7..44e3a5f 100644
--- a/arch/arm/xen/hypercall.S
+++ b/arch/arm/xen/hypercall.S
@@ -89,6 +89,7 @@ HYPERCALL2(memory_op);
 HYPERCALL2(physdev_op);
 HYPERCALL3(vcpu_op);
 HYPERCALL1(tmem_op);
+HYPERCALL2(multicall);
 
 ENTRY(privcmd_call)
 	stmdb sp!, {r4}
diff --git a/arch/arm64/xen/hypercall.S b/arch/arm64/xen/hypercall.S
index 531342e..8bbe940 100644
--- a/arch/arm64/xen/hypercall.S
+++ b/arch/arm64/xen/hypercall.S
@@ -80,6 +80,7 @@ HYPERCALL2(memory_op);
 HYPERCALL2(physdev_op);
 HYPERCALL3(vcpu_op);
 HYPERCALL1(tmem_op);
+HYPERCALL2(multicall);
 
 ENTRY(privcmd_call)
 	mov x16, x0
diff --git a/arch/x86/include/asm/xen/hypercall.h b/arch/x86/include/asm/xen/hypercall.h
index e709884..ca08a27 100644
--- a/arch/x86/include/asm/xen/hypercall.h
+++ b/arch/x86/include/asm/xen/hypercall.h
@@ -343,7 +343,7 @@ HYPERVISOR_memory_op(unsigned int cmd, void *arg)
 }
 
 static inline int
-HYPERVISOR_multicall(void *call_list, int nr_calls)
+HYPERVISOR_multicall(void *call_list, uint32_t nr_calls)
 {
 	return _hypercall2(int, multicall, call_list, nr_calls);
 }
diff --git a/arch/x86/include/asm/xen/interface.h b/arch/x86/include/asm/xen/interface.h
index fd9cb76..3400dba 100644
--- a/arch/x86/include/asm/xen/interface.h
+++ b/arch/x86/include/asm/xen/interface.h
@@ -54,6 +54,9 @@ typedef unsigned long xen_pfn_t;
 #define PRI_xen_pfn "lx"
 typedef unsigned long xen_ulong_t;
 #define PRI_xen_ulong "lx"
+typedef long xen_long_t;
+#define PRI_xen_long "lx"
+
 /* Guest handles for primitive C types. */
 __DEFINE_GUEST_HANDLE(uchar, unsigned char);
 __DEFINE_GUEST_HANDLE(uint,  unsigned int);
diff --git a/include/xen/interface/xen.h b/include/xen/interface/xen.h
index 0cd5ca3..de08213 100644
--- a/include/xen/interface/xen.h
+++ b/include/xen/interface/xen.h
@@ -275,9 +275,9 @@ DEFINE_GUEST_HANDLE_STRUCT(mmu_update);
  * NB. The fields are natural register size for this architecture.
  */
 struct multicall_entry {
-    unsigned long op;
-    long result;
-    unsigned long args[6];
+    xen_ulong_t op;
+    xen_long_t result;
+    xen_ulong_t args[6];
 };
 DEFINE_GUEST_HANDLE_STRUCT(multicall_entry);
 
-- 
1.7.10.4