[PATCH 4/5] x86/hvm: Improve grant_table_op hypercall dispatching

[Andrew Cooper <andrew.cooper3@citrix.com>]

hvm_grant_table_op() and hvm_grant_table_op_compat32() are almost identical,
but there is no need to have two functions instantiated at the end of
different function pointers.

Combine the two into a single hvm_grant_table_op() (folding
grant_table_op_is_allowed() into is now-single caller) and dispatch to
{do,compat}_grant_table_op() based on the hcall_64bit setting.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
---
 xen/arch/x86/hvm/hypercall.c | 40 +++++++++++++---------------------------
 1 file changed, 13 insertions(+), 27 deletions(-)

diff --git a/xen/arch/x86/hvm/hypercall.c b/xen/arch/x86/hvm/hypercall.c
index 0f3df4e..140676d 100644
--- a/xen/arch/x86/hvm/hypercall.c
+++ b/xen/arch/x86/hvm/hypercall.c
@@ -46,9 +46,11 @@ static long hvm_memory_op(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
     return rc;
 }
 
-static int grant_table_op_is_allowed(unsigned int cmd)
+static long hvm_grant_table_op(
+    unsigned int cmd, XEN_GUEST_HANDLE_PARAM(void) uop, unsigned int count)
 {
-    switch (cmd) {
+    switch ( cmd )
+    {
     case GNTTABOP_query_size:
     case GNTTABOP_setup_table:
     case GNTTABOP_set_version:
@@ -57,19 +59,16 @@ static int grant_table_op_is_allowed(unsigned int cmd)
     case GNTTABOP_map_grant_ref:
     case GNTTABOP_unmap_grant_ref:
     case GNTTABOP_swap_grant_ref:
-        return 1;
-    default:
-        /* all other commands need auditing */
-        return 0;
+        break;
+
+    default: /* All other commands need auditing. */
+        return -ENOSYS;
     }
-}
 
-static long hvm_grant_table_op(
-    unsigned int cmd, XEN_GUEST_HANDLE_PARAM(void) uop, unsigned int count)
-{
-    if ( !grant_table_op_is_allowed(cmd) )
-        return -ENOSYS; /* all other commands need auditing */
-    return do_grant_table_op(cmd, uop, count);
+    if ( current->arch.hvm_vcpu.hcall_64bit )
+        return do_grant_table_op(cmd, uop, count);
+    else
+        return compat_grant_table_op(cmd, uop, count);
 }
 
 static long hvm_physdev_op(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
@@ -89,15 +88,6 @@ static long hvm_physdev_op(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
     }
 }
 
-static long hvm_grant_table_op_compat32(unsigned int cmd,
-                                        XEN_GUEST_HANDLE_PARAM(void) uop,
-                                        unsigned int count)
-{
-    if ( !grant_table_op_is_allowed(cmd) )
-        return -ENOSYS;
-    return compat_grant_table_op(cmd, uop, count);
-}
-
 static long hvm_physdev_op_compat32(
     int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
 {
@@ -130,13 +120,11 @@ static long hvm_physdev_op_compat32(
 
 #define do_physdev_op         hvm_physdev_op
 #define compat_physdev_op     hvm_physdev_op_compat32
-#define do_grant_table_op     hvm_grant_table_op
-#define compat_grant_table_op hvm_grant_table_op_compat32
 #define do_arch_1             paging_domctl_continuation
 
 static const hypercall_table_t hvm_hypercall_table[] = {
     HVM_CALL(memory_op),
-    COMPAT_CALL(grant_table_op),
+    HVM_CALL(grant_table_op),
     COMPAT_CALL(vcpu_op),
     COMPAT_CALL(physdev_op),
     COMPAT_CALL(xen_version),
@@ -160,8 +148,6 @@ static const hypercall_table_t hvm_hypercall_table[] = {
 
 #undef do_physdev_op
 #undef compat_physdev_op
-#undef do_grant_table_op
-#undef compat_grant_table_op
 #undef do_arch_1
 
 #undef HYPERCALL
-- 
2.1.4


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