[PATCH v3 1/2] xen/x86: Return virtual address from alloc_stub_page()

[Jason Andryuk <jason.andryuk@xxxxxxx>]

Currently alloc_stub_page() returns the virtual address of the mapped
stubs page, and the caller adds the per-CPU offset.  Make
alloc_stub_page() return the final address.  This is in preparation for
changing the stubs allocation where the offset will not be tied to the
CPU number.

The call to alloc_stub_page() in setup.c:start_xen() did not add the
offset as it is assumed to run on CPU0.

Change the local variable stub_page to stub_va to reflect the value.

Signed-off-by: Jason Andryuk <jason.andryuk@xxxxxxx>
---
 xen/arch/x86/smpboot.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/smpboot.c b/xen/arch/x86/smpboot.c
index ff05955bae..d7619f534b 100644
--- a/xen/arch/x86/smpboot.c
+++ b/xen/arch/x86/smpboot.c
@@ -675,7 +675,7 @@ unsigned long alloc_stub_page(unsigned int cpu, unsigned 
long *mfn)
     else if ( !*mfn )
         *mfn = mfn_x(page_to_mfn(pg));
 
-    return stub_va;
+    return stub_va ? stub_va + STUB_BUF_CPU_OFFS(cpu) : 0;
 }
 
 void cpu_exit_clear(unsigned int cpu)
@@ -1044,7 +1044,7 @@ static int cpu_smpboot_alloc(unsigned int cpu)
     unsigned int i, memflags = 0;
     nodeid_t node = cpu_to_node(cpu);
     seg_desc_t *gdt;
-    unsigned long stub_page;
+    unsigned long stub_va;
     int rc = -ENOMEM;
 
     if ( node != NUMA_NO_NODE )
@@ -1099,10 +1099,10 @@ static int cpu_smpboot_alloc(unsigned int cpu)
             break;
         }
     BUG_ON(i == cpu);
-    stub_page = alloc_stub_page(cpu, &per_cpu(stubs.mfn, cpu));
-    if ( !stub_page )
+    stub_va = alloc_stub_page(cpu, &per_cpu(stubs.mfn, cpu));
+    if ( !stub_va )
         goto out;
-    per_cpu(stubs.addr, cpu) = stub_page + STUB_BUF_CPU_OFFS(cpu);
+    per_cpu(stubs.addr, cpu) = stub_va;
 
     rc = setup_cpu_root_pgt(cpu);
     if ( rc )
-- 
2.54.0