[Xen-devel] [PATCH v2 06/11] xen/hvmlite: Prepare cpu_initialize_context() routine for HVMlite SMP

[Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>]

Subsequent patch will add support for starting secondary VCPUs in
HVMlite guest. This patch exists to simmplify code review.

No functional changes (except for introduction of 'if (!xen_hvmlite)').

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
---
 arch/x86/xen/smp.c |  104 ++++++++++++++++++++++++++++-----------------------
 1 files changed, 57 insertions(+), 47 deletions(-)

diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 3f4ebf0..5fc4afb 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -390,70 +390,80 @@ cpu_initialize_context(unsigned int cpu, struct 
task_struct *idle)
        if (cpumask_test_and_set_cpu(cpu, xen_cpu_initialized_map))
                return 0;
 
-       ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL);
-       if (ctxt == NULL)
-               return -ENOMEM;
+       if (!xen_hvmlite) {
 
-       gdt = get_cpu_gdt_table(cpu);
+               ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL);
+               if (ctxt == NULL)
+                       return -ENOMEM;
+
+               gdt = get_cpu_gdt_table(cpu);
 
 #ifdef CONFIG_X86_32
-       /* Note: PVH is not yet supported on x86_32. */
-       ctxt->user_regs.fs = __KERNEL_PERCPU;
-       ctxt->user_regs.gs = __KERNEL_STACK_CANARY;
+               /* Note: PVH is not yet supported on x86_32. */
+               ctxt->user_regs.fs = __KERNEL_PERCPU;
+               ctxt->user_regs.gs = __KERNEL_STACK_CANARY;
 #endif
-       memset(&ctxt->fpu_ctxt, 0, sizeof(ctxt->fpu_ctxt));
+               memset(&ctxt->fpu_ctxt, 0, sizeof(ctxt->fpu_ctxt));
 
-       if (!xen_feature(XENFEAT_auto_translated_physmap)) {
-               ctxt->user_regs.eip = (unsigned long)cpu_bringup_and_idle;
-               ctxt->flags = VGCF_IN_KERNEL;
-               ctxt->user_regs.eflags = 0x1000; /* IOPL_RING1 */
-               ctxt->user_regs.ds = __USER_DS;
-               ctxt->user_regs.es = __USER_DS;
-               ctxt->user_regs.ss = __KERNEL_DS;
+               if (!xen_feature(XENFEAT_auto_translated_physmap)) {
+                       ctxt->user_regs.eip =
+                               (unsigned long)cpu_bringup_and_idle;
+                       ctxt->flags = VGCF_IN_KERNEL;
+                       ctxt->user_regs.eflags = 0x1000; /* IOPL_RING1 */
+                       ctxt->user_regs.ds = __USER_DS;
+                       ctxt->user_regs.es = __USER_DS;
+                       ctxt->user_regs.ss = __KERNEL_DS;
 
-               xen_copy_trap_info(ctxt->trap_ctxt);
+                       xen_copy_trap_info(ctxt->trap_ctxt);
 
-               ctxt->ldt_ents = 0;
+                       ctxt->ldt_ents = 0;
 
-               BUG_ON((unsigned long)gdt & ~PAGE_MASK);
+                       BUG_ON((unsigned long)gdt & ~PAGE_MASK);
 
-               gdt_mfn = arbitrary_virt_to_mfn(gdt);
-               make_lowmem_page_readonly(gdt);
-               make_lowmem_page_readonly(mfn_to_virt(gdt_mfn));
+                       gdt_mfn = arbitrary_virt_to_mfn(gdt);
+                       make_lowmem_page_readonly(gdt);
+                       make_lowmem_page_readonly(mfn_to_virt(gdt_mfn));
 
-               ctxt->gdt_frames[0] = gdt_mfn;
-               ctxt->gdt_ents      = GDT_ENTRIES;
+                       ctxt->gdt_frames[0] = gdt_mfn;
+                       ctxt->gdt_ents      = GDT_ENTRIES;
 
-               ctxt->kernel_ss = __KERNEL_DS;
-               ctxt->kernel_sp = idle->thread.sp0;
+                       ctxt->kernel_ss = __KERNEL_DS;
+                       ctxt->kernel_sp = idle->thread.sp0;
 
 #ifdef CONFIG_X86_32
-               ctxt->event_callback_cs     = __KERNEL_CS;
-               ctxt->failsafe_callback_cs  = __KERNEL_CS;
+                       ctxt->event_callback_cs     = __KERNEL_CS;
+                       ctxt->failsafe_callback_cs  = __KERNEL_CS;
 #else
-               ctxt->gs_base_kernel = per_cpu_offset(cpu);
+                       ctxt->gs_base_kernel = per_cpu_offset(cpu);
 #endif
-               ctxt->event_callback_eip    =
-                                       (unsigned long)xen_hypervisor_callback;
-               ctxt->failsafe_callback_eip =
-                                       (unsigned long)xen_failsafe_callback;
-               ctxt->user_regs.cs = __KERNEL_CS;
-               per_cpu(xen_cr3, cpu) = __pa(swapper_pg_dir);
-       }
+                       ctxt->event_callback_eip    =
+                               (unsigned long)xen_hypervisor_callback;
+                       ctxt->failsafe_callback_eip =
+                               (unsigned long)xen_failsafe_callback;
+                       ctxt->user_regs.cs = __KERNEL_CS;
+                       per_cpu(xen_cr3, cpu) = __pa(swapper_pg_dir);
+               }
 #ifdef CONFIG_XEN_PVH
-       else {
-               /*
-                * The vcpu comes on kernel page tables which have the NX pte
-                * bit set. This means before DS/SS is touched, NX in
-                * EFER must be set. Hence the following assembly glue code.
-                */
-               ctxt->user_regs.eip = (unsigned long)xen_pvh_early_cpu_init;
-               ctxt->user_regs.rdi = cpu;
-               ctxt->user_regs.rsi = true;  /* entry == true */
-       }
+               else {
+                       /*
+                        * The vcpu comes on kernel page tables which have the
+                        * NX pte bit set. This means before DS/SS is touched,
+                        * NX in EFER must be set. Hence the following assembly
+                        * glue code.
+                        */
+                       ctxt->user_regs.eip =
+                               (unsigned long)xen_pvh_early_cpu_init;
+                       ctxt->user_regs.rdi = cpu;
+                       ctxt->user_regs.rsi = true;  /* entry == true */
+               }
 #endif
-       ctxt->user_regs.esp = idle->thread.sp0 - sizeof(struct pt_regs);
-       ctxt->ctrlreg[3] = xen_pfn_to_cr3(virt_to_gfn(swapper_pg_dir));
+               ctxt->user_regs.esp = idle->thread.sp0 - sizeof(struct pt_regs);
+               ctxt->ctrlreg[3] = xen_pfn_to_cr3(virt_to_gfn(swapper_pg_dir));
+       } else {
+               ctxt = NULL; /* To quiet down compiler */
+               BUG();
+       }
+
        if (HYPERVISOR_vcpu_op(VCPUOP_initialise, cpu, ctxt))
                BUG();
 
-- 
1.7.1


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