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

From: Boris Ostrovsky
Date: Mon Feb 01 2016 - 10:42:50 EST


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