# HG changeset patch # User Keir Fraser # Date 1226491295 0 # Node ID 8e18dd41c6c7bb0980b29393b275c564cfb96437 # Parent 2bd99c5faa420612544a9d94e298332e0e72a86a x86: reduce GDT switching Both idle and HVM vCPU-s can easily run on the GDT mapped into general hypervisor space (rather than that placed in per-vCPU virtual space). This makes unnecessary some of the additions c/s 18520 did. Signed-off-by: Jan Beulich Index: xen-3.3.1-testing/xen/arch/x86/cpu/common.c =================================================================== --- xen-3.3.1-testing.orig/xen/arch/x86/cpu/common.c +++ xen-3.3.1-testing/xen/arch/x86/cpu/common.c @@ -564,7 +564,10 @@ void __cpuinit cpu_init(void) { int cpu = smp_processor_id(); struct tss_struct *t = &init_tss[cpu]; - char gdt_load[10]; + struct desc_ptr gdt_desc = { + .base = (unsigned long)(this_cpu(gdt_table) - FIRST_RESERVED_GDT_ENTRY), + .limit = LAST_RESERVED_GDT_BYTE + }; if (cpu_test_and_set(cpu, cpu_initialized)) { printk(KERN_WARNING "CPU#%d already initialized!\n", cpu); @@ -578,9 +581,7 @@ void __cpuinit cpu_init(void) /* Install correct page table. */ write_ptbase(current); - *(unsigned short *)(&gdt_load[0]) = LAST_RESERVED_GDT_BYTE; - *(unsigned long *)(&gdt_load[2]) = GDT_VIRT_START(current); - asm volatile ( "lgdt %0" : "=m" (gdt_load) ); + asm volatile ( "lgdt %0" : : "m" (gdt_desc) ); /* No nested task. */ asm volatile ("pushf ; andw $0xbfff,(%"__OP"sp) ; popf" ); Index: xen-3.3.1-testing/xen/arch/x86/domain.c =================================================================== --- xen-3.3.1-testing.orig/xen/arch/x86/domain.c +++ xen-3.3.1-testing/xen/arch/x86/domain.c @@ -309,12 +309,7 @@ int vcpu_initialise(struct vcpu *v) if ( is_idle_domain(d) ) { v->arch.schedule_tail = continue_idle_domain; - if ( v->vcpu_id ) - v->arch.cr3 = d->vcpu[0]->arch.cr3; - else if ( !*idle_vcpu ) - v->arch.cr3 = __pa(idle_pg_table); - else if ( !(v->arch.cr3 = clone_idle_pagetable(v)) ) - return -ENOMEM; + v->arch.cr3 = __pa(idle_pg_table); } v->arch.guest_context.ctrlreg[4] = @@ -1171,14 +1166,18 @@ static void paravirt_ctxt_switch_to(stru } } +static inline int need_full_gdt(struct vcpu *v) +{ + return (!is_hvm_vcpu(v) && !is_idle_vcpu(v)); +} + static void __context_switch(void) { struct cpu_user_regs *stack_regs = guest_cpu_user_regs(); - unsigned int i, cpu = smp_processor_id(); + unsigned int cpu = smp_processor_id(); struct vcpu *p = per_cpu(curr_vcpu, cpu); struct vcpu *n = current; struct desc_struct *gdt; - struct page_info *page; struct desc_ptr gdt_desc; ASSERT(p != n); @@ -1207,16 +1206,19 @@ static void __context_switch(void) gdt = !is_pv_32on64_vcpu(n) ? per_cpu(gdt_table, cpu) : per_cpu(compat_gdt_table, cpu); - page = virt_to_page(gdt); - for (i = 0; i < NR_RESERVED_GDT_PAGES; ++i) + if ( need_full_gdt(n) ) { - l1e_write(n->domain->arch.mm_perdomain_pt + - (n->vcpu_id << GDT_LDT_VCPU_SHIFT) + - FIRST_RESERVED_GDT_PAGE + i, - l1e_from_page(page + i, __PAGE_HYPERVISOR)); + struct page_info *page = virt_to_page(gdt); + unsigned int i; + for ( i = 0; i < NR_RESERVED_GDT_PAGES; i++ ) + l1e_write(n->domain->arch.mm_perdomain_pt + + (n->vcpu_id << GDT_LDT_VCPU_SHIFT) + + FIRST_RESERVED_GDT_PAGE + i, + l1e_from_page(page + i, __PAGE_HYPERVISOR)); } - if ( p->vcpu_id != n->vcpu_id ) + if ( need_full_gdt(p) && + ((p->vcpu_id != n->vcpu_id) || !need_full_gdt(n)) ) { gdt_desc.limit = LAST_RESERVED_GDT_BYTE; gdt_desc.base = (unsigned long)(gdt - FIRST_RESERVED_GDT_ENTRY); @@ -1225,8 +1227,10 @@ static void __context_switch(void) write_ptbase(n); - if ( p->vcpu_id != n->vcpu_id ) + if ( need_full_gdt(n) && + ((p->vcpu_id != n->vcpu_id) || !need_full_gdt(p)) ) { + gdt_desc.limit = LAST_RESERVED_GDT_BYTE; gdt_desc.base = GDT_VIRT_START(n); asm volatile ( "lgdt %0" : : "m" (gdt_desc) ); } Index: xen-3.3.1-testing/xen/arch/x86/domain_build.c =================================================================== --- xen-3.3.1-testing.orig/xen/arch/x86/domain_build.c +++ xen-3.3.1-testing/xen/arch/x86/domain_build.c @@ -707,6 +707,7 @@ int __init construct_dom0( /* Install the new page tables. */ local_irq_disable(); + /* We run on dom0's page tables for the final part of the build process. */ write_ptbase(v); /* Copy the OS image and free temporary buffer. */ @@ -719,11 +720,11 @@ int __init construct_dom0( (parms.virt_hypercall >= v_end) ) { write_ptbase(current); - local_irq_enable(); printk("Invalid HYPERCALL_PAGE field in ELF notes.\n"); return -1; } - hypercall_page_initialise(d, (void *)(unsigned long)parms.virt_hypercall); + hypercall_page_initialise( + d, (void *)(unsigned long)parms.virt_hypercall); } /* Copy the initial ramdisk. */ @@ -804,7 +805,7 @@ int __init construct_dom0( xlat_start_info(si, XLAT_start_info_console_dom0); #endif - /* Reinstate the caller's page tables. */ + /* Return to idle domain's page tables. */ write_ptbase(current); local_irq_enable(); Index: xen-3.3.1-testing/xen/arch/x86/hvm/vmx/vmcs.c =================================================================== --- xen-3.3.1-testing.orig/xen/arch/x86/hvm/vmx/vmcs.c +++ xen-3.3.1-testing/xen/arch/x86/hvm/vmx/vmcs.c @@ -444,6 +444,8 @@ static void vmx_set_host_env(struct vcpu { unsigned int cpu = smp_processor_id(); + __vmwrite(HOST_GDTR_BASE, + (unsigned long)(this_cpu(gdt_table) - FIRST_RESERVED_GDT_ENTRY)); __vmwrite(HOST_IDTR_BASE, (unsigned long)idt_tables[cpu]); __vmwrite(HOST_TR_SELECTOR, TSS_ENTRY << 3); @@ -541,9 +543,6 @@ static int construct_vmcs(struct vcpu *v __vmwrite(IO_BITMAP_A, virt_to_maddr((char *)hvm_io_bitmap + 0)); __vmwrite(IO_BITMAP_B, virt_to_maddr((char *)hvm_io_bitmap + PAGE_SIZE)); - /* Host GDTR base. */ - __vmwrite(HOST_GDTR_BASE, GDT_VIRT_START(v)); - /* Host data selectors. */ __vmwrite(HOST_SS_SELECTOR, __HYPERVISOR_DS); __vmwrite(HOST_DS_SELECTOR, __HYPERVISOR_DS); Index: xen-3.3.1-testing/xen/arch/x86/setup.c =================================================================== --- xen-3.3.1-testing.orig/xen/arch/x86/setup.c +++ xen-3.3.1-testing/xen/arch/x86/setup.c @@ -230,7 +230,6 @@ static void __init percpu_init_areas(voi static void __init init_idle_domain(void) { struct domain *idle_domain; - unsigned int i; /* Domain creation requires that scheduler structures are initialised. */ scheduler_init(); @@ -243,12 +242,6 @@ static void __init init_idle_domain(void idle_vcpu[0] = this_cpu(curr_vcpu) = current; setup_idle_pagetable(); - - for (i = 0; i < NR_RESERVED_GDT_PAGES; ++i) - idle_domain->arch.mm_perdomain_pt[FIRST_RESERVED_GDT_PAGE + i] = - l1e_from_page(virt_to_page(boot_cpu_gdt_table) + i, - __PAGE_HYPERVISOR); - } static void __init srat_detect_node(int cpu) @@ -456,6 +449,7 @@ void __init __start_xen(unsigned long mb parse_video_info(); set_current((struct vcpu *)0xfffff000); /* debug sanity */ + idle_vcpu[0] = current; set_processor_id(0); /* needed early, for smp_processor_id() */ if ( cpu_has_efer ) rdmsrl(MSR_EFER, this_cpu(efer)); Index: xen-3.3.1-testing/xen/arch/x86/smpboot.c =================================================================== --- xen-3.3.1-testing.orig/xen/arch/x86/smpboot.c +++ xen-3.3.1-testing/xen/arch/x86/smpboot.c @@ -828,7 +828,7 @@ static int __devinit do_boot_cpu(int api */ { unsigned long boot_error; - unsigned int i; + unsigned int order; int timeout; unsigned long start_eip; unsigned short nmi_high = 0, nmi_low = 0; @@ -864,21 +864,21 @@ static int __devinit do_boot_cpu(int api gdt = per_cpu(gdt_table, cpu); if (gdt == boot_cpu_gdt_table) { - i = get_order_from_pages(NR_RESERVED_GDT_PAGES); + order = get_order_from_pages(NR_RESERVED_GDT_PAGES); #ifdef __x86_64__ #ifdef CONFIG_COMPAT - page = alloc_domheap_pages(NULL, i, + page = alloc_domheap_pages(NULL, order, MEMF_node(cpu_to_node(cpu))); per_cpu(compat_gdt_table, cpu) = gdt = page_to_virt(page); memcpy(gdt, boot_cpu_compat_gdt_table, NR_RESERVED_GDT_PAGES * PAGE_SIZE); gdt[PER_CPU_GDT_ENTRY - FIRST_RESERVED_GDT_ENTRY].a = cpu; #endif - page = alloc_domheap_pages(NULL, i, + page = alloc_domheap_pages(NULL, order, MEMF_node(cpu_to_node(cpu))); per_cpu(gdt_table, cpu) = gdt = page_to_virt(page); #else - per_cpu(gdt_table, cpu) = gdt = alloc_xenheap_pages(i); + per_cpu(gdt_table, cpu) = gdt = alloc_xenheap_pages(order); #endif memcpy(gdt, boot_cpu_gdt_table, NR_RESERVED_GDT_PAGES * PAGE_SIZE); @@ -886,13 +886,6 @@ static int __devinit do_boot_cpu(int api gdt[PER_CPU_GDT_ENTRY - FIRST_RESERVED_GDT_ENTRY].a = cpu; } - for (i = 0; i < NR_RESERVED_GDT_PAGES; ++i) - v->domain->arch.mm_perdomain_pt - [(v->vcpu_id << GDT_LDT_VCPU_SHIFT) + - FIRST_RESERVED_GDT_PAGE + i] - = l1e_from_page(virt_to_page(gdt) + i, - __PAGE_HYPERVISOR); - #ifdef __i386__ if (!per_cpu(doublefault_tss, cpu)) { per_cpu(doublefault_tss, cpu) = alloc_xenheap_page(); Index: xen-3.3.1-testing/xen/arch/x86/x86_32/mm.c =================================================================== --- xen-3.3.1-testing.orig/xen/arch/x86/x86_32/mm.c +++ xen-3.3.1-testing/xen/arch/x86/x86_32/mm.c @@ -132,30 +132,6 @@ void __init setup_idle_pagetable(void) __PAGE_HYPERVISOR)); } -unsigned long clone_idle_pagetable(struct vcpu *v) -{ - unsigned int i; - struct domain *d = v->domain; - l3_pgentry_t *l3_table = v->arch.pae_l3_cache.table[0]; - l2_pgentry_t *l2_table = alloc_xenheap_page(); - - if ( !l2_table ) - return 0; - - memcpy(l3_table, idle_pg_table, L3_PAGETABLE_ENTRIES * sizeof(*l3_table)); - l3_table[l3_table_offset(PERDOMAIN_VIRT_START)] = - l3e_from_page(virt_to_page(l2_table), _PAGE_PRESENT); - - copy_page(l2_table, idle_pg_table_l2 + - l3_table_offset(PERDOMAIN_VIRT_START) * L2_PAGETABLE_ENTRIES); - for ( i = 0; i < PDPT_L2_ENTRIES; ++i ) - l2_table[l2_table_offset(PERDOMAIN_VIRT_START) + i] = - l2e_from_page(virt_to_page(d->arch.mm_perdomain_pt) + i, - __PAGE_HYPERVISOR); - - return __pa(l3_table); -} - void __init zap_low_mappings(l2_pgentry_t *dom0_l2) { int i; Index: xen-3.3.1-testing/xen/arch/x86/x86_64/mm.c =================================================================== --- xen-3.3.1-testing.orig/xen/arch/x86/x86_64/mm.c +++ xen-3.3.1-testing/xen/arch/x86/x86_64/mm.c @@ -21,7 +21,6 @@ #include #include #include -#include #include #include #include @@ -207,24 +206,6 @@ void __init setup_idle_pagetable(void) __PAGE_HYPERVISOR)); } -unsigned long clone_idle_pagetable(struct vcpu *v) -{ - struct domain *d = v->domain; - struct page_info *page = alloc_domheap_page(NULL, - MEMF_node(vcpu_to_node(v))); - l4_pgentry_t *l4_table = page_to_virt(page); - - if ( !page ) - return 0; - - copy_page(l4_table, idle_pg_table); - l4_table[l4_table_offset(PERDOMAIN_VIRT_START)] = - l4e_from_page(virt_to_page(d->arch.mm_perdomain_l3), - __PAGE_HYPERVISOR); - - return __pa(l4_table); -} - void __init zap_low_mappings(void) { BUG_ON(num_online_cpus() != 1); Index: xen-3.3.1-testing/xen/include/asm-x86/page.h =================================================================== --- xen-3.3.1-testing.orig/xen/include/asm-x86/page.h +++ xen-3.3.1-testing/xen/include/asm-x86/page.h @@ -278,7 +278,6 @@ extern unsigned int m2p_compat_vstart; #endif void paging_init(void); void setup_idle_pagetable(void); -unsigned long clone_idle_pagetable(struct vcpu *); #endif /* !defined(__ASSEMBLY__) */ #define _PAGE_PRESENT 0x001U