diff options
Diffstat (limited to 'arch/x86/xen')
| -rw-r--r-- | arch/x86/xen/apic.c | 27 | ||||
| -rw-r--r-- | arch/x86/xen/enlighten.c | 32 | ||||
| -rw-r--r-- | arch/x86/xen/enlighten_hvm.c | 6 | ||||
| -rw-r--r-- | arch/x86/xen/enlighten_pv.c | 3 | ||||
| -rw-r--r-- | arch/x86/xen/enlighten_pvh.c | 69 | ||||
| -rw-r--r-- | arch/x86/xen/mmu_pv.c | 14 | ||||
| -rw-r--r-- | arch/x86/xen/setup.c | 44 | ||||
| -rw-r--r-- | arch/x86/xen/smp.c | 2 | ||||
| -rw-r--r-- | arch/x86/xen/smp.h | 2 | ||||
| -rw-r--r-- | arch/x86/xen/smp_pv.c | 69 | ||||
| -rw-r--r-- | arch/x86/xen/vga.c | 1 | ||||
| -rw-r--r-- | arch/x86/xen/xen-asm.S | 10 | ||||
| -rw-r--r-- | arch/x86/xen/xen-head.S | 2 | ||||
| -rw-r--r-- | arch/x86/xen/xen-ops.h | 14 |
14 files changed, 177 insertions, 118 deletions
diff --git a/arch/x86/xen/apic.c b/arch/x86/xen/apic.c index 9dd5490b3318..8b045dd25196 100644 --- a/arch/x86/xen/apic.c +++ b/arch/x86/xen/apic.c @@ -33,12 +33,6 @@ static unsigned int xen_io_apic_read(unsigned apic, unsigned reg) return 0xfd; } -static u32 xen_set_apic_id(u32 x) -{ - WARN_ON(1); - return x; -} - static u32 xen_get_apic_id(u32 x) { return ((x)>>24) & 0xFFu; @@ -49,20 +43,20 @@ static u32 xen_apic_read(u32 reg) struct xen_platform_op op = { .cmd = XENPF_get_cpuinfo, .interface_version = XENPF_INTERFACE_VERSION, - .u.pcpu_info.xen_cpuid = 0, }; - int ret; - - /* Shouldn't need this as APIC is turned off for PV, and we only - * get called on the bootup processor. But just in case. */ - if (!xen_initial_domain() || smp_processor_id()) - return 0; + int ret, cpu; if (reg == APIC_LVR) return 0x14; if (reg != APIC_ID) return 0; + cpu = smp_processor_id(); + if (!xen_initial_domain()) + return cpu ? cpuid_to_apicid[cpu] << 24 : 0; + + op.u.pcpu_info.xen_cpuid = cpu; + ret = HYPERVISOR_platform_op(&op); if (ret) op.u.pcpu_info.apic_id = BAD_APICID; @@ -110,11 +104,6 @@ static int xen_madt_oem_check(char *oem_id, char *oem_table_id) return xen_pv_domain(); } -static u32 xen_phys_pkg_id(u32 initial_apic_id, int index_msb) -{ - return initial_apic_id >> index_msb; -} - static u32 xen_cpu_present_to_apicid(int cpu) { if (cpu_present(cpu)) @@ -133,11 +122,9 @@ static struct apic xen_pv_apic __ro_after_init = { .disable_esr = 0, .cpu_present_to_apicid = xen_cpu_present_to_apicid, - .phys_pkg_id = xen_phys_pkg_id, /* detect_ht */ .max_apic_id = UINT_MAX, .get_apic_id = xen_get_apic_id, - .set_apic_id = xen_set_apic_id, .calc_dest_apicid = apic_flat_calc_apicid, diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index 3c61bb98c10e..a01ca255b0c6 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -6,6 +6,7 @@ #include <linux/console.h> #include <linux/cpu.h> #include <linux/kexec.h> +#include <linux/memblock.h> #include <linux/slab.h> #include <linux/panic_notifier.h> @@ -350,3 +351,34 @@ void xen_arch_unregister_cpu(int num) } EXPORT_SYMBOL(xen_arch_unregister_cpu); #endif + +/* Amount of extra memory space we add to the e820 ranges */ +struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata; + +void __init xen_add_extra_mem(unsigned long start_pfn, unsigned long n_pfns) +{ + unsigned int i; + + /* + * No need to check for zero size, should happen rarely and will only + * write a new entry regarded to be unused due to zero size. + */ + for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) { + /* Add new region. */ + if (xen_extra_mem[i].n_pfns == 0) { + xen_extra_mem[i].start_pfn = start_pfn; + xen_extra_mem[i].n_pfns = n_pfns; + break; + } + /* Append to existing region. */ + if (xen_extra_mem[i].start_pfn + xen_extra_mem[i].n_pfns == + start_pfn) { + xen_extra_mem[i].n_pfns += n_pfns; + break; + } + } + if (i == XEN_EXTRA_MEM_MAX_REGIONS) + printk(KERN_WARNING "Warning: not enough extra memory regions\n"); + + memblock_reserve(PFN_PHYS(start_pfn), PFN_PHYS(n_pfns)); +} diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c index 3f8c34707c50..c001a2296582 100644 --- a/arch/x86/xen/enlighten_hvm.c +++ b/arch/x86/xen/enlighten_hvm.c @@ -148,7 +148,9 @@ static void xen_hvm_shutdown(void) if (kexec_in_progress) xen_reboot(SHUTDOWN_soft_reset); } +#endif +#ifdef CONFIG_CRASH_DUMP static void xen_hvm_crash_shutdown(struct pt_regs *regs) { native_machine_crash_shutdown(regs); @@ -168,7 +170,7 @@ static int xen_cpu_up_prepare_hvm(unsigned int cpu) */ xen_uninit_lock_cpu(cpu); - if (cpu_acpi_id(cpu) != U32_MAX) + if (cpu_acpi_id(cpu) != CPU_ACPIID_INVALID) per_cpu(xen_vcpu_id, cpu) = cpu_acpi_id(cpu); else per_cpu(xen_vcpu_id, cpu) = cpu; @@ -236,6 +238,8 @@ static void __init xen_hvm_guest_init(void) #ifdef CONFIG_KEXEC_CORE machine_ops.shutdown = xen_hvm_shutdown; +#endif +#ifdef CONFIG_CRASH_DUMP machine_ops.crash_shutdown = xen_hvm_crash_shutdown; #endif } diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c index aeb33e0a3f76..ace2eb054053 100644 --- a/arch/x86/xen/enlighten_pv.c +++ b/arch/x86/xen/enlighten_pv.c @@ -200,6 +200,9 @@ static void __init xen_pv_init_platform(void) xen_set_mtrr_data(); else mtrr_overwrite_state(NULL, 0, MTRR_TYPE_WRBACK); + + /* Adjust nr_cpu_ids before "enumeration" happens */ + xen_smp_count_cpus(); } static void __init xen_pv_guest_late_init(void) diff --git a/arch/x86/xen/enlighten_pvh.c b/arch/x86/xen/enlighten_pvh.c index ada3868c02c2..27a2a02ef8fb 100644 --- a/arch/x86/xen/enlighten_pvh.c +++ b/arch/x86/xen/enlighten_pvh.c @@ -1,9 +1,11 @@ // SPDX-License-Identifier: GPL-2.0 #include <linux/acpi.h> #include <linux/export.h> +#include <linux/mm.h> #include <xen/hvc-console.h> +#include <asm/bootparam.h> #include <asm/io_apic.h> #include <asm/hypervisor.h> #include <asm/e820/api.h> @@ -72,3 +74,70 @@ void __init mem_map_via_hcall(struct boot_params *boot_params_p) } boot_params_p->e820_entries = memmap.nr_entries; } + +/* + * Reserve e820 UNUSABLE regions to inflate the memory balloon. + * + * On PVH dom0 the host memory map is used, RAM regions available to dom0 are + * located as the same place as in the native memory map, but since dom0 gets + * less memory than the total amount of host RAM the ranges that can't be + * populated are converted from RAM -> UNUSABLE. Use such regions (up to the + * ratio signaled in EXTRA_MEM_RATIO) in order to inflate the balloon driver at + * boot. Doing so prevents the guest (even if just temporary) from using holes + * in the memory map in order to map grants or foreign addresses, and + * hopefully limits the risk of a clash with a device MMIO region. Ideally the + * hypervisor should notify us which memory ranges are suitable for creating + * foreign mappings, but that's not yet implemented. + */ +void __init xen_reserve_extra_memory(struct boot_params *bootp) +{ + unsigned int i, ram_pages = 0, extra_pages; + + for (i = 0; i < bootp->e820_entries; i++) { + struct boot_e820_entry *e = &bootp->e820_table[i]; + + if (e->type != E820_TYPE_RAM) + continue; + ram_pages += PFN_DOWN(e->addr + e->size) - PFN_UP(e->addr); + } + + /* Max amount of extra memory. */ + extra_pages = EXTRA_MEM_RATIO * ram_pages; + + /* + * Convert UNUSABLE ranges to RAM and reserve them for foreign mapping + * purposes. + */ + for (i = 0; i < bootp->e820_entries && extra_pages; i++) { + struct boot_e820_entry *e = &bootp->e820_table[i]; + unsigned long pages; + + if (e->type != E820_TYPE_UNUSABLE) + continue; + + pages = min(extra_pages, + PFN_DOWN(e->addr + e->size) - PFN_UP(e->addr)); + + if (pages != (PFN_DOWN(e->addr + e->size) - PFN_UP(e->addr))) { + struct boot_e820_entry *next; + + if (bootp->e820_entries == + ARRAY_SIZE(bootp->e820_table)) + /* No space left to split - skip region. */ + continue; + + /* Split entry. */ + next = e + 1; + memmove(next, e, + (bootp->e820_entries - i) * sizeof(*e)); + bootp->e820_entries++; + next->addr = PAGE_ALIGN(e->addr) + PFN_PHYS(pages); + e->size = next->addr - e->addr; + next->size -= e->size; + } + e->type = E820_TYPE_RAM; + extra_pages -= pages; + + xen_add_extra_mem(PFN_UP(e->addr), pages); + } +} diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c index 72af496a160c..54e0d311dcc9 100644 --- a/arch/x86/xen/mmu_pv.c +++ b/arch/x86/xen/mmu_pv.c @@ -913,7 +913,7 @@ static void drop_mm_ref_this_cpu(void *info) struct mm_struct *mm = info; if (this_cpu_read(cpu_tlbstate.loaded_mm) == mm) - leave_mm(smp_processor_id()); + leave_mm(); /* * If this cpu still has a stale cr3 reference, then make sure @@ -1059,7 +1059,7 @@ static void __init xen_cleanmfnmap_pmd(pmd_t *pmd, bool unpin) pte_t *pte_tbl; int i; - if (pmd_large(*pmd)) { + if (pmd_leaf(*pmd)) { pa = pmd_val(*pmd) & PHYSICAL_PAGE_MASK; xen_free_ro_pages(pa, PMD_SIZE); return; @@ -1082,7 +1082,7 @@ static void __init xen_cleanmfnmap_pud(pud_t *pud, bool unpin) pmd_t *pmd_tbl; int i; - if (pud_large(*pud)) { + if (pud_leaf(*pud)) { pa = pud_val(*pud) & PHYSICAL_PAGE_MASK; xen_free_ro_pages(pa, PUD_SIZE); return; @@ -1104,7 +1104,7 @@ static void __init xen_cleanmfnmap_p4d(p4d_t *p4d, bool unpin) pud_t *pud_tbl; int i; - if (p4d_large(*p4d)) { + if (p4d_leaf(*p4d)) { pa = p4d_val(*p4d) & PHYSICAL_PAGE_MASK; xen_free_ro_pages(pa, P4D_SIZE); return; @@ -1863,7 +1863,7 @@ static phys_addr_t __init xen_early_virt_to_phys(unsigned long vaddr) if (!pud_present(pud)) return 0; pa = pud_val(pud) & PTE_PFN_MASK; - if (pud_large(pud)) + if (pud_leaf(pud)) return pa + (vaddr & ~PUD_MASK); pmd = native_make_pmd(xen_read_phys_ulong(pa + pmd_index(vaddr) * @@ -1871,7 +1871,7 @@ static phys_addr_t __init xen_early_virt_to_phys(unsigned long vaddr) if (!pmd_present(pmd)) return 0; pa = pmd_val(pmd) & PTE_PFN_MASK; - if (pmd_large(pmd)) + if (pmd_leaf(pmd)) return pa + (vaddr & ~PMD_MASK); pte = native_make_pte(xen_read_phys_ulong(pa + pte_index(vaddr) * @@ -2520,7 +2520,7 @@ out: } EXPORT_SYMBOL_GPL(xen_remap_pfn); -#ifdef CONFIG_KEXEC_CORE +#ifdef CONFIG_VMCORE_INFO phys_addr_t paddr_vmcoreinfo_note(void) { if (xen_pv_domain()) diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c index b3e37961065a..380591028cb8 100644 --- a/arch/x86/xen/setup.c +++ b/arch/x86/xen/setup.c @@ -38,9 +38,6 @@ #define GB(x) ((uint64_t)(x) * 1024 * 1024 * 1024) -/* Amount of extra memory space we add to the e820 ranges */ -struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata; - /* Number of pages released from the initial allocation. */ unsigned long xen_released_pages; @@ -64,18 +61,6 @@ static struct { } xen_remap_buf __initdata __aligned(PAGE_SIZE); static unsigned long xen_remap_mfn __initdata = INVALID_P2M_ENTRY; -/* - * The maximum amount of extra memory compared to the base size. The - * main scaling factor is the size of struct page. At extreme ratios - * of base:extra, all the base memory can be filled with page - * structures for the extra memory, leaving no space for anything - * else. - * - * 10x seems like a reasonable balance between scaling flexibility and - * leaving a practically usable system. - */ -#define EXTRA_MEM_RATIO (10) - static bool xen_512gb_limit __initdata = IS_ENABLED(CONFIG_XEN_512GB); static void __init xen_parse_512gb(void) @@ -96,35 +81,6 @@ static void __init xen_parse_512gb(void) xen_512gb_limit = val; } -static void __init xen_add_extra_mem(unsigned long start_pfn, - unsigned long n_pfns) -{ - int i; - - /* - * No need to check for zero size, should happen rarely and will only - * write a new entry regarded to be unused due to zero size. - */ - for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) { - /* Add new region. */ - if (xen_extra_mem[i].n_pfns == 0) { - xen_extra_mem[i].start_pfn = start_pfn; - xen_extra_mem[i].n_pfns = n_pfns; - break; - } - /* Append to existing region. */ - if (xen_extra_mem[i].start_pfn + xen_extra_mem[i].n_pfns == - start_pfn) { - xen_extra_mem[i].n_pfns += n_pfns; - break; - } - } - if (i == XEN_EXTRA_MEM_MAX_REGIONS) - printk(KERN_WARNING "Warning: not enough extra memory regions\n"); - - memblock_reserve(PFN_PHYS(start_pfn), PFN_PHYS(n_pfns)); -} - static void __init xen_del_extra_mem(unsigned long start_pfn, unsigned long n_pfns) { diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c index 1fb9a1644d94..935771726f9c 100644 --- a/arch/x86/xen/smp.c +++ b/arch/x86/xen/smp.c @@ -135,8 +135,6 @@ void __init xen_smp_cpus_done(unsigned int max_cpus) { if (xen_hvm_domain()) native_smp_cpus_done(max_cpus); - else - calculate_max_logical_packages(); } void xen_smp_send_reschedule(int cpu) diff --git a/arch/x86/xen/smp.h b/arch/x86/xen/smp.h index c20cbb14c82b..b8efdbc693f7 100644 --- a/arch/x86/xen/smp.h +++ b/arch/x86/xen/smp.h @@ -19,6 +19,7 @@ extern void xen_smp_intr_free(unsigned int cpu); int xen_smp_intr_init_pv(unsigned int cpu); void xen_smp_intr_free_pv(unsigned int cpu); +void xen_smp_count_cpus(void); void xen_smp_cpus_done(unsigned int max_cpus); void xen_smp_send_reschedule(int cpu); @@ -44,6 +45,7 @@ static inline int xen_smp_intr_init_pv(unsigned int cpu) return 0; } static inline void xen_smp_intr_free_pv(unsigned int cpu) {} +static inline void xen_smp_count_cpus(void) { } #endif /* CONFIG_SMP */ #endif diff --git a/arch/x86/xen/smp_pv.c b/arch/x86/xen/smp_pv.c index a0f07bbfcd6e..27d1a5b7f571 100644 --- a/arch/x86/xen/smp_pv.c +++ b/arch/x86/xen/smp_pv.c @@ -29,6 +29,7 @@ #include <asm/idtentry.h> #include <asm/desc.h> #include <asm/cpu.h> +#include <asm/apic.h> #include <asm/io_apic.h> #include <xen/interface/xen.h> @@ -73,7 +74,6 @@ static void cpu_bringup(void) } cpu = smp_processor_id(); smp_store_cpu_info(cpu); - cpu_data(cpu).x86_max_cores = 1; set_cpu_sibling_map(cpu); speculative_store_bypass_ht_init(); @@ -149,39 +149,16 @@ int xen_smp_intr_init_pv(unsigned int cpu) return rc; } -static void __init _get_smp_config(unsigned int early) +static void __init xen_pv_smp_config(void) { - int i, rc; - unsigned int subtract = 0; - - if (early) - return; - - num_processors = 0; - disabled_cpus = 0; - for (i = 0; i < nr_cpu_ids; i++) { - rc = HYPERVISOR_vcpu_op(VCPUOP_is_up, i, NULL); - if (rc >= 0) { - num_processors++; - set_cpu_possible(i, true); - } else { - set_cpu_possible(i, false); - set_cpu_present(i, false); - subtract++; - } - } -#ifdef CONFIG_HOTPLUG_CPU - /* This is akin to using 'nr_cpus' on the Linux command line. - * Which is OK as when we use 'dom0_max_vcpus=X' we can only - * have up to X, while nr_cpu_ids is greater than X. This - * normally is not a problem, except when CPU hotplugging - * is involved and then there might be more than X CPUs - * in the guest - which will not work as there is no - * hypercall to expand the max number of VCPUs an already - * running guest has. So cap it up to X. */ - if (subtract) - set_nr_cpu_ids(nr_cpu_ids - subtract); -#endif + u32 apicid = 0; + int i; + + topology_register_boot_apic(apicid++); + + for (i = 1; i < nr_cpu_ids; i++) + topology_register_apic(apicid++, CPU_ACPIID_INVALID, true); + /* Pretend to be a proper enumerated system */ smp_found_config = 1; } @@ -224,8 +201,6 @@ static void __init xen_pv_smp_prepare_cpus(unsigned int max_cpus) smp_prepare_cpus_common(); - cpu_data(0).x86_max_cores = 1; - speculative_store_bypass_ht_init(); xen_pmu_init(0); @@ -434,6 +409,20 @@ static irqreturn_t xen_irq_work_interrupt(int irq, void *dev_id) return IRQ_HANDLED; } +void __init xen_smp_count_cpus(void) +{ + unsigned int cpus; + + for (cpus = 0; cpus < nr_cpu_ids; cpus++) { + if (HYPERVISOR_vcpu_op(VCPUOP_is_up, cpus, NULL) < 0) + break; + } + + pr_info("Xen PV: Detected %u vCPUS\n", cpus); + if (cpus < nr_cpu_ids) + set_nr_cpu_ids(cpus); +} + static const struct smp_ops xen_smp_ops __initconst = { .smp_prepare_boot_cpu = xen_pv_smp_prepare_boot_cpu, .smp_prepare_cpus = xen_pv_smp_prepare_cpus, @@ -458,6 +447,12 @@ void __init xen_smp_init(void) smp_ops = xen_smp_ops; /* Avoid searching for BIOS MP tables */ - x86_init.mpparse.find_smp_config = x86_init_noop; - x86_init.mpparse.get_smp_config = _get_smp_config; + x86_init.mpparse.find_mptable = x86_init_noop; + x86_init.mpparse.early_parse_smp_cfg = x86_init_noop; + + /* XEN/PV Dom0 has halfways sane topology information via CPUID/MADT */ + if (xen_initial_domain()) + x86_init.mpparse.parse_smp_cfg = x86_init_noop; + else + x86_init.mpparse.parse_smp_cfg = xen_pv_smp_config; } diff --git a/arch/x86/xen/vga.c b/arch/x86/xen/vga.c index d97adab8420f..f7547807b0bd 100644 --- a/arch/x86/xen/vga.c +++ b/arch/x86/xen/vga.c @@ -2,7 +2,6 @@ #include <linux/screen_info.h> #include <linux/init.h> -#include <asm/bootparam.h> #include <asm/setup.h> #include <xen/interface/xen.h> diff --git a/arch/x86/xen/xen-asm.S b/arch/x86/xen/xen-asm.S index 1a9cd18dfbd3..83189cf5cdce 100644 --- a/arch/x86/xen/xen-asm.S +++ b/arch/x86/xen/xen-asm.S @@ -28,7 +28,7 @@ * non-zero. */ SYM_FUNC_START(xen_irq_disable_direct) - movb $1, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask + movb $1, PER_CPU_VAR(xen_vcpu_info + XEN_vcpu_info_mask) RET SYM_FUNC_END(xen_irq_disable_direct) @@ -69,7 +69,7 @@ SYM_FUNC_END(check_events) SYM_FUNC_START(xen_irq_enable_direct) FRAME_BEGIN /* Unmask events */ - movb $0, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask + movb $0, PER_CPU_VAR(xen_vcpu_info + XEN_vcpu_info_mask) /* * Preempt here doesn't matter because that will deal with any @@ -78,7 +78,7 @@ SYM_FUNC_START(xen_irq_enable_direct) */ /* Test for pending */ - testb $0xff, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_pending + testb $0xff, PER_CPU_VAR(xen_vcpu_info + XEN_vcpu_info_pending) jz 1f call check_events @@ -97,7 +97,7 @@ SYM_FUNC_END(xen_irq_enable_direct) * x86 use opposite senses (mask vs enable). */ SYM_FUNC_START(xen_save_fl_direct) - testb $0xff, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask + testb $0xff, PER_CPU_VAR(xen_vcpu_info + XEN_vcpu_info_mask) setz %ah addb %ah, %ah RET @@ -113,7 +113,7 @@ SYM_FUNC_END(xen_read_cr2); SYM_FUNC_START(xen_read_cr2_direct) FRAME_BEGIN - _ASM_MOV PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_arch_cr2, %_ASM_AX + _ASM_MOV PER_CPU_VAR(xen_vcpu_info + XEN_vcpu_info_arch_cr2), %_ASM_AX FRAME_END RET SYM_FUNC_END(xen_read_cr2_direct); diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S index a0ea285878db..04101b984f24 100644 --- a/arch/x86/xen/xen-head.S +++ b/arch/x86/xen/xen-head.S @@ -49,7 +49,7 @@ SYM_CODE_START(startup_xen) ANNOTATE_NOENDBR cld - leaq (__end_init_task - PTREGS_SIZE)(%rip), %rsp + leaq (__end_init_task - TOP_OF_KERNEL_STACK_PADDING - PTREGS_SIZE)(%rip), %rsp /* Set up %gs. * diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h index a87ab36889e7..79cf93f2c92f 100644 --- a/arch/x86/xen/xen-ops.h +++ b/arch/x86/xen/xen-ops.h @@ -163,4 +163,18 @@ void xen_hvm_post_suspend(int suspend_cancelled); static inline void xen_hvm_post_suspend(int suspend_cancelled) {} #endif +/* + * The maximum amount of extra memory compared to the base size. The + * main scaling factor is the size of struct page. At extreme ratios + * of base:extra, all the base memory can be filled with page + * structures for the extra memory, leaving no space for anything + * else. + * + * 10x seems like a reasonable balance between scaling flexibility and + * leaving a practically usable system. + */ +#define EXTRA_MEM_RATIO (10) + +void xen_add_extra_mem(unsigned long start_pfn, unsigned long n_pfns); + #endif /* XEN_OPS_H */ |