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author | Jeremy Fitzhardinge <jeremy@xensource.com> | 2007-07-18 03:37:06 +0200 |
---|---|---|
committer | Jeremy Fitzhardinge <jeremy@goop.org> | 2007-07-18 17:47:44 +0200 |
commit | f87e4cac4f4e940b328d3deb5b53e642e3881f43 (patch) | |
tree | 7409f86561e5f97459378abd2ae21e9a5c82bfea /arch/i386/xen/enlighten.c | |
parent | xen: Implement sched_clock (diff) | |
download | linux-f87e4cac4f4e940b328d3deb5b53e642e3881f43.tar.xz linux-f87e4cac4f4e940b328d3deb5b53e642e3881f43.zip |
xen: SMP guest support
This is a fairly straightforward Xen implementation of smp_ops.
Xen has its own IPI mechanisms, and has no dependency on any
APIC-based IPI. The smp_ops hooks and the flush_tlb_others pv_op
allow a Xen guest to avoid all APIC code in arch/i386 (the only apic
operation is a single apic_read for the apic version number).
One subtle point which needs to be addressed is unpinning pagetables
when another cpu may have a lazy tlb reference to the pagetable. Xen
will not allow an in-use pagetable to be unpinned, so we must find any
other cpus with a reference to the pagetable and get them to shoot
down their references.
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Andi Kleen <ak@suse.de>
Diffstat (limited to 'arch/i386/xen/enlighten.c')
-rw-r--r-- | arch/i386/xen/enlighten.c | 115 |
1 files changed, 89 insertions, 26 deletions
diff --git a/arch/i386/xen/enlighten.c b/arch/i386/xen/enlighten.c index a9ba834295a2..de62d66e0893 100644 --- a/arch/i386/xen/enlighten.c +++ b/arch/i386/xen/enlighten.c @@ -24,6 +24,7 @@ #include <linux/mm.h> #include <linux/page-flags.h> #include <linux/highmem.h> +#include <linux/smp.h> #include <xen/interface/xen.h> #include <xen/interface/physdev.h> @@ -40,6 +41,7 @@ #include <asm/setup.h> #include <asm/desc.h> #include <asm/pgtable.h> +#include <asm/tlbflush.h> #include "xen-ops.h" #include "mmu.h" @@ -56,7 +58,7 @@ DEFINE_PER_CPU(unsigned long, xen_cr3); struct start_info *xen_start_info; EXPORT_SYMBOL_GPL(xen_start_info); -static void xen_vcpu_setup(int cpu) +void xen_vcpu_setup(int cpu) { per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu]; } @@ -347,23 +349,14 @@ static void xen_write_idt_entry(struct desc_struct *dt, int entrynum, } } -/* Load a new IDT into Xen. In principle this can be per-CPU, so we - hold a spinlock to protect the static traps[] array (static because - it avoids allocation, and saves stack space). */ -static void xen_load_idt(const struct Xgt_desc_struct *desc) +static void xen_convert_trap_info(const struct Xgt_desc_struct *desc, + struct trap_info *traps) { - static DEFINE_SPINLOCK(lock); - static struct trap_info traps[257]; - - int cpu = smp_processor_id(); unsigned in, out, count; - per_cpu(idt_desc, cpu) = *desc; - count = (desc->size+1) / 8; BUG_ON(count > 256); - spin_lock(&lock); for (in = out = 0; in < count; in++) { const u32 *entry = (u32 *)(desc->address + in * 8); @@ -371,6 +364,31 @@ static void xen_load_idt(const struct Xgt_desc_struct *desc) out++; } traps[out].address = 0; +} + +void xen_copy_trap_info(struct trap_info *traps) +{ + const struct Xgt_desc_struct *desc = &get_cpu_var(idt_desc); + + xen_convert_trap_info(desc, traps); + + put_cpu_var(idt_desc); +} + +/* Load a new IDT into Xen. In principle this can be per-CPU, so we + hold a spinlock to protect the static traps[] array (static because + it avoids allocation, and saves stack space). */ +static void xen_load_idt(const struct Xgt_desc_struct *desc) +{ + static DEFINE_SPINLOCK(lock); + static struct trap_info traps[257]; + int cpu = smp_processor_id(); + + per_cpu(idt_desc, cpu) = *desc; + + spin_lock(&lock); + + xen_convert_trap_info(desc, traps); xen_mc_flush(); if (HYPERVISOR_set_trap_table(traps)) @@ -428,6 +446,12 @@ static unsigned long xen_apic_read(unsigned long reg) { return 0; } + +static void xen_apic_write(unsigned long reg, unsigned long val) +{ + /* Warn to see if there's any stray references */ + WARN_ON(1); +} #endif static void xen_flush_tlb(void) @@ -449,6 +473,40 @@ static void xen_flush_tlb_single(unsigned long addr) BUG(); } +static void xen_flush_tlb_others(const cpumask_t *cpus, struct mm_struct *mm, + unsigned long va) +{ + struct mmuext_op op; + cpumask_t cpumask = *cpus; + + /* + * A couple of (to be removed) sanity checks: + * + * - current CPU must not be in mask + * - mask must exist :) + */ + BUG_ON(cpus_empty(cpumask)); + BUG_ON(cpu_isset(smp_processor_id(), cpumask)); + BUG_ON(!mm); + + /* If a CPU which we ran on has gone down, OK. */ + cpus_and(cpumask, cpumask, cpu_online_map); + if (cpus_empty(cpumask)) + return; + + if (va == TLB_FLUSH_ALL) { + op.cmd = MMUEXT_TLB_FLUSH_MULTI; + op.arg2.vcpumask = (void *)cpus; + } else { + op.cmd = MMUEXT_INVLPG_MULTI; + op.arg1.linear_addr = va; + op.arg2.vcpumask = (void *)cpus; + } + + if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF)) + BUG(); +} + static unsigned long xen_read_cr2(void) { return x86_read_percpu(xen_vcpu)->arch.cr2; @@ -460,18 +518,6 @@ static void xen_write_cr4(unsigned long cr4) native_write_cr4(cr4 & ~X86_CR4_TSD); } -/* - * Page-directory addresses above 4GB do not fit into architectural %cr3. - * When accessing %cr3, or equivalent field in vcpu_guest_context, guests - * must use the following accessor macros to pack/unpack valid MFNs. - * - * Note that Xen is using the fact that the pagetable base is always - * page-aligned, and putting the 12 MSB of the address into the 12 LSB - * of cr3. - */ -#define xen_pfn_to_cr3(pfn) (((unsigned)(pfn) << 12) | ((unsigned)(pfn) >> 20)) -#define xen_cr3_to_pfn(cr3) (((unsigned)(cr3) >> 12) | ((unsigned)(cr3) << 20)) - static unsigned long xen_read_cr3(void) { return x86_read_percpu(xen_cr3); @@ -740,8 +786,8 @@ static const struct paravirt_ops xen_paravirt_ops __initdata = { .io_delay = xen_io_delay, #ifdef CONFIG_X86_LOCAL_APIC - .apic_write = paravirt_nop, - .apic_write_atomic = paravirt_nop, + .apic_write = xen_apic_write, + .apic_write_atomic = xen_apic_write, .apic_read = xen_apic_read, .setup_boot_clock = paravirt_nop, .setup_secondary_clock = paravirt_nop, @@ -751,6 +797,7 @@ static const struct paravirt_ops xen_paravirt_ops __initdata = { .flush_tlb_user = xen_flush_tlb, .flush_tlb_kernel = xen_flush_tlb, .flush_tlb_single = xen_flush_tlb_single, + .flush_tlb_others = xen_flush_tlb_others, .pte_update = paravirt_nop, .pte_update_defer = paravirt_nop, @@ -796,6 +843,19 @@ static const struct paravirt_ops xen_paravirt_ops __initdata = { .set_lazy_mode = xen_set_lazy_mode, }; +#ifdef CONFIG_SMP +static const struct smp_ops xen_smp_ops __initdata = { + .smp_prepare_boot_cpu = xen_smp_prepare_boot_cpu, + .smp_prepare_cpus = xen_smp_prepare_cpus, + .cpu_up = xen_cpu_up, + .smp_cpus_done = xen_smp_cpus_done, + + .smp_send_stop = xen_smp_send_stop, + .smp_send_reschedule = xen_smp_send_reschedule, + .smp_call_function_mask = xen_smp_call_function_mask, +}; +#endif /* CONFIG_SMP */ + /* First C function to be called on Xen boot */ asmlinkage void __init xen_start_kernel(void) { @@ -808,6 +868,9 @@ asmlinkage void __init xen_start_kernel(void) /* Install Xen paravirt ops */ paravirt_ops = xen_paravirt_ops; +#ifdef CONFIG_SMP + smp_ops = xen_smp_ops; +#endif xen_setup_features(); |