| Message ID | 1253839640-12695-4-git-send-email-zamsden@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 09/25/2009 03:47 AM, Zachary Amsden wrote: > Both VMX and SVM require per-cpu memory allocation, which is done at module > init time, for only online cpus. When bringing a new CPU online, we must > also allocate this structure. The method chosen to implement this is to > make the CPU online notifier available via a call to the arch code. This > allows memory allocation to be done smoothly, without any need to allocate > extra structures. > > Note: CPU up notifiers may call KVM callback before calling cpufreq callbacks. > This would causes the CPU frequency not to be detected (and it is not always > clear on non-constant TSC platforms what the bringup TSC rate will be, so the > guess of using tsc_khz could be wrong). So, we clear the rate to zero in such > a case and add logic to query it upon entry. > > Signed-off-by: Zachary Amsden<zamsden@redhat.com> > --- > arch/x86/include/asm/kvm_host.h | 2 ++ > arch/x86/kvm/svm.c | 15 +++++++++++++-- > arch/x86/kvm/vmx.c | 17 +++++++++++++++++ > arch/x86/kvm/x86.c | 13 +++++++++---- > include/linux/kvm_host.h | 6 ++++++ > virt/kvm/kvm_main.c | 6 ++---- > 6 files changed, 49 insertions(+), 10 deletions(-) > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index 299cc1b..b7dd14b 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -459,6 +459,7 @@ struct descriptor_table { > struct kvm_x86_ops { > int (*cpu_has_kvm_support)(void); /* __init */ > int (*disabled_by_bios)(void); /* __init */ > + int (*cpu_hotadd)(int cpu); > int (*hardware_enable)(void *dummy); > void (*hardware_disable)(void *dummy); > void (*check_processor_compatibility)(void *rtn); > @@ -791,6 +792,7 @@ asmlinkage void kvm_handle_fault_on_reboot(void); > _ASM_PTR " 666b, 667b \n\t" \ > ".popsection" > > +#define KVM_ARCH_WANT_HOTPLUG_NOTIFIER > #define KVM_ARCH_WANT_MMU_NOTIFIER > int kvm_unmap_hva(struct kvm *kvm, unsigned long hva); > int kvm_age_hva(struct kvm *kvm, unsigned long hva); > diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c > index 9a4daca..8f99d0c 100644 > --- a/arch/x86/kvm/svm.c > +++ b/arch/x86/kvm/svm.c > @@ -330,13 +330,13 @@ static int svm_hardware_enable(void *garbage) > return -EBUSY; > > if (!has_svm()) { > - printk(KERN_ERR "svm_cpu_init: err EOPNOTSUPP on %d\n", me); > + printk(KERN_ERR "svm_hardware_enable: err EOPNOTSUPP on %d\n", me); > return -EINVAL; > } > svm_data = per_cpu(svm_data, me); > > if (!svm_data) { > - printk(KERN_ERR "svm_cpu_init: svm_data is NULL on %d\n", > + printk(KERN_ERR "svm_hardware_enable: svm_data is NULL on %d\n", > me); > return -EINVAL; > } > @@ -394,6 +394,16 @@ err_1: > > } > > +static __cpuinit int svm_cpu_hotadd(int cpu) > +{ > + struct svm_cpu_data *svm_data = per_cpu(svm_data, cpu); > + > + if (svm_data) > + return 0; > + > + return svm_cpu_init(cpu); > +} > + > static void set_msr_interception(u32 *msrpm, unsigned msr, > int read, int write) > { > @@ -2858,6 +2868,7 @@ static struct kvm_x86_ops svm_x86_ops = { > .hardware_setup = svm_hardware_setup, > .hardware_unsetup = svm_hardware_unsetup, > .check_processor_compatibility = svm_check_processor_compat, > + .cpu_hotadd = svm_cpu_hotadd, > .hardware_enable = svm_hardware_enable, > .hardware_disable = svm_hardware_disable, > .cpu_has_accelerated_tpr = svm_cpu_has_accelerated_tpr, > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 3fe0d42..b8a8428 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -1408,6 +1408,22 @@ static __exit void hardware_unsetup(void) > free_kvm_area(); > } > > +static __cpuinit int vmx_cpu_hotadd(int cpu) > +{ > + struct vmcs *vmcs; > + > + if (per_cpu(vmxarea, cpu)) > + return 0; > + > + vmcs = alloc_vmcs_cpu(cpu); > + if (!vmcs) > + return -ENOMEM; > + > + per_cpu(vmxarea, cpu) = vmcs; > + > + return 0; > +} > + > static void fix_pmode_dataseg(int seg, struct kvm_save_segment *save) > { > struct kvm_vmx_segment_field *sf =&kvm_vmx_segment_fields[seg]; > @@ -3925,6 +3941,7 @@ static struct kvm_x86_ops vmx_x86_ops = { > .hardware_setup = hardware_setup, > .hardware_unsetup = hardware_unsetup, > .check_processor_compatibility = vmx_check_processor_compat, > + .cpu_hotadd = vmx_cpu_hotadd, > .hardware_enable = hardware_enable, > .hardware_disable = hardware_disable, > .cpu_has_accelerated_tpr = report_flexpriority, > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index c18e2fc..66c6bb9 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -1326,6 +1326,8 @@ out: > void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) > { > kvm_x86_ops->vcpu_load(vcpu, cpu); > + if (unlikely(per_cpu(cpu_tsc_khz, cpu) == 0)) > + per_cpu(cpu_tsc_khz, cpu) = cpufreq_quick_get(cpu); > kvm_request_guest_time_update(vcpu); > } > > @@ -4699,12 +4701,15 @@ int kvm_arch_vcpu_reset(struct kvm_vcpu *vcpu) > return kvm_x86_ops->vcpu_reset(vcpu); > } > > +int kvm_arch_cpu_hotadd(int cpu) > +{ > + if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC)) > + per_cpu(cpu_tsc_khz, cpu) = 0; > + return kvm_x86_ops->cpu_hotadd(cpu); > +} > + > int kvm_arch_hardware_enable(void *garbage) > { > - if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC)) { > - int cpu = raw_smp_processor_id(); > - per_cpu(cpu_tsc_khz, cpu) = cpufreq_quick_get(cpu); > - } > return kvm_x86_ops->hardware_enable(garbage); > } > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index 0bf9ee9..2f075c4 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -345,6 +345,12 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id); > int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu); > void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu); > > +#ifdef KVM_ARCH_WANT_HOTPLUG_NOTIFIER > +int kvm_arch_cpu_hotadd(int cpu); > +#else > +#define kvm_arch_cpu_hotadd(x) (0) > +#endif > + > int kvm_arch_vcpu_reset(struct kvm_vcpu *vcpu); > int kvm_arch_hardware_enable(void *garbage); > void kvm_arch_hardware_disable(void *garbage); > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index e27b7a9..7818b51 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -1716,9 +1716,6 @@ static int kvm_cpu_hotplug(struct notifier_block *notifier, unsigned long val, > { > int cpu = (long)v; > > - if (!kvm_usage_count) > - return NOTIFY_OK; > - > Why? You'll now do hardware_enable() even if kvm is not in use. > val&= ~CPU_TASKS_FROZEN; > switch (val) { > case CPU_DYING: > @@ -1734,7 +1731,8 @@ static int kvm_cpu_hotplug(struct notifier_block *notifier, unsigned long val, > case CPU_ONLINE: > printk(KERN_INFO "kvm: enabling virtualization on CPU%d\n", > cpu); > - smp_call_function_single(cpu, hardware_enable, NULL, 1); > + if (!kvm_arch_cpu_hotadd(cpu)) > + smp_call_function_single(cpu, hardware_enable, NULL, 1); > break; > } > if (!blah) when blah is not a boolean or a pointer is confusing.
On 09/26/2009 10:52 PM, Avi Kivity wrote: > On 09/25/2009 03:47 AM, Zachary Amsden wrote: >> >> --- a/virt/kvm/kvm_main.c >> +++ b/virt/kvm/kvm_main.c >> @@ -1716,9 +1716,6 @@ static int kvm_cpu_hotplug(struct >> notifier_block *notifier, unsigned long val, >> { >> int cpu = (long)v; >> >> - if (!kvm_usage_count) >> - return NOTIFY_OK; >> - > > Why? You'll now do hardware_enable() even if kvm is not in use. Because otherwise you'll never allocate and hardware_enable_all will fail: Switch to broadcast mode on CPU1 svm_hardware_enable: svm_data is NULL on 1 kvm: enabling virtualization on CPU1 failed qemu-system-x86[8698]: segfault at 20 ip 00000000004db22f sp 00007fff0a3b4560 error 6 in qemu-system-x86_64[400000+21f000] Perhaps I can make this work better by putting the allocation within hardware_enable_all. Zach -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 299cc1b..b7dd14b 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -459,6 +459,7 @@ struct descriptor_table { struct kvm_x86_ops { int (*cpu_has_kvm_support)(void); /* __init */ int (*disabled_by_bios)(void); /* __init */ + int (*cpu_hotadd)(int cpu); int (*hardware_enable)(void *dummy); void (*hardware_disable)(void *dummy); void (*check_processor_compatibility)(void *rtn); @@ -791,6 +792,7 @@ asmlinkage void kvm_handle_fault_on_reboot(void); _ASM_PTR " 666b, 667b \n\t" \ ".popsection" +#define KVM_ARCH_WANT_HOTPLUG_NOTIFIER #define KVM_ARCH_WANT_MMU_NOTIFIER int kvm_unmap_hva(struct kvm *kvm, unsigned long hva); int kvm_age_hva(struct kvm *kvm, unsigned long hva); diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 9a4daca..8f99d0c 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -330,13 +330,13 @@ static int svm_hardware_enable(void *garbage) return -EBUSY; if (!has_svm()) { - printk(KERN_ERR "svm_cpu_init: err EOPNOTSUPP on %d\n", me); + printk(KERN_ERR "svm_hardware_enable: err EOPNOTSUPP on %d\n", me); return -EINVAL; } svm_data = per_cpu(svm_data, me); if (!svm_data) { - printk(KERN_ERR "svm_cpu_init: svm_data is NULL on %d\n", + printk(KERN_ERR "svm_hardware_enable: svm_data is NULL on %d\n", me); return -EINVAL; } @@ -394,6 +394,16 @@ err_1: } +static __cpuinit int svm_cpu_hotadd(int cpu) +{ + struct svm_cpu_data *svm_data = per_cpu(svm_data, cpu); + + if (svm_data) + return 0; + + return svm_cpu_init(cpu); +} + static void set_msr_interception(u32 *msrpm, unsigned msr, int read, int write) { @@ -2858,6 +2868,7 @@ static struct kvm_x86_ops svm_x86_ops = { .hardware_setup = svm_hardware_setup, .hardware_unsetup = svm_hardware_unsetup, .check_processor_compatibility = svm_check_processor_compat, + .cpu_hotadd = svm_cpu_hotadd, .hardware_enable = svm_hardware_enable, .hardware_disable = svm_hardware_disable, .cpu_has_accelerated_tpr = svm_cpu_has_accelerated_tpr, diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 3fe0d42..b8a8428 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -1408,6 +1408,22 @@ static __exit void hardware_unsetup(void) free_kvm_area(); } +static __cpuinit int vmx_cpu_hotadd(int cpu) +{ + struct vmcs *vmcs; + + if (per_cpu(vmxarea, cpu)) + return 0; + + vmcs = alloc_vmcs_cpu(cpu); + if (!vmcs) + return -ENOMEM; + + per_cpu(vmxarea, cpu) = vmcs; + + return 0; +} + static void fix_pmode_dataseg(int seg, struct kvm_save_segment *save) { struct kvm_vmx_segment_field *sf = &kvm_vmx_segment_fields[seg]; @@ -3925,6 +3941,7 @@ static struct kvm_x86_ops vmx_x86_ops = { .hardware_setup = hardware_setup, .hardware_unsetup = hardware_unsetup, .check_processor_compatibility = vmx_check_processor_compat, + .cpu_hotadd = vmx_cpu_hotadd, .hardware_enable = hardware_enable, .hardware_disable = hardware_disable, .cpu_has_accelerated_tpr = report_flexpriority, diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index c18e2fc..66c6bb9 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1326,6 +1326,8 @@ out: void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) { kvm_x86_ops->vcpu_load(vcpu, cpu); + if (unlikely(per_cpu(cpu_tsc_khz, cpu) == 0)) + per_cpu(cpu_tsc_khz, cpu) = cpufreq_quick_get(cpu); kvm_request_guest_time_update(vcpu); } @@ -4699,12 +4701,15 @@ int kvm_arch_vcpu_reset(struct kvm_vcpu *vcpu) return kvm_x86_ops->vcpu_reset(vcpu); } +int kvm_arch_cpu_hotadd(int cpu) +{ + if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC)) + per_cpu(cpu_tsc_khz, cpu) = 0; + return kvm_x86_ops->cpu_hotadd(cpu); +} + int kvm_arch_hardware_enable(void *garbage) { - if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC)) { - int cpu = raw_smp_processor_id(); - per_cpu(cpu_tsc_khz, cpu) = cpufreq_quick_get(cpu); - } return kvm_x86_ops->hardware_enable(garbage); } diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 0bf9ee9..2f075c4 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -345,6 +345,12 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id); int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu); void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu); +#ifdef KVM_ARCH_WANT_HOTPLUG_NOTIFIER +int kvm_arch_cpu_hotadd(int cpu); +#else +#define kvm_arch_cpu_hotadd(x) (0) +#endif + int kvm_arch_vcpu_reset(struct kvm_vcpu *vcpu); int kvm_arch_hardware_enable(void *garbage); void kvm_arch_hardware_disable(void *garbage); diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index e27b7a9..7818b51 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1716,9 +1716,6 @@ static int kvm_cpu_hotplug(struct notifier_block *notifier, unsigned long val, { int cpu = (long)v; - if (!kvm_usage_count) - return NOTIFY_OK; - val &= ~CPU_TASKS_FROZEN; switch (val) { case CPU_DYING: @@ -1734,7 +1731,8 @@ static int kvm_cpu_hotplug(struct notifier_block *notifier, unsigned long val, case CPU_ONLINE: printk(KERN_INFO "kvm: enabling virtualization on CPU%d\n", cpu); - smp_call_function_single(cpu, hardware_enable, NULL, 1); + if (!kvm_arch_cpu_hotadd(cpu)) + smp_call_function_single(cpu, hardware_enable, NULL, 1); break; } return NOTIFY_OK;
Both VMX and SVM require per-cpu memory allocation, which is done at module init time, for only online cpus. When bringing a new CPU online, we must also allocate this structure. The method chosen to implement this is to make the CPU online notifier available via a call to the arch code. This allows memory allocation to be done smoothly, without any need to allocate extra structures. Note: CPU up notifiers may call KVM callback before calling cpufreq callbacks. This would causes the CPU frequency not to be detected (and it is not always clear on non-constant TSC platforms what the bringup TSC rate will be, so the guess of using tsc_khz could be wrong). So, we clear the rate to zero in such a case and add logic to query it upon entry. Signed-off-by: Zachary Amsden <zamsden@redhat.com> --- arch/x86/include/asm/kvm_host.h | 2 ++ arch/x86/kvm/svm.c | 15 +++++++++++++-- arch/x86/kvm/vmx.c | 17 +++++++++++++++++ arch/x86/kvm/x86.c | 13 +++++++++---- include/linux/kvm_host.h | 6 ++++++ virt/kvm/kvm_main.c | 6 ++---- 6 files changed, 49 insertions(+), 10 deletions(-)