On Wed, Nov 21, 2012 at 11:27:19PM +0800, Zhang Yanfei wrote:
> The notifier will be registered in vmclear_notifier_list when loading
> kvm-intel module. And the bitmap indicates whether we should do
> VMCLEAR operation in kdump. The bits in the bitmap are set/unset
> according to different conditions.
>
> Signed-off-by: Zhang Yanfei <zhangyanfei@xxxxxxxxxxxxxx>
> ---
> arch/x86/kvm/vmx.c | 77 +++++++++++++++++++++++++++++++++++++++++++++++++++-
> 1 files changed, 76 insertions(+), 1 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 4ff0ab9..eea55b3 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -41,6 +41,7 @@
> #include <asm/i387.h>
> #include <asm/xcr.h>
> #include <asm/perf_event.h>
> +#include <asm/kexec.h>
>
> #include "trace.h"
>
> @@ -963,6 +964,49 @@ static void vmcs_load(struct vmcs *vmcs)
> vmcs, phys_addr);
> }
>
> +#ifdef CONFIG_KEXEC
> +/*
> + * This bitmap is used to indicate whether the vmclear
> + * operation is enabled on all cpus. All disabled by
> + * default.
> + */
> +static cpumask_t crash_vmclear_enabled_bitmap = CPU_MASK_NONE;
> +
> +static inline void crash_enable_local_vmclear(int cpu)
> +{
> + cpumask_set_cpu(cpu, &crash_vmclear_enabled_bitmap);
> +}
> +
> +static inline void crash_disable_local_vmclear(int cpu)
> +{
> + cpumask_clear_cpu(cpu, &crash_vmclear_enabled_bitmap);
> +}
> +
> +static inline int crash_local_vmclear_enabled(int cpu)
> +{
> + return cpumask_test_cpu(cpu, &crash_vmclear_enabled_bitmap);
> +}
> +
> +static void vmclear_local_loaded_vmcss(void);
> +static int crash_vmclear_local_loaded_vmcss(struct notifier_block *this,
> + unsigned long val, void *ptr)
> +{
> + int cpu = raw_smp_processor_id();
> +
> + if (crash_local_vmclear_enabled(cpu))
> + vmclear_local_loaded_vmcss();
> +
> + return NOTIFY_DONE;
> +}
> +
> +static struct notifier_block crash_vmclear_notifier = {
> + .notifier_call = crash_vmclear_local_loaded_vmcss,
> +};
> +#else
> +static inline void crash_enable_local_vmclear(int cpu) { }
> +static inline void crash_disable_local_vmclear(int cpu) { }
> +#endif /* CONFIG_KEXEC */
> +
> static void __loaded_vmcs_clear(void *arg)
> {
> struct loaded_vmcs *loaded_vmcs = arg;
> @@ -972,8 +1016,10 @@ static void __loaded_vmcs_clear(void *arg)
> return; /* vcpu migration can race with cpu offline */
> if (per_cpu(current_vmcs, cpu) == loaded_vmcs->vmcs)
> per_cpu(current_vmcs, cpu) = NULL;
> + crash_disable_local_vmclear(cpu);
> list_del(&loaded_vmcs->loaded_vmcss_on_cpu_link);
> loaded_vmcs_init(loaded_vmcs);
> + crash_enable_local_vmclear(cpu);
> }
>
> static void loaded_vmcs_clear(struct loaded_vmcs *loaded_vmcs)
> @@ -1491,8 +1537,10 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
>
> kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
> local_irq_disable();
> + crash_disable_local_vmclear(cpu);
> list_add(&vmx->loaded_vmcs->loaded_vmcss_on_cpu_link,
> &per_cpu(loaded_vmcss_on_cpu, cpu));
> + crash_enable_local_vmclear(cpu);
> local_irq_enable();
>
> /*
> @@ -2302,6 +2350,18 @@ static int hardware_enable(void *garbage)
> return -EBUSY;
>
> INIT_LIST_HEAD(&per_cpu(loaded_vmcss_on_cpu, cpu));
> +
> + /*
> + * Now we can enable the vmclear operation in kdump
> + * since the loaded_vmcss_on_cpu list on this cpu
> + * has been initialized.
> + *
> + * Though the cpu is not in VMX operation now, there
> + * is no problem to enable the vmclear operation
> + * for the loaded_vmcss_on_cpu list is empty!
> + */
> + crash_enable_local_vmclear(cpu);
> +
> rdmsrl(MSR_IA32_FEATURE_CONTROL, old);
>
> test_bits = FEATURE_CONTROL_LOCKED;
> @@ -2335,7 +2395,6 @@ static void vmclear_local_loaded_vmcss(void)
> __loaded_vmcs_clear(v);
> }
>
> -
> /* Just like cpu_vmxoff(), but with the __kvm_handle_fault_on_reboot()
> * tricks.
> */
> @@ -2348,6 +2407,12 @@ static void hardware_disable(void *garbage)
> {
> if (vmm_exclusive) {
> vmclear_local_loaded_vmcss();
> + /*
> + * vmclear operation in kdump should be disabled here
> + * because the cpu is going to exit VMX operation
> + * and the loaded_vmcss_on_cpu list may not be empty!
> + */
> + crash_disable_local_vmclear(raw_smp_processor_id());
> kvm_cpu_vmxoff();
How come its not empty? vmclear_local_loaded_vmcss cleared it, didnt it?
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