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KVM: VMX: provide the vmclear function and a bitmap to support VMCLEAR in kdump

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The vmclear function will be assigned to the callback function pointer
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@cn.fujitsu.com>
Acked-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
This commit is contained in:
Zhang Yanfei 2012-12-06 23:43:34 +08:00 • committed by Gleb Natapov
parent f23d1f4a11
commit 8f536b7697
1 changed files with 67 additions and 0 deletions
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67
arch/x86/kvm/vmx.c
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@ -42,6 +42,7 @@
#include <asm/i387.h> #include <asm/i387.h>
#include <asm/xcr.h> #include <asm/xcr.h>
#include <asm/perf_event.h> #include <asm/perf_event.h>
#include <asm/kexec.h>
#include "trace.h" #include "trace.h"
@ -987,6 +988,46 @@ static void vmcs_load(struct vmcs *vmcs)
vmcs, phys_addr); 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 crash_vmclear_local_loaded_vmcss(void)
{
int cpu = raw_smp_processor_id();
struct loaded_vmcs *v;
if (!crash_local_vmclear_enabled(cpu))
return;
list_for_each_entry(v, &per_cpu(loaded_vmcss_on_cpu, cpu),
loaded_vmcss_on_cpu_link)
vmcs_clear(v->vmcs);
}
#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) static void __loaded_vmcs_clear(void *arg)
{ {
struct loaded_vmcs *loaded_vmcs = arg; struct loaded_vmcs *loaded_vmcs = arg;
@ -996,6 +1037,7 @@ static void __loaded_vmcs_clear(void *arg)
return; /* vcpu migration can race with cpu offline */ return; /* vcpu migration can race with cpu offline */
if (per_cpu(current_vmcs, cpu) == loaded_vmcs->vmcs) if (per_cpu(current_vmcs, cpu) == loaded_vmcs->vmcs)
per_cpu(current_vmcs, cpu) = NULL; per_cpu(current_vmcs, cpu) = NULL;
crash_disable_local_vmclear(cpu);
list_del(&loaded_vmcs->loaded_vmcss_on_cpu_link); list_del(&loaded_vmcs->loaded_vmcss_on_cpu_link);
/* /*
@ -1007,6 +1049,7 @@ static void __loaded_vmcs_clear(void *arg)
smp_wmb(); smp_wmb();
loaded_vmcs_init(loaded_vmcs); loaded_vmcs_init(loaded_vmcs);
crash_enable_local_vmclear(cpu);
} }
static void loaded_vmcs_clear(struct loaded_vmcs *loaded_vmcs) static void loaded_vmcs_clear(struct loaded_vmcs *loaded_vmcs)
@ -1530,6 +1573,7 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu); kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
local_irq_disable(); local_irq_disable();
crash_disable_local_vmclear(cpu);
/* /*
* Read loaded_vmcs->cpu should be before fetching * Read loaded_vmcs->cpu should be before fetching
@ -1540,6 +1584,7 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
list_add(&vmx->loaded_vmcs->loaded_vmcss_on_cpu_link, list_add(&vmx->loaded_vmcs->loaded_vmcss_on_cpu_link,
&per_cpu(loaded_vmcss_on_cpu, cpu)); &per_cpu(loaded_vmcss_on_cpu, cpu));
crash_enable_local_vmclear(cpu);
local_irq_enable(); local_irq_enable();
/* /*
@ -2353,6 +2398,18 @@ static int hardware_enable(void *garbage)
return -EBUSY; return -EBUSY;
INIT_LIST_HEAD(&per_cpu(loaded_vmcss_on_cpu, cpu)); 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); rdmsrl(MSR_IA32_FEATURE_CONTROL, old);
test_bits = FEATURE_CONTROL_LOCKED; test_bits = FEATURE_CONTROL_LOCKED;
@ -7383,6 +7440,11 @@ static int __init vmx_init(void)
if (r) if (r)
goto out3; goto out3;
#ifdef CONFIG_KEXEC
rcu_assign_pointer(crash_vmclear_loaded_vmcss,
crash_vmclear_local_loaded_vmcss);
#endif
vmx_disable_intercept_for_msr(MSR_FS_BASE, false); vmx_disable_intercept_for_msr(MSR_FS_BASE, false);
vmx_disable_intercept_for_msr(MSR_GS_BASE, false); vmx_disable_intercept_for_msr(MSR_GS_BASE, false);
vmx_disable_intercept_for_msr(MSR_KERNEL_GS_BASE, true); vmx_disable_intercept_for_msr(MSR_KERNEL_GS_BASE, true);
@ -7420,6 +7482,11 @@ static void __exit vmx_exit(void)
free_page((unsigned long)vmx_io_bitmap_b); free_page((unsigned long)vmx_io_bitmap_b);
free_page((unsigned long)vmx_io_bitmap_a); free_page((unsigned long)vmx_io_bitmap_a);
#ifdef CONFIG_KEXEC
rcu_assign_pointer(crash_vmclear_loaded_vmcss, NULL);
synchronize_rcu();
#endif
kvm_exit(); kvm_exit();
} }