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Commit 8f536b76 authored by Zhang Yanfei's avatar Zhang Yanfei Committed by Gleb Natapov
Browse files

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



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: default avatarZhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: default avatarEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: default avatarGleb Natapov <gleb@redhat.com>
parent f23d1f4a

arch/x86/kvm/vmx.c

+67 −0
Original line number Diff line number Diff line
@@ -42,6 +42,7 @@ 
#include <asm/i387.h>

#include <asm/xcr.h>

#include <asm/perf_event.h>

#include <asm/kexec.h>



#include "trace.h"
@@ -987,6 +988,46 @@ 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 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)

{

	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 */

	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);



	/*
@@ -1007,6 +1049,7 @@ static void __loaded_vmcs_clear(void *arg) 
	smp_wmb();



	loaded_vmcs_init(loaded_vmcs);

	crash_enable_local_vmclear(cpu);

}



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);

		local_irq_disable();

		crash_disable_local_vmclear(cpu);



		/*

		 * 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,

			 &per_cpu(loaded_vmcss_on_cpu, cpu));

		crash_enable_local_vmclear(cpu);

		local_irq_enable();



		/*
@@ -2353,6 +2398,18 @@ 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;
@@ -7383,6 +7440,11 @@ static int __init vmx_init(void) 
	if (r)

		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_GS_BASE, false);

	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_a);



#ifdef CONFIG_KEXEC

	rcu_assign_pointer(crash_vmclear_loaded_vmcss, NULL);

	synchronize_rcu();

#endif



	kvm_exit();

}