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Commit 8018c27b authored by Ingo Molnar's avatar Ingo Molnar Committed by Linus Torvalds
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[PATCH] kvm: fix GFP_KERNEL allocation in atomic section in kvm_dev_ioctl_create_vcpu() 



fix an GFP_KERNEL allocation in atomic section: kvm_dev_ioctl_create_vcpu()
called kvm_mmu_init(), which calls alloc_pages(), while holding the vcpu.

The fix is to set up the MMU state in two phases: kvm_mmu_create() and
kvm_mmu_setup().

(NOTE: free_vcpus does an kvm_mmu_destroy() call so there's no need for any
extra teardown branch on allocation/init failure here.)

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Cc: Avi Kivity <avi@qumranet.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 55a54f79

drivers/kvm/kvm.h

+2 −1
Original line number Diff line number Diff line
@@ -319,7 +319,8 @@ int kvm_init_arch(struct kvm_arch_ops *ops, struct module *module); 
void kvm_exit_arch(void);



void kvm_mmu_destroy(struct kvm_vcpu *vcpu);

int kvm_mmu_init(struct kvm_vcpu *vcpu);

int kvm_mmu_create(struct kvm_vcpu *vcpu);

int kvm_mmu_setup(struct kvm_vcpu *vcpu);



int kvm_mmu_reset_context(struct kvm_vcpu *vcpu);

void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot);

drivers/kvm/kvm_main.c

+6 −4
Original line number Diff line number Diff line
@@ -522,12 +522,14 @@ static int kvm_dev_ioctl_create_vcpu(struct kvm *kvm, int n) 
	if (r < 0)

		goto out_free_vcpus;



	kvm_arch_ops->vcpu_load(vcpu);

	r = kvm_mmu_create(vcpu);

	if (r < 0)

		goto out_free_vcpus;



	r = kvm_arch_ops->vcpu_setup(vcpu);

	kvm_arch_ops->vcpu_load(vcpu);

	r = kvm_mmu_setup(vcpu);

	if (r >= 0)

		r = kvm_mmu_init(vcpu);



		r = kvm_arch_ops->vcpu_setup(vcpu);

	vcpu_put(vcpu);



	if (r < 0)

drivers/kvm/mmu.c

+9 −15
Original line number Diff line number Diff line
@@ -639,28 +639,22 @@ static int alloc_mmu_pages(struct kvm_vcpu *vcpu) 
	return -ENOMEM;

}



int kvm_mmu_init(struct kvm_vcpu *vcpu)

int kvm_mmu_create(struct kvm_vcpu *vcpu)

{

	int r;



	ASSERT(vcpu);

	ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa));

	ASSERT(list_empty(&vcpu->free_pages));



	r = alloc_mmu_pages(vcpu);

	if (r)

		goto out;



	r = init_kvm_mmu(vcpu);

	if (r)

		goto out_free_pages;

	return alloc_mmu_pages(vcpu);

}



	return 0;

int kvm_mmu_setup(struct kvm_vcpu *vcpu)

{

	ASSERT(vcpu);

	ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa));

	ASSERT(!list_empty(&vcpu->free_pages));



out_free_pages:

	free_mmu_pages(vcpu);

out:

	return r;

	return init_kvm_mmu(vcpu);

}



void kvm_mmu_destroy(struct kvm_vcpu *vcpu)