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[PATCH] kvm: fix GFP_KERNEL allocation in atomic section in kvm_dev_ioctl_create_vcpu()

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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: Ingo Molnar <mingo@elte.hu>
Cc: Avi Kivity <avi@qumranet.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Ingo Molnar 2006-12-29 16:50:01 -08:00 committed by Linus Torvalds
parent 55a54f79e0
commit 8018c27b26
3 changed files with 17 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
drivers/kvm/kvm.h
View File

@ -319,7 +319,8 @@ int kvm_init_arch(struct kvm_arch_ops *ops, struct module *module);
void kvm_exit_arch(void); void kvm_exit_arch(void);
void kvm_mmu_destroy(struct kvm_vcpu *vcpu); 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); int kvm_mmu_reset_context(struct kvm_vcpu *vcpu);
void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot); void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot);

10
drivers/kvm/kvm_main.c
View File

@ -522,12 +522,14 @@ static int kvm_dev_ioctl_create_vcpu(struct kvm *kvm, int n)
if (r < 0) if (r < 0)
goto out_free_vcpus; goto out_free_vcpus;
r = kvm_mmu_create(vcpu);
if (r < 0)
goto out_free_vcpus;
kvm_arch_ops->vcpu_load(vcpu); kvm_arch_ops->vcpu_load(vcpu);
r = kvm_mmu_setup(vcpu);
r = kvm_arch_ops->vcpu_setup(vcpu);
if (r >= 0) if (r >= 0)
r = kvm_mmu_init(vcpu); r = kvm_arch_ops->vcpu_setup(vcpu);
vcpu_put(vcpu); vcpu_put(vcpu);
if (r < 0) if (r < 0)

24
drivers/kvm/mmu.c
View File

@ -639,28 +639,22 @@ error_1:
return -ENOMEM; return -ENOMEM;
} }
int kvm_mmu_init(struct kvm_vcpu *vcpu) int kvm_mmu_create(struct kvm_vcpu *vcpu)
{ {
int r;
ASSERT(vcpu); ASSERT(vcpu);
ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa)); ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa));
ASSERT(list_empty(&vcpu->free_pages)); ASSERT(list_empty(&vcpu->free_pages));
r = alloc_mmu_pages(vcpu); return alloc_mmu_pages(vcpu);
if (r) }
goto out;
r = init_kvm_mmu(vcpu); int kvm_mmu_setup(struct kvm_vcpu *vcpu)
if (r) {
goto out_free_pages; ASSERT(vcpu);
ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa));
ASSERT(!list_empty(&vcpu->free_pages));
return 0; return init_kvm_mmu(vcpu);
out_free_pages:
free_mmu_pages(vcpu);
out:
return r;
} }
void kvm_mmu_destroy(struct kvm_vcpu *vcpu) void kvm_mmu_destroy(struct kvm_vcpu *vcpu)