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Commit 965b58a5 authored by Ingo Molnar's avatar Ingo Molnar Committed by Linus Torvalds
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[PATCH] KVM: Fix GFP_KERNEL alloc in atomic section bug 



KVM does kmalloc() in an atomic section while having preemption disabled via
vcpu_load().  Fix this by moving the ->*_msr setup from the vcpu_setup method
to the vcpu_create method.

(This is also a small speedup for setting up a vcpu, which can in theory be
more frequent than the vcpu_create method).

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent cd36beec

drivers/kvm/vmx.c

+21 −11
Original line number Original line Diff line number Diff line
@@ -1094,14 +1094,6 @@ static int vmx_vcpu_setup(struct kvm_vcpu *vcpu) 
	rdmsrl(MSR_IA32_SYSENTER_EIP, a);

	rdmsrl(MSR_IA32_SYSENTER_EIP, a);

	vmcs_writel(HOST_IA32_SYSENTER_EIP, a);   /* 22.2.3 */

	vmcs_writel(HOST_IA32_SYSENTER_EIP, a);   /* 22.2.3 */





	ret = -ENOMEM;

	vcpu->guest_msrs = kmalloc(PAGE_SIZE, GFP_KERNEL);

	if (!vcpu->guest_msrs)

		goto out;

	vcpu->host_msrs = kmalloc(PAGE_SIZE, GFP_KERNEL);

	if (!vcpu->host_msrs)

		goto out_free_guest_msrs;



	for (i = 0; i < NR_VMX_MSR; ++i) {

	for (i = 0; i < NR_VMX_MSR; ++i) {

		u32 index = vmx_msr_index[i];

		u32 index = vmx_msr_index[i];

		u32 data_low, data_high;

		u32 data_low, data_high;
@@ -1155,8 +1147,6 @@ static int vmx_vcpu_setup(struct kvm_vcpu *vcpu) 




	return 0;

	return 0;





out_free_guest_msrs:

	kfree(vcpu->guest_msrs);

out:

out:

	return ret;

	return ret;

}

}
@@ -1906,13 +1896,33 @@ static int vmx_create_vcpu(struct kvm_vcpu *vcpu) 
{

{

	struct vmcs *vmcs;

	struct vmcs *vmcs;





	vcpu->guest_msrs = kmalloc(PAGE_SIZE, GFP_KERNEL);

	if (!vcpu->guest_msrs)

		return -ENOMEM;



	vcpu->host_msrs = kmalloc(PAGE_SIZE, GFP_KERNEL);

	if (!vcpu->host_msrs)

		goto out_free_guest_msrs;



	vmcs = alloc_vmcs();

	vmcs = alloc_vmcs();

	if (!vmcs)

	if (!vmcs)

		return -ENOMEM;

		goto out_free_msrs;



	vmcs_clear(vmcs);

	vmcs_clear(vmcs);

	vcpu->vmcs = vmcs;

	vcpu->vmcs = vmcs;

	vcpu->launched = 0;

	vcpu->launched = 0;



	return 0;

	return 0;



out_free_msrs:

	kfree(vcpu->host_msrs);

	vcpu->host_msrs = NULL;



out_free_guest_msrs:

	kfree(vcpu->guest_msrs);

	vcpu->guest_msrs = NULL;



	return -ENOMEM;

}

}





static struct kvm_arch_ops vmx_arch_ops = {

static struct kvm_arch_ops vmx_arch_ops = {