linux-kernel - Re: [PATCH v5 08/12] Inject asynchronous page fault into a guest if page is swapped out.

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Message-ID: <4C73BC02.7090606@redhat.com>
Date:	Tue, 24 Aug 2010 15:33:06 +0300
From:	Avi Kivity <avi@...hat.com>
To:	Gleb Natapov <gleb@...hat.com>
CC:	kvm@...r.kernel.org, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org, mingo@...e.hu,
	a.p.zijlstra@...llo.nl, tglx@...utronix.de, hpa@...or.com,
	riel@...hat.com, cl@...ux-foundation.org, mtosatti@...hat.com
Subject: Re: [PATCH v5 08/12] Inject asynchronous page fault into a guest
 if page is swapped out.

  On 08/24/2010 03:28 PM, Gleb Natapov wrote:
> On Mon, Aug 23, 2010 at 07:17:20PM +0300, Avi Kivity wrote:
>>> +static int apf_put_user(struct kvm_vcpu *vcpu, u32 val)
>>> +{
>>> +	if (unlikely(vcpu->arch.apf_memslot_ver !=
>>> +		     vcpu->kvm->memslot_version)) {
>>> +		u64 gpa = vcpu->arch.apf_msr_val&   ~0x3f;
>>> +		unsigned long addr;
>>> +		int offset = offset_in_page(gpa);
>>> +
>>> +		addr = gfn_to_hva(vcpu->kvm, gpa>>   PAGE_SHIFT);
>>> +		vcpu->arch.apf_data = (u32 __user *)(addr + offset);
>>> +		if (kvm_is_error_hva(addr)) {
>>> +			vcpu->arch.apf_data = NULL;
>>> +			return -EFAULT;
>>> +		}
>>> +	}
>>> +
>>> +	return put_user(val, vcpu->arch.apf_data);
>>> +}
>> This nice cache needs to be outside apf to reduce complexity for
>> reviewers and since it is useful for others.
>>
>> Would be good to have memslot-cached kvm_put_guest() and kvm_get_guest().
>>
> Something like this? (only compile tested)

Yes, exactly.

-- 
error compiling committee.c: too many arguments to function

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