From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jan Kiszka <jan.kiszka@siemens.com>
Subject: Re: [PATCH] KVM: move DR register access handling into generic code.
Date: Mon, 12 Apr 2010 18:09:50 +0200
Message-ID: <4BC345CE.2060301@siemens.com>
References: <20100412122712.GC23554@redhat.com> <4BC3341E.2050108@redhat.com>
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Cc: Gleb Natapov <gleb@redhat.com>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"mtosatti@redhat.com" <mtosatti@redhat.com>
To: Avi Kivity <avi@redhat.com>
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Avi Kivity wrote:
> On 04/12/2010 03:27 PM, Gleb Natapov wrote:
>> Currently both SVM and VMX have their own DR handling code. Move it to
>> x86.c.
>>
>>    
> 
> The standard process is to make them identical first and finally merge 
> identical code, but I guess we can skip it in this case (Jan?)

Looks OK, I would just...

> +int kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val)
> +{
> +	switch (dr) {
> +	case 0 ... 3:
> +		vcpu->arch.db[dr] = val;
> +		if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP))
> +			vcpu->arch.eff_db[dr] = val;
> +		break;
> +	case 4:
> +		if (kvm_read_cr4_bits(vcpu, X86_CR4_DE)) {
> +			kvm_queue_exception(vcpu, UD_VECTOR);
> +			return 1;
> +		}
> +		/* fall through */
> +	case 6:
> +		if (val & 0xffffffff00000000ULL) {
> +			kvm_inject_gp(vcpu, 0);
> +			return -1;

...either return 1 or -1 on failure.

Jan

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