linux-kernel - Re: [PATCH v2 1/2] KVM: nVMX: enhance allocate/free

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Date:	Tue, 15 Sep 2015 14:54:45 +0200
From:	Paolo Bonzini <pbonzini@...hat.com>
To:	Wanpeng Li <wanpeng.li@...mail.com>
Cc:	Jan Kiszka <jan.kiszka@...mens.com>, Bandan Das <bsd@...hat.com>,
	Wincy Van <fanwenyi0529@...il.com>, kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/2] KVM: nVMX: enhance allocate/free_vpid to handle
 shadow vpid



On 15/09/2015 12:30, Wanpeng Li wrote:
> +	if (!nested) {
> +		vpid = find_first_zero_bit(vmx_vpid_bitmap, VMX_NR_VPIDS);
> +		if (vpid < VMX_NR_VPIDS) {
>  		vmx->vpid = vpid;
>  		__set_bit(vpid, vmx_vpid_bitmap);
> +		}
> +	} else {
> +		vpid = find_first_zero_bit(vmx_vpid_bitmap, VMX_NR_VPIDS);
> +		if (vpid < VMX_NR_VPIDS) {
> +			vmx->nested.vpid02 = vpid;
> +			__set_bit(vpid, vmx_vpid_bitmap);
> +		}

Messy indentation, and a lot of duplicate code.  Can you instead have
(which I think was Jan's suggestion too):

static int allocate_vpid(void);
static void free_vpid(int vpid);

That said, I like the simple solution to the "too many VPIDs for each L1
VCPU" processor.

Paolo
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