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Date:   Tue, 19 Jul 2022 22:12:43 +0800
From:   Chao Peng <chao.p.peng@linux.intel.com>
To:     "Gupta, Pankaj" <pankaj.gupta@amd.com>
Cc:     kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
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        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
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Subject: Re: [PATCH v7 13/14] KVM: Enable and expose KVM_MEM_PRIVATE
Message-ID: <20220719141243.GB84779@chaop.bj.intel.com>
Reply-To: Chao Peng <chao.p.peng@linux.intel.com>
References: <20220706082016.2603916-1-chao.p.peng@linux.intel.com>
 <20220706082016.2603916-14-chao.p.peng@linux.intel.com>
 <de1e15b8-b7e7-d077-eff8-0992bd06e38a@amd.com>
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On Tue, Jul 19, 2022 at 11:55:24AM +0200, Gupta, Pankaj wrote:

...

> > @@ -4712,12 +4813,10 @@ static long kvm_vm_ioctl(struct file *filp,
> >   			(u32 __user *)(argp + offsetof(typeof(mem), flags))))
> >   			goto out;
> > -		if (flags & KVM_MEM_PRIVATE) {
> > -			r = -EINVAL;
> > -			goto out;
> > -		}
> > -
> > -		size = sizeof(struct kvm_userspace_memory_region);
> > +		if (flags & KVM_MEM_PRIVATE)
> > +			size = sizeof(struct kvm_userspace_memory_region_ext);
> 
> Not sure if we use kvm_userspace_memory_region_ext or kvm_user_mem_region,
> just for readability.

Somehow, but majorly for code maintainability, kvm_user_mem_region is
designed to be the alias of kvm_userspace_memory_region_ext so in the
code we can access the 'unpacked' fields using something like
'mem.usersapce_addr' instead of 'mem.region.userspace_addr'.

Chao
> 
> > +		else
> > +			size = sizeof(struct kvm_userspace_memory_region);
> >   		if (copy_from_user(&mem, argp, size))
> >   			goto out;