Re: [PATCH] KVM: x86/mmu: x86: Don't overflow lpage_info when checking attributes

From: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
To: "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"dongli.zhang@oracle.com" <dongli.zhang@oracle.com>
Cc: "pbonzini@redhat.com" <pbonzini@redhat.com>,
	"seanjc@google.com" <seanjc@google.com>,
	"hao.p.peng@linux.intel.com" <hao.p.peng@linux.intel.com>,
	"Yamahata, Isaku" <isaku.yamahata@intel.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] KVM: x86/mmu: x86: Don't overflow lpage_info when checking attributes
Date: Wed, 13 Mar 2024 16:25:42 +0000	[thread overview]
Message-ID: <60d6242e12030c744ff88322b84d0aa586e2d43d.camel@intel.com> (raw)
In-Reply-To: <ccb21523-54b8-770a-bdac-c63f9c8080db@oracle.com>

On Wed, 2024-03-13 at 02:49 -0700, Dongli Zhang wrote:
> The memslot id=10 has:
> - base_gfn=1048576
> - npages=1024
> 
> Therefore, "level - 1  will not contain an entry for each GFN at page
> size
> level". If aligned, we expect lpage_info[0] to have 512 elements.
> 
> 1GB: lpage_info[1] has 1 element
> 2MB: lpage_info[0] has 2 elemtnts

1048576 GFN is 2MB aligned, 1024 pages is also 2MB aligned. There are
512 4k pages in a 2MB huge page, so size of 2 for npages=1024 looks
right to me. One struct for each potential 2MB huge page in the range.

I think overall you are saying in this response that you didn't find
any problem in the analysis or fix. Is that correct?