From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from co9outboundpool.messaging.microsoft.com (co9ehsobe005.messaging.microsoft.com [207.46.163.28]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (Client CN "mail.global.frontbridge.com", Issuer "MSIT Machine Auth CA 2" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 5B1D32C00B1 for ; Tue, 24 Sep 2013 08:32:43 +1000 (EST) Message-ID: <1379975475.24959.45.camel@snotra.buserror.net> Subject: Re: [PATCH 5/6 v7] kvm: booke: clear host tlb reference flag on guest tlb invalidation From: Scott Wood To: Bharat Bhushan Date: Mon, 23 Sep 2013 17:31:15 -0500 In-Reply-To: <1379907769-31452-1-git-send-email-Bharat.Bhushan@freescale.com> References: <1379907769-31452-1-git-send-email-Bharat.Bhushan@freescale.com> Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Cc: kvm@vger.kernel.org, agraf@suse.de, kvm-ppc@vger.kernel.org, Bharat Bhushan , paulus@samba.org, linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Mon, 2013-09-23 at 09:12 +0530, Bharat Bhushan wrote: > On booke, "struct tlbe_ref" contains host tlb mapping information > (pfn: for guest-pfn to pfn, flags: attribute associated with this mapping) > for a guest tlb entry. So when a guest creates a TLB entry then > "struct tlbe_ref" is set to point to valid "pfn" and set attributes in > "flags" field of the above said structure. When a guest TLB entry is > invalidated then flags field of corresponding "struct tlbe_ref" is > updated to point that this is no more valid, also we selectively clear > some other attribute bits, example: if E500_TLB_BITMAP was set then we clear > E500_TLB_BITMAP, if E500_TLB_TLB0 is set then we clear this. > > Ideally we should clear complete "flags" as this entry is invalid and does not > have anything to re-used. The other part of the problem is that when we use > the same entry again then also we do not clear (started doing or-ing etc). > > So far it was working because the selectively clearing mentioned above > actually clears "flags" what was set during TLB mapping. But the problem > starts coming when we add more attributes to this then we need to selectively > clear them and which is not needed. > > This patch we do both > - Clear "flags" when invalidating; > - Clear "flags" when reusing same entry later > > Signed-off-by: Bharat Bhushan > --- > v6->7 > - Comment re-phrased Reviewed-by: Scott Wood -Scott