From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46283) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WwnUY-0007h1-J6 for qemu-devel@nongnu.org; Tue, 17 Jun 2014 03:07:45 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WwnUK-0002cQ-OF for qemu-devel@nongnu.org; Tue, 17 Jun 2014 03:07:38 -0400 Received: from mail-pd0-f180.google.com ([209.85.192.180]:51593) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WwnUK-0002c9-JK for qemu-devel@nongnu.org; Tue, 17 Jun 2014 03:07:24 -0400 Received: by mail-pd0-f180.google.com with SMTP id fp1so2002196pdb.11 for ; Tue, 17 Jun 2014 00:07:23 -0700 (PDT) Message-ID: <539FE926.6040207@ozlabs.ru> Date: Tue, 17 Jun 2014 17:07:18 +1000 From: Alexey Kardashevskiy MIME-Version: 1.0 References: <1402905233-26510-1-git-send-email-aik@ozlabs.ru> <1402905233-26510-5-git-send-email-aik@ozlabs.ru> In-Reply-To: <1402905233-26510-5-git-send-email-aik@ozlabs.ru> Content-Type: text/plain; charset=KOI8-R Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 4/7] spapr: Split memory nodes to power-of-two blocks List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Nishanth Aravamudan , qemu-ppc@nongnu.org, Alexander Graf On 06/16/2014 05:53 PM, Alexey Kardashevskiy wrote: > Linux kernel expects nodes to have power-of-two size and > does WARN_ON if this is not the case: > [ 0.041052] devtmpfs: initialized > [ 0.041292] ------------[ cut here ]------------ > [ 0.041456] WARNING: at drivers/base/memory.c:115 > > This splits memory nodes into set of smaller blocks with > a size which is a power of two. This makes sure the start > address of every node is aligned to the node size. > > Signed-off-by: Alexey Kardashevskiy > --- > hw/ppc/spapr.c | 14 ++++++++++++-- > 1 file changed, 12 insertions(+), 2 deletions(-) > > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c > index 666b676..10202e2 100644 > --- a/hw/ppc/spapr.c > +++ b/hw/ppc/spapr.c > @@ -710,8 +710,18 @@ static int spapr_populate_memory(sPAPREnvironment *spapr, void *fdt) > mem_start += spapr->rma_size; > node_size -= spapr->rma_size; > } > - spapr_populate_memory_node(fdt, i, mem_start, node_size); > - mem_start += node_size; > + for ( ; node_size; ) { > + hwaddr sizetmp = pow2floor(node_size); > + > + /* mem_start != 0 here */ > + if (ffs(mem_start) < ffs(sizetmp)) { > + sizetmp = MIN(sizetmp, 1 << (ffs(mem_start) - 1)); And I do not need MIN() here. Uff. > + } > + > + spapr_populate_memory_node(fdt, i, mem_start, sizetmp); > + node_size -= sizetmp; > + mem_start += sizetmp; > + } > } > > return 0; > -- Alexey