From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55888) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1X2XPo-0006Kz-ER for qemu-devel@nongnu.org; Wed, 02 Jul 2014 23:10:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1X2XPf-0006xb-5V for qemu-devel@nongnu.org; Wed, 02 Jul 2014 23:10:28 -0400 Received: from e23smtp09.au.ibm.com ([202.81.31.142]:48218) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1X2XPe-0006wi-DB for qemu-devel@nongnu.org; Wed, 02 Jul 2014 23:10:19 -0400 Received: from /spool/local by e23smtp09.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 3 Jul 2014 13:10:15 +1000 From: Alexey Kardashevskiy Date: Thu, 3 Jul 2014 13:10:05 +1000 Message-Id: <1404357007-29507-5-git-send-email-aik@ozlabs.ru> In-Reply-To: <1404357007-29507-1-git-send-email-aik@ozlabs.ru> References: <1404357007-29507-1-git-send-email-aik@ozlabs.ru> Subject: [Qemu-devel] [PATCH v3 4/6] 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: Alexey Kardashevskiy , Nishanth Aravamudan , qemu-ppc@nongnu.org, Alexander Graf Linux kernel expects nodes to have power-of-two size and does WARN_ON if this is not the case: [ 0.041456] WARNING: at drivers/base/memory.c:115 which is: === /* Validate blk_sz is a power of 2 and not less than section size */ if ((block_sz & (block_sz - 1)) || (block_sz < MIN_MEMORY_BLOCK_SIZE)) { WARN_ON(1); block_sz = MIN_MEMORY_BLOCK_SIZE; } === 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 --- Changes: v3: * s/ffs/ffsl/ as addresses are 64bit long v2: * tiny code cleanup in "sizetmp = MIN(sizetmp, 1 << (ffs(mem_start) - 1))" * updated commit log with a piece of kernel code doing WARN_ON --- 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 ec6d541..680d7f9 100644 --- a/hw/ppc/spapr.c +++ b/hw/ppc/spapr.c @@ -662,8 +662,18 @@ 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 (ffsl(mem_start) < ffsl(sizetmp)) { + sizetmp = 1ULL << (ffsl(mem_start) - 1); + } + + spapr_populate_memory_node(fdt, i, mem_start, sizetmp); + node_size -= sizetmp; + mem_start += sizetmp; + } } return 0; -- 2.0.0