From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58945) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e2A9x-0002x9-Oe for qemu-devel@nongnu.org; Wed, 11 Oct 2017 02:06:26 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1e2A9r-0007gD-U4 for qemu-devel@nongnu.org; Wed, 11 Oct 2017 02:06:25 -0400 Received: from 1.mo4.mail-out.ovh.net ([178.33.248.196]:40178) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1e2A9r-0007cM-OG for qemu-devel@nongnu.org; Wed, 11 Oct 2017 02:06:19 -0400 Received: from player772.ha.ovh.net (b6.ovh.net [213.186.33.56]) by mo4.mail-out.ovh.net (Postfix) with ESMTP id 75D40E3EEB for ; Wed, 11 Oct 2017 08:06:10 +0200 (CEST) Date: Wed, 11 Oct 2017 08:06:03 +0200 From: Greg Kurz Message-ID: <20171011080603.7d9d5e24@bahia.lan> In-Reply-To: <20171011000649.22012-1-david@gibson.dropbear.id.au> References: <20171011000649.22012-1-david@gibson.dropbear.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCHv2] spapr: Correct RAM size calculation for HPT resizing List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: David Gibson Cc: lvivier@redhat.com, clg@kaod.org, qemu-ppc@nongnu.org, qemu-devel@nongnu.org On Wed, 11 Oct 2017 11:06:49 +1100 David Gibson wrote: > In order to prevent the guest from forcing the allocation of large amounts > of qemu memory (or host kernel memory, in the case of KVM HV), we limit > the size of Hashed Page Table (HPT) it is allowed to allocated, based on > its RAM size. > > However, the current calculation is not correct: it only adds up the size > of plugged memory, ignoring the base memory size. This patch corrects it. > > While we're there, use get_plugged_memory_size() instead of directly > calling pc_existing_dimms_capacity(). The only difference is that it > will abort on failure, which is right: a failure here indicates something > wrong within qemu. > > Signed-off-by: David Gibson > --- > hw/ppc/spapr_hcall.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > Changes in v2: > * Also remove redundant initializer of current_ram_size > * And use ram_size machine attribute instead of the ram_size global. Reviewed-by: Greg Kurz > diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c > index 8d72bb7c1c..0d59d1534d 100644 > --- a/hw/ppc/spapr_hcall.c > +++ b/hw/ppc/spapr_hcall.c > @@ -472,7 +472,7 @@ static target_ulong h_resize_hpt_prepare(PowerPCCPU *cpu, > target_ulong flags = args[0]; > int shift = args[1]; > sPAPRPendingHPT *pending = spapr->pending_hpt; > - uint64_t current_ram_size = MACHINE(spapr)->ram_size; > + uint64_t current_ram_size; > int rc; > > if (spapr->resize_hpt == SPAPR_RESIZE_HPT_DISABLED) { > @@ -494,7 +494,7 @@ static target_ulong h_resize_hpt_prepare(PowerPCCPU *cpu, > return H_PARAMETER; > } > > - current_ram_size = pc_existing_dimms_capacity(&error_fatal); > + current_ram_size = MACHINE(spapr)->ram_size + get_plugged_memory_size(); > > /* We only allow the guest to allocate an HPT one order above what > * we'd normally give them (to stop a small guest claiming a huge