From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39730) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e1v4s-0007zu-9w for qemu-devel@nongnu.org; Tue, 10 Oct 2017 10:00:20 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1e1v4i-0001tt-O9 for qemu-devel@nongnu.org; Tue, 10 Oct 2017 10:00:10 -0400 References: <20171010132159.15787-1-david@gibson.dropbear.id.au> From: Laurent Vivier Message-ID: <0639ec04-a340-4d8b-995f-249b6dd93cf6@redhat.com> Date: Tue, 10 Oct 2017 15:59:51 +0200 MIME-Version: 1.0 In-Reply-To: <20171010132159.15787-1-david@gibson.dropbear.id.au> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] spapr: Correct RAM size calculation for HPT resizing List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: David Gibson , groug@kaod.org, clg@kaod.org Cc: qemu-ppc@nongnu.org, qemu-devel@nongnu.org On 10/10/2017 15:21, 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 | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c > index 8d72bb7c1c..06af1b15c0 100644 > --- a/hw/ppc/spapr_hcall.c > +++ b/hw/ppc/spapr_hcall.c > @@ -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 = 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 > According to the content of qmp_query_memory_size_summary(), it's the good way to compute the memory size... Reviewed-by: Laurent Vivier