From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:35226) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gmwWd-000413-Pt for qemu-devel@nongnu.org; Fri, 25 Jan 2019 03:07:44 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gmwSx-0001Yq-Rf for qemu-devel@nongnu.org; Fri, 25 Jan 2019 03:03:56 -0500 References: <1548349076-350255-1-git-send-email-imammedo@redhat.com> From: David Hildenbrand Message-ID: <3b4eef57-dc27-356e-5487-0b9b53a75cb1@redhat.com> Date: Fri, 25 Jan 2019 09:03:49 +0100 MIME-Version: 1.0 In-Reply-To: <1548349076-350255-1-git-send-email-imammedo@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] s390x: remove direct reference to mem_path global form s90x code List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Igor Mammedov , qemu-devel@nongnu.org Cc: pasic@linux.ibm.com, cohuck@redhat.com, borntraeger@de.ibm.com, rth@twiddle.net, qemu-s390x@nongnu.org On 24.01.19 17:57, Igor Mammedov wrote: > I plan to deprecate -mem-path option and replace it with memory-backend, > for that it's necessary to get rid of mem_path global variable. > Do it for s390x case, replacing it with alternative way to enable > 1Mb hugepages capability. > > Signed-off-by: Igor Mammedov > --- > PS: > Original code nor the new one probably is not entirely correct when > huge pages are enabled in case where mixed initial RAM and memory > backends are used, backend's page size might not match initial RAM's > so I'm not sure if enabling 1MB cap is correct in this case on s390 > (should it be the same for all RAM???). > With new approach 1Mb cap is not enabled if the smallest page size > is not 1Mb. There is no memory hotplug (DIMM/NVDIMM), so there really only is initial memory. > --- > target/s390x/kvm.c | 37 ++++++++++++++++--------------------- > 1 file changed, 16 insertions(+), 21 deletions(-) > > diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c > index 2ebf26a..22e868a 100644 > --- a/target/s390x/kvm.c > +++ b/target/s390x/kvm.c > @@ -285,33 +285,28 @@ void kvm_s390_crypto_reset(void) > } > } > > -static int kvm_s390_configure_mempath_backing(KVMState *s) > +static int kvm_s390_configure_hugepage_backing(KVMState *s) > { > - size_t path_psize = qemu_mempath_getpagesize(mem_path); > + size_t psize = qemu_getrampagesize(); > > - if (path_psize == 4 * KiB) { if you keep this (modified) check you have to do minimal changes in the code below. (e.g. not indent error messages) > - return 0; > - } > -> - if (!hpage_1m_allowed()) { > - error_report("This QEMU machine does not support huge page " > - "mappings"); > - return -EINVAL; > - } > + if (psize == 1 * MiB) { > + if (!hpage_1m_allowed()) { > + error_report("This QEMU machine does not support huge page " > + "mappings"); > + return -EINVAL; > + } > > - if (path_psize != 1 * MiB) { > + if (kvm_vm_enable_cap(s, KVM_CAP_S390_HPAGE_1M, 0)) { > + error_report("Memory backing with 1M pages was specified, " > + "but KVM does not support this memory backing"); > + return -EINVAL; > + } > + cap_hpage_1m = 1; > + } else if (psize == 2 * GiB) { > error_report("Memory backing with 2G pages was specified, " > "but KVM does not support this memory backing"); > return -EINVAL; > } > - > - if (kvm_vm_enable_cap(s, KVM_CAP_S390_HPAGE_1M, 0)) { > - error_report("Memory backing with 1M pages was specified, " > - "but KVM does not support this memory backing"); > - return -EINVAL; > - } > - > - cap_hpage_1m = 1; > return 0; > } > > @@ -319,7 +314,7 @@ int kvm_arch_init(MachineState *ms, KVMState *s) > { > MachineClass *mc = MACHINE_GET_CLASS(ms); > > - if (mem_path && kvm_s390_configure_mempath_backing(s)) { > + if (kvm_s390_configure_hugepage_backing(s)) { > return -EINVAL; > } > > Apart from that looks good to me. -- Thanks, David / dhildenb