From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46506) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZXiyI-00089d-As for qemu-devel@nongnu.org; Fri, 04 Sep 2015 00:51:31 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZXiyF-0000Ww-6E for qemu-devel@nongnu.org; Fri, 04 Sep 2015 00:51:30 -0400 From: David Gibson Date: Fri, 4 Sep 2015 14:51:39 +1000 Message-Id: <1441342300-28318-2-git-send-email-david@gibson.dropbear.id.au> In-Reply-To: <1441342300-28318-1-git-send-email-david@gibson.dropbear.id.au> References: <1441342300-28318-1-git-send-email-david@gibson.dropbear.id.au> Subject: [Qemu-devel] [RFCv2 1/2] pseries: Fix incorrect calculation of threads per socket for chip-id List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: aik@ozlabs.ru, mdroth@linux.vnet.ibm.com Cc: David Gibson , qemu-ppc@nongnu.org, qemu-devel@nongnu.org, agraf@suse.de The device tree presented to pseries machine type guests includes an ibm,chip-id property which gives essentially the socket number of each vcpu core (individual vcpu threads don't get a node in the device tree). To calculate this, it uses a vcpus_per_socket variable computed as (smp_cpus / #sockets). This is correct for the usual case where smp_cpus == smp_threads * smp_cores * #sockets. However, you can start QEMU with the number of cores and threads mismatching the total number of vcpus (whether that _should_ be permitted is a topic for another day). It's a bit hard to say what the "real" number of vcpus per socket here is, but for most purposes (smp_threads * smp_cores) will more meaningfully match how QEMU behaves with respect to socket boundaries. Signed-off-by: David Gibson --- hw/ppc/spapr.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c index 783763f..dbc295b 100644 --- a/hw/ppc/spapr.c +++ b/hw/ppc/spapr.c @@ -595,8 +595,7 @@ static void spapr_populate_cpu_dt(CPUState *cs, void *fdt, int offset, uint32_t page_sizes_prop[64]; size_t page_sizes_prop_size; QemuOpts *opts = qemu_opts_find(qemu_find_opts("smp-opts"), NULL); - unsigned sockets = opts ? qemu_opt_get_number(opts, "sockets", 0) : 0; - uint32_t cpus_per_socket = sockets ? (smp_cpus / sockets) : 1; + uint32_t vcpus_per_socket = smp_threads * smp_cores; uint32_t pft_size_prop[] = {0, cpu_to_be32(spapr->htab_shift)}; _FDT((fdt_setprop_cell(fdt, offset, "reg", index))); @@ -665,7 +664,7 @@ static void spapr_populate_cpu_dt(CPUState *cs, void *fdt, int offset, } _FDT((fdt_setprop_cell(fdt, offset, "ibm,chip-id", - cs->cpu_index / cpus_per_socket))); + cs->cpu_index / vcpus_per_socket))); _FDT((fdt_setprop(fdt, offset, "ibm,pft-size", pft_size_prop, sizeof(pft_size_prop)))); -- 2.4.3