From 894ea3ecd38f4d09353cea19bb20002892d2b8b3 Mon Sep 17 00:00:00 2001 From: Greg Kurz Date: Tue, 26 Nov 2019 17:46:28 +0100 Subject: [PATCH] spapr/xics: Configure number of servers in KVM MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The XICS-on-XIVE KVM devices now has an attribute to configure the number of interrupt servers. This allows to greatly optimize the usage of the VP space in the XIVE HW, and thus to start a lot more VMs. Only set this attribute if available in order to support older POWER9 KVM and pre-POWER9 XICS KVM devices. The XICS-on-XIVE KVM device now reports the exhaustion of VPs upon the connection of the first VCPU. Check that in order to have a chance to provide a hint to the user. ` Signed-off-by: Greg Kurz Message-Id: <157478678846.67101.9660531022460517710.stgit@bahia.tlslab.ibm.com> Reviewed-by: Cédric Le Goater Signed-off-by: David Gibson --- hw/intc/xics_kvm.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/hw/intc/xics_kvm.c b/hw/intc/xics_kvm.c index a1f1b7b0d3..8d6156578f 100644 --- a/hw/intc/xics_kvm.c +++ b/hw/intc/xics_kvm.c @@ -165,8 +165,15 @@ void icp_kvm_realize(DeviceState *dev, Error **errp) ret = kvm_vcpu_enable_cap(cs, KVM_CAP_IRQ_XICS, 0, kernel_xics_fd, vcpu_id); if (ret < 0) { - error_setg(errp, "Unable to connect CPU%ld to kernel XICS: %s", vcpu_id, - strerror(errno)); + Error *local_err = NULL; + + error_setg(&local_err, "Unable to connect CPU%ld to kernel XICS: %s", + vcpu_id, strerror(errno)); + if (errno == ENOSPC) { + error_append_hint(&local_err, "Try -smp maxcpus=N with N < %u\n", + MACHINE(qdev_get_machine())->smp.max_cpus); + } + error_propagate(errp, local_err); return; } enabled_icp = g_malloc(sizeof(*enabled_icp)); @@ -399,6 +406,16 @@ int xics_kvm_connect(SpaprInterruptController *intc, uint32_t nr_servers, goto fail; } + /* Tell KVM about the # of VCPUs we may have (POWER9 and newer only) */ + if (kvm_device_check_attr(rc, KVM_DEV_XICS_GRP_CTRL, + KVM_DEV_XICS_NR_SERVERS)) { + if (kvm_device_access(rc, KVM_DEV_XICS_GRP_CTRL, + KVM_DEV_XICS_NR_SERVERS, &nr_servers, true, + &local_err)) { + goto fail; + } + } + kernel_xics_fd = rc; kvm_kernel_irqchip = true; kvm_msi_via_irqfd_allowed = true; -- 2.11.4.GIT