From db3e0a8dd430a11e8dde6aee4e1f9cca4af0e015 Mon Sep 17 00:00:00 2001 From: Zeng Guang Date: Thu, 25 Aug 2022 10:52:46 +0800 Subject: [PATCH] target/i386: Set maximum APIC ID to KVM prior to vCPU creation from mainline-v7.2.0-rc0 commit 19e2a9fb9da067acba95b3be83588bda5a3f6a99 category: feature feature: Optimization of IPI virtualization bugzilla: https://gitee.com/openeuler/intel-qemu/issues/I6Y34T Intel-SIG: commit 19e2a9fb9da0 ("target/i386: Set maximum APIC ID to KVM prior to vCPU creation") ------------------------------------------------ Specify maximum possible APIC ID assigned for current VM session to KVM prior to the creation of vCPUs. By this setting, KVM can set up VM-scoped data structure indexed by the APIC ID, e.g. Posted-Interrupt Descriptor pointer table to support Intel IPI virtualization, with the most optimal memory footprint. It can be achieved by calling KVM_ENABLE_CAP for KVM_CAP_MAX_VCPU_ID capability once KVM has enabled it. Ignoring the return error if KVM doesn't support this capability yet. Signed-off-by: Zeng Guang Acked-by: Peter Xu Acked-by: Michael S. Tsirkin Message-Id: <20220825025246.26618-1-guang.zeng@intel.com> Signed-off-by: Paolo Bonzini [ jason: amend commit log ] Signed-off-by: Jason Zeng --- hw/i386/x86.c | 4 ++++ target/i386/kvm/kvm-stub.c | 5 +++++ target/i386/kvm/kvm.c | 5 +++++ target/i386/kvm/kvm_i386.h | 2 ++ 4 files changed, 16 insertions(+) diff --git a/hw/i386/x86.c b/hw/i386/x86.c index f64639b873..a3258d78fa 100644 --- a/hw/i386/x86.c +++ b/hw/i386/x86.c @@ -152,6 +152,10 @@ void x86_cpus_init(X86MachineState *x86ms, int default_cpu_version) exit(EXIT_FAILURE); } + if (kvm_enabled()) { + kvm_set_max_apic_id(x86ms->apic_id_limit); + } + possible_cpus = mc->possible_cpu_arch_ids(ms); for (i = 0; i < ms->smp.cpus; i++) { x86_cpu_new(x86ms, possible_cpus->cpus[i].arch_id, &error_fatal); diff --git a/target/i386/kvm/kvm-stub.c b/target/i386/kvm/kvm-stub.c index f6e7e4466e..e052f1c7b0 100644 --- a/target/i386/kvm/kvm-stub.c +++ b/target/i386/kvm/kvm-stub.c @@ -44,3 +44,8 @@ bool kvm_hyperv_expand_features(X86CPU *cpu, Error **errp) { abort(); } + +void kvm_set_max_apic_id(uint32_t max_apic_id) +{ + return; +} diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c index b8257e7e5f..7212ed98a9 100644 --- a/target/i386/kvm/kvm.c +++ b/target/i386/kvm/kvm.c @@ -5270,3 +5270,8 @@ void kvm_arch_accel_class_init(ObjectClass *oc) "Clock cycles without an event window " "after which a notification VM exit occurs"); } + +void kvm_set_max_apic_id(uint32_t max_apic_id) +{ + kvm_vm_enable_cap(kvm_state, KVM_CAP_MAX_VCPU_ID, 0, max_apic_id); +} diff --git a/target/i386/kvm/kvm_i386.h b/target/i386/kvm/kvm_i386.h index 4124912c20..58590138e5 100644 --- a/target/i386/kvm/kvm_i386.h +++ b/target/i386/kvm/kvm_i386.h @@ -54,4 +54,6 @@ uint64_t kvm_swizzle_msi_ext_dest_id(uint64_t address); bool kvm_enable_sgx_provisioning(KVMState *s); void kvm_request_xsave_components(X86CPU *cpu, uint64_t mask); +void kvm_set_max_apic_id(uint32_t max_apic_id); + #endif -- 2.27.0