[PATCH v2 29/45] kvm/vmx: Use get/put_online_cpus_atomic() to prevent CPU offline
From: Srivatsa S. Bhat <hidden>
Date: 2013-06-25 20:34:17
Also in:
kvm, linux-arch, linux-pm, lkml, netdev
Subsystem:
kernel virtual machine for x86 (kvm/x86), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Sean Christopherson, Paolo Bonzini, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
Once stop_machine() is gone from the CPU offline path, we won't be able to depend on disabling preemption to prevent CPUs from going offline from under us. Use the get/put_online_cpus_atomic() APIs to prevent CPUs from going offline, while invoking from atomic context. Cc: Gleb Natapov <redacted> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Thomas Gleixner <redacted> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: x86@kernel.org Cc: kvm@vger.kernel.org Signed-off-by: Srivatsa S. Bhat <redacted> --- arch/x86/kvm/vmx.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 260a919..4e1e966 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c@@ -26,6 +26,7 @@ #include <linux/mm.h> #include <linux/highmem.h> #include <linux/sched.h> +#include <linux/cpu.h> #include <linux/moduleparam.h> #include <linux/mod_devicetable.h> #include <linux/ftrace_event.h>
@@ -7164,12 +7165,12 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id) if (!vmm_exclusive) kvm_cpu_vmxoff(); - cpu = get_cpu(); + cpu = get_online_cpus_atomic(); vmx_vcpu_load(&vmx->vcpu, cpu); vmx->vcpu.cpu = cpu; err = vmx_vcpu_setup(vmx); vmx_vcpu_put(&vmx->vcpu); - put_cpu(); + put_online_cpus_atomic(); if (err) goto free_vmcs; if (vm_need_virtualize_apic_accesses(kvm)) {
@@ -7706,12 +7707,12 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch) vmx->nested.vmcs01_tsc_offset = vmcs_read64(TSC_OFFSET); - cpu = get_cpu(); + cpu = get_online_cpus_atomic(); vmx->loaded_vmcs = vmcs02; vmx_vcpu_put(vcpu); vmx_vcpu_load(vcpu, cpu); vcpu->cpu = cpu; - put_cpu(); + put_online_cpus_atomic(); vmx_segment_cache_clear(vmx);
@@ -8023,12 +8024,12 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu) leave_guest_mode(vcpu); prepare_vmcs12(vcpu, vmcs12); - cpu = get_cpu(); + cpu = get_online_cpus_atomic(); vmx->loaded_vmcs = &vmx->vmcs01; vmx_vcpu_put(vcpu); vmx_vcpu_load(vcpu, cpu); vcpu->cpu = cpu; - put_cpu(); + put_online_cpus_atomic(); vmx_segment_cache_clear(vmx);