[PATCH v4 5/8] KVM: introduce kvm_make_vcpus_request_mask() API

Vitaly Kuznetsov
2018-05-16T15:23:52Z

Hyper-V style PV TLB flush hypercalls inmplementation will use this API.
To avoid memory allocation in CONFIG_CPUMASK_OFFSTACK case add
cpumask_var_t argument.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
include/linux/kvm_host.h | 3 +++
virt/kvm/kvm_main.c | 34 ++++++++++++++++++++++++++--------
2 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 6d6e79c59e68..14e710d639c7 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -730,6 +730,9 @@ void kvm_put_guest_fpu(struct kvm_vcpu *vcpu);

void kvm_flush_remote_tlbs(struct kvm *kvm);
void kvm_reload_remote_mmus(struct kvm *kvm);
+
+bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req,
+ unsigned long *vcpu_bitmap, cpumask_var_t tmp);
bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req);

long kvm_arch_dev_ioctl(struct file *filp,
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index c7b2e927f699..b125d94307d2 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -203,29 +203,47 @@ static inline bool kvm_kick_many_cpus(const struct cpumask *cpus, bool wait)
return true;
}

-bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req)
+bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req,
+ unsigned long *vcpu_bitmap, cpumask_var_t tmp)
{
int i, cpu, me;
- cpumask_var_t cpus;
- bool called;
struct kvm_vcpu *vcpu;
-
- zalloc_cpumask_var(&cpus, GFP_ATOMIC);
+ bool called;

me = get_cpu();
+
kvm_for_each_vcpu(i, vcpu, kvm) {
+ if (!test_bit(i, vcpu_bitmap))
+ continue;
+
kvm_make_request(req, vcpu);
cpu = vcpu->cpu;

if (!(req & KVM_REQUEST_NO_WAKEUP) && kvm_vcpu_wake_up(vcpu))
continue;

- if (cpus != NULL && cpu != -1 && cpu != me &&
+ if (tmp != NULL && cpu != -1 && cpu != me &&
kvm_request_needs_ipi(vcpu, req))
- __cpumask_set_cpu(cpu, cpus);
+ __cpumask_set_cpu(cpu, tmp);
}
- called = kvm_kick_many_cpus(cpus, !!(req & KVM_REQUEST_WAIT));
+
+ called = kvm_kick_many_cpus(tmp, !!(req & KVM_REQUEST_WAIT));
put_cpu();
+
+ return called;
+}
+
+bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req)
+{
+ cpumask_var_t cpus;
+ bool called;
+ static unsigned long vcpu_bitmap[BITS_TO_LONGS(KVM_MAX_VCPUS)]
+ = {[0 ... BITS_TO_LONGS(KVM_MAX_VCPUS)-1] = ULONG_MAX};
+
+ zalloc_cpumask_var(&cpus, GFP_ATOMIC);
+
+ called = kvm_make_vcpus_request_mask(kvm, req, vcpu_bitmap, cpus);
+
free_cpumask_var(cpus);
return called;
}
--
2.14.3