Sean Christopherson [off-list ref] writes:

On Fri, Sep 03, 2021, Vitaly Kuznetsov wrote:

quoted

kvm_make_vcpus_request_mask() already disables preemption so just like
kvm_make_all_cpus_request_except() it can be switched to using
pre-allocated per-cpu cpumasks. This allows for improvements for both
users of the function: in Hyper-V emulation code 'tlb_flush' can now be
dropped from 'struct kvm_vcpu_hv' and kvm_make_scan_ioapic_request_mask()
gets rid of dynamic allocation.

cpumask_available() checks in kvm_make_vcpu_request() and
kvm_kick_many_cpus() can now be dropped as they checks for an impossible
condition: kvm_init() makes sure per-cpu masks are allocated.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---

Reviewed-by: Sean Christopherson <seanjc@google.com>

Thanks!

quoted

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a4752dcc2a75..91c1e6c98b0f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c

@@ -9224,14 +9224,8 @@ static void process_smi(struct kvm_vcpu *vcpu)
 void kvm_make_scan_ioapic_request_mask(struct kvm *kvm,
 				       unsigned long *vcpu_bitmap)
 {
-	cpumask_var_t cpus;
-
-	zalloc_cpumask_var(&cpus, GFP_ATOMIC);
-
 	kvm_make_vcpus_request_mask(kvm, KVM_REQ_SCAN_IOAPIC,
-				    vcpu_bitmap, cpus);
-
-	free_cpumask_var(cpus);
+				    vcpu_bitmap);

Nit, this can all go on a single line.

Sorry, you've mentioned this on v4 but I forgot. Hope this can be fixed
upon commit...

quoted

 }
 
 void kvm_make_scan_ioapic_request(struct kvm *kvm)

-- 
Vitaly