Re: [PATCH v3 1/4] x86/kvm: add boot parameter for adding vcpu-id bits
From: Sean Christopherson <seanjc@google.com>
Date: 2021-11-17 23:44:49
Also in:
kvm, lkml
On Tue, Nov 16, 2021, Juergen Gross wrote:
quoted hunk ↗ jump to hunk
diff --git a/arch/x86/kvm/ioapic.c b/arch/x86/kvm/ioapic.c index 816a82515dcd..64ba9b1c8b3d 100644 --- a/arch/x86/kvm/ioapic.c +++ b/arch/x86/kvm/ioapic.c@@ -685,11 +685,21 @@ static const struct kvm_io_device_ops ioapic_mmio_ops = { int kvm_ioapic_init(struct kvm *kvm) { struct kvm_ioapic *ioapic; + size_t sz; int ret; - ioapic = kzalloc(sizeof(struct kvm_ioapic), GFP_KERNEL_ACCOUNT); + sz = sizeof(struct kvm_ioapic) + + sizeof(*ioapic->rtc_status.dest_map.map) * + BITS_TO_LONGS(KVM_MAX_VCPU_IDS) + + sizeof(*ioapic->rtc_status.dest_map.vectors) * + (KVM_MAX_VCPU_IDS); + ioapic = kzalloc(sz, GFP_KERNEL_ACCOUNT); if (!ioapic) return -ENOMEM; + ioapic->rtc_status.dest_map.map = (void *)(ioapic + 1);
Oof. Just do separate allocations. I highly doubt the performance of the emulated RTC hinges on the spatial locality of the bitmap and array. The array is going to end up in a second page for most configuration anyways.
+ ioapic->rtc_status.dest_map.vectors = + (void *)(ioapic->rtc_status.dest_map.map + + BITS_TO_LONGS(KVM_MAX_VCPU_IDS)); spin_lock_init(&ioapic->lock); INIT_DELAYED_WORK(&ioapic->eoi_inject, kvm_ioapic_eoi_inject_work); kvm->arch.vioapic = ioapic;