Commit 038f8c11 authored by Jan Kiszka's avatar Jan Kiszka Committed by Marcelo Tosatti
Browse files

KVM: x86: Convert tsc_write_lock to raw_spinlock 



Code under this lock requires non-preemptibility. Ensure this also over
-rt by converting it to raw spinlock.

Signed-off-by: default avatarJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 7049467b

arch/x86/include/asm/kvm_host.h

+1 −1
Original line number Original line Diff line number Diff line
@@ -448,7 +448,7 @@ struct kvm_arch { 




	unsigned long irq_sources_bitmap;

	unsigned long irq_sources_bitmap;

	s64 kvmclock_offset;

	s64 kvmclock_offset;

	spinlock_t tsc_write_lock;

	raw_spinlock_t tsc_write_lock;

	u64 last_tsc_nsec;

	u64 last_tsc_nsec;

	u64 last_tsc_offset;

	u64 last_tsc_offset;

	u64 last_tsc_write;

	u64 last_tsc_write;

arch/x86/kvm/x86.c

+3 −3
Original line number Original line Diff line number Diff line
@@ -1017,7 +1017,7 @@ void kvm_write_tsc(struct kvm_vcpu *vcpu, u64 data) 
	unsigned long flags;

	unsigned long flags;

	s64 sdiff;

	s64 sdiff;





	spin_lock_irqsave(&kvm->arch.tsc_write_lock, flags);

	raw_spin_lock_irqsave(&kvm->arch.tsc_write_lock, flags);

	offset = data - native_read_tsc();

	offset = data - native_read_tsc();

	ns = get_kernel_ns();

	ns = get_kernel_ns();

	elapsed = ns - kvm->arch.last_tsc_nsec;

	elapsed = ns - kvm->arch.last_tsc_nsec;
@@ -1050,7 +1050,7 @@ void kvm_write_tsc(struct kvm_vcpu *vcpu, u64 data) 
	kvm->arch.last_tsc_write = data;

	kvm->arch.last_tsc_write = data;

	kvm->arch.last_tsc_offset = offset;

	kvm->arch.last_tsc_offset = offset;

	kvm_x86_ops->write_tsc_offset(vcpu, offset);

	kvm_x86_ops->write_tsc_offset(vcpu, offset);

	spin_unlock_irqrestore(&kvm->arch.tsc_write_lock, flags);

	raw_spin_unlock_irqrestore(&kvm->arch.tsc_write_lock, flags);





	/* Reset of TSC must disable overshoot protection below */

	/* Reset of TSC must disable overshoot protection below */

	vcpu->arch.hv_clock.tsc_timestamp = 0;

	vcpu->arch.hv_clock.tsc_timestamp = 0;
@@ -6004,7 +6004,7 @@ int kvm_arch_init_vm(struct kvm *kvm) 
	/* Reserve bit 0 of irq_sources_bitmap for userspace irq source */

	/* Reserve bit 0 of irq_sources_bitmap for userspace irq source */

	set_bit(KVM_USERSPACE_IRQ_SOURCE_ID, &kvm->arch.irq_sources_bitmap);

	set_bit(KVM_USERSPACE_IRQ_SOURCE_ID, &kvm->arch.irq_sources_bitmap);





	spin_lock_init(&kvm->arch.tsc_write_lock);

	raw_spin_lock_init(&kvm->arch.tsc_write_lock);





	return 0;

	return 0;

}

}

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