KVM: MMIO: Lock coalesced device when checking for available entry (c298125f) · Commits · 戴 / test

virt/kvm/coalesced_mmio.c

+27 −15

Original line number	Diff line number	Diff line
		@@ -25,23 +25,8 @@ static int coalesced_mmio_in_range(struct kvm_coalesced_mmio_dev *dev,
		gpa_t addr, int len)
		{
		struct kvm_coalesced_mmio_zone *zone;
		struct kvm_coalesced_mmio_ring *ring;
		unsigned avail;
		int i;

		/* Are we able to batch it ? */

		/* last is the first free entry
		* check if we don't meet the first used entry
		* there is always one unused entry in the buffer
		*/
		ring = dev->kvm->coalesced_mmio_ring;
		avail = (ring->first - ring->last - 1) % KVM_COALESCED_MMIO_MAX;
		if (avail < KVM_MAX_VCPUS) {
		/* full */
		return 0;
		}

		/* is it in a batchable area ? */

		for (i = 0; i < dev->nb_zones; i++) {
		@@ -58,16 +43,43 @@ static int coalesced_mmio_in_range(struct kvm_coalesced_mmio_dev *dev,
		return 0;
		}

		static int coalesced_mmio_has_room(struct kvm_coalesced_mmio_dev *dev)
		{
		struct kvm_coalesced_mmio_ring *ring;
		unsigned avail;

		/* Are we able to batch it ? */

		/* last is the first free entry
		* check if we don't meet the first used entry
		* there is always one unused entry in the buffer
		*/
		ring = dev->kvm->coalesced_mmio_ring;
		avail = (ring->first - ring->last - 1) % KVM_COALESCED_MMIO_MAX;
		if (avail == 0) {
		/* full */
		return 0;
		}

		return 1;
		}

		static int coalesced_mmio_write(struct kvm_io_device *this,
		gpa_t addr, int len, const void *val)
		{
		struct kvm_coalesced_mmio_dev *dev = to_mmio(this);
		struct kvm_coalesced_mmio_ring *ring = dev->kvm->coalesced_mmio_ring;

		if (!coalesced_mmio_in_range(dev, addr, len))
		return -EOPNOTSUPP;

		spin_lock(&dev->lock);

		if (!coalesced_mmio_has_room(dev)) {
		spin_unlock(&dev->lock);
		return -EOPNOTSUPP;
		}

		/* copy data in first free entry of the ring */

		ring->coalesced_mmio[ring->last].phys_addr = addr;

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