[PATCH 5.16 0950/1017] Revert "virtio-pci: harden INTX interrupts"

Greg Kroah-Hartman
2022-04-05T13:48:37Z

From: Jason Wang <jasowang@redhat.com>

commit 7b79edfb862d6b1ecc66479419ae67a7db2d02e3 upstream.

This reverts commit 080cd7c3ac8701081d143a15ba17dd9475313188. Since
the MSI-X interrupts hardening will be reverted in the next patch. We
will rework the interrupt hardening in the future.

Fixes: 080cd7c3ac87 ("virtio-pci: harden INTX interrupts")
Signed-off-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20220323031524.6555-1-jasowang@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/virtio/virtio_pci_common.c | 23 ++---------------------
drivers/virtio/virtio_pci_common.h | 1 -
2 files changed, 2 insertions(+), 22 deletions(-)

--- a/drivers/virtio/virtio_pci_common.c
+++ b/drivers/virtio/virtio_pci_common.c
@@ -30,16 +30,8 @@ void vp_disable_cbs(struct virtio_device
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
int i;

- if (vp_dev->intx_enabled) {
- /*
- * The below synchronize() guarantees that any
- * interrupt for this line arriving after
- * synchronize_irq() has completed is guaranteed to see
- * intx_soft_enabled == false.
- */
- WRITE_ONCE(vp_dev->intx_soft_enabled, false);
+ if (vp_dev->intx_enabled)
synchronize_irq(vp_dev->pci_dev->irq);
- }

for (i = 0; i < vp_dev->msix_vectors; ++i)
disable_irq(pci_irq_vector(vp_dev->pci_dev, i));
@@ -51,16 +43,8 @@ void vp_enable_cbs(struct virtio_device
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
int i;

- if (vp_dev->intx_enabled) {
- disable_irq(vp_dev->pci_dev->irq);
- /*
- * The above disable_irq() provides TSO ordering and
- * as such promotes the below store to store-release.
- */
- WRITE_ONCE(vp_dev->intx_soft_enabled, true);
- enable_irq(vp_dev->pci_dev->irq);
+ if (vp_dev->intx_enabled)
return;
- }

for (i = 0; i < vp_dev->msix_vectors; ++i)
enable_irq(pci_irq_vector(vp_dev->pci_dev, i));
@@ -113,9 +97,6 @@ static irqreturn_t vp_interrupt(int irq,
struct virtio_pci_device *vp_dev = opaque;
u8 isr;

- if (!READ_ONCE(vp_dev->intx_soft_enabled))
- return IRQ_NONE;
-
/* reading the ISR has the effect of also clearing it so it's very
* important to save off the value. */
isr = ioread8(vp_dev->isr);
--- a/drivers/virtio/virtio_pci_common.h
+++ b/drivers/virtio/virtio_pci_common.h
@@ -63,7 +63,6 @@ struct virtio_pci_device {
/* MSI-X support */
int msix_enabled;
int intx_enabled;
- bool intx_soft_enabled;
cpumask_var_t *msix_affinity_masks;
/* Name strings for interrupts. This size should be enough,
* and I'm too lazy to allocate each name separately. */