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McKenney" , david.kaplan@amd.com, konrad.wilk@oracle.com, Peter Zijlstra , Boqun Feng , f.hetzelt@tu-berlin.de, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, Thomas Gleixner X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" This patch tries to make sure the virtio interrupt handler for INTX won't be called after a reset and before virtio_device_ready(). We can't use IRQF_NO_AUTOEN since we're using shared interrupt (IRQF_SHARED). So this patch tracks the INTX enabling status in a new intx_soft_enabled variable and toggle it during in vp_disable/enable_vectors(). The INTX interrupt handler will check intx_soft_enabled before processing the actual interrupt. Cc: Boqun Feng Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Paul E. McKenney Signed-off-by: Jason Wang --- drivers/virtio/virtio_pci_common.c | 23 +++++++++++++++++++++-- drivers/virtio/virtio_pci_common.h | 1 + 2 files changed, 22 insertions(+), 2 deletions(-) diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c index 8d8f83aca721..1bce254a462a 100644 --- a/drivers/virtio/virtio_pci_common.c +++ b/drivers/virtio/virtio_pci_common.c @@ -30,8 +30,16 @@ void vp_disable_cbs(struct virtio_device *vdev) struct virtio_pci_device *vp_dev = to_vp_device(vdev); int i; - if (vp_dev->intx_enabled) + 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); 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)); @@ -43,8 +51,16 @@ void vp_enable_cbs(struct virtio_device *vdev) struct virtio_pci_device *vp_dev = to_vp_device(vdev); int i; - if (vp_dev->intx_enabled) + 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); return; + } for (i = 0; i < vp_dev->msix_vectors; ++i) enable_irq(pci_irq_vector(vp_dev->pci_dev, i)); @@ -97,6 +113,9 @@ static irqreturn_t vp_interrupt(int irq, void *opaque) 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); diff --git a/drivers/virtio/virtio_pci_common.h b/drivers/virtio/virtio_pci_common.h index 52e924603075..7b59e10063c3 100644 --- a/drivers/virtio/virtio_pci_common.h +++ b/drivers/virtio/virtio_pci_common.h @@ -64,6 +64,7 @@ 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. */ -- 2.25.1 _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization