| Message ID | 1278506062-4799-1-git-send-email-stefanha@linux.vnet.ibm.com |
|---|---|
| State | New |
| Headers | show |
On Wed, Jul 07, 2010 at 01:34:22PM +0100, Stefan Hajnoczi wrote: > The VRING_AVAIL_F_NO_INTERRUPT flag is a hint that interrupts should be > suppressed. It does not guarantee that interrupts will not be raised. > Therefore, make sure to clear the interrupt after each virtio-blk read. > This avoids a stuck interrupt interfering with the OS loaded later in > the boot process. > > Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Acked-by: Gleb Natapov <gleb@redhat.com> > --- > src/virtio-blk.c | 6 ++++++ > src/virtio-pci.h | 4 ++++ > 2 files changed, 10 insertions(+), 0 deletions(-) > > diff --git a/src/virtio-blk.c b/src/virtio-blk.c > index 16d9ad8..74af488 100644 > --- a/src/virtio-blk.c > +++ b/src/virtio-blk.c > @@ -62,6 +62,12 @@ virtio_blk_read(struct disk_op_s *op) > > /* Reclaim virtqueue element */ > vring_get_buf(vq, NULL); > + > + /* Clear interrupt status register. Avoid leaving interrupts stuck if > + * VRING_AVAIL_F_NO_INTERRUPT was ignored and interrupts were raised. > + */ > + vp_get_isr(GET_GLOBAL(vdrive_g->ioaddr)); > + > return status == VIRTIO_BLK_S_OK ? DISK_RET_SUCCESS : DISK_RET_EBADTRACK; > } > > diff --git a/src/virtio-pci.h b/src/virtio-pci.h > index 9da761d..d21d5a5 100644 > --- a/src/virtio-pci.h > +++ b/src/virtio-pci.h > @@ -71,6 +71,10 @@ static inline void vp_set_status(unsigned int ioaddr, u8 status) > outb(status, ioaddr + VIRTIO_PCI_STATUS); > } > > +static inline u8 vp_get_isr(unsigned int ioaddr) > +{ > + return inb(ioaddr + VIRTIO_PCI_ISR); > +} > > static inline void vp_reset(unsigned int ioaddr) > { > -- > 1.7.1 -- Gleb.
On Wed, Jul 07, 2010 at 01:34:22PM +0100, Stefan Hajnoczi wrote: > The VRING_AVAIL_F_NO_INTERRUPT flag is a hint that interrupts should be > suppressed. It does not guarantee that interrupts will not be raised. > Therefore, make sure to clear the interrupt after each virtio-blk read. > This avoids a stuck interrupt interfering with the OS loaded later in > the boot process. > > Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Thanks. Commit 4e0daae5. -Kevin
diff --git a/src/virtio-blk.c b/src/virtio-blk.c index 16d9ad8..74af488 100644 --- a/src/virtio-blk.c +++ b/src/virtio-blk.c @@ -62,6 +62,12 @@ virtio_blk_read(struct disk_op_s *op) /* Reclaim virtqueue element */ vring_get_buf(vq, NULL); + + /* Clear interrupt status register. Avoid leaving interrupts stuck if + * VRING_AVAIL_F_NO_INTERRUPT was ignored and interrupts were raised. + */ + vp_get_isr(GET_GLOBAL(vdrive_g->ioaddr)); + return status == VIRTIO_BLK_S_OK ? DISK_RET_SUCCESS : DISK_RET_EBADTRACK; } diff --git a/src/virtio-pci.h b/src/virtio-pci.h index 9da761d..d21d5a5 100644 --- a/src/virtio-pci.h +++ b/src/virtio-pci.h @@ -71,6 +71,10 @@ static inline void vp_set_status(unsigned int ioaddr, u8 status) outb(status, ioaddr + VIRTIO_PCI_STATUS); } +static inline u8 vp_get_isr(unsigned int ioaddr) +{ + return inb(ioaddr + VIRTIO_PCI_ISR); +} static inline void vp_reset(unsigned int ioaddr) {
The VRING_AVAIL_F_NO_INTERRUPT flag is a hint that interrupts should be suppressed. It does not guarantee that interrupts will not be raised. Therefore, make sure to clear the interrupt after each virtio-blk read. This avoids a stuck interrupt interfering with the OS loaded later in the boot process. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> --- src/virtio-blk.c | 6 ++++++ src/virtio-pci.h | 4 ++++ 2 files changed, 10 insertions(+), 0 deletions(-)