From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=56667 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OWTpj-00036p-5i for qemu-devel@nongnu.org; Wed, 07 Jul 2010 08:34:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1OWTpi-0005N7-3B for qemu-devel@nongnu.org; Wed, 07 Jul 2010 08:34:35 -0400 Received: from mtagate2.de.ibm.com ([195.212.17.162]:43777) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1OWTph-0005MR-Rq for qemu-devel@nongnu.org; Wed, 07 Jul 2010 08:34:34 -0400 Received: from d12nrmr1607.megacenter.de.ibm.com (d12nrmr1607.megacenter.de.ibm.com [9.149.167.49]) by mtagate2.de.ibm.com (8.13.1/8.13.1) with ESMTP id o67CYRfA013715 for ; Wed, 7 Jul 2010 12:34:27 GMT Received: from d12av04.megacenter.de.ibm.com (d12av04.megacenter.de.ibm.com [9.149.165.229]) by d12nrmr1607.megacenter.de.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o67CYOmB1691852 for ; Wed, 7 Jul 2010 14:34:27 +0200 Received: from d12av04.megacenter.de.ibm.com (loopback [127.0.0.1]) by d12av04.megacenter.de.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id o67CYOmK029972 for ; Wed, 7 Jul 2010 14:34:24 +0200 From: Stefan Hajnoczi Date: Wed, 7 Jul 2010 13:34:22 +0100 Message-Id: <1278506062-4799-1-git-send-email-stefanha@linux.vnet.ibm.com> Subject: [Qemu-devel] [SeaBIOS] [PATCH] virtio: Clear interrupt status register in virtio-blk List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: seabios@seabios.org Cc: qemu-devel@nongnu.org, Gleb Natapov , Stefan Hajnoczi 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 --- 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