From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42899) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Vas1B-00030a-Dj for qemu-devel@nongnu.org; Mon, 28 Oct 2013 14:58:30 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Vas16-0001LX-Hm for qemu-devel@nongnu.org; Mon, 28 Oct 2013 14:58:25 -0400 Received: from mx1.redhat.com ([209.132.183.28]:9890) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Vas16-0001LR-9m for qemu-devel@nongnu.org; Mon, 28 Oct 2013 14:58:20 -0400 Date: Mon, 28 Oct 2013 21:00:15 +0200 From: "Michael S. Tsirkin" Message-ID: <20131028190015.GA1923@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Subject: [Qemu-devel] [PATCH] ahci fix: windows boots fine. need to review with kwolf List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , Paolo Bonzini , Andreas =?iso-8859-1?Q?F=E4rber?= , Anthony Liguori , agraf@suse.de From: Alexander Graf When AHCI executes an asynchronous IDE command, it checked DRDY without checking either DRQ or BSY. This sometimes caused interrupt to be sent before command is actually completed. This resulted in a race condition: if guest then managed to access the device before command has completed, it would hang waiting for an interrupt. This was observed with windows 7 guests. To fix, check for DRQ or BSY in additiona to DRDY, if set, the command is asynchronous so delay the interrupt until asynchronous done callback is invoked. Reported-by: Michael S. Tsirkin Reviewed-by: Michael S. Tsirkin Tested-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/ide/ahci.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c index a8be62c..fbea9e8 100644 --- a/hw/ide/ahci.c +++ b/hw/ide/ahci.c @@ -961,7 +961,8 @@ static int handle_cmd(AHCIState *s, int port, int slot) /* We're ready to process the command in FIS byte 2. */ ide_exec_cmd(&s->dev[port].port, cmd_fis[2]); - if (s->dev[port].port.ifs[0].status & READY_STAT) { + if ((s->dev[port].port.ifs[0].status & (READY_STAT|DRQ_STAT|BUSY_STAT)) == + READY_STAT) { ahci_write_fis_d2h(&s->dev[port], cmd_fis); } } -- MST