| Message ID | 20131028190015.GA1923@redhat.com |
|---|---|
| State | New |
| Headers | show |
On Mon, Oct 28, 2013 at 09:00:15PM +0200, Michael S. Tsirkin wrote: > From: Alexander Graf <agraf@suse.de> > > 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 <mst@redhat.com> > Reviewed-by: Michael S. Tsirkin <mst@redhat.com> > Tested-by: Michael S. Tsirkin <mst@redhat.com> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Sorry about the subject, forgot to update it. I reposted with a fixed subject. > --- > 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
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); } }