From: Alexander Graf Date: Mon, 28 Oct 2013 19:01:51 +0000 (+0200) Subject: ahci: fix win7 hang on boot X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=8464b273d69c61e33c55347e5b6bc0659687bae2;p=qemu.git ahci: fix win7 hang on boot 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 Signed-off-by: Kevin Wolf --- diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c index a8be62cf99..fbea9e8886 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); } }