From 8464b273d69c61e33c55347e5b6bc0659687bae2 Mon Sep 17 00:00:00 2001 From: Alexander Graf Date: Mon, 28 Oct 2013 21:01:51 +0200 Subject: 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 --- hw/ide/ahci.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'hw/ide') 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); } } -- cgit v1.2.3