From 93623a848fba7757a0840b78d7b3874bab4d7a1b Mon Sep 17 00:00:00 2001 From: John Snow Date: Tue, 10 Jul 2018 23:06:15 +0200 Subject: [PATCH 206/268] ahci: fix PxCI register race MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: John Snow Message-id: <20180710230616.11000-3-jsnow@redhat.com> Patchwork-id: 81293 O-Subject: [RHEL-7.6 qemu-kvm-rhev PATCH 2/3] ahci: fix PxCI register race Bugzilla: 1584914 RH-Acked-by: Laurent Vivier RH-Acked-by: Laszlo Ersek RH-Acked-by: Stefan Hajnoczi Fixes: https://bugs.launchpad.net/qemu/+bug/1769189 AHCI presently signals completion prior to the PxCI register being cleared to indicate completion. If a guest driver attempts to issue a new command in its IRQ handler, it might be surprised to learn there is still a command pending. In the case of Windows 10's boot driver, it will actually poll the IRQ register hoping to find out when the command is done running -- which will never happen, as there isn't a command running. Fix this: clear PxCI in ahci_cmd_done and not in the asynchronous BH. Because it now runs synchronously, we don't need to check if the command is actually done by spying on the ATA registers. We know it's done. CC: qemu-stable Reported-by: François Guerraz Tested-by: Bruce Rogers Signed-off-by: John Snow Reviewed-by: Stefan Hajnoczi Reviewed-by: Jeff Cody Message-id: 20180531004323.4611-3-jsnow@redhat.com Signed-off-by: John Snow (cherry picked from commit 5694c7eacce6b263ad7497cc1bb76aad746cfd4e) Signed-off-by: John Snow Signed-off-by: Miroslav Rezanina --- hw/ide/ahci.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c index b7a6f68..a9558e4 100644 --- a/hw/ide/ahci.c +++ b/hw/ide/ahci.c @@ -532,13 +532,6 @@ static void ahci_check_cmd_bh(void *opaque) qemu_bh_delete(ad->check_bh); ad->check_bh = NULL; - if ((ad->busy_slot != -1) && - !(ad->port.ifs[0].status & (BUSY_STAT|DRQ_STAT))) { - /* no longer busy */ - ad->port_regs.cmd_issue &= ~(1 << ad->busy_slot); - ad->busy_slot = -1; - } - check_cmd(ad->hba, ad->port_no); } @@ -1425,6 +1418,12 @@ static void ahci_cmd_done(IDEDMA *dma) trace_ahci_cmd_done(ad->hba, ad->port_no); + /* no longer busy */ + if (ad->busy_slot != -1) { + ad->port_regs.cmd_issue &= ~(1 << ad->busy_slot); + ad->busy_slot = -1; + } + /* update d2h status */ ahci_write_fis_d2h(ad); -- 1.8.3.1