File 0064-ahci-fix-PxCI-register-race.patch of Package qemu

Overview Repositories Revisions Requests Users Attributes Meta

File 0064-ahci-fix-PxCI-register-race.patch of Package qemu (Revision c0e27852a6280021823822ba5f36979e)

Currently displaying revision c0e27852a6280021823822ba5f36979e , Show latest

From b523826a08ababd1e5d404ae34667c4947895e4f Mon Sep 17 00:00:00 2001
From: John Snow <jsnow@redhat.com>
Date: Thu, 31 May 2018 04:16:16 -0600
Subject: [PATCH] ahci: fix PxCI register race

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.

Signed-off-by: John Snow <jsnow@redhat.com>
[BR: BSC#1094406]
Signed-off-by: Bruce Rogers <brogers@suse.com>
---
 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 e22d7be05f..18b9a9c18b 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);

Places

File 0064-ahci-fix-PxCI-register-race.patch of Package qemu (Revision c0e27852a6280021823822ba5f36979e)

Places