ahci: advertise HOST_CAP_64

The AHCI emulation code supports 64-bit addressing and should advertise this
fact in the Host Capabilities register. Both Linux and Windows drivers test
this bit to decide if the upper 32 bits of various registers may be written
to, and at least some versions of Windows have a bug where DMA is attempted
with an address above 4GB but, in the absence of HOST_CAP_64, the upper 32
bits are left unititialized which leads to a memory corruption.

[Maintainer edit:

This fixes https://bugzilla.redhat.com/show_bug.cgi?id=1411105,
which affects Windows Server 2008 SP2 in some cases.]

Signed-off-by: Ladi Prosek <lprosek@redhat.com>
Message-id: 1484305370-6220-1-git-send-email-lprosek@redhat.com
[Amended commit message --js]
Signed-off-by: John Snow <jsnow@redhat.com>

diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c
index 3c19bdadc54cdac051752f41984f1fa4ccfca887..6a17acf639a4b0bf8fe2de4dfabcdcdd86978ed0 100644 (file)
--- a/hw/ide/ahci.c
+++ b/hw/ide/ahci.c
@@ -488,7 +488,7 @@ static void ahci_reg_init(AHCIState *s)
     s->control_regs.cap = (s->ports - 1) |
                           (AHCI_NUM_COMMAND_SLOTS << 8) |
                           (AHCI_SUPPORTED_SPEED_GEN1 << AHCI_SUPPORTED_SPEED) |
-                          HOST_CAP_NCQ | HOST_CAP_AHCI;
+                          HOST_CAP_NCQ | HOST_CAP_AHCI | HOST_CAP_64;
 
     s->control_regs.impl = (1 << s->ports) - 1;