From: Ladi Prosek <lpro...@redhat.com> 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 <lpro...@redhat.com> Message-id: 1484305370-6220-1-git-send-email-lpro...@redhat.com [Amended commit message --js] Signed-off-by: John Snow <js...@redhat.com> (cherry picked from commit 98cb5dccb192b0082626080890dac413473573c6) Signed-off-by: Michael Roth <mdr...@linux.vnet.ibm.com> --- hw/ide/ahci.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c index 3c19bda..6a17acf 100644 --- 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; -- 2.7.4
