Re: [Qemu-stable] [PATCH 58/81] ahci: advertise HOST_CAP_64

[John Snow]

On 03/20/2017 07:08 PM, Michael Roth wrote:
> From: Ladi Prosek <address@hidden>
> 
> 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 <address@hidden>
> Message-id: address@hidden
> [Amended commit message --js]
> Signed-off-by: John Snow <address@hidden>
> 
> (cherry picked from commit 98cb5dccb192b0082626080890dac413473573c6)
> Signed-off-by: Michael Roth <address@hidden>
> ---
>  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;
>  
> 

A reminder that if this is backported to 2.8.1, that you will need to
include the relevant seaBIOS fixes as well. Otherwise, rebooting under
that firmware breaks!

--js