Re: [Qemu-devel] [PATCH] ahci: Fix non-NCQ accesses for LBA > 16bits

[Jan Kiszka]

On 2011-05-18 14:48, Alexander Graf wrote:
> AHCI provides two ways of reading/writing data:
> 
>  1) NCQ
>  2) ATA commands with the LBA in the command FIS
> 
> In the second code path, we didn't handle any LBAs that were bigger than
> 16 bits, so whenever a guest that used high LBA numbers wanted to access
> data, the LBA got truncated down to 16 bits, giving the guest garbage.
> 
> This patch adds support for LBAs higher than 16 bits. I've tested that it
> works just fine with SeaBIOS and Linux guests. This patch also unbreaks
> the often reported grub errors people have seen with AHCI.

Cool! I actually had such a guest as well, but I didn't manage to look
closer so far. Now this patch cures it.

Jan

> 
> Signed-off-by: Alexander Graf <address@hidden>
> ---
>  hw/ide/ahci.c |    9 +++++++--
>  1 files changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c
> index c6e0c77..bc5c553 100644
> --- a/hw/ide/ahci.c
> +++ b/hw/ide/ahci.c
> @@ -884,8 +884,13 @@ static int handle_cmd(AHCIState *s, int port, int slot)
>          }
>  
>          if (ide_state->drive_kind != IDE_CD) {
> -            ide_set_sector(ide_state, (cmd_fis[6] << 16) | (cmd_fis[5] << 8) 
> |
> -                           cmd_fis[4]);
> +            ide_set_sector(ide_state, ((uint64_t)cmd_fis[10] << 40)
> +                                    | ((uint64_t)cmd_fis[9] << 32)
> +                                    | ((uint64_t)cmd_fis[8] << 24)
> +                                    | ((uint64_t)(cmd_fis[7] & 0xf) << 24)
> +                                    | ((uint64_t)cmd_fis[6] << 16)
> +                                    | ((uint64_t)cmd_fis[5] << 8)
> +                                    | cmd_fis[4]);
>          }
>  
>          /* Copy the ACMD field (ATAPI packet, if any) from the AHCI command

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