Re: [Xen-devel] [PATCH v2] xen/pass-through: ROM BAR handling adjustments

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Mon, 8 Jun 2015, Jan Beulich wrote:
> Expecting the ROM BAR to be written with an all ones value when sizing
> the region is wrong - the low bit has another meaning (enable/disable)
> and bits 1..10 are reserved. The PCI spec also mandates writing all
> ones to just the address portion of the register.
> 
> Use suitable constants also for initializing the ROM BAR register field
> description.
> 
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

Reviewed-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>

Added to my queue


> v2: Convert complex if() into simpler ones.
> 
> --- a/hw/xen/xen_pt.c
> +++ b/hw/xen/xen_pt.c
> @@ -249,10 +249,18 @@ static void xen_pt_pci_write_config(PCID
>  
>      /* check unused BAR register */
>      index = xen_pt_bar_offset_to_index(addr);
> -    if ((index >= 0) && (val > 0 && val < XEN_PT_BAR_ALLF) &&
> -        (s->bases[index].bar_flag == XEN_PT_BAR_FLAG_UNUSED)) {
> -        XEN_PT_WARN(d, "Guest attempt to set address to unused Base Address "
> -                    "Register. (addr: 0x%02x, len: %d)\n", addr, len);
> +    if ((index >= 0) && (val != 0)) {
> +        uint32_t chk = val;
> +
> +        if (index == PCI_ROM_SLOT)
> +            chk |= (uint32_t)~PCI_ROM_ADDRESS_MASK;
> +
> +        if ((chk != XEN_PT_BAR_ALLF) &&
> +            (s->bases[index].bar_flag == XEN_PT_BAR_FLAG_UNUSED)) {
> +            XEN_PT_WARN(d, "Guest attempt to set address to unused "
> +                        "Base Address Register. (addr: 0x%02x, len: %d)\n",
> +                        addr, len);
> +        }
>      }
>  
>      /* find register group entry */
> --- a/hw/xen/xen_pt_config_init.c
> +++ b/hw/xen/xen_pt_config_init.c
> @@ -729,8 +729,8 @@ static XenPTRegInfo xen_pt_emu_reg_heade
>          .offset     = PCI_ROM_ADDRESS,
>          .size       = 4,
>          .init_val   = 0x00000000,
> -        .ro_mask    = 0x000007FE,
> -        .emu_mask   = 0xFFFFF800,
> +        .ro_mask    = ~PCI_ROM_ADDRESS_MASK & ~PCI_ROM_ADDRESS_ENABLE,
> +        .emu_mask   = (uint32_t)PCI_ROM_ADDRESS_MASK,
>          .init       = xen_pt_bar_reg_init,
>          .u.dw.read  = xen_pt_long_reg_read,
>          .u.dw.write = xen_pt_exp_rom_bar_reg_write,
> 
> 
> 
> 

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