Re: [Xen-devel] [PATCH 3/3] VT-d: deal with 5500/5520/X58 errata

["Zhang, Xiantao" <xiantao.zhang@xxxxxxxxx>]

Looks fine, Acked! Thanks! 
Xiantao

> -----Original Message-----
> From: Jan Beulich [mailto:JBeulich@xxxxxxxx]
> Sent: Wednesday, March 20, 2013 12:48 AM
> To: xen-devel
> Cc: Jacob Shin; suravee.suthikulpanit@xxxxxxx; Andrew Cooper; Malcolm
> Crossley; Zhang, Xiantao
> Subject: [PATCH 3/3] VT-d: deal with 5500/5520/X58 errata
> 
> http://www.intel.com/content/www/us/en/chipsets/5520-and-5500-chipset-ioh-
> specification-update.html
> 
> Stepping B-3 has two errata (#47 and #53) related to Interrupt
> remapping, to which the workaround is for the BIOS to completely disable
> interrupt remapping.  These errata are fixed in stepping C-2.
> 
> Unfortunately this chipset stepping is very common and many BIOSes are
> not disabling interrupt remapping on this stepping .  We can detect this in
> Xen and prevent Xen from using the problematic interrupt remapping feature.
> 
> The Intel 5500/5520/X58 chipset does not support VT-d
> Extended Interrupt Mode(EIM). This means the iommu_supports_eim() check
> always fails and so x2apic mode cannot be enabled in Xen before this quirk
> disables the interrupt remapping feature.
> 
> Signed-off-by: Malcolm Crossley <malcolm.crossley@xxxxxxxxxx>
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> 
> Gate the function call to check the quirk on interrupt remapping being
> requested to get enabled, and upon failure disable the IOMMU to be in
> line with what the changes for XSA-36 (plus follow-ups) did.
> 
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> 
> --- a/xen/drivers/passthrough/vtd/iommu.c
> +++ b/xen/drivers/passthrough/vtd/iommu.c
> @@ -2125,6 +2125,11 @@ int __init intel_vtd_setup(void)
>      }
> 
>      platform_quirks_init();
> +    if ( !iommu_enable )
> +    {
> +        ret = -ENODEV;
> +        goto error;
> +    }
> 
>      /* We enable the following features only if they are supported by all 
> VT-d
>       * engines: Snoop Control, DMA passthrough, Queued Invalidation and
> --- a/xen/drivers/passthrough/vtd/quirks.c
> +++ b/xen/drivers/passthrough/vtd/quirks.c
> @@ -244,6 +244,29 @@ void vtd_ops_postamble_quirk(struct iomm
>      }
>  }
> 
> +/* 5500/5520/X58 Chipset Interrupt remapping errata, for stepping B-3.
> + * Fixed in stepping C-2. */
> +static void __init tylersburg_intremap_quirk(void)
> +{
> +    uint32_t bus, device;
> +    uint8_t rev;
> +
> +    for ( bus = 0; bus < 0x100; bus++ )
> +    {
> +        /* Match on System Management Registers on Device 20 Function 0 */
> +        device = pci_conf_read32(0, bus, 20, 0, PCI_VENDOR_ID);
> +        rev = pci_conf_read8(0, bus, 20, 0, PCI_REVISION_ID);
> +
> +        if ( rev == 0x13 && device == 0x342e8086 )
> +        {
> +            printk(XENLOG_WARNING VTDPREFIX
> +                   "Disabling IOMMU due to Intel 5500/5520/X58 Chipset 
> errata #47,
> #53\n");
> +            iommu_enable = 0;
> +            break;
> +        }
> +    }
> +}
> +
>  /* initialize platform identification flags */
>  void __init platform_quirks_init(void)
>  {
> @@ -264,6 +287,10 @@ void __init platform_quirks_init(void)
> 
>      /* ioremap IGD MMIO+0x2000 page */
>      map_igd_reg();
> +
> +    /* Tylersburg interrupt remap quirk */
> +    if ( iommu_intremap )
> +        tylersburg_intremap_quirk();
>  }
> 
>  /*
> 
> 


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