Re: [Xen-devel] [PATCH] VT-d: improve RMRR validity checking

[Alex Williamson <alex.williamson@xxxxxx>]

On Thu, 2010-03-11 at 11:44 +0800, Weidong Han wrote:   
> good suggestion to check the device type. I cooked a new patch. It skips 
> checking IOAPIC and HPET. pls have a try.

I like this approach better, but the patch doesn't work as is.  The
problem is acpi_scope is getting incremented as a structure instead of
by length bytes.  It either needs to be cast on the increment, or maybe
cast on use like this:

Signed-off-by: Alex Williamson <alex.williamson@xxxxxx>

diff -r 132ac04cbdba xen/drivers/passthrough/vtd/dmar.c
--- a/xen/drivers/passthrough/vtd/dmar.c        Tue Mar 09 18:18:19 2010 +0000
+++ b/xen/drivers/passthrough/vtd/dmar.c        Wed Mar 10 21:46:49 2010 -0700
@@ -407,9 +407,15 @@
     {
         u8 b, d, f;
         int i, invalid_cnt = 0;
+        void *p;
 
-        for ( i = 0; i < dmaru->scope.devices_cnt; i++ )
+        for ( i = 0, p = dev_scope_start; i < dmaru->scope.devices_cnt;
+              i++, p += ((struct acpi_dev_scope *)p)->length )
         {
+            if ( ((struct acpi_dev_scope *)p)->dev_type == ACPI_DEV_IOAPIC ||
+                 ((struct acpi_dev_scope *)p)->dev_type == ACPI_DEV_MSI_HPET )
+                continue;
+
             b = PCI_BUS(dmaru->scope.devices[i]);
             d = PCI_SLOT(dmaru->scope.devices[i]);
             f = PCI_FUNC(dmaru->scope.devices[i]);


> diff -r cadf1bae9ee2 xen/drivers/passthrough/vtd/dmar.c
> --- a/xen/drivers/passthrough/vtd/dmar.c    Thu Feb 25 18:26:45 2010 +0800
> +++ b/xen/drivers/passthrough/vtd/dmar.c    Thu Mar 11 19:39:45 2010 +0800
> @@ -407,9 +407,15 @@ acpi_parse_one_drhd(struct acpi_dmar_ent
>      {
>          u8 b, d, f;
>          int i, invalid_cnt = 0;
> +        struct acpi_dev_scope *acpi_scope = dev_scope_start;
> 
>          for ( i = 0; i < dmaru->scope.devices_cnt; i++ )
>          {
> +            acpi_scope += (i == 0) ? 0 : acpi_scope->length;
> +            if ( acpi_scope->dev_type == ACPI_DEV_IOAPIC ||
> +                 acpi_scope->dev_type == ACPI_DEV_MSI_HPET )
> +                continue;
> +
>              b = PCI_BUS(dmaru->scope.devices[i]);
>              d = PCI_SLOT(dmaru->scope.devices[i]);
>              f = PCI_FUNC(dmaru->scope.devices[i]);
> 
> 



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