>>> On 07.10.11 at 03:51, "Kay, Allen M" <allen.m.kay@xxxxxxxxx> wrote:
> For RMRR case, looks like you miss the following change (or something
> similar):
>
> -for ( i = 0; i < rmrru->scope.devices_cnt; i++ )
> +for (; i < rmrru->scope.devices_cnt; i++ )
Indeed.
> Otherwise, the logic for handling non-zero PCI segments looks reasonable.
So do I take this as an acked-by-with-above-change?
> Allen
>
> -----Original Message-----
> From: Jan Beulich [mailto:JBeulich@xxxxxxxx]
> Sent: Tuesday, October 04, 2011 4:30 AM
> To: xen-devel@xxxxxxxxxxxxxxxxxxx
> Cc: Kay, Allen M
> Subject: [PATCH] VT-d: don't reject possibly valid DRHD or RMRR
>
> If a non-zero PCI segment isn't accessible during Xen boot (because
> firmware decided to not enter the necessary MMIO space into the E820
> table), devices referred to on those segments through DRHD or RMRR
> structures should not be rejected just because the devices can't be
> found.
>
> This is in line with what is being done in at least one other case
> already: Systems with more than one PCI segment (usually high end
> ones) are assumed to have valid firmware provided data, while systems
> with just segment 0 continue to have their firmware tables validated.
>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
>
> --- a/xen/drivers/passthrough/pci.c
> +++ b/xen/drivers/passthrough/pci.c
> @@ -53,6 +53,11 @@ static inline struct pci_seg *get_pseg(u
> return radix_tree_lookup(&pci_segments, seg);
> }
>
> +bool_t pci_known_segment(u16 seg)
> +{
> + return get_pseg(seg) != NULL;
> +}
> +
> static struct pci_seg *alloc_pseg(u16 seg)
> {
> struct pci_seg *pseg = get_pseg(seg);
> --- a/xen/drivers/passthrough/vtd/dmar.c
> +++ b/xen/drivers/passthrough/vtd/dmar.c
> @@ -444,10 +444,14 @@ acpi_parse_one_drhd(struct acpi_dmar_ent
> else
> {
> u8 b, d, f;
> - int i, invalid_cnt = 0;
> + unsigned int i = 0, invalid_cnt = 0;
> void *p;
>
> - for ( i = 0, p = dev_scope_start; i < dmaru->scope.devices_cnt;
> + /* Skip checking if segment is not accessible yet. */
> + if ( !pci_known_segment(drhd->segment) )
> + i = UINT_MAX;
> +
> + for ( 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 ||
> @@ -549,7 +553,12 @@ acpi_parse_one_rmrr(struct acpi_dmar_ent
> else
> {
> u8 b, d, f;
> - int i, ignore = 0;
> + bool_t ignore = 0;
> + unsigned int i = 0;
> +
> + /* Skip checking if segment is not accessible yet. */
> + if ( !pci_known_segment(rmrr->segment) )
> + i = UINT_MAX;
>
> for ( i = 0; i < rmrru->scope.devices_cnt; i++ )
> {
> --- a/xen/include/xen/pci.h
> +++ b/xen/include/xen/pci.h
> @@ -82,6 +82,7 @@ enum {
> DEV_TYPE_PCI,
> };
>
> +bool_t pci_known_segment(u16 seg);
> int pci_device_detect(u16 seg, u8 bus, u8 dev, u8 func);
> int scan_pci_devices(void);
> int pdev_type(u16 seg, u8 bus, u8 devfn);
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