Re: [Xen-devel] [v3][PATCH 15/16] xen/vtd: enable USB device assignment

["Tian, Kevin" <kevin.tian@xxxxxxxxx>]

> From: Chen, Tiejun
> Sent: Thursday, June 11, 2015 9:15 AM
> 
> Before we refine RMRR mechanism, USB RMRR may conflict with guest bios
> region so we always ignore USB RMRR. 

If USB RMRR conflicts with guest bios, the conflict is always there
before and after your refinement. :-)

> Now this can be gone when we enable
> pci_force to check/reserve RMRR.
> 
> Signed-off-by: Tiejun Chen <tiejun.chen@xxxxxxxxx>

Acked-by: Kevin Tian <kevin.tian@xxxxxxxxx> except one small comment below

> ---
>  xen/drivers/passthrough/vtd/dmar.h  |  1 -
>  xen/drivers/passthrough/vtd/iommu.c | 11 ++---------
>  xen/drivers/passthrough/vtd/utils.c |  7 -------
>  3 files changed, 2 insertions(+), 17 deletions(-)
> 
> diff --git a/xen/drivers/passthrough/vtd/dmar.h 
> b/xen/drivers/passthrough/vtd/dmar.h
> index af1feef..af205f5 100644
> --- a/xen/drivers/passthrough/vtd/dmar.h
> +++ b/xen/drivers/passthrough/vtd/dmar.h
> @@ -129,7 +129,6 @@ do {                                                \
> 
>  int vtd_hw_check(void);
>  void disable_pmr(struct iommu *iommu);
> -int is_usb_device(u16 seg, u8 bus, u8 devfn);
>  int is_igd_drhd(struct acpi_drhd_unit *drhd);
> 
>  #endif /* _DMAR_H_ */
> diff --git a/xen/drivers/passthrough/vtd/iommu.c
> b/xen/drivers/passthrough/vtd/iommu.c
> index d7c9e1c..d3233b8 100644
> --- a/xen/drivers/passthrough/vtd/iommu.c
> +++ b/xen/drivers/passthrough/vtd/iommu.c
> @@ -2229,11 +2229,9 @@ static int reassign_device_ownership(
>      /*
>       * If the device belongs to the hardware domain, and it has RMRR, don't
>       * remove it from the hardware domain, because BIOS may use RMRR at
> -     * booting time. Also account for the special casing of USB below (in
> -     * intel_iommu_assign_device()).
> +     * booting time.

this code is run-time right?

>       */
> -    if ( !is_hardware_domain(source) &&
> -         !is_usb_device(pdev->seg, pdev->bus, pdev->devfn) )
> +    if ( !is_hardware_domain(source) )
>      {
>          const struct acpi_rmrr_unit *rmrr;
>          u16 bdf;
> @@ -2283,13 +2281,8 @@ static int intel_iommu_assign_device(
>      if ( ret )
>          return ret;
> 
> -    /* FIXME: Because USB RMRR conflicts with guest bios region,
> -     * ignore USB RMRR temporarily.
> -     */
>      seg = pdev->seg;
>      bus = pdev->bus;
> -    if ( is_usb_device(seg, bus, pdev->devfn) )
> -        return 0;
> 
>      /* Setup rmrr identity mapping */
>      for_each_rmrr_device( rmrr, bdf, i )
> diff --git a/xen/drivers/passthrough/vtd/utils.c 
> b/xen/drivers/passthrough/vtd/utils.c
> index bd14c02..b8a077f 100644
> --- a/xen/drivers/passthrough/vtd/utils.c
> +++ b/xen/drivers/passthrough/vtd/utils.c
> @@ -29,13 +29,6 @@
>  #include "extern.h"
>  #include <asm/io_apic.h>
> 
> -int is_usb_device(u16 seg, u8 bus, u8 devfn)
> -{
> -    u16 class = pci_conf_read16(seg, bus, PCI_SLOT(devfn), PCI_FUNC(devfn),
> -                                PCI_CLASS_DEVICE);
> -    return (class == 0xc03);
> -}
> -
>  /* Disable vt-d protected memory registers. */
>  void disable_pmr(struct iommu *iommu)
>  {
> --
> 1.9.1


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