Re: [Xen-devel] [v8][PATCH 17/17] xen/vtd: re-enable USB device assignment if enable pci_force

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Mon, Dec 01, 2014 at 05:24:35PM +0800, Tiejun Chen wrote:
> Before we refine RMRR mechanism, USB RMRR may conflict with guest bios
> region so we always ignore USB RMRR. Now this can be gone when we enable
> pci_force to check/reserve RMRR.
> 
> Signed-off-by: Tiejun Chen <tiejun.chen@xxxxxxxxx>
> ---
>  xen/drivers/passthrough/vtd/dmar.h  |  1 +
>  xen/drivers/passthrough/vtd/iommu.c | 12 ++++++++----
>  xen/drivers/passthrough/vtd/utils.c | 18 ++++++++++++++++++
>  3 files changed, 27 insertions(+), 4 deletions(-)
> 
> diff --git a/xen/drivers/passthrough/vtd/dmar.h 
> b/xen/drivers/passthrough/vtd/dmar.h
> index a57c0d4..832dc32 100644
> --- a/xen/drivers/passthrough/vtd/dmar.h
> +++ b/xen/drivers/passthrough/vtd/dmar.h
> @@ -132,6 +132,7 @@ do {                                                \
>  int vtd_hw_check(void);
>  void disable_pmr(struct iommu *iommu);
>  int is_usb_device(u16 seg, u8 bus, u8 devfn);
> +int is_reserve_device_memory(struct domain *d, 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 ba40209..1f1ceb7 100644
> --- a/xen/drivers/passthrough/vtd/iommu.c
> +++ b/xen/drivers/passthrough/vtd/iommu.c
> @@ -2264,9 +2264,11 @@ static int reassign_device_ownership(
>       * 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()).
> +     * But if we already check to reserve RMRR, this should be fine.
>       */
>      if ( !is_hardware_domain(source) &&
> -         !is_usb_device(pdev->seg, pdev->bus, pdev->devfn) )
> +         !is_usb_device(pdev->seg, pdev->bus, pdev->devfn) &&
> +         !is_reserve_device_memory(source, pdev->bus, pdev->devfn) )
>      {
>          const struct acpi_rmrr_unit *rmrr;
>          u16 bdf;
> @@ -2315,12 +2317,14 @@ static int intel_iommu_assign_device(
>      if ( ret )
>          return ret;
>  
> -    /* FIXME: Because USB RMRR conflicts with guest bios region,
> -     * ignore USB RMRR temporarily.
> +    /*
> +     * Because USB RMRR conflicts with guest bios region,
> +     * ignore USB RMRR temporarily in case of non-reserving-RMRR.
>       */
>      seg = pdev->seg;
>      bus = pdev->bus;
> -    if ( is_usb_device(seg, bus, pdev->devfn) )
> +    if ( is_usb_device(seg, bus, pdev->devfn) &&
> +         !is_reserve_device_memory(d, bus, pdev->devfn) )
>          return 0;
>  
>      /* Setup rmrr identity mapping */
> diff --git a/xen/drivers/passthrough/vtd/utils.c 
> b/xen/drivers/passthrough/vtd/utils.c
> index a33564b..1045ac1 100644
> --- a/xen/drivers/passthrough/vtd/utils.c
> +++ b/xen/drivers/passthrough/vtd/utils.c
> @@ -36,6 +36,24 @@ int is_usb_device(u16 seg, u8 bus, u8 devfn)
>      return (class == 0xc03);
>  }
>  
> +int is_reserve_device_memory(struct domain *d, u8 bus, u8 devfn)
> +{
> +    int i = 0;
> +
> +    if ( d->arch.hvm_domain.pci_force == PCI_DEV_RDM_CHECK )
> +        return 1;

Ouch. What if the 'hvm_domain' is not there? Please check
first for that.
> +
> +    for ( i = 0; i < d->arch.hvm_domain.num_pcidevs; i++ )
> +    {
> +        if ( d->arch.hvm_domain.pcidevs[i].bus == bus &&
> +             d->arch.hvm_domain.pcidevs[i].devfn == devfn &&
> +             d->arch.hvm_domain.pcidevs[i].flags == PCI_DEV_RDM_CHECK )
> +        return 1;
> +    }
> +
> +    return 0;
> +}
> +
>  /* Disable vt-d protected memory registers. */
>  void disable_pmr(struct iommu *iommu)
>  {
> -- 
> 1.9.1
> 

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