Re: [Xen-devel] [PATCH v2 1/4] x86/dom0: prevent access to MMCFG areas for PVH Dom0

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

> From: Roger Pau Monne
> Sent: Saturday, August 12, 2017 12:43 AM
> 
> They are emulated by Xen, so they must not be mapped into Dom0 p2m.
> Introduce a helper function to add the MMCFG areas to the list of
> denied iomem regions for PVH Dom0.
> 
> Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>

this patch is a general fix, not just for inclusive mapping. please send
it separately.

> ---
> Cc: Jan Beulich <jbeulich@xxxxxxxx>
> Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> ---
> Changes since RFC:
>  - Introduce as helper instead of exposing the internal mmcfg
>    variables to the Dom0 builder.
> ---
>  xen/arch/x86/dom0_build.c         |  4 ++++
>  xen/arch/x86/x86_64/mmconfig_64.c | 21 +++++++++++++++++++++
>  xen/include/xen/pci.h             |  2 ++
>  3 files changed, 27 insertions(+)
> 
> diff --git a/xen/arch/x86/dom0_build.c b/xen/arch/x86/dom0_build.c
> index 0c125e61eb..3e0910d779 100644
> --- a/xen/arch/x86/dom0_build.c
> +++ b/xen/arch/x86/dom0_build.c
> @@ -440,6 +440,10 @@ int __init dom0_setup_permissions(struct domain
> *d)
>              rc |= rangeset_add_singleton(mmio_ro_ranges, mfn);
>      }
> 
> +    /* For PVH prevent access to the MMCFG areas. */
> +    if ( dom0_pvh )
> +        rc |= pci_mmcfg_set_domain_permissions(d);
> +
>      return rc;
>  }
> 
> diff --git a/xen/arch/x86/x86_64/mmconfig_64.c
> b/xen/arch/x86/x86_64/mmconfig_64.c
> index e84a67dfc4..271fad407f 100644
> --- a/xen/arch/x86/x86_64/mmconfig_64.c
> +++ b/xen/arch/x86/x86_64/mmconfig_64.c
> @@ -15,6 +15,8 @@
>  #include <xen/pci_regs.h>
>  #include <xen/iommu.h>
>  #include <xen/rangeset.h>
> +#include <xen/sched.h>
> +#include <xen/iocap.h>
> 
>  #include "mmconfig.h"
> 
> @@ -175,6 +177,25 @@ void pci_mmcfg_arch_disable(unsigned int idx)
>             cfg->pci_segment, cfg->start_bus_number, cfg->end_bus_number);
>  }
> 
> +int pci_mmcfg_set_domain_permissions(struct domain *d)
> +{
> +    unsigned int idx;
> +    int rc = 0;
> +
> +    for ( idx = 0; idx < pci_mmcfg_config_num; idx++ )
> +    {
> +        const struct acpi_mcfg_allocation *cfg = pci_mmcfg_virt[idx].cfg;
> +        unsigned long start = PFN_DOWN(cfg->address) +
> +                              PCI_BDF(cfg->start_bus_number, 0, 0);
> +        unsigned long end = PFN_DOWN(cfg->address) +
> +                            PCI_BDF(cfg->end_bus_number, ~0, ~0);
> +
> +        rc |= iomem_deny_access(d, start, end);
> +    }
> +
> +    return rc;
> +}
> +
>  bool_t pci_mmcfg_decode(unsigned long mfn, unsigned int *seg,
>                          unsigned int *bdf)
>  {
> diff --git a/xen/include/xen/pci.h b/xen/include/xen/pci.h
> index 59b6e8a81c..ea6a66b248 100644
> --- a/xen/include/xen/pci.h
> +++ b/xen/include/xen/pci.h
> @@ -170,4 +170,6 @@ int msixtbl_pt_register(struct domain *, struct pirq
> *, uint64_t gtable);
>  void msixtbl_pt_unregister(struct domain *, struct pirq *);
>  void msixtbl_pt_cleanup(struct domain *d);
> 
> +int pci_mmcfg_set_domain_permissions(struct domain *d);
> +
>  #endif /* __XEN_PCI_H__ */
> --
> 2.11.0 (Apple Git-81)
> 
> 
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