Re: [RFC][PATCH 02/13] introduce XENMEM_reserved_device_memory_map

["Chen, Tiejun" <tiejun.chen@intel.com>]

On 2015/4/23 20:59, Jan Beulich wrote:
>>>> On 23.04.15 at 14:32, <tiejun.chen@intel.com> wrote:
>> But if you already have one just please ignore this and tell me
>
> Here's what I currently have:

Could you resend me this as an attached file? Then I can apply that 
properly without any miss?

Thanks
Tiejun

>
> introduce XENMEM_reserved_device_memory_map
>
> This is a prerequisite for punching holes into HVM and PVH guests' P2M
> to allow passing through devices that are associated with (on VT-d)
> RMRRs.
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
> Acked-by: Kevin Tian <kevin.tian@intel.com>
> ---
> v??: Comment iommu_grdm_t typedef. Comment on the purpose of the new
>       hypercall in the public header. (Both requested by Tim.)
>
> --- unstable.orig/xen/common/compat/memory.c
> +++ unstable/xen/common/compat/memory.c
> @@ -17,6 +17,37 @@ CHECK_TYPE(domid);
>   CHECK_mem_access_op;
>   CHECK_vmemrange;
>
> +#ifdef HAS_PASSTHROUGH
> +struct get_reserved_device_memory {
> +    struct compat_reserved_device_memory_map map;
> +    unsigned int used_entries;
> +};
> +
> +static int get_reserved_device_memory(xen_pfn_t start,
> +                                      xen_ulong_t nr, void *ctxt)
> +{
> +    struct get_reserved_device_memory *grdm = ctxt;
> +
> +    if ( grdm->used_entries < grdm->map.nr_entries )
> +    {
> +        struct compat_reserved_device_memory rdm = {
> +            .start_pfn = start, .nr_pages = nr
> +        };
> +
> +        if ( rdm.start_pfn != start || rdm.nr_pages != nr )
> +            return -ERANGE;
> +
> +        if ( __copy_to_compat_offset(grdm->map.buffer, grdm->used_entries,
> +                                     &rdm, 1) )
> +            return -EFAULT;
> +    }
> +
> +    ++grdm->used_entries;
> +
> +    return 0;
> +}
> +#endif
> +
>   int compat_memory_op(unsigned int cmd, XEN_GUEST_HANDLE_PARAM(void) compat)
>   {
>       int split, op = cmd & MEMOP_CMD_MASK;
> @@ -303,6 +334,29 @@ int compat_memory_op(unsigned int cmd, X
>               break;
>           }
>
> +#ifdef HAS_PASSTHROUGH
> +        case XENMEM_reserved_device_memory_map:
> +        {
> +            struct get_reserved_device_memory grdm;
> +
> +            if ( copy_from_guest(&grdm.map, compat, 1) ||
> +                 !compat_handle_okay(grdm.map.buffer, grdm.map.nr_entries) )
> +                return -EFAULT;
> +
> +            grdm.used_entries = 0;
> +            rc = iommu_get_reserved_device_memory(get_reserved_device_memory,
> +                                                  &grdm);
> +
> +            if ( !rc && grdm.map.nr_entries < grdm.used_entries )
> +                rc = -ENOBUFS;
> +            grdm.map.nr_entries = grdm.used_entries;
> +            if ( __copy_to_guest(compat, &grdm.map, 1) )
> +                rc = -EFAULT;
> +
> +            return rc;
> +        }
> +#endif
> +
>           default:
>               return compat_arch_memory_op(cmd, compat);
>           }
> --- unstable.orig/xen/common/memory.c
> +++ unstable/xen/common/memory.c
> @@ -748,6 +748,34 @@ static int construct_memop_from_reservat
>       return 0;
>   }
>
> +#ifdef HAS_PASSTHROUGH
> +struct get_reserved_device_memory {
> +    struct xen_reserved_device_memory_map map;
> +    unsigned int used_entries;
> +};
> +
> +static int get_reserved_device_memory(xen_pfn_t start,
> +                                      xen_ulong_t nr, void *ctxt)
> +{
> +    struct get_reserved_device_memory *grdm = ctxt;
> +
> +    if ( grdm->used_entries < grdm->map.nr_entries )
> +    {
> +        struct xen_reserved_device_memory rdm = {
> +            .start_pfn = start, .nr_pages = nr
> +        };
> +
> +        if ( __copy_to_guest_offset(grdm->map.buffer, grdm->used_entries,
> +                                    &rdm, 1) )
> +            return -EFAULT;
> +    }
> +
> +    ++grdm->used_entries;
> +
> +    return 0;
> +}
> +#endif
> +
>   long do_memory_op(unsigned long cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
>   {
>       struct domain *d;
> @@ -1162,6 +1190,32 @@ long do_memory_op(unsigned long cmd, XEN
>           break;
>       }
>
> +#ifdef HAS_PASSTHROUGH
> +    case XENMEM_reserved_device_memory_map:
> +    {
> +        struct get_reserved_device_memory grdm;
> +
> +        if ( unlikely(start_extent) )
> +            return -ENOSYS;
> +
> +        if ( copy_from_guest(&grdm.map, arg, 1) ||
> +             !guest_handle_okay(grdm.map.buffer, grdm.map.nr_entries) )
> +            return -EFAULT;
> +
> +        grdm.used_entries = 0;
> +        rc = iommu_get_reserved_device_memory(get_reserved_device_memory,
> +                                              &grdm);
> +
> +        if ( !rc && grdm.map.nr_entries < grdm.used_entries )
> +            rc = -ENOBUFS;
> +        grdm.map.nr_entries = grdm.used_entries;
> +        if ( __copy_to_guest(arg, &grdm.map, 1) )
> +            rc = -EFAULT;
> +
> +        break;
> +    }
> +#endif
> +
>       default:
>           rc = arch_memory_op(cmd, arg);
>           break;
> --- unstable.orig/xen/drivers/passthrough/iommu.c
> +++ unstable/xen/drivers/passthrough/iommu.c
> @@ -344,6 +344,16 @@ void iommu_crash_shutdown(void)
>       iommu_enabled = iommu_intremap = 0;
>   }
>
> +int iommu_get_reserved_device_memory(iommu_grdm_t *func, void *ctxt)
> +{
> +    const struct iommu_ops *ops = iommu_get_ops();
> +
> +    if ( !iommu_enabled || !ops->get_reserved_device_memory )
> +        return 0;
> +
> +    return ops->get_reserved_device_memory(func, ctxt);
> +}
> +
>   bool_t iommu_has_feature(struct domain *d, enum iommu_feature feature)
>   {
>       const struct hvm_iommu *hd = domain_hvm_iommu(d);
> --- unstable.orig/xen/drivers/passthrough/vtd/dmar.c
> +++ unstable/xen/drivers/passthrough/vtd/dmar.c
> @@ -893,3 +893,20 @@ int platform_supports_x2apic(void)
>       unsigned int mask = ACPI_DMAR_INTR_REMAP | ACPI_DMAR_X2APIC_OPT_OUT;
>       return cpu_has_x2apic && ((dmar_flags & mask) == ACPI_DMAR_INTR_REMAP);
>   }
> +
> +int intel_iommu_get_reserved_device_memory(iommu_grdm_t *func, void *ctxt)
> +{
> +    struct acpi_rmrr_unit *rmrr;
> +    int rc = 0;
> +
> +    list_for_each_entry(rmrr, &acpi_rmrr_units, list)
> +    {
> +        rc = func(PFN_DOWN(rmrr->base_address),
> +                  PFN_UP(rmrr->end_address) - PFN_DOWN(rmrr->base_address),
> +                  ctxt);
> +        if ( rc )
> +            break;
> +    }
> +
> +    return rc;
> +}
> --- unstable.orig/xen/drivers/passthrough/vtd/extern.h
> +++ unstable/xen/drivers/passthrough/vtd/extern.h
> @@ -75,6 +75,7 @@ int domain_context_mapping_one(struct do
>                                  u8 bus, u8 devfn, const struct pci_dev *);
>   int domain_context_unmap_one(struct domain *domain, struct iommu *iommu,
>                                u8 bus, u8 devfn);
> +int intel_iommu_get_reserved_device_memory(iommu_grdm_t *func, void *ctxt);
>
>   unsigned int io_apic_read_remap_rte(unsigned int apic, unsigned int reg);
>   void io_apic_write_remap_rte(unsigned int apic,
> --- unstable.orig/xen/drivers/passthrough/vtd/iommu.c
> +++ unstable/xen/drivers/passthrough/vtd/iommu.c
> @@ -2491,6 +2491,7 @@ const struct iommu_ops intel_iommu_ops =
>       .crash_shutdown = vtd_crash_shutdown,
>       .iotlb_flush = intel_iommu_iotlb_flush,
>       .iotlb_flush_all = intel_iommu_iotlb_flush_all,
> +    .get_reserved_device_memory = intel_iommu_get_reserved_device_memory,
>       .dump_p2m_table = vtd_dump_p2m_table,
>   };
>
> --- unstable.orig/xen/include/public/memory.h
> +++ unstable/xen/include/public/memory.h
> @@ -573,7 +573,29 @@ struct xen_vnuma_topology_info {
>   typedef struct xen_vnuma_topology_info xen_vnuma_topology_info_t;
>   DEFINE_XEN_GUEST_HANDLE(xen_vnuma_topology_info_t);
>
> -/* Next available subop number is 27 */
> +/*
> + * With some legacy devices, certain guest-physical addresses cannot safely
> + * be used for other purposes, e.g. to map guest RAM.  This hypercall
> + * enumerates those regions so the toolstack can avoid using them.
> + */
> +#define XENMEM_reserved_device_memory_map   27
> +struct xen_reserved_device_memory {
> +    xen_pfn_t start_pfn;
> +    xen_ulong_t nr_pages;
> +};
> +typedef struct xen_reserved_device_memory xen_reserved_device_memory_t;
> +DEFINE_XEN_GUEST_HANDLE(xen_reserved_device_memory_t);
> +
> +struct xen_reserved_device_memory_map {
> +    /* IN/OUT */
> +    unsigned int nr_entries;
> +    /* OUT */
> +    XEN_GUEST_HANDLE(xen_reserved_device_memory_t) buffer;
> +};
> +typedef struct xen_reserved_device_memory_map xen_reserved_device_memory_map_t;
> +DEFINE_XEN_GUEST_HANDLE(xen_reserved_device_memory_map_t);
> +
> +/* Next available subop number is 28 */
>
>   #endif /* __XEN_PUBLIC_MEMORY_H__ */
>
> --- unstable.orig/xen/include/xen/iommu.h
> +++ unstable/xen/include/xen/iommu.h
> @@ -121,6 +121,14 @@ void iommu_dt_domain_destroy(struct doma
>
>   struct page_info;
>
> +/*
> + * Any non-zero value returned from callbacks of this type will cause the
> + * function the callback was handed to terminate its iteration. Assigning
> + * meaning of these non-zero values is left to the top level caller /
> + * callback pair.
> + */
> +typedef int iommu_grdm_t(xen_pfn_t start, xen_ulong_t nr, void *ctxt);
> +
>   struct iommu_ops {
>       int (*init)(struct domain *d);
>       void (*hwdom_init)(struct domain *d);
> @@ -152,12 +160,14 @@ struct iommu_ops {
>       void (*crash_shutdown)(void);
>       void (*iotlb_flush)(struct domain *d, unsigned long gfn, unsigned int page_count);
>       void (*iotlb_flush_all)(struct domain *d);
> +    int (*get_reserved_device_memory)(iommu_grdm_t *, void *);
>       void (*dump_p2m_table)(struct domain *d);
>   };
>
>   void iommu_suspend(void);
>   void iommu_resume(void);
>   void iommu_crash_shutdown(void);
> +int iommu_get_reserved_device_memory(iommu_grdm_t *, void *);
>
>   void iommu_share_p2m_table(struct domain *d);
>
> --- unstable.orig/xen/include/xlat.lst
> +++ unstable/xen/include/xlat.lst
> @@ -61,9 +61,10 @@
>   !	memory_exchange			memory.h
>   !	memory_map			memory.h
>   !	memory_reservation		memory.h
> -?	mem_access_op		memory.h
> +?	mem_access_op			memory.h
>   !	pod_target			memory.h
>   !	remove_from_physmap		memory.h
> +!	reserved_device_memory_map	memory.h
>   ?	vmemrange			memory.h
>   !	vnuma_topology_info		memory.h
>   ?	physdev_eoi			physdev.h
>
>
>