Re: [Xen-devel] [PATCH 2/4] iommu: generalize iommu_inclusive_mapping

[Paul Durrant <Paul.Durrant@xxxxxxxxxx>]

> -----Original Message-----
> From: Xen-devel [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxxx] On Behalf
> Of Roger Pau Monne
> Sent: 27 July 2018 16:32
> To: xen-devel@xxxxxxxxxxxxxxxxxxxx
> Cc: Kevin Tian <kevin.tian@xxxxxxxxx>; Stefano Stabellini
> <sstabellini@xxxxxxxxxx>; Wei Liu <wei.liu2@xxxxxxxxxx>; George Dunlap
> <George.Dunlap@xxxxxxxxxx>; Andrew Cooper
> <Andrew.Cooper3@xxxxxxxxxx>; Ian Jackson <Ian.Jackson@xxxxxxxxxx>; Tim
> (Xen.org) <tim@xxxxxxx>; Julien Grall <julien.grall@xxxxxxx>; Jan Beulich
> <jbeulich@xxxxxxxx>; Roger Pau Monne <roger.pau@xxxxxxxxxx>
> Subject: [Xen-devel] [PATCH 2/4] iommu: generalize
> iommu_inclusive_mapping
> 
> Introduce a new iommu=inclusive generic option that supersedes
> iommu_inclusive_mapping. This should be a non-functional change on
> Intel hardware, while AMD hardware will gain the same functionality of
> mapping almost everything below the 4GB boundary.
> 
> Note that is a noop for ARM hardware.
> 
> Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
> ---
> Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> Cc: George Dunlap <George.Dunlap@xxxxxxxxxxxxx>
> Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
> Cc: Jan Beulich <jbeulich@xxxxxxxx>
> Cc: Julien Grall <julien.grall@xxxxxxx>
> Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> Cc: Tim Deegan <tim@xxxxxxx>
> Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
> Cc: Kevin Tian <kevin.tian@xxxxxxxxx>
> ---
>  docs/misc/xen-command-line.markdown   | 14 ++++++
>  xen/drivers/passthrough/arm/iommu.c   |  4 ++
>  xen/drivers/passthrough/iommu.c       |  6 +++
>  xen/drivers/passthrough/vtd/extern.h  |  2 -
>  xen/drivers/passthrough/vtd/iommu.c   |  6 ---
>  xen/drivers/passthrough/vtd/x86/vtd.c | 66 +------------------------
>  xen/drivers/passthrough/x86/iommu.c   | 70
> +++++++++++++++++++++++++++
>  xen/include/xen/iommu.h               |  2 +
>  8 files changed, 97 insertions(+), 73 deletions(-)
> 
> diff --git a/docs/misc/xen-command-line.markdown b/docs/misc/xen-
> command-line.markdown
> index 65b4754418..91a8bfc9a6 100644
> --- a/docs/misc/xen-command-line.markdown
> +++ b/docs/misc/xen-command-line.markdown
> @@ -1198,6 +1198,17 @@ detection of systems known to misbehave upon
> accesses to that port.
> 
>  >> Enable IOMMU debugging code (implies `verbose`).
> 
> +> `inclusive`

This is a dom0 (or hwdom) specific setting so perhaps dom0-inclusive?

Actually the dom0 iommu options are starting to get unwieldy as they are 
conflated with the general host iommu options so I think it may be worthwhile 
splitting things out into a separate 'dom0-iommu=' top level parameter at this 
stage. (My reasons are slightly selfish as I intend to add another dom0 iommu 
option to give it just reserved regions, to avoid unnecessary set-up if we know 
it will be using PV-IOMMU).

Cheers,

  Paul

> +
> +> Default: `true`
> +
> +>> Use this to work around firmware issues providing incorrect RMRR or
> IVMD
> +>> entries. Rather than only mapping RAM pages for IOMMU accesses for
> Dom0,
> +>> with this option all pages up to 4GB, not marked as unusable in the E820
> +>> table, will get a mapping established. Note that this option is only
> +>> applicable to a PV dom0. Also note that if `dom0-strict` mode is enabled
> +>> then conventional RAM pages not assigned to dom0 will not be mapped.
> +
>  ### iommu\_dev\_iotlb\_timeout
>  > `= <integer>`
> 
> @@ -1212,6 +1223,9 @@ wait descriptor timed out', try increasing this value.
> 
>  > Default: `true`
> 
> +**WARNING: This command line option is deprecated, and superseded by
> +_iommu=inclusive_ - using both options in combination is undefined.**
> +
>  Use this to work around firmware issues providing incorrect RMRR entries.
>  Rather than only mapping RAM pages for IOMMU accesses for Dom0, with
> this
>  option all pages up to 4GB, not marked as unusable in the E820 table, will
> diff --git a/xen/drivers/passthrough/arm/iommu.c
> b/xen/drivers/passthrough/arm/iommu.c
> index 95b1abb972..325997b19f 100644
> --- a/xen/drivers/passthrough/arm/iommu.c
> +++ b/xen/drivers/passthrough/arm/iommu.c
> @@ -73,3 +73,7 @@ int arch_iommu_populate_page_table(struct domain
> *d)
>      /* The IOMMU shares the p2m with the CPU */
>      return -ENOSYS;
>  }
> +
> +void __hwdom_init arch_iommu_hwdom_init(struct domain *d)
> +{
> +}
> diff --git a/xen/drivers/passthrough/iommu.c
> b/xen/drivers/passthrough/iommu.c
> index 70d218f910..3f3aa71b2c 100644
> --- a/xen/drivers/passthrough/iommu.c
> +++ b/xen/drivers/passthrough/iommu.c
> @@ -47,6 +47,9 @@ integer_param("iommu_dev_iotlb_timeout",
> iommu_dev_iotlb_timeout);
>   *   no-igfx                    Disable VT-d for IGD devices (insecure)
>   *   no-amd-iommu-perdev-intremap Don't use per-device interrupt
> remapping
>   *                              tables (insecure)
> + *   inclusive                  Map additional regions into the IOMMU page
> + *                              tables in order to workaround bugs in ACPI
> + *                              tables.
>   */
>  custom_param("iommu", parse_iommu_param);
>  bool_t __initdata iommu_enable = 1;
> @@ -60,6 +63,7 @@ bool_t __read_mostly iommu_passthrough;
>  bool_t __read_mostly iommu_snoop = 1;
>  bool_t __read_mostly iommu_qinval = 1;
>  bool_t __read_mostly iommu_intremap = 1;
> +bool __hwdom_initdata iommu_inclusive = true;
> 
>  /*
>   * In the current implementation of VT-d posted interrupts, in some
> extreme
> @@ -208,6 +212,8 @@ void __hwdom_init iommu_hwdom_init(struct
> domain *d)
>      }
> 
>      hd->platform_ops->hwdom_init(d);
> +
> +    arch_iommu_hwdom_init(d);
>  }
> 
>  void iommu_teardown(struct domain *d)
> diff --git a/xen/drivers/passthrough/vtd/extern.h
> b/xen/drivers/passthrough/vtd/extern.h
> index fb7edfaef9..91cadc602e 100644
> --- a/xen/drivers/passthrough/vtd/extern.h
> +++ b/xen/drivers/passthrough/vtd/extern.h
> @@ -99,6 +99,4 @@ void pci_vtd_quirk(const struct pci_dev *);
>  bool_t platform_supports_intremap(void);
>  bool_t platform_supports_x2apic(void);
> 
> -void vtd_set_hwdom_mapping(struct domain *d);
> -
>  #endif // _VTD_EXTERN_H_
> diff --git a/xen/drivers/passthrough/vtd/iommu.c
> b/xen/drivers/passthrough/vtd/iommu.c
> index 1710256823..569ec4aec2 100644
> --- a/xen/drivers/passthrough/vtd/iommu.c
> +++ b/xen/drivers/passthrough/vtd/iommu.c
> @@ -1304,12 +1304,6 @@ static void __hwdom_init
> intel_iommu_hwdom_init(struct domain *d)
>  {
>      struct acpi_drhd_unit *drhd;
> 
> -    if ( !iommu_passthrough && is_pv_domain(d) )
> -    {
> -        /* Set up 1:1 page table for hardware domain. */
> -        vtd_set_hwdom_mapping(d);
> -    }
> -
>      setup_hwdom_pci_devices(d, setup_hwdom_device);
>      setup_hwdom_rmrr(d);
> 
> diff --git a/xen/drivers/passthrough/vtd/x86/vtd.c
> b/xen/drivers/passthrough/vtd/x86/vtd.c
> index cc2bfea162..55d74a97e2 100644
> --- a/xen/drivers/passthrough/vtd/x86/vtd.c
> +++ b/xen/drivers/passthrough/vtd/x86/vtd.c
> @@ -35,8 +35,7 @@
>   * iommu_inclusive_mapping: when set, all memory below 4GB is included in
> dom0
>   * 1:1 iommu mappings except xen and unusable regions.
>   */
> -static bool_t __hwdom_initdata iommu_inclusive_mapping = 1;
> -boolean_param("iommu_inclusive_mapping", iommu_inclusive_mapping);
> +boolean_param("iommu_inclusive_mapping", iommu_inclusive);
> 
>  void *map_vtd_domain_page(u64 maddr)
>  {
> @@ -108,66 +107,3 @@ void hvm_dpci_isairq_eoi(struct domain *d,
> unsigned int isairq)
>      spin_unlock(&d->event_lock);
>  }
> 
> -void __hwdom_init vtd_set_hwdom_mapping(struct domain *d)
> -{
> -    unsigned long i, j, tmp, top, max_pfn;
> -
> -    BUG_ON(!is_hardware_domain(d));
> -
> -    max_pfn = (GB(4) >> PAGE_SHIFT) - 1;
> -    top = max(max_pdx, pfn_to_pdx(max_pfn) + 1);
> -
> -    for ( i = 0; i < top; i++ )
> -    {
> -        unsigned long pfn = pdx_to_pfn(i);
> -        bool map;
> -        int rc = 0;
> -
> -        /*
> -         * Set up 1:1 mapping for dom0. Default to include only
> -         * conventional RAM areas and let RMRRs include needed reserved
> -         * regions. When set, the inclusive mapping additionally maps in
> -         * every pfn up to 4GB except those that fall in unusable ranges.
> -         */
> -        if ( pfn > max_pfn && !mfn_valid(_mfn(pfn)) )
> -            continue;
> -
> -        if ( iommu_inclusive_mapping && pfn <= max_pfn )
> -            map = !page_is_ram_type(pfn, RAM_TYPE_UNUSABLE);
> -        else
> -            map = page_is_ram_type(pfn, RAM_TYPE_CONVENTIONAL);
> -
> -        if ( !map )
> -            continue;
> -
> -        /* Exclude Xen bits */
> -        if ( xen_in_range(pfn) )
> -            continue;
> -
> -        /*
> -         * If dom0-strict mode is enabled then exclude conventional RAM
> -         * and let the common code map dom0's pages.
> -         */
> -        if ( iommu_dom0_strict &&
> -             page_is_ram_type(pfn, RAM_TYPE_CONVENTIONAL) )
> -            continue;
> -
> -        tmp = 1 << (PAGE_SHIFT - PAGE_SHIFT_4K);
> -        for ( j = 0; j < tmp; j++ )
> -        {
> -            int ret = iommu_map_page(d, pfn * tmp + j, pfn * tmp + j,
> -                                     IOMMUF_readable|IOMMUF_writable);
> -
> -            if ( !rc )
> -               rc = ret;
> -        }
> -
> -        if ( rc )
> -            printk(XENLOG_WARNING VTDPREFIX " d%d: IOMMU mapping failed:
> %d\n",
> -                   d->domain_id, rc);
> -
> -        if (!(i & (0xfffff >> (PAGE_SHIFT - PAGE_SHIFT_4K))))
> -            process_pending_softirqs();
> -    }
> -}
> -
> diff --git a/xen/drivers/passthrough/x86/iommu.c
> b/xen/drivers/passthrough/x86/iommu.c
> index 68182afd91..ba0bbd9a15 100644
> --- a/xen/drivers/passthrough/x86/iommu.c
> +++ b/xen/drivers/passthrough/x86/iommu.c
> @@ -20,6 +20,8 @@
>  #include <xen/softirq.h>
>  #include <xsm/xsm.h>
> 
> +#include <asm/setup.h>
> +
>  void iommu_update_ire_from_apic(
>      unsigned int apic, unsigned int reg, unsigned int value)
>  {
> @@ -132,6 +134,74 @@ void arch_iommu_domain_destroy(struct domain
> *d)
>  {
>  }
> 
> +void __hwdom_init arch_iommu_hwdom_init(struct domain *d)
> +{
> +    unsigned long i, j, tmp, top, max_pfn;
> +
> +    if ( iommu_passthrough || !is_pv_domain(d) )
> +        return;
> +
> +    BUG_ON(!is_hardware_domain(d));
> +
> +    max_pfn = (GB(4) >> PAGE_SHIFT) - 1;
> +    top = max(max_pdx, pfn_to_pdx(max_pfn) + 1);
> +
> +    for ( i = 0; i < top; i++ )
> +    {
> +        unsigned long pfn = pdx_to_pfn(i);
> +        bool map;
> +        int rc = 0;
> +
> +        /*
> +         * Set up 1:1 mapping for dom0. Default to include only
> +         * conventional RAM areas and let RMRRs include needed reserved
> +         * regions. When set, the inclusive mapping additionally maps in
> +         * every pfn up to 4GB except those that fall in unusable ranges.
> +         */
> +        if ( pfn > max_pfn && !mfn_valid(_mfn(pfn)) )
> +            continue;
> +
> +        if ( iommu_inclusive && pfn <= max_pfn )
> +            map = !page_is_ram_type(pfn, RAM_TYPE_UNUSABLE);
> +        else
> +            map = page_is_ram_type(pfn, RAM_TYPE_CONVENTIONAL);
> +
> +        if ( !map )
> +            continue;
> +
> +        /* Exclude Xen bits */
> +        if ( xen_in_range(pfn) )
> +            continue;
> +
> +        /*
> +         * If dom0-strict mode is enabled then exclude conventional RAM
> +         * and let the common code map dom0's pages.
> +         */
> +        if ( iommu_dom0_strict &&
> +             page_is_ram_type(pfn, RAM_TYPE_CONVENTIONAL) )
> +            continue;
> +
> +        tmp = 1 << (PAGE_SHIFT - PAGE_SHIFT_4K);
> +        for ( j = 0; j < tmp; j++ )
> +        {
> +            int ret = iommu_map_page(d, pfn * tmp + j, pfn * tmp + j,
> +                                     IOMMUF_readable|IOMMUF_writable);
> +
> +            if ( !rc )
> +               rc = ret;
> +        }
> +
> +        if ( rc )
> +            printk(XENLOG_WARNING "d%d: IOMMU mapping failed: %d\n",
> +                   d->domain_id, rc);
> +
> +        if (!(i & (0xfffff >> (PAGE_SHIFT - PAGE_SHIFT_4K))))
> +            process_pending_softirqs();
> +    }
> +
> +
> +}
> +
>  /*
>   * Local variables:
>   * mode: C
> diff --git a/xen/include/xen/iommu.h b/xen/include/xen/iommu.h
> index 6b42e3b876..787566a4e7 100644
> --- a/xen/include/xen/iommu.h
> +++ b/xen/include/xen/iommu.h
> @@ -35,6 +35,7 @@ extern bool_t iommu_snoop, iommu_qinval,
> iommu_intremap, iommu_intpost;
>  extern bool_t iommu_hap_pt_share;
>  extern bool_t iommu_debug;
>  extern bool_t amd_iommu_perdev_intremap;
> +extern bool iommu_inclusive;
> 
>  extern unsigned int iommu_dev_iotlb_timeout;
> 
> @@ -49,6 +50,7 @@ void arch_iommu_domain_destroy(struct domain *d);
>  int arch_iommu_domain_init(struct domain *d);
>  int arch_iommu_populate_page_table(struct domain *d);
>  void arch_iommu_check_autotranslated_hwdom(struct domain *d);
> +void arch_iommu_hwdom_init(struct domain *d);
> 
>  int iommu_construct(struct domain *d);
> 
> --
> 2.18.0
> 
> 
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