Re: [Xen-devel] [PATCH v6 2/3] Differentiate IO/mem resources tracked by ioreq server

[Paul Durrant <Paul.Durrant@xxxxxxxxxx>]

> -----Original Message-----
> From: Yu Zhang [mailto:yu.c.zhang@xxxxxxxxxxxxxxx]
> Sent: 19 August 2015 02:16
> To: xen-devel@xxxxxxxxxxxxx; Paul Durrant; Ian Jackson; Stefano Stabellini; 
> Ian
> Campbell; Wei Liu; Keir (Xen.org); jbeulich@xxxxxxxx; Andrew Cooper
> Cc: Kevin Tian; zhiyuan.lv@xxxxxxxxx
> Subject: [PATCH v6 2/3] Differentiate IO/mem resources tracked by ioreq
> server
> 
> Currently in ioreq server, guest write-protected ram pages are
> tracked in the same rangeset with device mmio resources. Yet
> unlike device mmio, which can be in big chunks, the guest write-
> protected pages may be discrete ranges with 4K bytes each.
> 
> This patch uses a seperate rangeset for the guest ram pages.
> And a new ioreq type, IOREQ_TYPE_WP_MEM, is defined.
> 
> Note: Previously, a new hypercall or subop was suggested to map
> write-protected pages into ioreq server. However, it turned out
> handler of this new hypercall would be almost the same with the
> existing pair - HVMOP_[un]map_io_range_to_ioreq_server, and there's
> already a type parameter in this hypercall. So no new hypercall
> defined, only a new type is introduced.
> 
> Signed-off-by: Yu Zhang <yu.c.zhang@xxxxxxxxxxxxxxx>
> ---
>  tools/libxc/include/xenctrl.h    | 31 ++++++++++++++++++++++
>  tools/libxc/xc_domain.c          | 55
> ++++++++++++++++++++++++++++++++++++++++
>  xen/arch/x86/hvm/hvm.c           | 23 ++++++++++++++++-
>  xen/include/asm-x86/hvm/domain.h |  4 +--
>  xen/include/public/hvm/hvm_op.h  |  1 +
>  5 files changed, 111 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
> index de3c0ad..3c276b7 100644
> --- a/tools/libxc/include/xenctrl.h
> +++ b/tools/libxc/include/xenctrl.h
> @@ -2010,6 +2010,37 @@ int
> xc_hvm_unmap_io_range_from_ioreq_server(xc_interface *xch,
>                                              int is_mmio,
>                                              uint64_t start,
>                                              uint64_t end);
> +/**
> + * This function registers a range of write-protected memory for emulation.
> + *
> + * @parm xch a handle to an open hypervisor interface.
> + * @parm domid the domain id to be serviced
> + * @parm id the IOREQ Server id.
> + * @parm start start of range
> + * @parm end end of range (inclusive).
> + * @return 0 on success, -1 on failure.
> + */
> +int xc_hvm_map_mem_range_to_ioreq_server(xc_interface *xch,
> +                                        domid_t domid,
> +                                        ioservid_t id,
> +                                        xen_pfn_t start,
> +                                        xen_pfn_t end);
> +
> +/**
> + * This function deregisters a range of write-protected memory for
> emulation.
> + *
> + * @parm xch a handle to an open hypervisor interface.
> + * @parm domid the domain id to be serviced
> + * @parm id the IOREQ Server id.
> + * @parm start start of range
> + * @parm end end of range (inclusive).
> + * @return 0 on success, -1 on failure.
> + */
> +int xc_hvm_unmap_mem_range_from_ioreq_server(xc_interface *xch,
> +                                            domid_t domid,
> +                                            ioservid_t id,
> +                                            xen_pfn_t start,
> +                                            xen_pfn_t end);
> 
>  /**
>   * This function registers a PCI device for config space emulation.
> diff --git a/tools/libxc/xc_domain.c b/tools/libxc/xc_domain.c
> index 2ee26fb..9db05b3 100644
> --- a/tools/libxc/xc_domain.c
> +++ b/tools/libxc/xc_domain.c
> @@ -1552,6 +1552,61 @@ int
> xc_hvm_unmap_io_range_from_ioreq_server(xc_interface *xch, domid_t
> domid,
>      return rc;
>  }
> 
> +int xc_hvm_map_mem_range_to_ioreq_server(xc_interface *xch,
> domid_t domid,
> +                                        ioservid_t id, xen_pfn_t start, 
> xen_pfn_t end)
> +{
> +    DECLARE_HYPERCALL;
> +    DECLARE_HYPERCALL_BUFFER(xen_hvm_io_range_t, arg);
> +    int rc;
> +
> +    arg = xc_hypercall_buffer_alloc(xch, arg, sizeof(*arg));
> +    if ( arg == NULL )
> +        return -1;
> +
> +    hypercall.op     = __HYPERVISOR_hvm_op;
> +    hypercall.arg[0] = HVMOP_map_io_range_to_ioreq_server;
> +    hypercall.arg[1] = HYPERCALL_BUFFER_AS_ARG(arg);
> +
> +    arg->domid = domid;
> +    arg->id = id;
> +    arg->type = HVMOP_IO_RANGE_WP_MEM;
> +    arg->start = start;
> +    arg->end = end;
> +
> +    rc = do_xen_hypercall(xch, &hypercall);
> +
> +    xc_hypercall_buffer_free(xch, arg);
> +    return rc;
> +}
> +
> +int xc_hvm_unmap_mem_range_from_ioreq_server(xc_interface *xch,
> domid_t domid,
> +                                            ioservid_t id, xen_pfn_t start, 
> xen_pfn_t end)
> +{
> +    DECLARE_HYPERCALL;
> +    DECLARE_HYPERCALL_BUFFER(xen_hvm_io_range_t, arg);
> +    int rc;
> +
> +    arg = xc_hypercall_buffer_alloc(xch, arg, sizeof(*arg));
> +    if ( arg == NULL )
> +        return -1;
> +
> +    hypercall.op     = __HYPERVISOR_hvm_op;
> +    hypercall.arg[0] = HVMOP_unmap_io_range_from_ioreq_server;
> +    hypercall.arg[1] = HYPERCALL_BUFFER_AS_ARG(arg);
> +
> +    arg->domid = domid;
> +    arg->id = id;
> +    arg->type = HVMOP_IO_RANGE_WP_MEM;
> +    arg->start = start;
> +    arg->end = end;
> +
> +    rc = do_xen_hypercall(xch, &hypercall);
> +
> +    xc_hypercall_buffer_free(xch, arg);
> +    return rc;
> +
> +}
> +
>  int xc_hvm_map_pcidev_to_ioreq_server(xc_interface *xch, domid_t
> domid,
>                                        ioservid_t id, uint16_t segment,
>                                        uint8_t bus, uint8_t device,
> diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
> index bc36b9d..d130497 100644
> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -938,8 +938,9 @@ static int hvm_ioreq_server_alloc_rangesets(struct
> hvm_ioreq_server *s,
> 
>          rc = asprintf(&name, "ioreq_server %d %s", s->id,
>                        (i == HVMOP_IO_RANGE_PORT) ? "port" :
> -                      (i == HVMOP_IO_RANGE_MEMORY) ? "memory" :
> +                      (i == HVMOP_IO_RANGE_MEMORY) ? "mmio" :
>                        (i == HVMOP_IO_RANGE_PCI) ? "pci" :
> +                      (i == HVMOP_IO_RANGE_WP_MEM) ? "wp-ed memory" :
>                        "");
>          if ( rc )
>              goto fail;
> @@ -1258,6 +1259,7 @@ static int
> hvm_map_io_range_to_ioreq_server(struct domain *d, ioservid_t id,
>              case HVMOP_IO_RANGE_PORT:
>              case HVMOP_IO_RANGE_MEMORY:
>              case HVMOP_IO_RANGE_PCI:
> +            case HVMOP_IO_RANGE_WP_MEM:
>                  r = s->range[type];
>                  break;
> 
> @@ -1309,6 +1311,7 @@ static int
> hvm_unmap_io_range_from_ioreq_server(struct domain *d, ioservid_t id,
>              case HVMOP_IO_RANGE_PORT:
>              case HVMOP_IO_RANGE_MEMORY:
>              case HVMOP_IO_RANGE_PCI:
> +            case HVMOP_IO_RANGE_WP_MEM:
>                  r = s->range[type];
>                  break;
> 
> @@ -2523,6 +2526,8 @@ struct hvm_ioreq_server
> *hvm_select_ioreq_server(struct domain *d,
>      uint32_t cf8;
>      uint8_t type;
>      uint64_t addr;
> +    p2m_type_t p2mt;
> +    struct page_info *ram_page;
> 
>      if ( list_empty(&d->arch.hvm_domain.ioreq_server.list) )
>          return NULL;
> @@ -2566,6 +2571,17 @@ struct hvm_ioreq_server
> *hvm_select_ioreq_server(struct domain *d,
>          type = (p->type == IOREQ_TYPE_PIO) ?
>               HVMOP_IO_RANGE_PORT: HVMOP_IO_RANGE_MEMORY;
>          addr = p->addr;
> +
> +        if ( type == HVMOP_IO_RANGE_PORT )

Shouldn't this check be for type HVMOP_IO_RANGE_MEMORY?

  Paul

> +        {
> +            ram_page = get_page_from_gfn(d, p->addr >> PAGE_SHIFT,
> +                                         &p2mt, P2M_UNSHARE);
> +            if ( p2mt == p2m_mmio_write_dm )
> +                type = HVMOP_IO_RANGE_WP_MEM;
> +
> +            if ( ram_page )
> +                put_page(ram_page);
> +        }
>      }
> 
>      list_for_each_entry ( s,
> @@ -2607,6 +2623,11 @@ struct hvm_ioreq_server
> *hvm_select_ioreq_server(struct domain *d,
>              }
> 
>              break;
> +        case HVMOP_IO_RANGE_WP_MEM:
> +            if ( rangeset_contains_singleton(r, addr >> PAGE_SHIFT) )
> +                return s;
> +
> +            break;
>          }
>      }
> 
> diff --git a/xen/include/asm-x86/hvm/domain.h b/xen/include/asm-
> x86/hvm/domain.h
> index 992d5d1..b2e4234 100644
> --- a/xen/include/asm-x86/hvm/domain.h
> +++ b/xen/include/asm-x86/hvm/domain.h
> @@ -48,8 +48,8 @@ struct hvm_ioreq_vcpu {
>      bool_t           pending;
>  };
> 
> -#define NR_IO_RANGE_TYPES (HVMOP_IO_RANGE_PCI + 1)
> -#define MAX_NR_IO_RANGES  256
> +#define NR_IO_RANGE_TYPES (HVMOP_IO_RANGE_WP_MEM + 1)
> +#define MAX_NR_IO_RANGES  8192
> 
>  struct hvm_ioreq_server {
>      struct list_head       list_entry;
> diff --git a/xen/include/public/hvm/hvm_op.h
> b/xen/include/public/hvm/hvm_op.h
> index 014546a..c02c91a 100644
> --- a/xen/include/public/hvm/hvm_op.h
> +++ b/xen/include/public/hvm/hvm_op.h
> @@ -331,6 +331,7 @@ struct xen_hvm_io_range {
>  # define HVMOP_IO_RANGE_PORT   0 /* I/O port range */
>  # define HVMOP_IO_RANGE_MEMORY 1 /* MMIO range */
>  # define HVMOP_IO_RANGE_PCI    2 /* PCI segment/bus/dev/func range */
> +# define HVMOP_IO_RANGE_WP_MEM 3 /* Write-protected memory
> range */
>      uint64_aligned_t start, end; /* IN - inclusive start and end of range */
>  };
>  typedef struct xen_hvm_io_range xen_hvm_io_range_t;
> --
> 1.9.1


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