Re: [PATCH v5 13/20] xen: setup Xen specific data for PVH

[Daniel Kiper]

On Wed, Nov 21, 2018 at 03:28:48PM +0100, Juergen Gross wrote:
> Initialize the needed Xen specific data. This is:
>
> - the Xen start of day page containing the console and Xenstore ring
>   page PFN and event channel
> - the grant table
> - the shared info page
>
> Write back the possibly modified memory map to the hypervisor in case
> the guest is reading it from there again.
>
> Set the RSDP address for the guest from the start_info page passed
> as boot parameter.
>
> Signed-off-by: Juergen Gross <address@hidden>
> Reviewed-by: Daniel Kiper <address@hidden>

One nitpick below...

> ---
> V4: write back memory map to Xen (Roger Pau Monné)
> V5: add comment (Daniel Kiper)
> ---
>  grub-core/kern/i386/xen/pvh.c | 120 
> ++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 120 insertions(+)
>
> diff --git a/grub-core/kern/i386/xen/pvh.c b/grub-core/kern/i386/xen/pvh.c
> index bb90874b3..6de84eb8e 100644
> --- a/grub-core/kern/i386/xen/pvh.c
> +++ b/grub-core/kern/i386/xen/pvh.c
> @@ -27,6 +27,7 @@
>  #include <grub/i386/linux.h>
>  #include <grub/machine/kernel.h>
>  #include <grub/machine/memory.h>
> +#include <xen/hvm/params.h>
>  #include <xen/memory.h>
>
>  #define XEN_MEMORY_MAP_SIZE   128
> @@ -37,6 +38,7 @@ static char hypercall_page[GRUB_XEN_PAGE_SIZE]
>    __attribute__ ((aligned (GRUB_XEN_PAGE_SIZE)));
>
>  static grub_uint32_t xen_cpuid_base;
> +static struct start_info grub_xen_start_page;
>  static struct grub_e820_mmap_entry map[XEN_MEMORY_MAP_SIZE];
>  static unsigned int nr_map_entries;
>
> @@ -110,6 +112,36 @@ grub_xen_hypercall (grub_uint32_t callno, grub_uint32_t 
> a0,
>    return __res;
>  }
>
> +static grub_uint32_t
> +grub_xen_get_param (int idx)
> +{
> +  struct xen_hvm_param xhv;
> +  int r;
> +
> +  xhv.domid = DOMID_SELF;
> +  xhv.index = idx;
> +  r = grub_xen_hypercall (__HYPERVISOR_hvm_op, HVMOP_get_param,
> +                       (grub_uint32_t) (&xhv), 0, 0, 0, 0);
> +  if (r < 0)
> +    grub_xen_panic ("Could not get parameter from Xen!\n");
> +  return xhv.value;
> +}
> +
> +static void *
> +grub_xen_add_physmap (unsigned int space, void *addr)
> +{
> +  struct xen_add_to_physmap xatp;
> +
> +  xatp.domid = DOMID_SELF;
> +  xatp.idx = 0;
> +  xatp.space = space;
> +  xatp.gpfn = (grub_addr_t) addr >> GRUB_XEN_LOG_PAGE_SIZE;
> +  if (grub_xen_hypercall (__HYPERVISOR_memory_op, XENMEM_add_to_physmap,
> +                       (grub_uint32_t) (&xatp), 0, 0, 0, 0))
> +    grub_xen_panic ("Memory_op hypercall failed!\n");
> +  return addr;
> +}
> +
>  static void
>  grub_xen_sort_mmap (void)
>  {
> @@ -196,12 +228,100 @@ grub_xen_get_mmap (void)
>    grub_xen_sort_mmap ();
>  }
>
> +static void
> +grub_xen_set_mmap (void)
> +{
> +  struct xen_foreign_memory_map memmap;
> +
> +  memmap.domid = DOMID_SELF;
> +  memmap.map.nr_entries = nr_map_entries;
> +  set_xen_guest_handle (memmap.map.buffer, map);
> +  grub_xen_hypercall (__HYPERVISOR_memory_op, XENMEM_set_memory_map,
> +                   (grub_uint32_t) (&memmap), 0, 0, 0, 0);
> +}
> +
> +static grub_uint64_t
> +grub_xen_find_page (grub_uint64_t start)
> +{
> +  unsigned int i, j;
> +  grub_uint64_t last = start;
> +
> +  /* Try to find a e820 map hole below 4G. */
> +  /* Relies on page-aligned entries (addr and len) and input (start). */

I would like to see above two comments as one as below.

/*
 * Try to find a e820 map hole below 4G.
 * Relies on page-aligned entries (addr and len) and input (start).
 */

You can retain my RB if you change that.

Daniel