Hi Julien,

On Wed, 2020-07-01 at 17:59 +0100, Julien Grall wrote:
> 
> On 01/07/2020 17:29, Anastasiia Lukianenko wrote:
> > From: Oleksandr Andrushchenko <oleksandr_andrushche...@epam.com>
> > 
> > Make required updates to run on u-boot.
> > 
> > Signed-off-by: Oleksandr Andrushchenko <
> > oleksandr_andrushche...@epam.com>
> > Signed-off-by: Anastasiia Lukianenko <
> > anastasiia_lukiane...@epam.com>
> > ---
> >   board/xen/xenguest_arm64/xenguest_arm64.c |  13 ++
> >   drivers/xen/Makefile                      |   1 +
> >   drivers/xen/gnttab.c                      | 258
> > ++++++++++++++++++++++
> >   drivers/xen/hypervisor.c                  |   2 +
> >   include/xen/gnttab.h                      |  25 +++
> >   5 files changed, 299 insertions(+)
> >   create mode 100644 drivers/xen/gnttab.c
> >   create mode 100644 include/xen/gnttab.h
> > 
> > diff --git a/board/xen/xenguest_arm64/xenguest_arm64.c
> > b/board/xen/xenguest_arm64/xenguest_arm64.c
> > index e8621f7174..b4e1650f99 100644
> > --- a/board/xen/xenguest_arm64/xenguest_arm64.c
> > +++ b/board/xen/xenguest_arm64/xenguest_arm64.c
> > @@ -22,6 +22,7 @@
> >   
> >   #include <linux/compiler.h>
> >   
> > +#include <xen/gnttab.h>
> >   #include <xen/hvm.h>
> >   
> >   DECLARE_GLOBAL_DATA_PTR;
> > @@ -64,6 +65,8 @@ static int setup_mem_map(void)
> >     struct fdt_resource res;
> >     const void *blob = gd->fdt_blob;
> >     u64 gfn;
> > +   phys_addr_t gnttab_base;
> > +   phys_size_t gnttab_sz;
> >   
> >     /*
> >      * Add "magic" region which is used by Xen to provide some
> > essentials
> > @@ -97,6 +100,16 @@ static int setup_mem_map(void)
> >                             PTE_BLOCK_INNER_SHARE);
> >     i++;
> >   
> > +   /* Get Xen's suggested physical page assignments for the grant
> > table. */
> > +   get_gnttab_base(&gnttab_base, &gnttab_sz);
> > +
> > +   xen_mem_map[i].virt = gnttab_base;
> > +   xen_mem_map[i].phys = gnttab_base;
> > +   xen_mem_map[i].size = gnttab_sz;
> > +   xen_mem_map[i].attrs = (PTE_BLOCK_MEMTYPE(MT_NORMAL) |
> > +                           PTE_BLOCK_INNER_SHARE);
> > +   i++;
> > +
> >     mem = get_next_memory_node(blob, -1);
> >     if (mem < 0) {
> >             printf("%s: Missing /memory node\n", __func__);
> > diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
> > index 9d0f604aaa..243b13277a 100644
> > --- a/drivers/xen/Makefile
> > +++ b/drivers/xen/Makefile
> > @@ -5,3 +5,4 @@
> >   obj-y += hypervisor.o
> >   obj-y += events.o
> >   obj-y += xenbus.o
> > +obj-y += gnttab.o
> > diff --git a/drivers/xen/gnttab.c b/drivers/xen/gnttab.c
> > new file mode 100644
> > index 0000000000..b18102e329
> > --- /dev/null
> > +++ b/drivers/xen/gnttab.c
> > @@ -0,0 +1,258 @@
> > +/*
> > +
> > *******************************************************************
> > *********
> > + * (C) 2006 - Cambridge University
> > + * (C) 2020 - EPAM Systems Inc.
> > +
> > *******************************************************************
> > *********
> > + *
> > + *         File: gnttab.c
> > + *   Author: Steven Smith (so...@cam.ac.uk)
> > + *  Changes: Grzegorz Milos (gm...@cam.ac.uk)
> > + *
> > + *         Date: July 2006
> > + *
> > + * Environment: Xen Minimal OS
> > + * Description: Simple grant tables implementation. About as
> > stupid as it's
> > + *  possible to be and still work.
> > + *
> > +
> > *******************************************************************
> > *********
> > + */
> > +#include <common.h>
> > +#include <linux/compiler.h>
> > +#include <log.h>
> > +#include <malloc.h>
> > +
> > +#include <asm/armv8/mmu.h>
> > +#include <asm/io.h>
> > +#include <asm/xen/system.h>
> > +
> > +#include <linux/bug.h>
> > +
> > +#include <xen/gnttab.h>
> > +#include <xen/hvm.h>
> > +
> > +#include <xen/interface/memory.h>
> > +
> > +DECLARE_GLOBAL_DATA_PTR;
> > +
> > +#define NR_RESERVED_ENTRIES 8
> > +
> > +/* NR_GRANT_FRAMES must be less than or equal to that configured
> > in Xen */
> > +#define NR_GRANT_FRAMES 1
> > +#define NR_GRANT_ENTRIES (NR_GRANT_FRAMES * PAGE_SIZE /
> > sizeof(struct grant_entry_v1))
> > +
> > +static struct grant_entry_v1 *gnttab_table;
> > +static grant_ref_t gnttab_list[NR_GRANT_ENTRIES];
> > +
> > +static void put_free_entry(grant_ref_t ref)
> > +{
> > +   unsigned long flags;
> > +
> > +   local_irq_save(flags);
> > +   gnttab_list[ref] = gnttab_list[0];
> > +   gnttab_list[0]  = ref;
> > +   local_irq_restore(flags);
> > +}
> > +
> > +static grant_ref_t get_free_entry(void)
> > +{
> > +   unsigned int ref;
> > +   unsigned long flags;
> > +
> > +   local_irq_save(flags);
> > +   ref = gnttab_list[0];
> > +   BUG_ON(ref < NR_RESERVED_ENTRIES || ref >= NR_GRANT_ENTRIES);
> > +   gnttab_list[0] = gnttab_list[ref];
> > +   local_irq_restore(flags);
> > +   return ref;
> > +}
> > +
> > +grant_ref_t gnttab_grant_access(domid_t domid, unsigned long
> > frame, int readonly)
> > +{
> > +   grant_ref_t ref;
> > +
> > +   ref = get_free_entry();
> > +   gnttab_table[ref].frame = frame;
> > +   gnttab_table[ref].domid = domid;
> > +   wmb();
> > +   readonly *= GTF_readonly;
> > +   gnttab_table[ref].flags = GTF_permit_access | readonly;
> > +
> > +   return ref;
> > +}
> > +
> > +grant_ref_t gnttab_grant_transfer(domid_t domid, unsigned long
> > pfn)
> 
> It is not possible to transfer grant on Arm. So I would suggest to 
> remove the code related to it.
> 
> [...]

Makes sense, will remove.

> 
> > +unsigned long gnttab_end_transfer(grant_ref_t ref)
> 
> likewise.

Same above.

> 
> > +{
> > +   unsigned long frame;
> > +   u16 flags;
> > +
> > +   BUG_ON(ref >= NR_GRANT_ENTRIES || ref < NR_RESERVED_ENTRIES);
> > +
> > +   while (!((flags = gnttab_table[ref].flags) &
> > GTF_transfer_committed)) {
> > +           if (synch_cmpxchg(&gnttab_table[ref].flags, flags, 0)
> > == flags) {
> > +                   printf("Release unused transfer grant.\n");
> > +                   put_free_entry(ref);
> > +                   return 0;
> > +           }
> > +   }
> > +
> > +   /* If a transfer is in progress then wait until it is
> > completed. */
> > +   while (!(flags & GTF_transfer_completed))
> > +           flags = gnttab_table[ref].flags;
> > +
> > +   /* Read the frame number /after/ reading completion status. */
> > +   rmb();
> > +   frame = gnttab_table[ref].frame;
> > +
> > +   put_free_entry(ref);
> > +
> > +   return frame;
> > +}
> > +
> > +grant_ref_t gnttab_alloc_and_grant(void **map)
> > +{
> > +   unsigned long mfn;
> > +   grant_ref_t gref;
> > +
> > +   *map = (void *)memalign(PAGE_SIZE, PAGE_SIZE);
> > +   mfn = virt_to_mfn(*map);
> > +   gref = gnttab_grant_access(0, mfn, 0);
> > +   return gref;
> > +}
> > +
> > +static const char * const gnttabop_error_msgs[] =
> > GNTTABOP_error_msgs;
> > +
> > +const char *gnttabop_error(int16_t status)
> > +{
> > +   status = -status;
> > +   if (status < 0 || status >= ARRAY_SIZE(gnttabop_error_msgs))
> > +           return "bad status";
> > +   else
> > +           return gnttabop_error_msgs[status];
> > +}
> > +
> > +/* Get Xen's suggested physical page assignments for the grant
> > table. */
> > +void get_gnttab_base(phys_addr_t *gnttab_base, phys_size_t
> > *gnttab_sz)
> > +{
> > +   const void *blob = gd->fdt_blob;
> > +   struct fdt_resource res;
> > +   int mem;
> > +
> > +   mem = fdt_node_offset_by_compatible(blob, -1, "xen,xen");
> > +   if (mem < 0) {
> > +           printf("No xen,xen compatible found\n");
> > +           BUG();
> > +   }
> > +
> > +   mem = fdt_get_resource(blob, mem, "reg", 0, &res);
> > +   if (mem == -FDT_ERR_NOTFOUND) {
> > +           printf("No grant table base in the device tree\n");
> > +           BUG();
> > +   }
> > +
> > +   *gnttab_base = (phys_addr_t)res.start;
> > +   if (gnttab_sz)
> > +           *gnttab_sz = (phys_size_t)(res.end - res.start + 1);
> > +
> > +   debug("FDT suggests grant table base at %llx\n",
> > +         *gnttab_base);
> > +}
> > +
> > +void init_gnttab(void)
> > +{
> > +   struct xen_add_to_physmap xatp;
> > +   struct gnttab_setup_table setup;
> > +   xen_pfn_t frames[NR_GRANT_FRAMES];
> > +   int i, rc;
> > +
> > +   debug("%s\n", __func__);
> > +
> > +   for (i = NR_RESERVED_ENTRIES; i < NR_GRANT_ENTRIES; i++)
> > +           put_free_entry(i);
> > +
> > +   get_gnttab_base((phys_addr_t *)&gnttab_table, NULL);
> > +
> > +   for (i = 0; i < NR_GRANT_FRAMES; i++) {
> > +           xatp.domid = DOMID_SELF;
> > +           xatp.size = 0;
> > +           xatp.space = XENMAPSPACE_grant_table;
> > +           xatp.idx = i;
> > +           xatp.gpfn = PFN_DOWN((unsigned long)gnttab_table) + i;
> > +           rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap,
> > &xatp);
> > +           if (rc)
> > +                   printf("XENMEM_add_to_physmap failed; status =
> > %d\n",
> > +                          rc);
> > +           BUG_ON(rc != 0);
> > +   }
> > +
> > +   setup.dom = DOMID_SELF;
> > +   setup.nr_frames = NR_GRANT_FRAMES;
> > +   set_xen_guest_handle(setup.frame_list, frames);
> > +   rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup,
> > 1);
> > +   if (rc || setup.status) {
> > +           printf("GNTTABOP_setup_table failed; status = %s\n",
> > +                  gnttabop_error(setup.status));
> > +           BUG();
> > +   }
> 
> GNTTAOP_grant_table_op is not needed on Arm.
> 

Ok, will remove.

> > +}
> > +
> > +void fini_gnttab(void)
> > +{
> > +   struct xen_remove_from_physmap xrtp;
> > +   struct gnttab_setup_table setup;
> > +   int i, rc;
> > +
> > +   debug("%s\n", __func__);
> > +
> > +   for (i = 0; i < NR_GRANT_FRAMES; i++) {
> > +           xrtp.domid = DOMID_SELF;
> > +           xrtp.gpfn = PFN_DOWN((unsigned long)gnttab_table) + i;
> > +           rc = HYPERVISOR_memory_op(XENMEM_remove_from_physmap,
> > &xrtp);
> > +           if (rc)
> > +                   printf("XENMEM_remove_from_physmap failed;
> > status = %d\n",
> > +                          rc);
> > +           BUG_ON(rc != 0);
> > +   }
> > +
> > +   setup.dom = DOMID_SELF;
> > +   setup.nr_frames = 0;
> > +
> > +   HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1);
> > +   if (setup.status) {
> > +           printf("GNTTABOP_setup_table failed; status = %s\n",
> > +                  gnttabop_error(setup.status));
> > +           BUG();
> > +   }
> 
> The hypercall doesn't do any clean-up in Xen. So why are you calling 
> this from fini_gnttab()?

Will remove.

> 
> Cheers,
> 

Best regards,
Anastasiia

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