[PATCH 11/17] xen: Port Xen grant table driver from mini-os
Anastasiia Lukianenko
Anastasiia_Lukianenko at epam.com
Fri Jul 3 15:09:12 CEST 2020
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_andrushchenko at epam.com>
> >
> > Make required updates to run on u-boot.
> >
> > Signed-off-by: Oleksandr Andrushchenko <
> > oleksandr_andrushchenko at epam.com>
> > Signed-off-by: Anastasiia Lukianenko <
> > anastasiia_lukianenko at 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 (sos22 at cam.ac.uk)
> > + * Changes: Grzegorz Milos (gm281 at 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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