grub/grub-core/kern/i386/xen/pvh.c

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/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2018 Free Software Foundation, Inc.
*
* GRUB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#include <grub/kernel.h>
#include <grub/misc.h>
#include <grub/memory.h>
#include <grub/mm.h>
#include <grub/i386/cpuid.h>
#include <grub/i386/io.h>
#include <grub/xen.h>
#include <xen/hvm/start_info.h>
#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
grub_uint64_t grub_rsdp_addr;
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;
static void
grub_xen_cons_msg (const char *msg)
{
const char *c;
for (c = msg; *c; c++)
grub_outb (*c, XEN_HVM_DEBUGCONS_IOPORT);
}
static void
grub_xen_panic (const char *msg)
{
grub_xen_cons_msg (msg);
grub_xen_cons_msg ("System halted!\n");
asm volatile ("cli");
while (1)
{
asm volatile ("hlt");
}
}
static void
grub_xen_cpuid_base (void)
{
grub_uint32_t base, eax, signature[3];
for (base = 0x40000000; base < 0x40010000; base += 0x100)
{
grub_cpuid (base, eax, signature[0], signature[1], signature[2]);
if (!grub_memcmp ("XenVMMXenVMM", signature, 12) && (eax - base) >= 2)
{
xen_cpuid_base = base;
return;
}
}
grub_xen_panic ("Found no Xen signature!\n");
}
static void
grub_xen_setup_hypercall_page (void)
{
grub_uint32_t msr, addr, eax, ebx, ecx, edx;
/* Get base address of Xen-specific MSRs. */
grub_cpuid (xen_cpuid_base + 2, eax, ebx, ecx, edx);
msr = ebx;
addr = (grub_uint32_t) (&hypercall_page);
/* Specify hypercall page address for Xen. */
asm volatile ("wrmsr" : : "c" (msr), "a" (addr), "d" (0) : "memory");
}
int
grub_xen_hypercall (grub_uint32_t callno, grub_uint32_t a0,
grub_uint32_t a1, grub_uint32_t a2,
grub_uint32_t a3, grub_uint32_t a4,
grub_uint32_t a5 __attribute__ ((unused)))
{
grub_uint32_t res;
asm volatile ("call *%[callno]"
: "=a" (res), "+b" (a0), "+c" (a1), "+d" (a2),
"+S" (a3), "+D" (a4)
: [callno] "a" (&hypercall_page[callno * 32])
: "memory");
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)
{
grub_uint64_t from, to;
unsigned int i;
struct grub_e820_mmap_entry tmp;
/* Align map entries to page boundaries. */
for (i = 0; i < nr_map_entries; i++)
{
from = map[i].addr;
to = from + map[i].len;
if (map[i].type == GRUB_MEMORY_AVAILABLE)
{
from = ALIGN_UP (from, GRUB_XEN_PAGE_SIZE);
to = ALIGN_DOWN (to, GRUB_XEN_PAGE_SIZE);
}
else
{
from = ALIGN_DOWN (from, GRUB_XEN_PAGE_SIZE);
to = ALIGN_UP (to, GRUB_XEN_PAGE_SIZE);
}
map[i].addr = from;
map[i].len = to - from;
}
again:
/* Sort entries by start address. */
for (i = 1; i < nr_map_entries; i++)
{
if (map[i].addr >= map[i - 1].addr)
continue;
tmp = map[i];
map[i] = map[i - 1];
map[i - 1] = tmp;
i = 0;
}
/* Detect overlapping areas. */
for (i = 1; i < nr_map_entries; i++)
{
if (map[i].addr >= map[i - 1].addr + map[i - 1].len)
continue;
tmp = map[i - 1];
map[i - 1].len = map[i].addr - map[i - 1].addr;
if (map[i].addr + map[i].len >= tmp.addr + tmp.len)
continue;
if (nr_map_entries < ARRAY_SIZE (map))
{
map[nr_map_entries].addr = map[i].addr + map[i].len;
map[nr_map_entries].len = tmp.addr + tmp.len - map[nr_map_entries].addr;
map[nr_map_entries].type = tmp.type;
nr_map_entries++;
goto again;
}
}
/* Merge adjacent entries. */
for (i = 1; i < nr_map_entries; i++)
{
if (map[i].type == map[i - 1].type &&
map[i].addr == map[i - 1].addr + map[i - 1].len)
{
map[i - 1].len += map[i].len;
map[i] = map[nr_map_entries - 1];
nr_map_entries--;
goto again;
}
}
}
static void
grub_xen_get_mmap (void)
{
struct xen_memory_map memmap;
memmap.nr_entries = ARRAY_SIZE (map);
set_xen_guest_handle (memmap.buffer, map);
if (grub_xen_hypercall (__HYPERVISOR_memory_op, XENMEM_memory_map,
(grub_uint32_t) (&memmap), 0, 0, 0, 0))
grub_xen_panic ("Could not get memory map from Xen!\n");
nr_map_entries = memmap.nr_entries;
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 void
grub_xen_mm_init_regions (void)
{
grub_uint64_t modend, from, to;
unsigned int i;
modend = grub_modules_get_end ();
for (i = 0; i < nr_map_entries; i++)
{
if (map[i].type != GRUB_MEMORY_AVAILABLE)
continue;
from = map[i].addr;
to = from + map[i].len;
if (from < modend)
from = modend;
if (from >= to || from >= (1ULL << 32))
continue;
if (to > (1ULL << 32))
to = 1ULL << 32;
grub_mm_init_region ((void *) (grub_addr_t) from, to - from);
}
}
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).
*/
for (i = 0; i < nr_map_entries; i++)
{
if (last > map[i].addr + map[i].len)
continue;
if (last < map[i].addr)
return last;
if ((map[i].addr >> 32) || ((map[i].addr + map[i].len) >> 32))
break;
last = map[i].addr + map[i].len;
}
if (i == nr_map_entries)
return last;
/* No hole found, use the highest RAM page below 4G and reserve it. */
if (nr_map_entries == ARRAY_SIZE (map))
grub_xen_panic ("Memory map size limit reached!\n");
for (i = 0, j = 0; i < nr_map_entries; i++)
{
if (map[i].type != GRUB_MEMORY_AVAILABLE)
continue;
if (map[i].addr >> 32)
break;
j = i;
if ((map[i].addr + map[i].len) >> 32)
break;
}
if (map[j].type != GRUB_MEMORY_AVAILABLE)
grub_xen_panic ("No free memory page found!\n");
if ((map[j].addr + map[j].len) >> 32)
last = (1ULL << 32) - GRUB_XEN_PAGE_SIZE;
else
last = map[j].addr + map[j].len - GRUB_XEN_PAGE_SIZE;
map[nr_map_entries].addr = last;
map[nr_map_entries].len = GRUB_XEN_PAGE_SIZE;
map[nr_map_entries].type = GRUB_MEMORY_RESERVED;
nr_map_entries++;
grub_xen_sort_mmap ();
return last;
}
void
grub_xen_setup_pvh (void)
{
grub_addr_t par;
grub_xen_cpuid_base ();
grub_xen_setup_hypercall_page ();
grub_xen_get_mmap ();
/* Setup Xen data. */
grub_xen_start_page_addr = &grub_xen_start_page;
par = grub_xen_get_param (HVM_PARAM_CONSOLE_PFN);
grub_xen_start_page_addr->console.domU.mfn = par;
grub_xen_xcons = (void *) (grub_addr_t) (par << GRUB_XEN_LOG_PAGE_SIZE);
par = grub_xen_get_param (HVM_PARAM_CONSOLE_EVTCHN);
grub_xen_start_page_addr->console.domU.evtchn = par;
par = grub_xen_get_param (HVM_PARAM_STORE_PFN);
grub_xen_start_page_addr->store_mfn = par;
grub_xen_xenstore = (void *) (grub_addr_t) (par << GRUB_XEN_LOG_PAGE_SIZE);
par = grub_xen_get_param (HVM_PARAM_STORE_EVTCHN);
grub_xen_start_page_addr->store_evtchn = par;
par = grub_xen_find_page (0);
grub_xen_grant_table = grub_xen_add_physmap (XENMAPSPACE_grant_table,
(void *) par);
par = grub_xen_find_page (par + GRUB_XEN_PAGE_SIZE);
grub_xen_shared_info = grub_xen_add_physmap (XENMAPSPACE_shared_info,
(void *) par);
grub_xen_set_mmap ();
grub_xen_mm_init_regions ();
grub_rsdp_addr = pvh_start_info->rsdp_paddr;
}
grub_err_t
grub_machine_mmap_iterate (grub_memory_hook_t hook, void *hook_data)
{
unsigned int i;
for (i = 0; i < nr_map_entries; i++)
{
if (map[i].len && hook (map[i].addr, map[i].len, map[i].type, hook_data))
break;
}
return GRUB_ERR_NONE;
}