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![Konrad Rzeszutek Wilk](/assets/img/avatar_default.png)
The earlier attempts (24bdb0b62c
)
at fixing this problem caused other problems to surface (PV guests
with no PCI passthrough would have SWIOTLB turned on - which meant
64MB of precious contingous DMA32 memory being eaten up per guest).
The problem was: "on xen we add an extra memory region at the end of
the e820, and on this particular machine this extra memory region
would start below 4g and cross over the 4g boundary:
[0xfee01000-0x192655000)
Unfortunately e820_end_of_low_ram_pfn does not expect an
e820 layout like that so it returns 4g, therefore initial_memory_mapping
will map [0 - 0x100000000), that is a memory range that includes some
reserved memory regions."
The memory range was the IOAPIC regions, and with the 1-1 mapping
turned on, it would map them as RAM, not as MMIO regions. This caused
the hypervisor to complain. Fortunately this is experienced only under
the initial domain so we guard for it.
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
433 lines
12 KiB
C
433 lines
12 KiB
C
/*
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* Machine specific setup for xen
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*
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* Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
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*/
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/pm.h>
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#include <linux/memblock.h>
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#include <asm/elf.h>
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#include <asm/vdso.h>
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#include <asm/e820.h>
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#include <asm/setup.h>
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#include <asm/acpi.h>
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#include <asm/xen/hypervisor.h>
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#include <asm/xen/hypercall.h>
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#include <xen/xen.h>
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#include <xen/page.h>
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#include <xen/interface/callback.h>
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#include <xen/interface/memory.h>
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#include <xen/interface/physdev.h>
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#include <xen/features.h>
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#include "xen-ops.h"
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#include "vdso.h"
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/* These are code, but not functions. Defined in entry.S */
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extern const char xen_hypervisor_callback[];
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extern const char xen_failsafe_callback[];
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extern void xen_sysenter_target(void);
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extern void xen_syscall_target(void);
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extern void xen_syscall32_target(void);
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/* Amount of extra memory space we add to the e820 ranges */
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phys_addr_t xen_extra_mem_start, xen_extra_mem_size;
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/*
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* The maximum amount of extra memory compared to the base size. The
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* main scaling factor is the size of struct page. At extreme ratios
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* of base:extra, all the base memory can be filled with page
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* structures for the extra memory, leaving no space for anything
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* else.
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*
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* 10x seems like a reasonable balance between scaling flexibility and
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* leaving a practically usable system.
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*/
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#define EXTRA_MEM_RATIO (10)
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static void __init xen_add_extra_mem(unsigned long pages)
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{
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unsigned long pfn;
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u64 size = (u64)pages * PAGE_SIZE;
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u64 extra_start = xen_extra_mem_start + xen_extra_mem_size;
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if (!pages)
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return;
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e820_add_region(extra_start, size, E820_RAM);
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sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
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memblock_x86_reserve_range(extra_start, extra_start + size, "XEN EXTRA");
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xen_extra_mem_size += size;
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xen_max_p2m_pfn = PFN_DOWN(extra_start + size);
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for (pfn = PFN_DOWN(extra_start); pfn <= xen_max_p2m_pfn; pfn++)
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__set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
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}
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static unsigned long __init xen_release_chunk(phys_addr_t start_addr,
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phys_addr_t end_addr)
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{
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struct xen_memory_reservation reservation = {
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.address_bits = 0,
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.extent_order = 0,
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.domid = DOMID_SELF
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};
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unsigned long start, end;
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unsigned long len = 0;
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unsigned long pfn;
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int ret;
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start = PFN_UP(start_addr);
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end = PFN_DOWN(end_addr);
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if (end <= start)
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return 0;
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printk(KERN_INFO "xen_release_chunk: looking at area pfn %lx-%lx: ",
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start, end);
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for(pfn = start; pfn < end; pfn++) {
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unsigned long mfn = pfn_to_mfn(pfn);
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/* Make sure pfn exists to start with */
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if (mfn == INVALID_P2M_ENTRY || mfn_to_pfn(mfn) != pfn)
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continue;
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set_xen_guest_handle(reservation.extent_start, &mfn);
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reservation.nr_extents = 1;
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ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation,
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&reservation);
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WARN(ret != 1, "Failed to release memory %lx-%lx err=%d\n",
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start, end, ret);
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if (ret == 1) {
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__set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
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len++;
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}
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}
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printk(KERN_CONT "%ld pages freed\n", len);
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return len;
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}
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static unsigned long __init xen_return_unused_memory(unsigned long max_pfn,
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const struct e820map *e820)
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{
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phys_addr_t max_addr = PFN_PHYS(max_pfn);
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phys_addr_t last_end = ISA_END_ADDRESS;
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unsigned long released = 0;
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int i;
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/* Free any unused memory above the low 1Mbyte. */
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for (i = 0; i < e820->nr_map && last_end < max_addr; i++) {
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phys_addr_t end = e820->map[i].addr;
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end = min(max_addr, end);
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if (last_end < end)
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released += xen_release_chunk(last_end, end);
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last_end = max(last_end, e820->map[i].addr + e820->map[i].size);
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}
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if (last_end < max_addr)
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released += xen_release_chunk(last_end, max_addr);
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printk(KERN_INFO "released %ld pages of unused memory\n", released);
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return released;
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}
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static unsigned long __init xen_set_identity(const struct e820entry *list,
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ssize_t map_size)
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{
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phys_addr_t last = xen_initial_domain() ? 0 : ISA_END_ADDRESS;
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phys_addr_t start_pci = last;
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const struct e820entry *entry;
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unsigned long identity = 0;
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int i;
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for (i = 0, entry = list; i < map_size; i++, entry++) {
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phys_addr_t start = entry->addr;
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phys_addr_t end = start + entry->size;
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if (start < last)
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start = last;
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if (end <= start)
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continue;
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/* Skip over the 1MB region. */
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if (last > end)
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continue;
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if ((entry->type == E820_RAM) || (entry->type == E820_UNUSABLE)) {
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if (start > start_pci)
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identity += set_phys_range_identity(
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PFN_UP(start_pci), PFN_DOWN(start));
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/* Without saving 'last' we would gooble RAM too
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* at the end of the loop. */
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last = end;
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start_pci = end;
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continue;
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}
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start_pci = min(start, start_pci);
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last = end;
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}
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if (last > start_pci)
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identity += set_phys_range_identity(
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PFN_UP(start_pci), PFN_DOWN(last));
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return identity;
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}
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/**
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* machine_specific_memory_setup - Hook for machine specific memory setup.
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**/
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char * __init xen_memory_setup(void)
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{
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static struct e820entry map[E820MAX] __initdata;
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static struct e820entry map_raw[E820MAX] __initdata;
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unsigned long max_pfn = xen_start_info->nr_pages;
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unsigned long long mem_end;
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int rc;
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struct xen_memory_map memmap;
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unsigned long extra_pages = 0;
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unsigned long extra_limit;
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unsigned long identity_pages = 0;
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int i;
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int op;
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max_pfn = min(MAX_DOMAIN_PAGES, max_pfn);
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mem_end = PFN_PHYS(max_pfn);
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memmap.nr_entries = E820MAX;
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set_xen_guest_handle(memmap.buffer, map);
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op = xen_initial_domain() ?
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XENMEM_machine_memory_map :
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XENMEM_memory_map;
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rc = HYPERVISOR_memory_op(op, &memmap);
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if (rc == -ENOSYS) {
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BUG_ON(xen_initial_domain());
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memmap.nr_entries = 1;
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map[0].addr = 0ULL;
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map[0].size = mem_end;
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/* 8MB slack (to balance backend allocations). */
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map[0].size += 8ULL << 20;
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map[0].type = E820_RAM;
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rc = 0;
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}
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BUG_ON(rc);
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memcpy(map_raw, map, sizeof(map));
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e820.nr_map = 0;
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xen_extra_mem_start = mem_end;
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for (i = 0; i < memmap.nr_entries; i++) {
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unsigned long long end;
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/* Guard against non-page aligned E820 entries. */
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if (map[i].type == E820_RAM)
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map[i].size -= (map[i].size + map[i].addr) % PAGE_SIZE;
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end = map[i].addr + map[i].size;
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if (map[i].type == E820_RAM && end > mem_end) {
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/* RAM off the end - may be partially included */
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u64 delta = min(map[i].size, end - mem_end);
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map[i].size -= delta;
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end -= delta;
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extra_pages += PFN_DOWN(delta);
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/*
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* Set RAM below 4GB that is not for us to be unusable.
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* This prevents "System RAM" address space from being
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* used as potential resource for I/O address (happens
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* when 'allocate_resource' is called).
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*/
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if (delta &&
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(xen_initial_domain() && end < 0x100000000ULL))
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e820_add_region(end, delta, E820_UNUSABLE);
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}
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if (map[i].size > 0 && end > xen_extra_mem_start)
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xen_extra_mem_start = end;
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/* Add region if any remains */
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if (map[i].size > 0)
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e820_add_region(map[i].addr, map[i].size, map[i].type);
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}
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/* Align the balloon area so that max_low_pfn does not get set
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* to be at the _end_ of the PCI gap at the far end (fee01000).
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* Note that xen_extra_mem_start gets set in the loop above to be
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* past the last E820 region. */
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if (xen_initial_domain() && (xen_extra_mem_start < (1ULL<<32)))
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xen_extra_mem_start = (1ULL<<32);
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/*
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* In domU, the ISA region is normal, usable memory, but we
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* reserve ISA memory anyway because too many things poke
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* about in there.
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*
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* In Dom0, the host E820 information can leave gaps in the
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* ISA range, which would cause us to release those pages. To
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* avoid this, we unconditionally reserve them here.
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*/
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e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS,
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E820_RESERVED);
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/*
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* Reserve Xen bits:
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* - mfn_list
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* - xen_start_info
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* See comment above "struct start_info" in <xen/interface/xen.h>
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*/
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memblock_x86_reserve_range(__pa(xen_start_info->mfn_list),
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__pa(xen_start_info->pt_base),
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"XEN START INFO");
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sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
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extra_pages += xen_return_unused_memory(xen_start_info->nr_pages, &e820);
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/*
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* Clamp the amount of extra memory to a EXTRA_MEM_RATIO
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* factor the base size. On non-highmem systems, the base
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* size is the full initial memory allocation; on highmem it
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* is limited to the max size of lowmem, so that it doesn't
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* get completely filled.
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*
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* In principle there could be a problem in lowmem systems if
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* the initial memory is also very large with respect to
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* lowmem, but we won't try to deal with that here.
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*/
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extra_limit = min(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)),
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max_pfn + extra_pages);
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if (extra_limit >= max_pfn)
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extra_pages = extra_limit - max_pfn;
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else
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extra_pages = 0;
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xen_add_extra_mem(extra_pages);
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/*
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* Set P2M for all non-RAM pages and E820 gaps to be identity
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* type PFNs. We supply it with the non-sanitized version
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* of the E820.
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*/
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identity_pages = xen_set_identity(map_raw, memmap.nr_entries);
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printk(KERN_INFO "Set %ld page(s) to 1-1 mapping.\n", identity_pages);
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return "Xen";
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}
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/*
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* Set the bit indicating "nosegneg" library variants should be used.
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* We only need to bother in pure 32-bit mode; compat 32-bit processes
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* can have un-truncated segments, so wrapping around is allowed.
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*/
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static void __init fiddle_vdso(void)
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{
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#ifdef CONFIG_X86_32
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u32 *mask;
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mask = VDSO32_SYMBOL(&vdso32_int80_start, NOTE_MASK);
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*mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
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mask = VDSO32_SYMBOL(&vdso32_sysenter_start, NOTE_MASK);
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*mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
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#endif
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}
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static int __cpuinit register_callback(unsigned type, const void *func)
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{
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struct callback_register callback = {
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.type = type,
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.address = XEN_CALLBACK(__KERNEL_CS, func),
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.flags = CALLBACKF_mask_events,
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};
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return HYPERVISOR_callback_op(CALLBACKOP_register, &callback);
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}
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void __cpuinit xen_enable_sysenter(void)
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{
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int ret;
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unsigned sysenter_feature;
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#ifdef CONFIG_X86_32
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sysenter_feature = X86_FEATURE_SEP;
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#else
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sysenter_feature = X86_FEATURE_SYSENTER32;
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#endif
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if (!boot_cpu_has(sysenter_feature))
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return;
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ret = register_callback(CALLBACKTYPE_sysenter, xen_sysenter_target);
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if(ret != 0)
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setup_clear_cpu_cap(sysenter_feature);
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}
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void __cpuinit xen_enable_syscall(void)
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{
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#ifdef CONFIG_X86_64
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int ret;
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ret = register_callback(CALLBACKTYPE_syscall, xen_syscall_target);
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if (ret != 0) {
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printk(KERN_ERR "Failed to set syscall callback: %d\n", ret);
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/* Pretty fatal; 64-bit userspace has no other
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mechanism for syscalls. */
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}
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if (boot_cpu_has(X86_FEATURE_SYSCALL32)) {
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ret = register_callback(CALLBACKTYPE_syscall32,
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xen_syscall32_target);
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if (ret != 0)
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setup_clear_cpu_cap(X86_FEATURE_SYSCALL32);
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}
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#endif /* CONFIG_X86_64 */
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}
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void __init xen_arch_setup(void)
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{
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xen_panic_handler_init();
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HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments);
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HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables);
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if (!xen_feature(XENFEAT_auto_translated_physmap))
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HYPERVISOR_vm_assist(VMASST_CMD_enable,
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VMASST_TYPE_pae_extended_cr3);
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if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) ||
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register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback))
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BUG();
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xen_enable_sysenter();
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xen_enable_syscall();
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#ifdef CONFIG_ACPI
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if (!(xen_start_info->flags & SIF_INITDOMAIN)) {
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printk(KERN_INFO "ACPI in unprivileged domain disabled\n");
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disable_acpi();
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}
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#endif
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memcpy(boot_command_line, xen_start_info->cmd_line,
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MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ?
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COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE);
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/* Set up idle, making sure it calls safe_halt() pvop */
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#ifdef CONFIG_X86_32
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boot_cpu_data.hlt_works_ok = 1;
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#endif
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pm_idle = default_idle;
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boot_option_idle_override = IDLE_HALT;
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fiddle_vdso();
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}
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