Merge branch 'stable/128gb.v5.1' into stable/for-linus-3.7
* stable/128gb.v5.1:
xen/mmu: If the revector fails, don't attempt to revector anything else.
xen/p2m: When revectoring deal with holes in the P2M array.
xen/mmu: Release just the MFN list, not MFN list and part of pagetables.
xen/mmu: Remove from __ka space PMD entries for pagetables.
xen/mmu: Copy and revector the P2M tree.
xen/p2m: Add logic to revector a P2M tree to use __va leafs.
xen/mmu: Recycle the Xen provided L4, L3, and L2 pages
xen/mmu: For 64-bit do not call xen_map_identity_early
xen/mmu: use copy_page instead of memcpy.
xen/mmu: Provide comments describing the _ka and _va aliasing issue
xen/mmu: The xen_setup_kernel_pagetable doesn't need to return anything.
Revert "xen/x86: Workaround 64-bit hypervisor and 32-bit initial domain." and "xen/x86: Use memblock_reserve for sensitive areas."
xen/x86: Workaround 64-bit hypervisor and 32-bit initial domain.
xen/x86: Use memblock_reserve for sensitive areas.
xen/p2m: Fix the comment describing the P2M tree.
Conflicts:
arch/x86/xen/mmu.c
The pagetable_init is the old xen_pagetable_setup_done and xen_pagetable_setup_start
rolled in one.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 2766746..47b3acd 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1290,7 +1290,6 @@
{
struct physdev_set_iopl set_iopl;
int rc;
- pgd_t *pgd;
if (!xen_start_info)
return;
@@ -1382,8 +1381,6 @@
acpi_numa = -1;
#endif
- pgd = (pgd_t *)xen_start_info->pt_base;
-
/* Don't do the full vcpu_info placement stuff until we have a
possible map and a non-dummy shared_info. */
per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0];
@@ -1392,7 +1389,7 @@
early_boot_irqs_disabled = true;
xen_raw_console_write("mapping kernel into physical memory\n");
- pgd = xen_setup_kernel_pagetable(pgd, xen_start_info->nr_pages);
+ xen_setup_kernel_pagetable((pgd_t *)xen_start_info->pt_base, xen_start_info->nr_pages);
/* Allocate and initialize top and mid mfn levels for p2m structure */
xen_build_mfn_list_list();
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index dfc9004..5a16824 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -84,6 +84,7 @@
*/
DEFINE_SPINLOCK(xen_reservation_lock);
+#ifdef CONFIG_X86_32
/*
* Identity map, in addition to plain kernel map. This needs to be
* large enough to allocate page table pages to allocate the rest.
@@ -91,7 +92,7 @@
*/
#define LEVEL1_IDENT_ENTRIES (PTRS_PER_PTE * 4)
static RESERVE_BRK_ARRAY(pte_t, level1_ident_pgt, LEVEL1_IDENT_ENTRIES);
-
+#endif
#ifdef CONFIG_X86_64
/* l3 pud for userspace vsyscall mapping */
static pud_t level3_user_vsyscall[PTRS_PER_PUD] __page_aligned_bss;
@@ -1176,13 +1177,6 @@
static void xen_post_allocator_init(void);
-static void __init xen_pagetable_init(void)
-{
- paging_init();
- xen_setup_shared_info();
- xen_post_allocator_init();
-}
-
static __init void xen_mapping_pagetable_reserve(u64 start, u64 end)
{
/* reserve the range used */
@@ -1197,6 +1191,87 @@
}
}
+#ifdef CONFIG_X86_64
+static void __init xen_cleanhighmap(unsigned long vaddr,
+ unsigned long vaddr_end)
+{
+ unsigned long kernel_end = roundup((unsigned long)_brk_end, PMD_SIZE) - 1;
+ pmd_t *pmd = level2_kernel_pgt + pmd_index(vaddr);
+
+ /* NOTE: The loop is more greedy than the cleanup_highmap variant.
+ * We include the PMD passed in on _both_ boundaries. */
+ for (; vaddr <= vaddr_end && (pmd < (level2_kernel_pgt + PAGE_SIZE));
+ pmd++, vaddr += PMD_SIZE) {
+ if (pmd_none(*pmd))
+ continue;
+ if (vaddr < (unsigned long) _text || vaddr > kernel_end)
+ set_pmd(pmd, __pmd(0));
+ }
+ /* In case we did something silly, we should crash in this function
+ * instead of somewhere later and be confusing. */
+ xen_mc_flush();
+}
+#endif
+static void __init xen_pagetable_init(void)
+{
+#ifdef CONFIG_X86_64
+ unsigned long size;
+ unsigned long addr;
+#endif
+ paging_init();
+ xen_setup_shared_info();
+#ifdef CONFIG_X86_64
+ if (!xen_feature(XENFEAT_auto_translated_physmap)) {
+ unsigned long new_mfn_list;
+
+ size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
+
+ /* On 32-bit, we get zero so this never gets executed. */
+ new_mfn_list = xen_revector_p2m_tree();
+ if (new_mfn_list && new_mfn_list != xen_start_info->mfn_list) {
+ /* using __ka address and sticking INVALID_P2M_ENTRY! */
+ memset((void *)xen_start_info->mfn_list, 0xff, size);
+
+ /* We should be in __ka space. */
+ BUG_ON(xen_start_info->mfn_list < __START_KERNEL_map);
+ addr = xen_start_info->mfn_list;
+ /* We roundup to the PMD, which means that if anybody at this stage is
+ * using the __ka address of xen_start_info or xen_start_info->shared_info
+ * they are in going to crash. Fortunatly we have already revectored
+ * in xen_setup_kernel_pagetable and in xen_setup_shared_info. */
+ size = roundup(size, PMD_SIZE);
+ xen_cleanhighmap(addr, addr + size);
+
+ size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
+ memblock_free(__pa(xen_start_info->mfn_list), size);
+ /* And revector! Bye bye old array */
+ xen_start_info->mfn_list = new_mfn_list;
+ } else
+ goto skip;
+ }
+ /* At this stage, cleanup_highmap has already cleaned __ka space
+ * from _brk_limit way up to the max_pfn_mapped (which is the end of
+ * the ramdisk). We continue on, erasing PMD entries that point to page
+ * tables - do note that they are accessible at this stage via __va.
+ * For good measure we also round up to the PMD - which means that if
+ * anybody is using __ka address to the initial boot-stack - and try
+ * to use it - they are going to crash. The xen_start_info has been
+ * taken care of already in xen_setup_kernel_pagetable. */
+ addr = xen_start_info->pt_base;
+ size = roundup(xen_start_info->nr_pt_frames * PAGE_SIZE, PMD_SIZE);
+
+ xen_cleanhighmap(addr, addr + size);
+ xen_start_info->pt_base = (unsigned long)__va(__pa(xen_start_info->pt_base));
+#ifdef DEBUG
+ /* This is superflous and is not neccessary, but you know what
+ * lets do it. The MODULES_VADDR -> MODULES_END should be clear of
+ * anything at this stage. */
+ xen_cleanhighmap(MODULES_VADDR, roundup(MODULES_VADDR, PUD_SIZE) - 1);
+#endif
+skip:
+#endif
+ xen_post_allocator_init();
+}
static void xen_write_cr2(unsigned long cr2)
{
this_cpu_read(xen_vcpu)->arch.cr2 = cr2;
@@ -1652,7 +1727,7 @@
if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, 0))
BUG();
}
-
+#ifdef CONFIG_X86_32
static void __init xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn)
{
unsigned pmdidx, pteidx;
@@ -1703,7 +1778,7 @@
set_page_prot(pmd, PAGE_KERNEL_RO);
}
-
+#endif
void __init xen_setup_machphys_mapping(void)
{
struct xen_machphys_mapping mapping;
@@ -1731,7 +1806,20 @@
for (i = 0; i < PTRS_PER_PTE; i++)
pte[i] = xen_make_pte(pte[i].pte);
}
-
+static void __init check_pt_base(unsigned long *pt_base, unsigned long *pt_end,
+ unsigned long addr)
+{
+ if (*pt_base == PFN_DOWN(__pa(addr))) {
+ set_page_prot((void *)addr, PAGE_KERNEL);
+ clear_page((void *)addr);
+ (*pt_base)++;
+ }
+ if (*pt_end == PFN_DOWN(__pa(addr))) {
+ set_page_prot((void *)addr, PAGE_KERNEL);
+ clear_page((void *)addr);
+ (*pt_end)--;
+ }
+}
/*
* Set up the initial kernel pagetable.
*
@@ -1743,11 +1831,13 @@
* of the physical mapping once some sort of allocator has been set
* up.
*/
-pgd_t * __init xen_setup_kernel_pagetable(pgd_t *pgd,
- unsigned long max_pfn)
+void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
{
pud_t *l3;
pmd_t *l2;
+ unsigned long addr[3];
+ unsigned long pt_base, pt_end;
+ unsigned i;
/* max_pfn_mapped is the last pfn mapped in the initial memory
* mappings. Considering that on Xen after the kernel mappings we
@@ -1755,32 +1845,53 @@
* set max_pfn_mapped to the last real pfn mapped. */
max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list));
+ pt_base = PFN_DOWN(__pa(xen_start_info->pt_base));
+ pt_end = pt_base + xen_start_info->nr_pt_frames;
+
/* Zap identity mapping */
init_level4_pgt[0] = __pgd(0);
/* Pre-constructed entries are in pfn, so convert to mfn */
+ /* L4[272] -> level3_ident_pgt
+ * L4[511] -> level3_kernel_pgt */
convert_pfn_mfn(init_level4_pgt);
+
+ /* L3_i[0] -> level2_ident_pgt */
convert_pfn_mfn(level3_ident_pgt);
+ /* L3_k[510] -> level2_kernel_pgt
+ * L3_i[511] -> level2_fixmap_pgt */
convert_pfn_mfn(level3_kernel_pgt);
+ /* We get [511][511] and have Xen's version of level2_kernel_pgt */
l3 = m2v(pgd[pgd_index(__START_KERNEL_map)].pgd);
l2 = m2v(l3[pud_index(__START_KERNEL_map)].pud);
- memcpy(level2_ident_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);
- memcpy(level2_kernel_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);
+ addr[0] = (unsigned long)pgd;
+ addr[1] = (unsigned long)l3;
+ addr[2] = (unsigned long)l2;
+ /* Graft it onto L4[272][0]. Note that we creating an aliasing problem:
+ * Both L4[272][0] and L4[511][511] have entries that point to the same
+ * L2 (PMD) tables. Meaning that if you modify it in __va space
+ * it will be also modified in the __ka space! (But if you just
+ * modify the PMD table to point to other PTE's or none, then you
+ * are OK - which is what cleanup_highmap does) */
+ copy_page(level2_ident_pgt, l2);
+ /* Graft it onto L4[511][511] */
+ copy_page(level2_kernel_pgt, l2);
+ /* Get [511][510] and graft that in level2_fixmap_pgt */
l3 = m2v(pgd[pgd_index(__START_KERNEL_map + PMD_SIZE)].pgd);
l2 = m2v(l3[pud_index(__START_KERNEL_map + PMD_SIZE)].pud);
- memcpy(level2_fixmap_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);
-
- /* Set up identity map */
- xen_map_identity_early(level2_ident_pgt, max_pfn);
+ copy_page(level2_fixmap_pgt, l2);
+ /* Note that we don't do anything with level1_fixmap_pgt which
+ * we don't need. */
/* Make pagetable pieces RO */
set_page_prot(init_level4_pgt, PAGE_KERNEL_RO);
set_page_prot(level3_ident_pgt, PAGE_KERNEL_RO);
set_page_prot(level3_kernel_pgt, PAGE_KERNEL_RO);
set_page_prot(level3_user_vsyscall, PAGE_KERNEL_RO);
+ set_page_prot(level2_ident_pgt, PAGE_KERNEL_RO);
set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO);
set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO);
@@ -1791,22 +1902,28 @@
/* Unpin Xen-provided one */
pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
- /* Switch over */
- pgd = init_level4_pgt;
-
/*
* At this stage there can be no user pgd, and no page
* structure to attach it to, so make sure we just set kernel
* pgd.
*/
xen_mc_batch();
- __xen_write_cr3(true, __pa(pgd));
+ __xen_write_cr3(true, __pa(init_level4_pgt));
xen_mc_issue(PARAVIRT_LAZY_CPU);
- memblock_reserve(__pa(xen_start_info->pt_base),
- xen_start_info->nr_pt_frames * PAGE_SIZE);
+ /* We can't that easily rip out L3 and L2, as the Xen pagetables are
+ * set out this way: [L4], [L1], [L2], [L3], [L1], [L1] ... for
+ * the initial domain. For guests using the toolstack, they are in:
+ * [L4], [L3], [L2], [L1], [L1], order .. So for dom0 we can only
+ * rip out the [L4] (pgd), but for guests we shave off three pages.
+ */
+ for (i = 0; i < ARRAY_SIZE(addr); i++)
+ check_pt_base(&pt_base, &pt_end, addr[i]);
- return pgd;
+ /* Our (by three pages) smaller Xen pagetable that we are using */
+ memblock_reserve(PFN_PHYS(pt_base), (pt_end - pt_base) * PAGE_SIZE);
+ /* Revector the xen_start_info */
+ xen_start_info = (struct start_info *)__va(__pa(xen_start_info));
}
#else /* !CONFIG_X86_64 */
static RESERVE_BRK_ARRAY(pmd_t, initial_kernel_pmd, PTRS_PER_PMD);
@@ -1831,8 +1948,7 @@
*/
swapper_kernel_pmd =
extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
- memcpy(swapper_kernel_pmd, initial_kernel_pmd,
- sizeof(pmd_t) * PTRS_PER_PMD);
+ copy_page(swapper_kernel_pmd, initial_kernel_pmd);
swapper_pg_dir[KERNEL_PGD_BOUNDARY] =
__pgd(__pa(swapper_kernel_pmd) | _PAGE_PRESENT);
set_page_prot(swapper_kernel_pmd, PAGE_KERNEL_RO);
@@ -1849,8 +1965,7 @@
pv_mmu_ops.write_cr3 = &xen_write_cr3;
}
-pgd_t * __init xen_setup_kernel_pagetable(pgd_t *pgd,
- unsigned long max_pfn)
+void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
{
pmd_t *kernel_pmd;
@@ -1862,11 +1977,11 @@
512*1024);
kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd);
- memcpy(initial_kernel_pmd, kernel_pmd, sizeof(pmd_t) * PTRS_PER_PMD);
+ copy_page(initial_kernel_pmd, kernel_pmd);
xen_map_identity_early(initial_kernel_pmd, max_pfn);
- memcpy(initial_page_table, pgd, sizeof(pgd_t) * PTRS_PER_PGD);
+ copy_page(initial_page_table, pgd);
initial_page_table[KERNEL_PGD_BOUNDARY] =
__pgd(__pa(initial_kernel_pmd) | _PAGE_PRESENT);
@@ -1882,8 +1997,6 @@
memblock_reserve(__pa(xen_start_info->pt_base),
xen_start_info->nr_pt_frames * PAGE_SIZE);
-
- return initial_page_table;
}
#endif /* CONFIG_X86_64 */
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 76ba0e9..b5e4d30 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -22,7 +22,7 @@
*
* P2M_PER_PAGE depends on the architecture, as a mfn is always
* unsigned long (8 bytes on 64-bit, 4 bytes on 32), leading to
- * 512 and 1024 entries respectively.
+ * 512 and 1024 entries respectively.
*
* In short, these structures contain the Machine Frame Number (MFN) of the PFN.
*
@@ -139,11 +139,11 @@
* / | ~0, ~0, .... |
* | \---------------/
* |
- * p2m_missing p2m_missing
- * /------------------\ /------------\
- * | [p2m_mid_missing]+---->| ~0, ~0, ~0 |
- * | [p2m_mid_missing]+---->| ..., ~0 |
- * \------------------/ \------------/
+ * p2m_mid_missing p2m_missing
+ * /-----------------\ /------------\
+ * | [p2m_missing] +---->| ~0, ~0, ~0 |
+ * | [p2m_missing] +---->| ..., ~0 |
+ * \-----------------/ \------------/
*
* where ~0 is INVALID_P2M_ENTRY. IDENTITY is (PFN | IDENTITY_BIT)
*/
@@ -396,7 +396,85 @@
m2p_override_init();
}
+#ifdef CONFIG_X86_64
+#include <linux/bootmem.h>
+unsigned long __init xen_revector_p2m_tree(void)
+{
+ unsigned long va_start;
+ unsigned long va_end;
+ unsigned long pfn;
+ unsigned long pfn_free = 0;
+ unsigned long *mfn_list = NULL;
+ unsigned long size;
+ va_start = xen_start_info->mfn_list;
+ /*We copy in increments of P2M_PER_PAGE * sizeof(unsigned long),
+ * so make sure it is rounded up to that */
+ size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
+ va_end = va_start + size;
+
+ /* If we were revectored already, don't do it again. */
+ if (va_start <= __START_KERNEL_map && va_start >= __PAGE_OFFSET)
+ return 0;
+
+ mfn_list = alloc_bootmem_align(size, PAGE_SIZE);
+ if (!mfn_list) {
+ pr_warn("Could not allocate space for a new P2M tree!\n");
+ return xen_start_info->mfn_list;
+ }
+ /* Fill it out with INVALID_P2M_ENTRY value */
+ memset(mfn_list, 0xFF, size);
+
+ for (pfn = 0; pfn < ALIGN(MAX_DOMAIN_PAGES, P2M_PER_PAGE); pfn += P2M_PER_PAGE) {
+ unsigned topidx = p2m_top_index(pfn);
+ unsigned mididx;
+ unsigned long *mid_p;
+
+ if (!p2m_top[topidx])
+ continue;
+
+ if (p2m_top[topidx] == p2m_mid_missing)
+ continue;
+
+ mididx = p2m_mid_index(pfn);
+ mid_p = p2m_top[topidx][mididx];
+ if (!mid_p)
+ continue;
+ if ((mid_p == p2m_missing) || (mid_p == p2m_identity))
+ continue;
+
+ if ((unsigned long)mid_p == INVALID_P2M_ENTRY)
+ continue;
+
+ /* The old va. Rebase it on mfn_list */
+ if (mid_p >= (unsigned long *)va_start && mid_p <= (unsigned long *)va_end) {
+ unsigned long *new;
+
+ if (pfn_free > (size / sizeof(unsigned long))) {
+ WARN(1, "Only allocated for %ld pages, but we want %ld!\n",
+ size / sizeof(unsigned long), pfn_free);
+ return 0;
+ }
+ new = &mfn_list[pfn_free];
+
+ copy_page(new, mid_p);
+ p2m_top[topidx][mididx] = &mfn_list[pfn_free];
+ p2m_top_mfn_p[topidx][mididx] = virt_to_mfn(&mfn_list[pfn_free]);
+
+ pfn_free += P2M_PER_PAGE;
+
+ }
+ /* This should be the leafs allocated for identity from _brk. */
+ }
+ return (unsigned long)mfn_list;
+
+}
+#else
+unsigned long __init xen_revector_p2m_tree(void)
+{
+ return 0;
+}
+#endif
unsigned long get_phys_to_machine(unsigned long pfn)
{
unsigned topidx, mididx, idx;
@@ -430,7 +508,7 @@
free_page((unsigned long)p);
}
-/*
+/*
* Fully allocate the p2m structure for a given pfn. We need to check
* that both the top and mid levels are allocated, and make sure the
* parallel mfn tree is kept in sync. We may race with other cpus, so
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index d11ca11..3edb320 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -431,6 +431,24 @@
* - mfn_list
* - xen_start_info
* See comment above "struct start_info" in <xen/interface/xen.h>
+ * We tried to make the the memblock_reserve more selective so
+ * that it would be clear what region is reserved. Sadly we ran
+ * in the problem wherein on a 64-bit hypervisor with a 32-bit
+ * initial domain, the pt_base has the cr3 value which is not
+ * neccessarily where the pagetable starts! As Jan put it: "
+ * Actually, the adjustment turns out to be correct: The page
+ * tables for a 32-on-64 dom0 get allocated in the order "first L1",
+ * "first L2", "first L3", so the offset to the page table base is
+ * indeed 2. When reading xen/include/public/xen.h's comment
+ * very strictly, this is not a violation (since there nothing is said
+ * that the first thing in the page table space is pointed to by
+ * pt_base; I admit that this seems to be implied though, namely
+ * do I think that it is implied that the page table space is the
+ * range [pt_base, pt_base + nt_pt_frames), whereas that
+ * range here indeed is [pt_base - 2, pt_base - 2 + nt_pt_frames),
+ * which - without a priori knowledge - the kernel would have
+ * difficulty to figure out)." - so lets just fall back to the
+ * easy way and reserve the whole region.
*/
memblock_reserve(__pa(xen_start_info->mfn_list),
xen_start_info->pt_base - xen_start_info->mfn_list);
diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
index 202d4c1..bb5a810 100644
--- a/arch/x86/xen/xen-ops.h
+++ b/arch/x86/xen/xen-ops.h
@@ -27,7 +27,7 @@
void xen_setup_shared_info(void);
void xen_build_mfn_list_list(void);
void xen_setup_machphys_mapping(void);
-pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn);
+void xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn);
void xen_reserve_top(void);
extern unsigned long xen_max_p2m_pfn;
@@ -45,6 +45,7 @@
void xen_unplug_emulated_devices(void);
void __init xen_build_dynamic_phys_to_machine(void);
+unsigned long __init xen_revector_p2m_tree(void);
void xen_init_irq_ops(void);
void xen_setup_timer(int cpu);