lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Merge branches 'stable/p2m-identity.v4.9.1' and 'stable/e820' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen

Browse Source 
* 'stable/p2m-identity.v4.9.1' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen/m2p: Check whether the MFN has IDENTITY_FRAME bit set..
  xen/m2p: No need to catch exceptions when we know that there is no RAM
  xen/debug: WARN_ON when identity PFN has no _PAGE_IOMAP flag set.
  xen/debugfs: Add 'p2m' file for printing out the P2M layout.
  xen/setup: Set identity mapping for non-RAM E820 and E820 gaps.
  xen/mmu: WARN_ON when racing to swap middle leaf.
  xen/mmu: Set _PAGE_IOMAP if PFN is an identity PFN.
  xen/mmu: Add the notion of identity (1-1) mapping.
  xen: Mark all initial reserved pages for the balloon as INVALID_P2M_ENTRY.

* 'stable/e820' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen/e820: Don't mark balloon memory as E820_UNUSABLE when running as guest and fix overflow.
  xen/setup: Inhibit resource API from using System RAM E820 gaps as PCI mem gaps.
This commit is contained in:
Linus Torvalds
2011-03-15 10:32:15 -07:00
parent 521cb40b0c 706cc9d2a4 86b32122fd
commit c7146dd009
6 changed files with 498 additions and 21 deletions
Download Patch File Download Diff File Expand all files Collapse all files

39
arch/x86/include/asm/xen/page.h
View File

@@ -29,8 +29,10 @@ typedef struct xpaddr {
/**** MACHINE <-> PHYSICAL CONVERSION MACROS ****/ /**** MACHINE <-> PHYSICAL CONVERSION MACROS ****/
#define INVALID_P2M_ENTRY (~0UL) #define INVALID_P2M_ENTRY (~0UL)
#define FOREIGN_FRAME_BIT (1UL<<31) #define FOREIGN_FRAME_BIT (1UL<<(BITS_PER_LONG-1))
#define IDENTITY_FRAME_BIT (1UL<<(BITS_PER_LONG-2))
#define FOREIGN_FRAME(m) ((m) | FOREIGN_FRAME_BIT) #define FOREIGN_FRAME(m) ((m) | FOREIGN_FRAME_BIT)
#define IDENTITY_FRAME(m) ((m) | IDENTITY_FRAME_BIT)
/* Maximum amount of memory we can handle in a domain in pages */ /* Maximum amount of memory we can handle in a domain in pages */
#define MAX_DOMAIN_PAGES \ #define MAX_DOMAIN_PAGES \
@@ -41,12 +43,18 @@ extern unsigned int machine_to_phys_order;
extern unsigned long get_phys_to_machine(unsigned long pfn); extern unsigned long get_phys_to_machine(unsigned long pfn);
extern bool set_phys_to_machine(unsigned long pfn, unsigned long mfn); extern bool set_phys_to_machine(unsigned long pfn, unsigned long mfn);
extern bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn);
extern unsigned long set_phys_range_identity(unsigned long pfn_s,
unsigned long pfn_e);
extern int m2p_add_override(unsigned long mfn, struct page *page); extern int m2p_add_override(unsigned long mfn, struct page *page);
extern int m2p_remove_override(struct page *page); extern int m2p_remove_override(struct page *page);
extern struct page *m2p_find_override(unsigned long mfn); extern struct page *m2p_find_override(unsigned long mfn);
extern unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn); extern unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn);
#ifdef CONFIG_XEN_DEBUG_FS
extern int p2m_dump_show(struct seq_file *m, void *v);
#endif
static inline unsigned long pfn_to_mfn(unsigned long pfn) static inline unsigned long pfn_to_mfn(unsigned long pfn)
{ {
unsigned long mfn; unsigned long mfn;
@@ -57,7 +65,7 @@ static inline unsigned long pfn_to_mfn(unsigned long pfn)
mfn = get_phys_to_machine(pfn); mfn = get_phys_to_machine(pfn);
if (mfn != INVALID_P2M_ENTRY) if (mfn != INVALID_P2M_ENTRY)
mfn &= ~FOREIGN_FRAME_BIT; mfn &= ~(FOREIGN_FRAME_BIT | IDENTITY_FRAME_BIT);
return mfn; return mfn;
} }
@@ -73,25 +81,44 @@ static inline int phys_to_machine_mapping_valid(unsigned long pfn)
static inline unsigned long mfn_to_pfn(unsigned long mfn) static inline unsigned long mfn_to_pfn(unsigned long mfn)
{ {
unsigned long pfn; unsigned long pfn;
int ret = 0;
if (xen_feature(XENFEAT_auto_translated_physmap)) if (xen_feature(XENFEAT_auto_translated_physmap))
return mfn; return mfn;
if (unlikely((mfn >> machine_to_phys_order) != 0)) {
pfn = ~0;
goto try_override;
}
pfn = 0; pfn = 0;
/* /*
* The array access can fail (e.g., device space beyond end of RAM). * The array access can fail (e.g., device space beyond end of RAM).
* In such cases it doesn't matter what we return (we return garbage), * In such cases it doesn't matter what we return (we return garbage),
* but we must handle the fault without crashing! * but we must handle the fault without crashing!
*/ */
__get_user(pfn, &machine_to_phys_mapping[mfn]); ret = __get_user(pfn, &machine_to_phys_mapping[mfn]);
try_override:
/* ret might be < 0 if there are no entries in the m2p for mfn */
if (ret < 0)
pfn = ~0;
else if (get_phys_to_machine(pfn) != mfn)
/* /*
* If this appears to be a foreign mfn (because the pfn * If this appears to be a foreign mfn (because the pfn
* doesn't map back to the mfn), then check the local override * doesn't map back to the mfn), then check the local override
* table to see if there's a better pfn to use. * table to see if there's a better pfn to use.
*
* m2p_find_override_pfn returns ~0 if it doesn't find anything.
*/ */
if (get_phys_to_machine(pfn) != mfn) pfn = m2p_find_override_pfn(mfn, ~0);
pfn = m2p_find_override_pfn(mfn, pfn);
/*
* pfn is ~0 if there are no entries in the m2p for mfn or if the
* entry doesn't map back to the mfn and m2p_override doesn't have a
* valid entry for it.
*/
if (pfn == ~0 &&
get_phys_to_machine(mfn) == IDENTITY_FRAME(mfn))
pfn = mfn;
return pfn; return pfn;
} }

8
arch/x86/xen/Kconfig
View File

@@ -48,3 +48,11 @@ config XEN_DEBUG_FS
help help
Enable statistics output and various tuning options in debugfs. Enable statistics output and various tuning options in debugfs.
Enabling this option may incur a significant performance overhead. Enabling this option may incur a significant performance overhead.
config XEN_DEBUG
bool "Enable Xen debug checks"
depends on XEN
default n
help
Enable various WARN_ON checks in the Xen MMU code.
Enabling this option WILL incur a significant performance overhead.

72
arch/x86/xen/mmu.c
View File

@@ -46,6 +46,7 @@
#include <linux/module.h> #include <linux/module.h>
#include <linux/gfp.h> #include <linux/gfp.h>
#include <linux/memblock.h> #include <linux/memblock.h>
#include <linux/seq_file.h>
#include <asm/pgtable.h> #include <asm/pgtable.h>
#include <asm/tlbflush.h> #include <asm/tlbflush.h>
@@ -416,8 +417,12 @@ static pteval_t pte_pfn_to_mfn(pteval_t val)
if (val & _PAGE_PRESENT) { if (val & _PAGE_PRESENT) {
unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT; unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
pteval_t flags = val & PTE_FLAGS_MASK; pteval_t flags = val & PTE_FLAGS_MASK;
unsigned long mfn = pfn_to_mfn(pfn); unsigned long mfn;
if (!xen_feature(XENFEAT_auto_translated_physmap))
mfn = get_phys_to_machine(pfn);
else
mfn = pfn;
/* /*
* If there's no mfn for the pfn, then just create an * If there's no mfn for the pfn, then just create an
* empty non-present pte. Unfortunately this loses * empty non-present pte. Unfortunately this loses
@@ -427,8 +432,18 @@ static pteval_t pte_pfn_to_mfn(pteval_t val)
if (unlikely(mfn == INVALID_P2M_ENTRY)) { if (unlikely(mfn == INVALID_P2M_ENTRY)) {
mfn = 0; mfn = 0;
flags = 0; flags = 0;
} else {
/*
* Paramount to do this test _after_ the
* INVALID_P2M_ENTRY as INVALID_P2M_ENTRY &
* IDENTITY_FRAME_BIT resolves to true.
*/
mfn &= ~FOREIGN_FRAME_BIT;
if (mfn & IDENTITY_FRAME_BIT) {
mfn &= ~IDENTITY_FRAME_BIT;
flags |= _PAGE_IOMAP;
}
} }
val = ((pteval_t)mfn << PAGE_SHIFT) | flags; val = ((pteval_t)mfn << PAGE_SHIFT) | flags;
} }
@@ -532,6 +547,41 @@ pte_t xen_make_pte(pteval_t pte)
} }
PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte); PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte);
#ifdef CONFIG_XEN_DEBUG
pte_t xen_make_pte_debug(pteval_t pte)
{
phys_addr_t addr = (pte & PTE_PFN_MASK);
phys_addr_t other_addr;
bool io_page = false;
pte_t _pte;
if (pte & _PAGE_IOMAP)
io_page = true;
_pte = xen_make_pte(pte);
if (!addr)
return _pte;
if (io_page &&
(xen_initial_domain() || addr >= ISA_END_ADDRESS)) {
other_addr = pfn_to_mfn(addr >> PAGE_SHIFT) << PAGE_SHIFT;
WARN(addr != other_addr,
"0x%lx is using VM_IO, but it is 0x%lx!\n",
(unsigned long)addr, (unsigned long)other_addr);
} else {
pteval_t iomap_set = (_pte.pte & PTE_FLAGS_MASK) & _PAGE_IOMAP;
other_addr = (_pte.pte & PTE_PFN_MASK);
WARN((addr == other_addr) && (!io_page) && (!iomap_set),
"0x%lx is missing VM_IO (and wasn't fixed)!\n",
(unsigned long)addr);
}
return _pte;
}
PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte_debug);
#endif
pgd_t xen_make_pgd(pgdval_t pgd) pgd_t xen_make_pgd(pgdval_t pgd)
{ {
pgd = pte_pfn_to_mfn(pgd); pgd = pte_pfn_to_mfn(pgd);
@@ -1940,6 +1990,9 @@ __init void xen_ident_map_ISA(void)
static __init void xen_post_allocator_init(void) static __init void xen_post_allocator_init(void)
{ {
#ifdef CONFIG_XEN_DEBUG
pv_mmu_ops.make_pte = PV_CALLEE_SAVE(xen_make_pte_debug);
#endif
pv_mmu_ops.set_pte = xen_set_pte; pv_mmu_ops.set_pte = xen_set_pte;
pv_mmu_ops.set_pmd = xen_set_pmd; pv_mmu_ops.set_pmd = xen_set_pmd;
pv_mmu_ops.set_pud = xen_set_pud; pv_mmu_ops.set_pud = xen_set_pud;
@@ -2072,7 +2125,7 @@ static void xen_zap_pfn_range(unsigned long vaddr, unsigned int order,
in_frames[i] = virt_to_mfn(vaddr); in_frames[i] = virt_to_mfn(vaddr);
MULTI_update_va_mapping(mcs.mc, vaddr, VOID_PTE, 0); MULTI_update_va_mapping(mcs.mc, vaddr, VOID_PTE, 0);
set_phys_to_machine(virt_to_pfn(vaddr), INVALID_P2M_ENTRY); __set_phys_to_machine(virt_to_pfn(vaddr), INVALID_P2M_ENTRY);
if (out_frames) if (out_frames)
out_frames[i] = virt_to_pfn(vaddr); out_frames[i] = virt_to_pfn(vaddr);
@@ -2351,6 +2404,18 @@ EXPORT_SYMBOL_GPL(xen_remap_domain_mfn_range);
#ifdef CONFIG_XEN_DEBUG_FS #ifdef CONFIG_XEN_DEBUG_FS
static int p2m_dump_open(struct inode *inode, struct file *filp)
{
return single_open(filp, p2m_dump_show, NULL);
}
static const struct file_operations p2m_dump_fops = {
.open = p2m_dump_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static struct dentry *d_mmu_debug; static struct dentry *d_mmu_debug;
static int __init xen_mmu_debugfs(void) static int __init xen_mmu_debugfs(void)
@@ -2406,6 +2471,7 @@ static int __init xen_mmu_debugfs(void)
debugfs_create_u32("prot_commit_batched", 0444, d_mmu_debug, debugfs_create_u32("prot_commit_batched", 0444, d_mmu_debug,
&mmu_stats.prot_commit_batched); &mmu_stats.prot_commit_batched);
debugfs_create_file("p2m", 0600, d_mmu_debug, NULL, &p2m_dump_fops);
return 0; return 0;
} }
fs_initcall(xen_mmu_debugfs); fs_initcall(xen_mmu_debugfs);

324
arch/x86/xen/p2m.c
View File

@@ -23,6 +23,129 @@
* P2M_PER_PAGE depends on the architecture, as a mfn is always * 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 * 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.
*
* However not all entries are filled with MFNs. Specifically for all other
* leaf entries, or for the top root, or middle one, for which there is a void
* entry, we assume it is "missing". So (for example)
* pfn_to_mfn(0x90909090)=INVALID_P2M_ENTRY.
*
* We also have the possibility of setting 1-1 mappings on certain regions, so
* that:
* pfn_to_mfn(0xc0000)=0xc0000
*
* The benefit of this is, that we can assume for non-RAM regions (think
* PCI BARs, or ACPI spaces), we can create mappings easily b/c we
* get the PFN value to match the MFN.
*
* For this to work efficiently we have one new page p2m_identity and
* allocate (via reserved_brk) any other pages we need to cover the sides
* (1GB or 4MB boundary violations). All entries in p2m_identity are set to
* INVALID_P2M_ENTRY type (Xen toolstack only recognizes that and MFNs,
* no other fancy value).
*
* On lookup we spot that the entry points to p2m_identity and return the
* identity value instead of dereferencing and returning INVALID_P2M_ENTRY.
* If the entry points to an allocated page, we just proceed as before and
* return the PFN. If the PFN has IDENTITY_FRAME_BIT set we unmask that in
* appropriate functions (pfn_to_mfn).
*
* The reason for having the IDENTITY_FRAME_BIT instead of just returning the
* PFN is that we could find ourselves where pfn_to_mfn(pfn)==pfn for a
* non-identity pfn. To protect ourselves against we elect to set (and get) the
* IDENTITY_FRAME_BIT on all identity mapped PFNs.
*
* This simplistic diagram is used to explain the more subtle piece of code.
* There is also a digram of the P2M at the end that can help.
* Imagine your E820 looking as so:
*
* 1GB 2GB
* /-------------------+---------\/----\ /----------\ /---+-----\
* | System RAM | Sys RAM ||ACPI| | reserved | | Sys RAM |
* \-------------------+---------/\----/ \----------/ \---+-----/
* ^- 1029MB ^- 2001MB
*
* [1029MB = 263424 (0x40500), 2001MB = 512256 (0x7D100),
* 2048MB = 524288 (0x80000)]
*
* And dom0_mem=max:3GB,1GB is passed in to the guest, meaning memory past 1GB
* is actually not present (would have to kick the balloon driver to put it in).
*
* When we are told to set the PFNs for identity mapping (see patch: "xen/setup:
* Set identity mapping for non-RAM E820 and E820 gaps.") we pass in the start
* of the PFN and the end PFN (263424 and 512256 respectively). The first step
* is to reserve_brk a top leaf page if the p2m[1] is missing. The top leaf page
* covers 512^2 of page estate (1GB) and in case the start or end PFN is not
* aligned on 512^2*PAGE_SIZE (1GB) we loop on aligned 1GB PFNs from start pfn
* to end pfn. We reserve_brk top leaf pages if they are missing (means they
* point to p2m_mid_missing).
*
* With the E820 example above, 263424 is not 1GB aligned so we allocate a
* reserve_brk page which will cover the PFNs estate from 0x40000 to 0x80000.
* Each entry in the allocate page is "missing" (points to p2m_missing).
*
* Next stage is to determine if we need to do a more granular boundary check
* on the 4MB (or 2MB depending on architecture) off the start and end pfn's.
* We check if the start pfn and end pfn violate that boundary check, and if
* so reserve_brk a middle (p2m[x][y]) leaf page. This way we have a much finer
* granularity of setting which PFNs are missing and which ones are identity.
* In our example 263424 and 512256 both fail the check so we reserve_brk two
* pages. Populate them with INVALID_P2M_ENTRY (so they both have "missing"
* values) and assign them to p2m[1][2] and p2m[1][488] respectively.
*
* At this point we would at minimum reserve_brk one page, but could be up to
* three. Each call to set_phys_range_identity has at maximum a three page
* cost. If we were to query the P2M at this stage, all those entries from
* start PFN through end PFN (so 1029MB -> 2001MB) would return
* INVALID_P2M_ENTRY ("missing").
*
* The next step is to walk from the start pfn to the end pfn setting
* the IDENTITY_FRAME_BIT on each PFN. This is done in set_phys_range_identity.
* If we find that the middle leaf is pointing to p2m_missing we can swap it
* over to p2m_identity - this way covering 4MB (or 2MB) PFN space. At this
* point we do not need to worry about boundary aligment (so no need to
* reserve_brk a middle page, figure out which PFNs are "missing" and which
* ones are identity), as that has been done earlier. If we find that the
* middle leaf is not occupied by p2m_identity or p2m_missing, we dereference
* that page (which covers 512 PFNs) and set the appropriate PFN with
* IDENTITY_FRAME_BIT. In our example 263424 and 512256 end up there, and we
* set from p2m[1][2][256->511] and p2m[1][488][0->256] with
* IDENTITY_FRAME_BIT set.
*
* All other regions that are void (or not filled) either point to p2m_missing
* (considered missing) or have the default value of INVALID_P2M_ENTRY (also
* considered missing). In our case, p2m[1][2][0->255] and p2m[1][488][257->511]
* contain the INVALID_P2M_ENTRY value and are considered "missing."
*
* This is what the p2m ends up looking (for the E820 above) with this
* fabulous drawing:
*
* p2m /--------------\
* /-----\ | &mfn_list[0],| /-----------------\
* | 0 |------>| &mfn_list[1],| /---------------\ | ~0, ~0, .. |
* |-----| | ..., ~0, ~0 | | ~0, ~0, [x]---+----->| IDENTITY [@256] |
* | 1 |---\ \--------------/ | [p2m_identity]+\ | IDENTITY [@257] |
* |-----| \ | [p2m_identity]+\\ | .... |
* | 2 |--\ \-------------------->| ... | \\ \----------------/
* |-----| \ \---------------/ \\
* | 3 |\ \ \\ p2m_identity
* |-----| \ \-------------------->/---------------\ /-----------------\
* | .. +->+ | [p2m_identity]+-->| ~0, ~0, ~0, ... |
* \-----/ / | [p2m_identity]+-->| ..., ~0 |
* / /---------------\ | .... | \-----------------/
* / | IDENTITY[@0] | /-+-[x], ~0, ~0.. |
* / | IDENTITY[@256]|<----/ \---------------/
* / | ~0, ~0, .... |
* | \---------------/
* |
* p2m_missing p2m_missing
* /------------------\ /------------\
* | [p2m_mid_missing]+---->| ~0, ~0, ~0 |
* | [p2m_mid_missing]+---->| ..., ~0 |
* \------------------/ \------------/
*
* where ~0 is INVALID_P2M_ENTRY. IDENTITY is (PFN | IDENTITY_BIT)
*/ */
#include <linux/init.h> #include <linux/init.h>
@@ -30,6 +153,7 @@
#include <linux/list.h> #include <linux/list.h>
#include <linux/hash.h> #include <linux/hash.h>
#include <linux/sched.h> #include <linux/sched.h>
#include <linux/seq_file.h>
#include <asm/cache.h> #include <asm/cache.h>
#include <asm/setup.h> #include <asm/setup.h>
@@ -59,9 +183,15 @@ static RESERVE_BRK_ARRAY(unsigned long **, p2m_top, P2M_TOP_PER_PAGE);
static RESERVE_BRK_ARRAY(unsigned long, p2m_top_mfn, P2M_TOP_PER_PAGE); static RESERVE_BRK_ARRAY(unsigned long, p2m_top_mfn, P2M_TOP_PER_PAGE);
static RESERVE_BRK_ARRAY(unsigned long *, p2m_top_mfn_p, P2M_TOP_PER_PAGE); static RESERVE_BRK_ARRAY(unsigned long *, p2m_top_mfn_p, P2M_TOP_PER_PAGE);
static RESERVE_BRK_ARRAY(unsigned long, p2m_identity, P2M_PER_PAGE);
RESERVE_BRK(p2m_mid, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE))); RESERVE_BRK(p2m_mid, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE)));
RESERVE_BRK(p2m_mid_mfn, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE))); RESERVE_BRK(p2m_mid_mfn, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE)));
/* We might hit two boundary violations at the start and end, at max each
* boundary violation will require three middle nodes. */
RESERVE_BRK(p2m_mid_identity, PAGE_SIZE * 2 * 3);
static inline unsigned p2m_top_index(unsigned long pfn) static inline unsigned p2m_top_index(unsigned long pfn)
{ {
BUG_ON(pfn >= MAX_P2M_PFN); BUG_ON(pfn >= MAX_P2M_PFN);
@@ -221,6 +351,9 @@ void __init xen_build_dynamic_phys_to_machine(void)
p2m_top = extend_brk(PAGE_SIZE, PAGE_SIZE); p2m_top = extend_brk(PAGE_SIZE, PAGE_SIZE);
p2m_top_init(p2m_top); p2m_top_init(p2m_top);
p2m_identity = extend_brk(PAGE_SIZE, PAGE_SIZE);
p2m_init(p2m_identity);
/* /*
* The domain builder gives us a pre-constructed p2m array in * The domain builder gives us a pre-constructed p2m array in
* mfn_list for all the pages initially given to us, so we just * mfn_list for all the pages initially given to us, so we just
@@ -266,6 +399,14 @@ unsigned long get_phys_to_machine(unsigned long pfn)
mididx = p2m_mid_index(pfn); mididx = p2m_mid_index(pfn);
idx = p2m_index(pfn); idx = p2m_index(pfn);
/*
* The INVALID_P2M_ENTRY is filled in both p2m_*identity
* and in p2m_*missing, so returning the INVALID_P2M_ENTRY
* would be wrong.
*/
if (p2m_top[topidx][mididx] == p2m_identity)
return IDENTITY_FRAME(pfn);
return p2m_top[topidx][mididx][idx]; return p2m_top[topidx][mididx][idx];
} }
EXPORT_SYMBOL_GPL(get_phys_to_machine); EXPORT_SYMBOL_GPL(get_phys_to_machine);
@@ -335,9 +476,11 @@ static bool alloc_p2m(unsigned long pfn)
p2m_top_mfn_p[topidx] = mid_mfn; p2m_top_mfn_p[topidx] = mid_mfn;
} }
if (p2m_top[topidx][mididx] == p2m_missing) { if (p2m_top[topidx][mididx] == p2m_identity ||
p2m_top[topidx][mididx] == p2m_missing) {
/* p2m leaf page is missing */ /* p2m leaf page is missing */
unsigned long *p2m; unsigned long *p2m;
unsigned long *p2m_orig = p2m_top[topidx][mididx];
p2m = alloc_p2m_page(); p2m = alloc_p2m_page();
if (!p2m) if (!p2m)
@@ -345,7 +488,7 @@ static bool alloc_p2m(unsigned long pfn)
p2m_init(p2m); p2m_init(p2m);
if (cmpxchg(&mid[mididx], p2m_missing, p2m) != p2m_missing) if (cmpxchg(&mid[mididx], p2m_orig, p2m) != p2m_orig)
free_p2m_page(p2m); free_p2m_page(p2m);
else else
mid_mfn[mididx] = virt_to_mfn(p2m); mid_mfn[mididx] = virt_to_mfn(p2m);
@@ -354,11 +497,91 @@ static bool alloc_p2m(unsigned long pfn)
return true; return true;
} }
bool __early_alloc_p2m(unsigned long pfn)
{
unsigned topidx, mididx, idx;
topidx = p2m_top_index(pfn);
mididx = p2m_mid_index(pfn);
idx = p2m_index(pfn);
/* Pfff.. No boundary cross-over, lets get out. */
if (!idx)
return false;
WARN(p2m_top[topidx][mididx] == p2m_identity,
"P2M[%d][%d] == IDENTITY, should be MISSING (or alloced)!\n",
topidx, mididx);
/*
* Could be done by xen_build_dynamic_phys_to_machine..
*/
if (p2m_top[topidx][mididx] != p2m_missing)
return false;
/* Boundary cross-over for the edges: */
if (idx) {
unsigned long *p2m = extend_brk(PAGE_SIZE, PAGE_SIZE);
p2m_init(p2m);
p2m_top[topidx][mididx] = p2m;
}
return idx != 0;
}
unsigned long set_phys_range_identity(unsigned long pfn_s,
unsigned long pfn_e)
{
unsigned long pfn;
if (unlikely(pfn_s >= MAX_P2M_PFN || pfn_e >= MAX_P2M_PFN))
return 0;
if (unlikely(xen_feature(XENFEAT_auto_translated_physmap)))
return pfn_e - pfn_s;
if (pfn_s > pfn_e)
return 0;
for (pfn = (pfn_s & ~(P2M_MID_PER_PAGE * P2M_PER_PAGE - 1));
pfn < ALIGN(pfn_e, (P2M_MID_PER_PAGE * P2M_PER_PAGE));
pfn += P2M_MID_PER_PAGE * P2M_PER_PAGE)
{
unsigned topidx = p2m_top_index(pfn);
if (p2m_top[topidx] == p2m_mid_missing) {
unsigned long **mid = extend_brk(PAGE_SIZE, PAGE_SIZE);
p2m_mid_init(mid);
p2m_top[topidx] = mid;
}
}
__early_alloc_p2m(pfn_s);
__early_alloc_p2m(pfn_e);
for (pfn = pfn_s; pfn < pfn_e; pfn++)
if (!__set_phys_to_machine(pfn, IDENTITY_FRAME(pfn)))
break;
if (!WARN((pfn - pfn_s) != (pfn_e - pfn_s),
"Identity mapping failed. We are %ld short of 1-1 mappings!\n",
(pfn_e - pfn_s) - (pfn - pfn_s)))
printk(KERN_DEBUG "1-1 mapping on %lx->%lx\n", pfn_s, pfn);
return pfn - pfn_s;
}
/* Try to install p2m mapping; fail if intermediate bits missing */ /* Try to install p2m mapping; fail if intermediate bits missing */
bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn) bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
{ {
unsigned topidx, mididx, idx; unsigned topidx, mididx, idx;
if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) {
BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY);
return true;
}
if (unlikely(pfn >= MAX_P2M_PFN)) { if (unlikely(pfn >= MAX_P2M_PFN)) {
BUG_ON(mfn != INVALID_P2M_ENTRY); BUG_ON(mfn != INVALID_P2M_ENTRY);
return true; return true;
@@ -368,6 +591,21 @@ bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
mididx = p2m_mid_index(pfn); mididx = p2m_mid_index(pfn);
idx = p2m_index(pfn); idx = p2m_index(pfn);
/* For sparse holes were the p2m leaf has real PFN along with
* PCI holes, stick in the PFN as the MFN value.
*/
if (mfn != INVALID_P2M_ENTRY && (mfn & IDENTITY_FRAME_BIT)) {
if (p2m_top[topidx][mididx] == p2m_identity)
return true;
/* Swap over from MISSING to IDENTITY if needed. */
if (p2m_top[topidx][mididx] == p2m_missing) {
WARN_ON(cmpxchg(&p2m_top[topidx][mididx], p2m_missing,
p2m_identity) != p2m_missing);
return true;
}
}
if (p2m_top[topidx][mididx] == p2m_missing) if (p2m_top[topidx][mididx] == p2m_missing)
return mfn == INVALID_P2M_ENTRY; return mfn == INVALID_P2M_ENTRY;
@@ -378,11 +616,6 @@ bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
bool set_phys_to_machine(unsigned long pfn, unsigned long mfn) bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
{ {
if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) {
BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY);
return true;
}
if (unlikely(!__set_phys_to_machine(pfn, mfn))) { if (unlikely(!__set_phys_to_machine(pfn, mfn))) {
if (!alloc_p2m(pfn)) if (!alloc_p2m(pfn))
return false; return false;
@@ -520,3 +753,80 @@ unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn)
return ret; return ret;
} }
EXPORT_SYMBOL_GPL(m2p_find_override_pfn); EXPORT_SYMBOL_GPL(m2p_find_override_pfn);
#ifdef CONFIG_XEN_DEBUG_FS
int p2m_dump_show(struct seq_file *m, void *v)
{
static const char * const level_name[] = { "top", "middle",
"entry", "abnormal" };
static const char * const type_name[] = { "identity", "missing",
"pfn", "abnormal"};
#define TYPE_IDENTITY 0
#define TYPE_MISSING 1
#define TYPE_PFN 2
#define TYPE_UNKNOWN 3
unsigned long pfn, prev_pfn_type = 0, prev_pfn_level = 0;
unsigned int uninitialized_var(prev_level);
unsigned int uninitialized_var(prev_type);
if (!p2m_top)
return 0;
for (pfn = 0; pfn < MAX_DOMAIN_PAGES; pfn++) {
unsigned topidx = p2m_top_index(pfn);
unsigned mididx = p2m_mid_index(pfn);
unsigned idx = p2m_index(pfn);
unsigned lvl, type;
lvl = 4;
type = TYPE_UNKNOWN;
if (p2m_top[topidx] == p2m_mid_missing) {
lvl = 0; type = TYPE_MISSING;
} else if (p2m_top[topidx] == NULL) {
lvl = 0; type = TYPE_UNKNOWN;
} else if (p2m_top[topidx][mididx] == NULL) {
lvl = 1; type = TYPE_UNKNOWN;
} else if (p2m_top[topidx][mididx] == p2m_identity) {
lvl = 1; type = TYPE_IDENTITY;
} else if (p2m_top[topidx][mididx] == p2m_missing) {
lvl = 1; type = TYPE_MISSING;
} else if (p2m_top[topidx][mididx][idx] == 0) {
lvl = 2; type = TYPE_UNKNOWN;
} else if (p2m_top[topidx][mididx][idx] == IDENTITY_FRAME(pfn)) {
lvl = 2; type = TYPE_IDENTITY;
} else if (p2m_top[topidx][mididx][idx] == INVALID_P2M_ENTRY) {
lvl = 2; type = TYPE_MISSING;
} else if (p2m_top[topidx][mididx][idx] == pfn) {
lvl = 2; type = TYPE_PFN;
} else if (p2m_top[topidx][mididx][idx] != pfn) {
lvl = 2; type = TYPE_PFN;
}
if (pfn == 0) {
prev_level = lvl;
prev_type = type;
}
if (pfn == MAX_DOMAIN_PAGES-1) {
lvl = 3;
type = TYPE_UNKNOWN;
}
if (prev_type != type) {
seq_printf(m, " [0x%lx->0x%lx] %s\n",
prev_pfn_type, pfn, type_name[prev_type]);
prev_pfn_type = pfn;
prev_type = type;
}
if (prev_level != lvl) {
seq_printf(m, " [0x%lx->0x%lx] level %s\n",
prev_pfn_level, pfn, level_name[prev_level]);
prev_pfn_level = pfn;
prev_level = lvl;
}
}
return 0;
#undef TYPE_IDENTITY
#undef TYPE_MISSING
#undef TYPE_PFN
#undef TYPE_UNKNOWN
}
#endif

68
arch/x86/xen/setup.c
View File

@@ -52,6 +52,8 @@ phys_addr_t xen_extra_mem_start, xen_extra_mem_size;
static __init void xen_add_extra_mem(unsigned long pages) static __init void xen_add_extra_mem(unsigned long pages)
{ {
unsigned long pfn;
u64 size = (u64)pages * PAGE_SIZE; u64 size = (u64)pages * PAGE_SIZE;
u64 extra_start = xen_extra_mem_start + xen_extra_mem_size; u64 extra_start = xen_extra_mem_start + xen_extra_mem_size;
@@ -66,6 +68,9 @@ static __init void xen_add_extra_mem(unsigned long pages)
xen_extra_mem_size += size; xen_extra_mem_size += size;
xen_max_p2m_pfn = PFN_DOWN(extra_start + size); xen_max_p2m_pfn = PFN_DOWN(extra_start + size);
for (pfn = PFN_DOWN(extra_start); pfn <= xen_max_p2m_pfn; pfn++)
__set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
} }
static unsigned long __init xen_release_chunk(phys_addr_t start_addr, static unsigned long __init xen_release_chunk(phys_addr_t start_addr,
@@ -104,7 +109,7 @@ static unsigned long __init xen_release_chunk(phys_addr_t start_addr,
WARN(ret != 1, "Failed to release memory %lx-%lx err=%d\n", WARN(ret != 1, "Failed to release memory %lx-%lx err=%d\n",
start, end, ret); start, end, ret);
if (ret == 1) { if (ret == 1) {
set_phys_to_machine(pfn, INVALID_P2M_ENTRY); __set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
len++; len++;
} }
} }
@@ -138,12 +143,55 @@ static unsigned long __init xen_return_unused_memory(unsigned long max_pfn,
return released; return released;
} }
static unsigned long __init xen_set_identity(const struct e820entry *list,
ssize_t map_size)
{
phys_addr_t last = xen_initial_domain() ? 0 : ISA_END_ADDRESS;
phys_addr_t start_pci = last;
const struct e820entry *entry;
unsigned long identity = 0;
int i;
for (i = 0, entry = list; i < map_size; i++, entry++) {
phys_addr_t start = entry->addr;
phys_addr_t end = start + entry->size;
if (start < last)
start = last;
if (end <= start)
continue;
/* Skip over the 1MB region. */
if (last > end)
continue;
if (entry->type == E820_RAM) {
if (start > start_pci)
identity += set_phys_range_identity(
PFN_UP(start_pci), PFN_DOWN(start));
/* Without saving 'last' we would gooble RAM too
* at the end of the loop. */
last = end;
start_pci = end;
continue;
}
start_pci = min(start, start_pci);
last = end;
}
if (last > start_pci)
identity += set_phys_range_identity(
PFN_UP(start_pci), PFN_DOWN(last));
return identity;
}
/** /**
* machine_specific_memory_setup - Hook for machine specific memory setup. * machine_specific_memory_setup - Hook for machine specific memory setup.
**/ **/
char * __init xen_memory_setup(void) char * __init xen_memory_setup(void)
{ {
static struct e820entry map[E820MAX] __initdata; static struct e820entry map[E820MAX] __initdata;
static struct e820entry map_raw[E820MAX] __initdata;
unsigned long max_pfn = xen_start_info->nr_pages; unsigned long max_pfn = xen_start_info->nr_pages;
unsigned long long mem_end; unsigned long long mem_end;
@@ -151,6 +199,7 @@ char * __init xen_memory_setup(void)
struct xen_memory_map memmap; struct xen_memory_map memmap;
unsigned long extra_pages = 0; unsigned long extra_pages = 0;
unsigned long extra_limit; unsigned long extra_limit;
unsigned long identity_pages = 0;
int i; int i;
int op; int op;
@@ -176,6 +225,7 @@ char * __init xen_memory_setup(void)
} }
BUG_ON(rc); BUG_ON(rc);
memcpy(map_raw, map, sizeof(map));
e820.nr_map = 0; e820.nr_map = 0;
xen_extra_mem_start = mem_end; xen_extra_mem_start = mem_end;
for (i = 0; i < memmap.nr_entries; i++) { for (i = 0; i < memmap.nr_entries; i++) {
@@ -194,6 +244,15 @@ char * __init xen_memory_setup(void)
end -= delta; end -= delta;
extra_pages += PFN_DOWN(delta); extra_pages += PFN_DOWN(delta);
/*
* Set RAM below 4GB that is not for us to be unusable.
* This prevents "System RAM" address space from being
* used as potential resource for I/O address (happens
* when 'allocate_resource' is called).
*/
if (delta &&
(xen_initial_domain() && end < 0x100000000ULL))
e820_add_region(end, delta, E820_UNUSABLE);
} }
if (map[i].size > 0 && end > xen_extra_mem_start) if (map[i].size > 0 && end > xen_extra_mem_start)
@@ -251,6 +310,13 @@ char * __init xen_memory_setup(void)
xen_add_extra_mem(extra_pages); xen_add_extra_mem(extra_pages);
/*
* Set P2M for all non-RAM pages and E820 gaps to be identity
* type PFNs. We supply it with the non-sanitized version
* of the E820.
*/
identity_pages = xen_set_identity(map_raw, memmap.nr_entries);
printk(KERN_INFO "Set %ld page(s) to 1-1 mapping.\n", identity_pages);
return "Xen"; return "Xen";
} }

2
drivers/xen/balloon.c
View File

@@ -296,7 +296,7 @@ static int decrease_reservation(unsigned long nr_pages)
/* No more mappings: invalidate P2M and add to balloon. */ /* No more mappings: invalidate P2M and add to balloon. */
for (i = 0; i < nr_pages; i++) { for (i = 0; i < nr_pages; i++) {
pfn = mfn_to_pfn(frame_list[i]); pfn = mfn_to_pfn(frame_list[i]);
set_phys_to_machine(pfn, INVALID_P2M_ENTRY); __set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
balloon_append(pfn_to_page(pfn)); balloon_append(pfn_to_page(pfn));
} }