835 lines
25 KiB
C
835 lines
25 KiB
C
/*
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* Xen leaves the responsibility for maintaining p2m mappings to the
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* guests themselves, but it must also access and update the p2m array
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* during suspend/resume when all the pages are reallocated.
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*
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* The p2m table is logically a flat array, but we implement it as a
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* three-level tree to allow the address space to be sparse.
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*
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* Xen
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* |
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* p2m_top p2m_top_mfn
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* / \ / \
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* p2m_mid p2m_mid p2m_mid_mfn p2m_mid_mfn
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* / \ / \ / /
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* p2m p2m p2m p2m p2m p2m p2m ...
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*
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* The p2m_mid_mfn pages are mapped by p2m_top_mfn_p.
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*
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* The p2m_top and p2m_top_mfn levels are limited to 1 page, so the
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* maximum representable pseudo-physical address space is:
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* P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE pages
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*
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* P2M_PER_PAGE depends on the architecture, as a mfn is always
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* unsigned long (8 bytes on 64-bit, 4 bytes on 32), leading to
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* 512 and 1024 entries respectively.
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*
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* In short, these structures contain the Machine Frame Number (MFN) of the PFN.
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*
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* However not all entries are filled with MFNs. Specifically for all other
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* leaf entries, or for the top root, or middle one, for which there is a void
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* entry, we assume it is "missing". So (for example)
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* pfn_to_mfn(0x90909090)=INVALID_P2M_ENTRY.
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*
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* We also have the possibility of setting 1-1 mappings on certain regions, so
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* that:
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* pfn_to_mfn(0xc0000)=0xc0000
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*
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* The benefit of this is, that we can assume for non-RAM regions (think
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* PCI BARs, or ACPI spaces), we can create mappings easily b/c we
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* get the PFN value to match the MFN.
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*
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* For this to work efficiently we have one new page p2m_identity and
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* allocate (via reserved_brk) any other pages we need to cover the sides
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* (1GB or 4MB boundary violations). All entries in p2m_identity are set to
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* INVALID_P2M_ENTRY type (Xen toolstack only recognizes that and MFNs,
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* no other fancy value).
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*
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* On lookup we spot that the entry points to p2m_identity and return the
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* identity value instead of dereferencing and returning INVALID_P2M_ENTRY.
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* If the entry points to an allocated page, we just proceed as before and
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* return the PFN. If the PFN has IDENTITY_FRAME_BIT set we unmask that in
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* appropriate functions (pfn_to_mfn).
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*
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* The reason for having the IDENTITY_FRAME_BIT instead of just returning the
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* PFN is that we could find ourselves where pfn_to_mfn(pfn)==pfn for a
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* non-identity pfn. To protect ourselves against we elect to set (and get) the
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* IDENTITY_FRAME_BIT on all identity mapped PFNs.
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*
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* This simplistic diagram is used to explain the more subtle piece of code.
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* There is also a digram of the P2M at the end that can help.
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* Imagine your E820 looking as so:
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*
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* 1GB 2GB
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* /-------------------+---------\/----\ /----------\ /---+-----\
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* | System RAM | Sys RAM ||ACPI| | reserved | | Sys RAM |
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* \-------------------+---------/\----/ \----------/ \---+-----/
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* ^- 1029MB ^- 2001MB
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*
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* [1029MB = 263424 (0x40500), 2001MB = 512256 (0x7D100),
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* 2048MB = 524288 (0x80000)]
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*
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* And dom0_mem=max:3GB,1GB is passed in to the guest, meaning memory past 1GB
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* is actually not present (would have to kick the balloon driver to put it in).
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*
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* When we are told to set the PFNs for identity mapping (see patch: "xen/setup:
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* Set identity mapping for non-RAM E820 and E820 gaps.") we pass in the start
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* of the PFN and the end PFN (263424 and 512256 respectively). The first step
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* is to reserve_brk a top leaf page if the p2m[1] is missing. The top leaf page
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* covers 512^2 of page estate (1GB) and in case the start or end PFN is not
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* aligned on 512^2*PAGE_SIZE (1GB) we loop on aligned 1GB PFNs from start pfn
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* to end pfn. We reserve_brk top leaf pages if they are missing (means they
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* point to p2m_mid_missing).
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*
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* With the E820 example above, 263424 is not 1GB aligned so we allocate a
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* reserve_brk page which will cover the PFNs estate from 0x40000 to 0x80000.
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* Each entry in the allocate page is "missing" (points to p2m_missing).
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*
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* Next stage is to determine if we need to do a more granular boundary check
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* on the 4MB (or 2MB depending on architecture) off the start and end pfn's.
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* We check if the start pfn and end pfn violate that boundary check, and if
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* so reserve_brk a middle (p2m[x][y]) leaf page. This way we have a much finer
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* granularity of setting which PFNs are missing and which ones are identity.
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* In our example 263424 and 512256 both fail the check so we reserve_brk two
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* pages. Populate them with INVALID_P2M_ENTRY (so they both have "missing"
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* values) and assign them to p2m[1][2] and p2m[1][488] respectively.
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*
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* At this point we would at minimum reserve_brk one page, but could be up to
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* three. Each call to set_phys_range_identity has at maximum a three page
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* cost. If we were to query the P2M at this stage, all those entries from
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* start PFN through end PFN (so 1029MB -> 2001MB) would return
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* INVALID_P2M_ENTRY ("missing").
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*
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* The next step is to walk from the start pfn to the end pfn setting
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* the IDENTITY_FRAME_BIT on each PFN. This is done in set_phys_range_identity.
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* If we find that the middle leaf is pointing to p2m_missing we can swap it
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* over to p2m_identity - this way covering 4MB (or 2MB) PFN space. At this
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* point we do not need to worry about boundary aligment (so no need to
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* reserve_brk a middle page, figure out which PFNs are "missing" and which
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* ones are identity), as that has been done earlier. If we find that the
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* middle leaf is not occupied by p2m_identity or p2m_missing, we dereference
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* that page (which covers 512 PFNs) and set the appropriate PFN with
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* IDENTITY_FRAME_BIT. In our example 263424 and 512256 end up there, and we
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* set from p2m[1][2][256->511] and p2m[1][488][0->256] with
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* IDENTITY_FRAME_BIT set.
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*
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* All other regions that are void (or not filled) either point to p2m_missing
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* (considered missing) or have the default value of INVALID_P2M_ENTRY (also
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* considered missing). In our case, p2m[1][2][0->255] and p2m[1][488][257->511]
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* contain the INVALID_P2M_ENTRY value and are considered "missing."
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*
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* This is what the p2m ends up looking (for the E820 above) with this
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* fabulous drawing:
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*
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* p2m /--------------\
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* /-----\ | &mfn_list[0],| /-----------------\
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* | 0 |------>| &mfn_list[1],| /---------------\ | ~0, ~0, .. |
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* |-----| | ..., ~0, ~0 | | ~0, ~0, [x]---+----->| IDENTITY [@256] |
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* | 1 |---\ \--------------/ | [p2m_identity]+\ | IDENTITY [@257] |
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* |-----| \ | [p2m_identity]+\\ | .... |
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* | 2 |--\ \-------------------->| ... | \\ \----------------/
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* |-----| \ \---------------/ \\
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* | 3 |\ \ \\ p2m_identity
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* |-----| \ \-------------------->/---------------\ /-----------------\
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* | .. +->+ | [p2m_identity]+-->| ~0, ~0, ~0, ... |
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* \-----/ / | [p2m_identity]+-->| ..., ~0 |
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* / /---------------\ | .... | \-----------------/
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* / | IDENTITY[@0] | /-+-[x], ~0, ~0.. |
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* / | IDENTITY[@256]|<----/ \---------------/
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* / | ~0, ~0, .... |
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* | \---------------/
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* |
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* p2m_missing p2m_missing
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* /------------------\ /------------\
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* | [p2m_mid_missing]+---->| ~0, ~0, ~0 |
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* | [p2m_mid_missing]+---->| ..., ~0 |
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* \------------------/ \------------/
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*
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* where ~0 is INVALID_P2M_ENTRY. IDENTITY is (PFN | IDENTITY_BIT)
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/list.h>
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#include <linux/hash.h>
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#include <linux/sched.h>
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#include <linux/seq_file.h>
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#include <asm/cache.h>
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#include <asm/setup.h>
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#include <asm/xen/page.h>
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#include <asm/xen/hypercall.h>
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#include <asm/xen/hypervisor.h>
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#include "xen-ops.h"
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static void __init m2p_override_init(void);
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unsigned long xen_max_p2m_pfn __read_mostly;
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#define P2M_PER_PAGE (PAGE_SIZE / sizeof(unsigned long))
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#define P2M_MID_PER_PAGE (PAGE_SIZE / sizeof(unsigned long *))
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#define P2M_TOP_PER_PAGE (PAGE_SIZE / sizeof(unsigned long **))
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#define MAX_P2M_PFN (P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE)
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/* Placeholders for holes in the address space */
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static RESERVE_BRK_ARRAY(unsigned long, p2m_missing, P2M_PER_PAGE);
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static RESERVE_BRK_ARRAY(unsigned long *, p2m_mid_missing, P2M_MID_PER_PAGE);
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static RESERVE_BRK_ARRAY(unsigned long, p2m_mid_missing_mfn, P2M_MID_PER_PAGE);
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static RESERVE_BRK_ARRAY(unsigned long **, p2m_top, P2M_TOP_PER_PAGE);
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static RESERVE_BRK_ARRAY(unsigned long, p2m_top_mfn, P2M_TOP_PER_PAGE);
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static RESERVE_BRK_ARRAY(unsigned long *, p2m_top_mfn_p, P2M_TOP_PER_PAGE);
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static RESERVE_BRK_ARRAY(unsigned long, p2m_identity, P2M_PER_PAGE);
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RESERVE_BRK(p2m_mid, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE)));
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RESERVE_BRK(p2m_mid_mfn, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE)));
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/* We might hit two boundary violations at the start and end, at max each
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* boundary violation will require three middle nodes. */
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RESERVE_BRK(p2m_mid_identity, PAGE_SIZE * 2 * 3);
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static inline unsigned p2m_top_index(unsigned long pfn)
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{
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BUG_ON(pfn >= MAX_P2M_PFN);
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return pfn / (P2M_MID_PER_PAGE * P2M_PER_PAGE);
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}
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static inline unsigned p2m_mid_index(unsigned long pfn)
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{
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return (pfn / P2M_PER_PAGE) % P2M_MID_PER_PAGE;
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}
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static inline unsigned p2m_index(unsigned long pfn)
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{
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return pfn % P2M_PER_PAGE;
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}
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static void p2m_top_init(unsigned long ***top)
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{
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unsigned i;
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for (i = 0; i < P2M_TOP_PER_PAGE; i++)
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top[i] = p2m_mid_missing;
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}
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static void p2m_top_mfn_init(unsigned long *top)
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{
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unsigned i;
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for (i = 0; i < P2M_TOP_PER_PAGE; i++)
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top[i] = virt_to_mfn(p2m_mid_missing_mfn);
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}
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static void p2m_top_mfn_p_init(unsigned long **top)
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{
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unsigned i;
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for (i = 0; i < P2M_TOP_PER_PAGE; i++)
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top[i] = p2m_mid_missing_mfn;
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}
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static void p2m_mid_init(unsigned long **mid)
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{
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unsigned i;
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for (i = 0; i < P2M_MID_PER_PAGE; i++)
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mid[i] = p2m_missing;
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}
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static void p2m_mid_mfn_init(unsigned long *mid)
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{
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unsigned i;
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for (i = 0; i < P2M_MID_PER_PAGE; i++)
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mid[i] = virt_to_mfn(p2m_missing);
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}
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static void p2m_init(unsigned long *p2m)
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{
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unsigned i;
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for (i = 0; i < P2M_MID_PER_PAGE; i++)
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p2m[i] = INVALID_P2M_ENTRY;
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}
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/*
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* Build the parallel p2m_top_mfn and p2m_mid_mfn structures
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*
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* This is called both at boot time, and after resuming from suspend:
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* - At boot time we're called very early, and must use extend_brk()
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* to allocate memory.
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*
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* - After resume we're called from within stop_machine, but the mfn
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* tree should alreay be completely allocated.
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*/
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void __ref xen_build_mfn_list_list(void)
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{
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unsigned long pfn;
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/* Pre-initialize p2m_top_mfn to be completely missing */
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if (p2m_top_mfn == NULL) {
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p2m_mid_missing_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE);
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p2m_mid_mfn_init(p2m_mid_missing_mfn);
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p2m_top_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE);
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p2m_top_mfn_p_init(p2m_top_mfn_p);
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p2m_top_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE);
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p2m_top_mfn_init(p2m_top_mfn);
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} else {
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/* Reinitialise, mfn's all change after migration */
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p2m_mid_mfn_init(p2m_mid_missing_mfn);
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}
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for (pfn = 0; pfn < xen_max_p2m_pfn; pfn += P2M_PER_PAGE) {
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unsigned topidx = p2m_top_index(pfn);
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unsigned mididx = p2m_mid_index(pfn);
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unsigned long **mid;
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unsigned long *mid_mfn_p;
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mid = p2m_top[topidx];
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mid_mfn_p = p2m_top_mfn_p[topidx];
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/* Don't bother allocating any mfn mid levels if
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* they're just missing, just update the stored mfn,
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* since all could have changed over a migrate.
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*/
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if (mid == p2m_mid_missing) {
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BUG_ON(mididx);
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BUG_ON(mid_mfn_p != p2m_mid_missing_mfn);
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p2m_top_mfn[topidx] = virt_to_mfn(p2m_mid_missing_mfn);
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pfn += (P2M_MID_PER_PAGE - 1) * P2M_PER_PAGE;
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continue;
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}
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if (mid_mfn_p == p2m_mid_missing_mfn) {
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/*
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* XXX boot-time only! We should never find
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* missing parts of the mfn tree after
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* runtime. extend_brk() will BUG if we call
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* it too late.
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*/
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mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE);
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p2m_mid_mfn_init(mid_mfn_p);
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p2m_top_mfn_p[topidx] = mid_mfn_p;
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}
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p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p);
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mid_mfn_p[mididx] = virt_to_mfn(mid[mididx]);
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}
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}
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void xen_setup_mfn_list_list(void)
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{
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BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
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HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list =
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virt_to_mfn(p2m_top_mfn);
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HYPERVISOR_shared_info->arch.max_pfn = xen_max_p2m_pfn;
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}
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/* Set up p2m_top to point to the domain-builder provided p2m pages */
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void __init xen_build_dynamic_phys_to_machine(void)
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{
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unsigned long *mfn_list = (unsigned long *)xen_start_info->mfn_list;
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unsigned long max_pfn = min(MAX_DOMAIN_PAGES, xen_start_info->nr_pages);
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unsigned long pfn;
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xen_max_p2m_pfn = max_pfn;
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p2m_missing = extend_brk(PAGE_SIZE, PAGE_SIZE);
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p2m_init(p2m_missing);
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p2m_mid_missing = extend_brk(PAGE_SIZE, PAGE_SIZE);
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p2m_mid_init(p2m_mid_missing);
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p2m_top = extend_brk(PAGE_SIZE, PAGE_SIZE);
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p2m_top_init(p2m_top);
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p2m_identity = extend_brk(PAGE_SIZE, PAGE_SIZE);
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p2m_init(p2m_identity);
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/*
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* The domain builder gives us a pre-constructed p2m array in
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* mfn_list for all the pages initially given to us, so we just
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* need to graft that into our tree structure.
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*/
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for (pfn = 0; pfn < max_pfn; pfn += P2M_PER_PAGE) {
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unsigned topidx = p2m_top_index(pfn);
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unsigned mididx = p2m_mid_index(pfn);
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if (p2m_top[topidx] == p2m_mid_missing) {
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unsigned long **mid = extend_brk(PAGE_SIZE, PAGE_SIZE);
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p2m_mid_init(mid);
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p2m_top[topidx] = mid;
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}
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/*
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* As long as the mfn_list has enough entries to completely
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* fill a p2m page, pointing into the array is ok. But if
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* not the entries beyond the last pfn will be undefined.
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*/
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if (unlikely(pfn + P2M_PER_PAGE > max_pfn)) {
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unsigned long p2midx;
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p2midx = max_pfn % P2M_PER_PAGE;
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for ( ; p2midx < P2M_PER_PAGE; p2midx++)
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mfn_list[pfn + p2midx] = INVALID_P2M_ENTRY;
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}
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p2m_top[topidx][mididx] = &mfn_list[pfn];
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}
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m2p_override_init();
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}
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unsigned long get_phys_to_machine(unsigned long pfn)
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{
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unsigned topidx, mididx, idx;
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if (unlikely(pfn >= MAX_P2M_PFN))
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return INVALID_P2M_ENTRY;
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topidx = p2m_top_index(pfn);
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mididx = p2m_mid_index(pfn);
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idx = p2m_index(pfn);
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/*
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* The INVALID_P2M_ENTRY is filled in both p2m_*identity
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* and in p2m_*missing, so returning the INVALID_P2M_ENTRY
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* would be wrong.
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*/
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if (p2m_top[topidx][mididx] == p2m_identity)
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return IDENTITY_FRAME(pfn);
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return p2m_top[topidx][mididx][idx];
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}
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EXPORT_SYMBOL_GPL(get_phys_to_machine);
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static void *alloc_p2m_page(void)
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{
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|
return (void *)__get_free_page(GFP_KERNEL | __GFP_REPEAT);
|
|
}
|
|
|
|
static void free_p2m_page(void *p)
|
|
{
|
|
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
|
|
* the new pages are installed with cmpxchg; if we lose the race then
|
|
* simply free the page we allocated and use the one that's there.
|
|
*/
|
|
static bool alloc_p2m(unsigned long pfn)
|
|
{
|
|
unsigned topidx, mididx;
|
|
unsigned long ***top_p, **mid;
|
|
unsigned long *top_mfn_p, *mid_mfn;
|
|
|
|
topidx = p2m_top_index(pfn);
|
|
mididx = p2m_mid_index(pfn);
|
|
|
|
top_p = &p2m_top[topidx];
|
|
mid = *top_p;
|
|
|
|
if (mid == p2m_mid_missing) {
|
|
/* Mid level is missing, allocate a new one */
|
|
mid = alloc_p2m_page();
|
|
if (!mid)
|
|
return false;
|
|
|
|
p2m_mid_init(mid);
|
|
|
|
if (cmpxchg(top_p, p2m_mid_missing, mid) != p2m_mid_missing)
|
|
free_p2m_page(mid);
|
|
}
|
|
|
|
top_mfn_p = &p2m_top_mfn[topidx];
|
|
mid_mfn = p2m_top_mfn_p[topidx];
|
|
|
|
BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p);
|
|
|
|
if (mid_mfn == p2m_mid_missing_mfn) {
|
|
/* Separately check the mid mfn level */
|
|
unsigned long missing_mfn;
|
|
unsigned long mid_mfn_mfn;
|
|
|
|
mid_mfn = alloc_p2m_page();
|
|
if (!mid_mfn)
|
|
return false;
|
|
|
|
p2m_mid_mfn_init(mid_mfn);
|
|
|
|
missing_mfn = virt_to_mfn(p2m_mid_missing_mfn);
|
|
mid_mfn_mfn = virt_to_mfn(mid_mfn);
|
|
if (cmpxchg(top_mfn_p, missing_mfn, mid_mfn_mfn) != missing_mfn)
|
|
free_p2m_page(mid_mfn);
|
|
else
|
|
p2m_top_mfn_p[topidx] = mid_mfn;
|
|
}
|
|
|
|
if (p2m_top[topidx][mididx] == p2m_identity ||
|
|
p2m_top[topidx][mididx] == p2m_missing) {
|
|
/* p2m leaf page is missing */
|
|
unsigned long *p2m;
|
|
unsigned long *p2m_orig = p2m_top[topidx][mididx];
|
|
|
|
p2m = alloc_p2m_page();
|
|
if (!p2m)
|
|
return false;
|
|
|
|
p2m_init(p2m);
|
|
|
|
if (cmpxchg(&mid[mididx], p2m_orig, p2m) != p2m_orig)
|
|
free_p2m_page(p2m);
|
|
else
|
|
mid_mfn[mididx] = virt_to_mfn(p2m);
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
static bool __init __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 __init 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 */
|
|
bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
|
|
{
|
|
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)) {
|
|
BUG_ON(mfn != INVALID_P2M_ENTRY);
|
|
return true;
|
|
}
|
|
|
|
topidx = p2m_top_index(pfn);
|
|
mididx = p2m_mid_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)
|
|
return mfn == INVALID_P2M_ENTRY;
|
|
|
|
p2m_top[topidx][mididx][idx] = mfn;
|
|
|
|
return true;
|
|
}
|
|
|
|
bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
|
|
{
|
|
if (unlikely(!__set_phys_to_machine(pfn, mfn))) {
|
|
if (!alloc_p2m(pfn))
|
|
return false;
|
|
|
|
if (!__set_phys_to_machine(pfn, mfn))
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
#define M2P_OVERRIDE_HASH_SHIFT 10
|
|
#define M2P_OVERRIDE_HASH (1 << M2P_OVERRIDE_HASH_SHIFT)
|
|
|
|
static RESERVE_BRK_ARRAY(struct list_head, m2p_overrides, M2P_OVERRIDE_HASH);
|
|
static DEFINE_SPINLOCK(m2p_override_lock);
|
|
|
|
static void __init m2p_override_init(void)
|
|
{
|
|
unsigned i;
|
|
|
|
m2p_overrides = extend_brk(sizeof(*m2p_overrides) * M2P_OVERRIDE_HASH,
|
|
sizeof(unsigned long));
|
|
|
|
for (i = 0; i < M2P_OVERRIDE_HASH; i++)
|
|
INIT_LIST_HEAD(&m2p_overrides[i]);
|
|
}
|
|
|
|
static unsigned long mfn_hash(unsigned long mfn)
|
|
{
|
|
return hash_long(mfn, M2P_OVERRIDE_HASH_SHIFT);
|
|
}
|
|
|
|
/* Add an MFN override for a particular page */
|
|
int m2p_add_override(unsigned long mfn, struct page *page)
|
|
{
|
|
unsigned long flags;
|
|
unsigned long pfn;
|
|
unsigned long uninitialized_var(address);
|
|
unsigned level;
|
|
pte_t *ptep = NULL;
|
|
|
|
pfn = page_to_pfn(page);
|
|
if (!PageHighMem(page)) {
|
|
address = (unsigned long)__va(pfn << PAGE_SHIFT);
|
|
ptep = lookup_address(address, &level);
|
|
|
|
if (WARN(ptep == NULL || level != PG_LEVEL_4K,
|
|
"m2p_add_override: pfn %lx not mapped", pfn))
|
|
return -EINVAL;
|
|
}
|
|
|
|
page->private = mfn;
|
|
page->index = pfn_to_mfn(pfn);
|
|
|
|
if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn))))
|
|
return -ENOMEM;
|
|
|
|
if (!PageHighMem(page))
|
|
/* Just zap old mapping for now */
|
|
pte_clear(&init_mm, address, ptep);
|
|
|
|
spin_lock_irqsave(&m2p_override_lock, flags);
|
|
list_add(&page->lru, &m2p_overrides[mfn_hash(mfn)]);
|
|
spin_unlock_irqrestore(&m2p_override_lock, flags);
|
|
|
|
return 0;
|
|
}
|
|
|
|
int m2p_remove_override(struct page *page)
|
|
{
|
|
unsigned long flags;
|
|
unsigned long mfn;
|
|
unsigned long pfn;
|
|
unsigned long uninitialized_var(address);
|
|
unsigned level;
|
|
pte_t *ptep = NULL;
|
|
|
|
pfn = page_to_pfn(page);
|
|
mfn = get_phys_to_machine(pfn);
|
|
if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT))
|
|
return -EINVAL;
|
|
|
|
if (!PageHighMem(page)) {
|
|
address = (unsigned long)__va(pfn << PAGE_SHIFT);
|
|
ptep = lookup_address(address, &level);
|
|
|
|
if (WARN(ptep == NULL || level != PG_LEVEL_4K,
|
|
"m2p_remove_override: pfn %lx not mapped", pfn))
|
|
return -EINVAL;
|
|
}
|
|
|
|
spin_lock_irqsave(&m2p_override_lock, flags);
|
|
list_del(&page->lru);
|
|
spin_unlock_irqrestore(&m2p_override_lock, flags);
|
|
set_phys_to_machine(pfn, page->index);
|
|
|
|
if (!PageHighMem(page))
|
|
set_pte_at(&init_mm, address, ptep,
|
|
pfn_pte(pfn, PAGE_KERNEL));
|
|
/* No tlb flush necessary because the caller already
|
|
* left the pte unmapped. */
|
|
|
|
return 0;
|
|
}
|
|
|
|
struct page *m2p_find_override(unsigned long mfn)
|
|
{
|
|
unsigned long flags;
|
|
struct list_head *bucket = &m2p_overrides[mfn_hash(mfn)];
|
|
struct page *p, *ret;
|
|
|
|
ret = NULL;
|
|
|
|
spin_lock_irqsave(&m2p_override_lock, flags);
|
|
|
|
list_for_each_entry(p, bucket, lru) {
|
|
if (p->private == mfn) {
|
|
ret = p;
|
|
break;
|
|
}
|
|
}
|
|
|
|
spin_unlock_irqrestore(&m2p_override_lock, flags);
|
|
|
|
return ret;
|
|
}
|
|
|
|
unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn)
|
|
{
|
|
struct page *p = m2p_find_override(mfn);
|
|
unsigned long ret = pfn;
|
|
|
|
if (p)
|
|
ret = page_to_pfn(p);
|
|
|
|
return ret;
|
|
}
|
|
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
|