Commit graph

73 commits

Author SHA1 Message Date
Peter Maydell 293266a9d8
exec: Clean up includes
Clean up includes so that osdep.h is included first and headers
which it implies are not included manually.

This commit was created with scripts/clean-includes.

Backports commit 7b31bbc2e68605ab2f10dc609dd54cf4c7b5f49a from qemu
2018-02-19 00:49:55 -05:00
Peter Crosthwaite fd4e62bc1d
exec: Respect as_translate_internal length clamp
address_space_translate_internal will clamp the *plen length argument
based on the size of the memory region being queried. The iommu walker
logic in addresss_space_translate was ignoring this by discarding the
post fn call value of *plen. Fix by just always using *plen as the
length argument throughout the fn, removing the len local variable.

This fixes a bootloader bug when a single elf section spans multiple
QEMU memory regions.

Backports commit 23820dbfc79d1c9dce090b4c555994f2bb6a69b3 from qemu
2018-02-18 22:04:02 -05:00
Peter Crosthwaite ce997e1caf
qom/cpu: Add MemoryRegion property
Add a MemoryRegion property, which if set is used to construct
the CPU's initial (default) AddressSpace.

Backports commit 6731d864f80938e404dc3e5eb7f6b76b891e3e43 from qemu
2018-02-18 21:54:50 -05:00
Lioncash 6d5f465449
uc: Handle freeing of multiple address spaces 2018-02-18 21:36:50 -05:00
Lioncash 6a7974277a
Move RAMBlock deallocation to reclaim_ramblock
Backports a minor portion of commit 43771539d4666cba16298fc6b0ea63867425277c from qemu
2018-02-18 19:38:51 -05:00
Lioncash aa0ce52b97
exec: Add missing atomic reads 2018-02-18 19:28:02 -05:00
Peter Maydell 5192f806aa
exec.c: Use atomic_rcu_read() to access dispatch in memory_region_section_get_iotlb()
When accessing the dispatch pointer in an AddressSpace within an RCU
critical section we should always use atomic_rcu_read(). Fix an
access within memory_region_section_get_iotlb() which was incorrectly
doing a direct pointer access.

Backports commit 0b8e2c1002afddc8ef3d52fa6fc29e4768429f98 from qemu
2018-02-18 19:22:39 -05:00
Dr. David Alan Gilbert 75701d03ee
qemu_ram_foreach_block: pass up error value, and down the ramblock name
check the return value of the function it calls and error if it's non-0
Fixup qemu_rdma_init_one_block that is the only current caller,
  and rdma_add_block the only function it calls using it.

Pass the name of the ramblock to the function; helps in debugging.

Backports commit e3807054e20fb3b94d18cb751c437ee2f43b6fac from qemu
2018-02-18 19:17:18 -05:00
Paolo Bonzini 71beea204c
exec: avoid possible overwriting of mmaped area in qemu_ram_remap
It is not necessary to munmap an area before remapping it with MAP_FIXED;
if the memory region specified by addr and len overlaps pages of any
existing mapping, then the overlapped part of the existing mapping will
be discarded.

On the other hand, if QEMU does munmap the pages, there is a small
probability that another mmap sneaks in and catches the just-freed
portion of the address space.  In effect, munmap followed by
mmap(MAP_FIXED) is a use-after-free error, and Coverity flags it
as such.  Fix it.

Backports commit f18c69cfc554cf9776eb3c35b7510e17541afacb from qemu
2018-02-18 19:09:37 -05:00
Paolo Bonzini aad1027c96
Revert "exec: Respect as_tranlsate_internal length clamp"
This reverts commit c3c1bb9.
It causes problems with boards that declare memory regions shorter
than the registers they contain.

Backports commit 4025446f0ac6213335c22ec43f3c3d8362ce7286 from qemu
2018-02-18 19:07:44 -05:00
Michael S. Tsirkin 1cc51e4b53
exec: round up size on MR resize
Block size must fundamentally be a multiple of target page size.
Aligning automatically removes need to worry about the alignment
from callers.

Note: the only caller of qemu_ram_resize (acpi) already happens to have
size padded to a power of 2, but we would like to drop the padding in
ACPI core, and don't want to expose target page size knowledge to ACPI

Backports commit 129ddaf31be583fb7c97812e07e028661005ce42 from qemu
2018-02-18 19:02:27 -05:00
Lioncash 024ec1755e
Convert ram_list to RCU
Allow "unlocked" reads of the ram_list by using an RCU-enabled QLIST.

The ramlist mutex is kept.  call_rcu callbacks are run with the iothread
lock taken, but that may change in the future.  Writers still take the
ramlist mutex, but they no longer need to assume that the iothread lock
is taken.

Readers of the list, instead, no longer require either the iothread
or ramlist mutex, but they need to use rcu_read_lock() and
rcu_read_unlock().

One place in arch_init.c was downgrading from write side to read side
like this:

    qemu_mutex_lock_iothread()
    qemu_mutex_lock_ramlist()
    ...
    qemu_mutex_unlock_iothread()
    ...
    qemu_mutex_unlock_ramlist()

and the equivalent idiom is:

    qemu_mutex_lock_ramlist()
    rcu_read_lock()
    ...
    qemu_mutex_unlock_ramlist()
    ...
    rcu_read_unlock()

Backports the write barriers from commit 0dc3f44aca18b1be8b425f3f4feb4b3e8d68de2e in qemu
2018-02-18 18:53:49 -05:00
Mike Day 2b93290eea
exec: convert ram_list to QLIST
QLIST has RCU-friendly primitives, so switch to it.

Backports commit 0d53d9fe8a0dcb849bc7c9836e9e6a287f9aa787 from qemu
2018-02-18 18:49:24 -05:00
Paolo Bonzini 15b3a9358e
exec: fix madvise of NULL pointer
Coverity flags this as "dereference after null check".  Not quite a
dereference, since it will just EFAULT, but still nice to fix.

Backports commit a904c91196a9c5dbd7b9abcd3d40b0824286fb1c from qemu
2018-02-18 18:19:39 -05:00
Peter Maydell e07cd2542c
exec.c: Drop TARGET_HAS_ICE define and checks
The TARGET_HAS_ICE #define is intended to indicate whether a target-*
guest CPU implementation supports the breakpoint handling. However,
all our guest CPUs have that support (the only two which do not
define TARGET_HAS_ICE are unicore32 and openrisc, and in both those
cases the bp support is present and the lack of the #define is just
a bug). So remove the #define entirely: all new guest CPU support
should include breakpoint handling as part of the basic implementation.

Backports commit ec53b45bcd1f74f7a4c31331fa6d50b402cd6d26 from qemu
2018-02-18 18:17:14 -05:00
Amit Shah f64e3d4931
exec: add wrapper for host pointer access
host pointer accesses force pointer math, let's
add a wrapper to make them safer.

Backports relevant parts of commit 1240be24357ee292f8d05aa2abfdba75dd0ca25d from qemu
2018-02-18 18:10:17 -05:00
Paolo Bonzini 0696e7fe19
exec: allows 8-byte accesses in subpage_ops
Otherwise fw_cfg accesses are split into 4-byte ones before they reach the
fw_cfg ops / handlers.

Backports commit ff6cff7554be06e95f8d712f66cd16bd6681c746 from qemu
2018-02-18 18:06:37 -05:00
Paolo Bonzini a06611e45b
exec: skip MMIO regions correctly in cpu_physical_memory_write_rom_internal
Loading the BIOS in the mac99 machine is interesting, because there is a
PROM in the middle of the BIOS region (from 16K to 32K).  Before memory
region accesses were clamped, when QEMU was asked to load a BIOS from
0xfff00000 to 0xffffffff it would put even those 16K from the BIOS file
into the region.  This is weird because those 16K were not actually
visible between 0xfff04000 and 0xfff07fff.  However, it worked.

After clamping was added, this also worked.  In this case, the
cpu_physical_memory_write_rom_internal function split the write in
three parts: the first 16K were copied, the PROM area (second 16K) were
ignored, then the rest was copied.

Problems then started with commit 965eb2f (exec: do not clamp accesses
to MMIO regions, 2015-06-17).  Clamping accesses is not done for MMIO
regions because they can overlap wildly, and MMIO registers can be
expected to perform full-width accesses based only on their address
(with no respect for adjacent registers that could decode to completely
different MemoryRegions).  However, this lack of clamping also applied
to the PROM area!  cpu_physical_memory_write_rom_internal thus failed
to copy the third range above, i.e. only copied the first 16K of the BIOS.

In effect, address_space_translate is expecting _something else_ to do
the clamping for MMIO regions if the incoming length is large.  This
"something else" is memory_access_size in the case of address_space_rw,
so use the same logic in cpu_physical_memory_write_rom_internal.

Backports commit b242e0e0e2969c044a318e56f7988bbd84de1f63 from qemu
2018-02-18 17:57:08 -05:00
Paolo Bonzini 32996e48fc
exec: clamp accesses against the MemoryRegionSection
Because the clamping was done against the MemoryRegion,
address_space_rw was effectively broken if a write spanned
multiple sections that are not linear in underlying memory
(with the memory not being under an IOMMU).

This is visible with the MIPS rc4030 IOMMU, which is implemented
as a series of alias memory regions that point to the actual RAM.

Backports commit e4a511f8cc6f4a46d409fb5c9f72c38ba45f8d83 from qemu
2018-02-18 17:52:58 -05:00
Paolo Bonzini 26ba2e91f6
exec: do not clamp accesses to MMIO regions
It is common for MMIO registers to overlap, for example a 4 byte register
at 0xcf8 (totally random choice... :)) and a 1 byte register at 0xcf9.
If these registers are implemented via separate MemoryRegions, it is
wrong to clamp the accesses as the value written would be truncated.

Hence for these regions the effects of commit 23820db (exec: Respect
as_translate_internal length clamp, 2015-03-16, previously applied as
commit c3c1bb9) must be skipped.

Backports commit 965eb2fcdfe919ecced6c34803535ad32dc1249c from qemu
2018-02-18 17:50:27 -05:00
Peter Maydell 73efe6cda3
exec.c: Use cpu_get_phys_page_attrs_debug
Use cpu_get_phys_page_attrs_debug() when doing virtual-to-physical
conversions in debug related code, so that we can obtain the right
address space index and thus select the correct AddressSpace,
rather than always using cpu->as.

Backports commit 5232e4c798ba7a46261d3157b73d08fc598e7dcb from qemu
2018-02-17 23:26:09 -05:00
Peter Maydell 1dfba71bef
exec.c: Add cpu_get_address_space()
Add a function to return the AddressSpace for a CPU based on
its numerical index. (Callers outside exec.c don't have access
to the CPUAddressSpace struct so can't just fish it out of the
CPUState struct directly.)

Backports commit 651a5bc03705102de519ebf079a40ecc1da991db from qemu
2018-02-17 23:22:23 -05:00
Peter Maydell 2fe995a0da
exec.c: Pass MemTxAttrs to iotlb_to_region so it uses the right AS
Pass the MemTxAttrs for the memory access to iotlb_to_region(); this
allows it to determine the correct AddressSpace to use for the lookup.

Backports commit a54c87b68a0410d0cf6f8b84e42074a5cf463732 from qemu
2018-02-17 23:19:00 -05:00
Peter Maydell 8edd6ffdfd
cputlb.c: Use correct address space when looking up MemoryRegionSection
When looking up the MemoryRegionSection for the new TLB entry in
tlb_set_page_with_attrs(), use cpu_asidx_from_attrs() to determine
the correct address space index for the lookup, and pass it into
address_space_translate_for_iotlb().

Backports commit d7898cda81b6efa6b2d7a749882695cdcf280eaa from qemu
2018-02-17 23:15:22 -05:00
Peter Maydell 51369b67cd
exec.c: Allow target CPUs to define multiple AddressSpaces
Allow multiple calls to cpu_address_space_init(); each
call adds an entry to the cpu->ases array at the specified
index. It is up to the target-specific CPU code to actually use
these extra address spaces.

Since this multiple AddressSpace support won't work with
KVM, add an assertion to avoid confusing failures.

Backports commit 12ebc9a76dd7702aef0a3618717a826c19c34ef4 from qemu
2018-02-17 22:35:13 -05:00
Peter Maydell f1b237236c
exec.c: Don't set cpu->as until cpu_address_space_init
Rather than setting cpu->as unconditionally in cpu_exec_init
(and then having target-i386 override this later), don't set
it until the first call to cpu_address_space_init.

This requires us to initialise the address space for
both TCG and KVM (KVM doesn't need the AS listener but
it does require cpu->as to be set).

For target CPUs which don't set up any address spaces (currently
everything except i386), add the default address_space_memory
in qemu_init_vcpu().

Backports commit 56943e8cc14b7eeeab67d1942fa5d8bcafe3e53f from qemu
2018-02-17 22:24:36 -05:00
Paolo Bonzini 1650af8c8b
memory: try to inline constant-length reads
memcpy can take a large amount of time for small reads and writes.
Handle the common case of reading s/g descriptors from memory (there
is no corresponding "write" case that is as common, because writes
often use address_space_st* functions) by inlining the relevant
parts of address_space_read into the caller.

Backports commit 3cc8f884996584630734a90c9b3c535af81e3c92 from qemu
2018-02-17 20:44:39 -05:00
Paolo Bonzini 9a78c61145
memory: extract first iteration of address_space_read and address_space_write
We want to inline the case where there is only one iteration, because
then the compiler can also inline the memcpy. As a start, extract
everything after the first address_space_translate call.

Backports commit a203ac702e0720135fac8b1f2061d119814c1798 from qemu
2018-02-17 20:31:21 -05:00
Paolo Bonzini 0688343929
memory: split address_space_read and address_space_write
Rather than dispatching on is_write for every iteration, make
address_space_rw call one of the two functions. The amount of
duplicate logic is pretty small, and memory_access_is_direct can
be tweaked so that it inlines better in the callers.

Backports commit eb7eeb88628074207dd611472e712af775985e73 from qemu
2018-02-17 20:19:05 -05:00
Paolo Bonzini 52b3120995
exec: make qemu_ram_ptr_length more similar to qemu_get_ram_ptr
Notably, use qemu_get_ram_block to enjoy the MRU optimization.

Backports commit e81bcda529378f5ed8b9b0b59bb2b24b8ee1c814 from qemu
2018-02-17 19:46:37 -05:00
Eduardo Habkost 26791ea61b
exec: Eliminate qemu_ram_free_from_ptr()
Replace qemu_ram_free_from_ptr() with qemu_ram_free().

The only difference between qemu_ram_free_from_ptr() and
qemu_ram_free() is that g_free_rcu() is used instead of
call_rcu(reclaim_ramblock). We can safely replace it because:

* RAM blocks allocated by qemu_ram_alloc_from_ptr() always have
RAM_PREALLOC set;
* reclaim_ramblock(block) will do nothing except g_free(block)
if RAM_PREALLOC is set at block->flags.

Backports commit a29ac16632aec6065c72985b9f7eeb1ca6fbef4a from qemu
2018-02-17 19:37:45 -05:00
Don Slutz 86436964b5
exec: Stop using memory after free
memory_region_unref(mr) can free memory.

For example I got:

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7f43280d4700 (LWP 4462)]
0x00007f43323283c0 in phys_section_destroy (mr=0x7f43259468b0)
at /home/don/xen/tools/qemu-xen-dir/exec.c:1023
1023 if (mr->subpage) {
(gdb) bt
at /home/don/xen/tools/qemu-xen-dir/exec.c:1023
at /home/don/xen/tools/qemu-xen-dir/exec.c:1034
at /home/don/xen/tools/qemu-xen-dir/exec.c:2205
(gdb) p mr
$1 = (MemoryRegion *) 0x7f43259468b0

And this change prevents this.

Backports commit 55b4e80b047300e1512df02887b7448ba3786b62 from qemu
2018-02-17 19:11:50 -05:00
Dr. David Alan Gilbert 60975685ce
qemu_ram_block_by_name
Add a function to find a RAMBlock by name; use it in two
of the places that already open code that loop; we've
got another use later in postcopy.

Backports commit e3dd74934f2d2c8c67083995928ff68e8c1d0030 from qemu
2018-02-17 18:01:16 -05:00
Dr. David Alan Gilbert cc088f84b5
qemu_ram_block_from_host
Postcopy sends RAMBlock names and offsets over the wire (since it can't
rely on the order of ramaddr being the same), and it starts out with
HVA fault addresses from the kernel.

qemu_ram_block_from_host translates a HVA into a RAMBlock, an offset
in the RAMBlock and the global ram_addr_t value.

Rewrite qemu_ram_addr_from_host to use qemu_ram_block_from_host.

Provide qemu_ram_get_idstr since its the actual name text sent on the
wire.

Backports commit 422148d3e56c3c9a07c0cf36c1e0a0b76f09c357 from qemu
2018-02-17 17:54:03 -05:00
Paolo Bonzini 479f36ef8e
exec: avoid unnecessary cacheline bounce on ram_list.mru_block
Whenever the MRU cache hits for the list of RAM blocks, qemu_get_ram_block
does an unnecessary write that causes a processor cache line to bounce
from one core to another. This causes a performance hit.

Backports commit 68851b98e5bf6d397498b74f1776801274ab8d48 from qemu
2018-02-17 17:21:04 -05:00
Peter Maydell e1a4e4208f
pc: resizeable ROM blocks
This makes ROM blocks resizeable. This infrastructure is required for other
functionality we have queued.

Backports commit aaf03019175949eda5087329448b8a0033b89479 from qemu
2018-02-17 17:18:38 -05:00
Lioncash ad7663551b
memory: call begin, log_start and commit when registering a new listener
This ensures that cpu_reload_memory_map() is called as soon as
tcg_cpu_address_space_init() is called, and before cpu->memory_dispatch
is used. qemu-system-s390x never changes the address spaces after
tcg_cpu_address_space_init() is called, and thus tcg_commit() is never
called. This causes a SIGSEGV.

Because memory_map_init() will now call mem_commit(), we have to
initialize io_mem_* before address_space_memory and friends.

Backports commit 680a4783dc13f1059c03d11da58193d76c19ead6 from qemu
2018-02-17 15:24:15 -05:00
Michael S. Tsirkin 722c58affb
exec: factor out duplicate mmap code
Anonymous and file-backed RAM allocation are now almost exactly the same.

Reduce code duplication by moving RAM mmap code out of oslib-posix.c and
exec.c.

Backports commit 794e8f301a17953efa78ab7538019ec43c59e82a from qemu
2018-02-17 15:24:03 -05:00
Peter Crosthwaite afb48e9fc5
cputlb: Change tlb_set_dirty() arg to cpu
Change tlb_set_dirty() to accept a CPU instead of an env pointer. This
allows for removal of another CPUArchState usage from prototypes that
need to be QOMified.

Backports commit bcae01e468d961ad9afaf4148329147e4be209ab from qemu
2018-02-17 15:23:52 -05:00
Peter Maydell 400fd62ba7
exec.c: Use pow2floor() rather than hand-calculation
Use pow2floor() to round down to the nearest power of 2,
rather than an inline calculation.

Backports commit 6554f5c03793bb8a3d5dedcebf758a1694fa186c from qemu
2018-02-17 15:23:35 -05:00
Peter Crosthwaite 9e23308b66
cpu: Change cpu_exec_init() arg to cpu, not env
The callers (most of them in target-foo/cpu.c) to this function all
have the cpu pointer handy. Just pass it to avoid an ENV_GET_CPU() from
core code (in exec.c).

Backports commit 4bad9e392e788a218967167a38ce2ae7a32a6231 from qemu
2018-02-17 15:23:18 -05:00
Peter Crosthwaite 8200453545
translate-all: Change tb_flush() env argument to cpu
All of the core-code usages of this API have the cpu pointer handy so
pass it in. There are only 3 architecture specific usages (2 of which
are commented out) which can just use ENV_GET_CPU() locally to get the
cpu pointer. The reduces core code usage of the CPU env, which brings
us closer to common-obj'ing these core files.

Backports commit bbd77c180d7ff1b04a7661bb878939b2e1d23798 from qemu
2018-02-17 15:23:18 -05:00
Eduardo Habkost 79c95aa18b
cpu: Initialize breakpoint/watchpoint lists in cpu_common_initfn()
One small step in the simplification of cpu_exec_init().

Backports commit 7c39163e389e6e6e16965606fb5a26abcdb6ad73 from qemu
2018-02-17 15:23:18 -05:00
Eduardo Habkost 4e39fabd4d
cpu: No need to zero-initialize CPUState::numa_node
QOM objects are already zero-filled when instantiated, there's no need
to explicitly set numa_node to 0.

Backports commit 199fc85acd0571902eeefef6ea861b8ba4c8201f from qemu
2018-02-17 15:23:18 -05:00
Paolo Bonzini a6ea34ee0c
exec: skip MMIO regions correctly in cpu_physical_memory_write_rom_internal
Loading the BIOS in the mac99 machine is interesting, because there is a
PROM in the middle of the BIOS region (from 16K to 32K). Before memory
region accesses were clamped, when QEMU was asked to load a BIOS from
0xfff00000 to 0xffffffff it would put even those 16K from the BIOS file
into the region. This is weird because those 16K were not actually
visible between 0xfff04000 and 0xfff07fff. However, it worked.

After clamping was added, this also worked. In this case, the
cpu_physical_memory_write_rom_internal function split the write in
three parts: the first 16K were copied, the PROM area (second 16K) were
ignored, then the rest was copied.

Problems then started with commit 965eb2f (exec: do not clamp accesses
to MMIO regions, 2015-06-17). Clamping accesses is not done for MMIO
regions because they can overlap wildly, and MMIO registers can be
expected to perform full-width accesses based only on their address
(with no respect for adjacent registers that could decode to completely
different MemoryRegions). However, this lack of clamping also applied
to the PROM area! cpu_physical_memory_write_rom_internal thus failed
to copy the third range above, i.e. only copied the first 16K of the BIOS.

In effect, address_space_translate is expecting _something else_ to do
the clamping for MMIO regions if the incoming length is large. This
"something else" is memory_access_size in the case of address_space_rw,
so use the same logic in cpu_physical_memory_write_rom_internal.

Backports commit b242e0e0e2969c044a318e56f7988bbd84de1f63 from qemu
2018-02-17 15:23:16 -05:00
Stefan Hajnoczi fc7b95d06a
memory: replace cpu_physical_memory_reset_dirty() with test-and-clear
The cpu_physical_memory_reset_dirty() function is sometimes used
together with cpu_physical_memory_get_dirty(). This is not atomic since
two separate accesses to the dirty memory bitmap are made.

Turn cpu_physical_memory_reset_dirty() and
cpu_physical_memory_clear_dirty_range_type() into the atomic
cpu_physical_memory_test_and_clear_dirty().

Backports commit 03eebc9e3246b9b3f5925aa41f7dfd7c1e467875 from qemu
2018-02-13 11:25:45 -05:00
Paolo Bonzini 6d509f7333
exec: only check relevant bitmaps for cleanliness
Most of the time, not all bitmaps have to be marked as dirty;
do not do anything if the interesting ones are already dirty.
Previously, any clean bitmap would have cause all the bitmaps to be
marked dirty.

In fact, unless running TCG most of the time bitmap operations need
not be done at all, because memory_region_is_logging returns zero.
In this case, skip the call to cpu_physical_memory_range_includes_clean
altogether as well.

With this patch, cpu_physical_memory_set_dirty_range is called
unconditionally, so there need not be anymore a separate call to
xen_modified_memory.

Backports commit e87f7778b64d4a6a78e16c288c7fdc6c15317d5f from qemu
2018-02-13 11:03:26 -05:00
Paolo Bonzini 1b1f82cef7
exec: invert return value of cpu_physical_memory_get_clean, rename
While it is obvious that cpu_physical_memory_get_dirty returns true even if
a single page is dirty, the same is not true for cpu_physical_memory_get_clean;
one would expect that it returns true only if all the pages are clean, but
it actually looks for even one clean page. (By contrast, the caller of that
function, cpu_physical_memory_range_includes_clean, has a good name).

To clarify, rename the function to cpu_physical_memory_all_dirty and return
true if _all_ the pages are dirty. This is the opposite of the previous
meaning, because "all are 1" is the same as "not (any is 0)", so we have to
modify cpu_physical_memory_range_includes_clean as well

Backports commit 72b47e79cef36ed6ffc718f10e21001d7ec2a66f from qemu
2018-02-13 09:54:12 -05:00
Paolo Bonzini b5c9645a0f
translate-all: remove unnecessary argument to tb_invalidate_phys_range
The is_cpu_write_access argument is always 0, remove it.

Backports commit 358653391b0c0beaa0e3f9e28304e1918cd223b3 from qemu
2018-02-13 09:04:51 -05:00
Paolo Bonzini 9847ba46d6
exec: optimize phys_page_set_level
phys_page_set_level is writing zeroes to a struct that has just been
filled in by phys_map_node_alloc. Instead, tell phys_map_node_alloc
whether to fill in the page "as a leaf" or "as a non-leaf".

memcpy is faster than struct assignment, which copies each bitfield
individually. A compiler bug (https://gcc.gnu.org/PR66391), and
small memcpys like this one are special-cased anyway, and optimized
to a register move, so just use the memcpy.

This cuts the cost of phys_page_set_level from 25% to 5% when
booting qboot.

Backports commit db94604b20278c1dc227a04e4c564d80230e6c3f from qemu
2018-02-13 08:38:24 -05:00