Just as with test_bit, the non-atomic set/clear/change helpers can be better
optimised by the compiler in the case that the nr parameter is constant, and
it often is.
This results in a general replacement of `mov $imm, %reg; bt* %reg, mem` with
the shorter and more simple `op $imm, mem`, also reducing register pressure.
The net diffstat is:
add/remove: 0/1 grow/shrink: 5/17 up/down: 90/-301 (-211)
As a piece of minor cleanup, drop unnecessary brackets in the test_bit()
macro, and fix the indentation.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Dario Faggioli <dfaggioli@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
struct timer is only 48 bytes and repl_timer has a 1-to-1 correspondance with
struct rt_private, so having it referenced by pointer is wasteful.
This avoids one memory allocation in rt_init(), and the resulting diffstat is:
add/remove: 0/0 grow/shrink: 0/7 up/down: 0/-156 (-156)
function old new delta
rt_switch_sched 134 133 -1
rt_context_saved 278 271 -7
rt_vcpu_remove 253 245 -8
rt_vcpu_sleep 234 218 -16
repl_timer_handler 761 744 -17
rt_deinit 44 20 -24
rt_init 219 136 -83
As an extra bit of cleanup noticed while making this change, there is no need
to call cpumask_clear() on an zeroed memory allocation.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Dario Faggioli <dfaggioli@suse.com>
Reviewed-by: Meng Xu <mengxu@cis.upenn.edu>
c/s b6c2c7f48a unfortunately broke booting on affected systems. Most of the
time, ioemul_handle_quirk() doesn't write a custom stub, and the redundant
call was depending on the seemingly-pointless writing of the default stub.
Alter the ioemul_handle_quirk() API to return a boolean if a custom stub was
written, allowing its caller to know whether it should write a default stub
instead.
Finally, adjust the /* Regular stubs */ comment to make it clearer that the 16
refers to the length of the emul stub opcode.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
... rather than obtaining it via function pointer. The internal ucode_mod_map
function pointer can also be dropped.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
There is one static bootstrap_map() function which is passed via function
pointer to all of its users. This is wasteful.
Export bootstrap_map() for all x86 users, and drop the function pointer
parameter from the construct_dom0*() infrastructure.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
The opcode potentially written into ctxt->io_emul_stub[] in the case
that ioemul_handle_quirk() is overriding the default logic isnt
accounted for in the build-time check that the stubs are large enough.
Introduce IOEMUL_QUIRK_STUB_BYTES and use for both the main and quirk
stub cases. As a slim optimisation, avoid writing out the default stub
when we know we are going to overwrite it.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Intel says for CPUID leaf 0Bh:
"Software must not use EBX[15:0] to enumerate processor
topology of the system. This value in this field
(EBX[15:0]) is only intended for display/diagnostic
purposes. The actual number of logical processors
available to BIOS/OS/Applications may be different from
the value of EBX[15:0], depending on software and platform
hardware configurations."
And yet, we're using them to derive the number cores in a package
and the number of siblings in a core.
Derive the number of siblings and cores from EAX instead, which is
intended for that.
Signed-off-by: Jan H. Schönherr <jschoenh@amazon.de>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
This logic is not as clear as it could be. Add some comments to help.
Rearrange the asm block in __prepare_to_wait() to separate the GPR
saving/restoring from the internal logic.
While tweaking, add an unreachable() following the jmp in
check_wakeup_from_wait().
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
This reduces the number of code gadgets which can be attacked with arbitrary
guest-controlled GPR values.
This is part of XSA-254.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
No practical change.
One side effect in debug builds is that %rbp is inverted in the manner
expected by the stack unwinder to indicate a interrupt frame.
This is part of XSA-254.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Results in a more predictable (i.e. linear) memory access pattern.
No functional change.
This is part of XSA-254.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Save all GPRs on entry to Xen.
The entry_int82() path is via a DPL1 gate, only usable by 32bit PV guests, so
can get away with only saving the 32bit registers. All other entrypoints can
be reached from 32 or 64bit contexts.
This is part of XSA-254.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
In case the vCPU has pending events to inject. This fixes a bug that
happened if the guest mapped the vcpu info area using
VCPUOP_register_vcpu_info without having setup the event channel
upcall, and then setup the upcall vector.
In this scenario the guest would not receive any upcalls, because the
call to VCPUOP_register_vcpu_info would have marked the vCPU as having
pending events, but the vector could not be injected because it was
not yet setup.
This has not caused issues so far because all the consumers first
setup the vector callback and then map the vcpu info page, but there's
no limitation that prevents doing it in the inverse order.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
This patch adds the old value param and the onchangeonly option
to the VM_EVENT_REASON_MOV_TO_MSR event.
The param was added to the vm_event_mov_to_msr struct and to the
hvm_monitor_msr function. Finally I've changed the bool_t param
to a bool for the hvm_msr_write_intercept function.
Signed-off-by: Alexandru Isaila <aisaila@bitdefender.com>
Acked-by: Tamas K Lengyel <tamas@tklengyel.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
c/s 4187f79dc7 "x86/msr: introduce struct msr_vcpu_policy" introduced a
per-vcpu memory allocation, but failed to free it in the clean vcpu
destruction case.
This is XSA-253.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Barriers are a complicated topic, a source of confusion, and their incorrect
use is a common cause of bugs. It really doesn't help when Xen's API is the
same as Linux, but its ABI different.
Bring the two back in line, so programmers stand a chance of actually getting
their usage correct.
Drop the links in the comment, both of which are now stale. Instead, refer to
the vendor system manuals in a generic way.
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Dario Faggioli <dario.faggioli@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
x86's current implementation of wmb() is a compiler barrier. As a result, the
only change in this patch is to remove an mfence instruction from
cpuidle_disable_deep_cstate().
None of these barriers serve any purpose. They are not synchronising with
remote cpus, and their compiler-barrier properties are not needed for
correctness purposes.
Furthermore, these wmb()'s specifically do not want to turn into sfence
instructions in future changes where wmb()'s implementation is corrected.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
In case 1, it passes down the BLACK color from G to p and u, and maintains
the color of n. By doing so, it maintains the black height of the sub-tree.
While in the comment, it marks the color of n to BLACK. This is a typo
and not consistents with the code.
This patch fixs this typo in comment.
Signed-off-by: Wei Yang <weiyang@linux.vnet.ibm.com>
Acked-by: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[Linux commit 1b9c53e849aa65776d4f611d99aa09f856518dad]
Ported to Xen for rb_insert_color API.
Signed-off-by: Praveen Kumar <kpraveen.lkml@gmail.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Various minor optimizations in rb_erase():
- Avoid multiple loading of node->__rb_parent_color when computing parent
and color information (possibly not in close sequence, as there might
be further branches in the algorithm)
- In the 1-child subcase of case 1, copy the __rb_parent_color field from
the erased node to the child instead of recomputing it from the desired
parent and color
- When searching for the erased node's successor, differentiate between
cases 2 and 3 based on whether any left links were followed. This avoids
a condition later down.
- In case 3, keep a pointer to the erased node's right child so we don't
have to refetch it later to adjust its parent.
- In the no-childs subcase of cases 2 and 3, place the rebalance assigment
last so that the compiler can remove the following if(rebalance) test.
Also, added some comments to illustrate cases 2 and 3.
Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[Linux commit 4f035ad67f4633c233cb3642711d49b4efc9c82d]
Ported to Xen.
Signed-off-by: Praveen Kumar <kpraveen.lkml@gmail.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
An interesting observation for rb_erase() is that when a node has
exactly one child, the node must be black and the child must be red.
An interesting consequence is that removing such a node can be done by
simply replacing it with its child and making the child black,
which we can do efficiently in rb_erase(). __rb_erase_color() then
only needs to handle the no-childs case and can be modified accordingly.
Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[Linux commit 46b6135a7402ac23c5b25f2bd79b03bab8f98278]
Ported to Xen.
Signed-off-by: Praveen Kumar <kpraveen.lkml@gmail.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Add __rb_change_child() as an inline helper function to replace code that
would otherwise be duplicated 4 times in the source.
No changes to binary size or speed.
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[Linux commit 7abc704ae399fcb9c51ca200b0456f8a975a8011]
Ported to Xen.
Signed-off-by: Praveen Kumar <kpraveen.lkml@gmail.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
When looking to fetch a node's sibling, we went through a sequence of:
- check if node is the parent's left child
- if it is, then fetch the parent's right child
This can be replaced with:
- fetch the parent's right child as an assumed sibling
- check that node is NOT the fetched child
This avoids fetching the parent's left child when node is actually
that child. Saves a bit on code size, though it doesn't seem to make
a large difference in speed.
Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[Linux commit 59633abf34e2f44b8e772a2c12a92132aa7c2220]
Ported to Xen.
Signed-off-by: Praveen Kumar <kpraveen.lkml@gmail.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
There's no need for
- advancing the handles and at the same time using
__copy_{from,to}_guest_offset(),
- an "out" label,
- local variables "done" and (function scope) "rc".
To better reflect its resulting use also rename the function's "start"
parameter to "extent".
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
..., largely to shrink code size a little:
- use TEST instead of CMP with zero immediate
- use MOVZWL instead of AND with 0xffff immediate
- compute final highmem_bk value in registers, accessing memory just
once
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
The bounds check needs to be done after the increment, not before, or
else it needs to use a one lower immediate. Also use word operations
rather than byte ones for both the increment and the compare (allowing
E820_BIOS_MAX to be more easily bumped, should the need ever arise).
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Permissions that had been granted before should not be revoked when
handling unrelated errors.
Reported-by: HW42 <hw42@ipsumj.de>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
None of the models MISC_ENABLE MSR access is excluded for support 64-bit
mode - drop the conditional from early_init_intel(). Also convert
pointless rdmsr_safe() elsewhere to rdmsrl().
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
There is no functional change. Xen currently assignes smp_* meaning to
the non-smp_* barriers.
All of these uses are just to deal with shared memory between multiple
processors, which means that the smp_*() varients are the correct ones to use.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Dario Faggioli <dario.faggioli@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
In __rb_erase_color(), we often already have pointers to the nodes being
rotated and/or know what their colors must be, so we can generate more
efficient code than the generic __rb_rotate_left() and __rb_rotate_right()
functions.
Also when the current node is red or when flipping the sibling's color,
the parent is already known so we can use the more efficient
rb_set_parent_color() function to set the desired color.
Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[Linux commit 6280d2356fd8ad0936a63c10dc1e6accf48d0c61]
Ported to Xen.
Signed-off-by: Praveen Kumar <kpraveen.lkml@gmail.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
In __rb_erase_color(), we have to select one of 3 cases depending on the
color on the 'other' node children. If both children are black, we flip a
few node colors and iterate. Otherwise, we do either one or two tree
rotations, depending on the color of the 'other' child opposite to 'node',
and then we are done.
The corresponding logic had duplicate checks for the color of the 'other'
child opposite to 'node'. It was checking it first to determine if both
children are black, and then to determine how many tree rotations are
required. Rearrange the logic to avoid that extra check.
Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[Linux commit e125d1471a4f8f1bf7ea9a83deb8d23cb40bd712]
Ported to Xen.
Signed-off-by: Praveen Kumar <kpraveen.lkml@gmail.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
In __rb_erase_color(), we were always setting a node to black after
exiting the main loop. And in one case, after fixing up the tree to
satisfy all rbtree invariants, we were setting the current node to root
just to guarantee a loop exit, at which point the root would be set to
black. However this is not necessary, as the root of an rbtree is already
known to be black. The only case where the color flip is required is when
we exit the loop due to the current node being red, and it's easiest to
just do the flip at that point instead of doing it after the loop.
[adrian.hunter@intel.com: perf tools: fix build for another rbtree.c change]
Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[Linux commit d6ff1273928ebf15466a85b7e1810cd00e72998b]
Ported only rbtree.c to Xen.
Signed-off-by: Praveen Kumar <kpraveen.lkml@gmail.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
- Use the newly introduced rb_set_parent_color() function to flip the color
of nodes whose parent is already known.
- Optimize rb_parent() when the node is known to be red - there is no need
to mask out the color in that case.
- Flipping gparent's color to red requires us to fetch its rb_parent_color
field, so we can reuse it as the parent value for the next loop iteration.
- Do not use __rb_rotate_left() and __rb_rotate_right() to handle tree
rotations: we already have pointers to all relevant nodes, and know their
colors (either because we want to adjust it, or because we've tested it,
or we can deduce it as black due to the node proximity to a known red node).
So we can generate more efficient code by making use of the node pointers
we already have, and setting both the parent and color attributes for
nodes all at once. Also in Case 2, some node attributes don't have to
be set because we know another tree rotation (Case 3) will always follow
and override them.
Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[Linux commit 5bc9188aa207dafd47eab57df7c4fe5b3d3f636a]
Ported to Xen.
Signed-off-by: Praveen Kumar <kpraveen.lkml@gmail.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
The root node of an rbtree must always be black. However,
rb_insert_color() only needs to maintain this invariant when it has been
broken - that is, when it exits the loop due to the current (red) node
being the root. In all other cases (exiting after tree rotations, or
exiting due to an existing black parent) the invariant is already
satisfied, so there is no need to adjust the root node color.
Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[Linux commit 6d58452dc066db61acdff7b84671db1b11a3de1c]
Ported to Xen.
Signed-off-by: Praveen Kumar <kpraveen.lkml@gmail.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
It is a well known property of rbtrees that insertion never requires more
than two tree rotations. In our implementation, after one loop iteration
identified one or two necessary tree rotations, we would iterate and look
for more. However at that point the node's parent would always be black,
which would cause us to exit the loop.
We can make the code flow more obvious by just adding a break statement
after the tree rotations, where we know we are done. Additionally, in the
cases where two tree rotations are necessary, we don't have to update the
'node' pointer as it wouldn't be used until the next loop iteration, which
we now avoid due to this break statement.
Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[Linux commit 1f0528653e41ec230c60f5738820e8a544731399]
Ported to Xen.
Signed-off-by: Praveen Kumar <kpraveen.lkml@gmail.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Empty nodes have no color. We can make use of this property to simplify
the code emitted by the RB_EMPTY_NODE and RB_CLEAR_NODE macros. Also,
we can get rid of the rb_init_node function which had been introduced by
commit 88d19cf37952 ("timers: Add rb_init_node() to allow for stack
allocated rb nodes") to avoid some issue with the empty node's color not
being initialized.
I'm not sure what the RB_EMPTY_NODE checks in rb_prev() / rb_next() are
doing there, though. axboe introduced them in commit 10fd48f2376d
("rbtree: fixed reversed RB_EMPTY_NODE and rb_next/prev"). The way I
see it, the 'empty node' abstraction is only used by rbtree users to
flag nodes that they haven't inserted in any rbtree, so asking the
predecessor or successor of such nodes doesn't make any sense.
One final rb_init_node() caller was recently added in sysctl code to
implement faster sysctl name lookups. This code doesn't make use of
RB_EMPTY_NODE at all, and from what I could see it only called
rb_init_node() under the mistaken assumption that such initialization was
required before node insertion.
[sfr@canb.auug.org.au: fix net/ceph/osd_client.c build]
Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[Linux commit 4c199a93a2d36b277a9fd209a0f2793f8460a215]
Ported rbtree.h and rbtree.c changes which are relevant to Xen.
Signed-off-by: Praveen Kumar <kpraveen.lkml@gmail.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Furthermore, notice that the initial checks:
if (!node->rb_left)
child = node->rb_right;
else if (!node->rb_right)
child = node->rb_left;
else
{
...
}
guarantee that old->rb_right is set in the final else branch, therefore
we can omit checking that again.
Signed-off-by: Wolfram Strepp <wstrepp@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[Linux commit 4b324126e0c6c3a5080ca3ec0981e8766ed6f1ee]
Ported to Xen.
Signed-off-by: Praveen Kumar <kpraveen.lkml@gmail.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Along with c/s d7128e7350 switching the runtime choice of best nops, switch
the compile-time default to P6 nops. This is more efficient on most
processors for alternative points which add/remove code, rather than switch
between two different pieces of code.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
shadow_one_bit_enable() sets PG_SH_enable (if not already set of course)
in addition to the bit being requested. Make shadow_one_bit_disable()
behave similarly - clear PG_SH_enable if that's the only bit remaining.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Tim Deegan <tim@xen.org>
Andrew Cooper
Dario Faggioli
Jan H. Schönherr
Roger Pau Monné
Alexandru Isaila
Wei Yang
Michel Lespinasse
Jan Beulich
Wolfram Strepp