See patch comment for technical details.
Concerning the timeline, this was first discovered in the aftermath of
XSA-156 which caused #DB to be intercepted unconditionally, but only in
its SingleStep + STI form which is restricted to privileged software.
After working with Intel and identifying the problematic vmentry check,
this workaround was suggested, and the patch was posted in an RFC
series. Outstanding work for that series (not breaking Introspection)
is still pending, and this fix from it (which wouldn't have been good
enough in its original form) wasn't committed.
A vmentry failure was reported to xen-devel, and debugging identified
this bug in its SingleStep + MovSS form by way of INT1, which does not
involve the use of any privileged instructions, and proving this to be a
security issue.
This is XSA-308
Reported-by: Håkon Alstadheim <hakon@alstadheim.priv.no>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Kevin Tian <kevin.tian@intel.com>
These functions getting used with the 2nd and 3rd arguments being equal
wasn't well defined: Arm64 reliably returns the value of the 2nd
argument in this case, while on x86 for bitmaps up to 64 bits wide the
return value was undefined (due to the undefined behavior of a shift of
a value by the number of bits it's wide) when the incoming value was 64.
On Arm32 an actual out of bounds access would happen when the
size/offset value is a multiple of 32; if this access doesn't fault, the
return value would have been sufficiently correct afaict.
Make the functions consistently tolerate the last two arguments being
equal (and in fact the 3rd argument being greater or equal to the 2nd),
in favor of finding and fixing all the use sites that violate the
original more strict assumption.
This is XSA-307.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Julien Grall <julien@xen.org>
Begin to document how the x86 build of Xen boots. It is by no means complete,
but is a start.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Needing to pass PYTHON=python3 into hypervisor builds is irritating and
unnecessary. Locate a suitable interpreter automatically, defaulting to Py3
if it is available.
Reported-by: Steven Haigh <netwiz@crc.id.au>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: George Dunlap <george.dunlap@citrix.com>
Release-acked-by: Juergen Gross <jgross@suse.com>
The script is 664 rather than 775, so the banner conversion doesn't actually
work if $(PYTHON) is empty:
/bin/sh: tools/fig-to-oct.py: Permission denied
make[3]: *** [include/xen/compile.h] Error 126
make[3]: Leaving directory `/builds/xen-project/people/andyhhp/xen/xen'
Fixing this is easy, but using python here is wasteful. compile.h doesn't
need XEN_BANNER rendering in octal, and text is much more simple to handle.
Replace fig-to-oct.py with a smaller sed script. This could be a shell
one-liner, but it is much more simple to comment sensibly, and doesn't need to
include the added cognative load of makefile and shell escaping.
While changing this logic, take the opportunity to optimise the banner
space (and time on the serial port) by dropping trailing whitespace, which is
84 characters for current staging.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: George Dunlap <george.dunlap@citrix.com>
The script is Python 2 specific, and fails with string/binary issues with
Python 3:
Traceback (most recent call last):
File "gen-policy.py", line 14, in <module>
for char in sys.stdin.read():
File "/usr/lib/python3.5/codecs.py", line 321, in decode
(result, consumed) = self._buffer_decode(data, self.errors, final)
UnicodeDecodeError: 'utf-8' codec can't decode byte 0x8c in position 0: invalid start byte
Fixing the script to be compatible isn't hard, but using python here is
wasteful. Drop the script entirely, and write an equivelent flask-policy.S
instead. This removes the need for a $(PYTHON) and $(CC) pass.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Acked-by: Julien Grall <julien@xen.org>
Release-acked-by: Juergen Gross <jgross@suse.com>
When using global pages a full tlb flush can only be performed by
toggling the PGE bit in CR4, which is usually quite expensive in terms
of performance when running virtualized. This is specially relevant on
AMD or Hygon hardware, which doesn't have the ability to do selective
CR4 trapping, but can also be relevant on e.g. Intel if the underlying
hypervisor also traps accesses to the PGE CR4 bit.
In order to avoid this performance penalty, do not use global pages
when running virtualized on AMD or Hygon hardware. A command line option
'global-pages' is provided in order to allow the user to select whether
global pages will be enabled for PV guests.
The above figures are from a PV shim running on AMD hardware with
32 vCPUs:
PGE enabled, x2APIC mode:
(XEN) Global lock flush_lock: addr=ffff82d0804b01c0, lockval=1adb1adb, not locked
(XEN) lock:1841883(1375128998543), block:1658716(10193054890781)
Average lock time: 746588ns
Average block time: 6145147ns
PGE disabled, x2APIC mode:
(XEN) Global lock flush_lock: addr=ffff82d0804af1c0, lockval=a8bfa8bf, not locked
(XEN) lock:2730175(657505389886), block:2039716(2963768247738)
Average lock time: 240829ns
Average block time: 1453029ns
As seen from the above figures the lock and block time of the flush
lock is reduced to approximately 1/3 of the original value.
Note that XEN_MINIMAL_CR4 and mmu_cr4_features are not modified, and
thus global pages are left enabled for the hypervisor. This is not an
issue because the code to switch the control registers (cr3 and cr4)
already takes into account such situation and performs the necessary
flushes. The same already happens when using XPTI or PCIDE, as the
guest cr4 doesn't have global pages enabled in that case either.
Also note that the suspend and resume code is correct in writing
mmu_cr4_features into cr4 on resume, since that's the cr4 used by the
idle vCPU which is the context used by the suspend and resume routine.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
If the feature is not present Xen will try to force X86_BUG_FPU_PTRS
feature at CPU identification time. This is especially noticeable in
PV-shim that usually hotplugs its vCPUs. We either need to restrict this
action for boot CPU only or allow secondary CPUs to modify
forced CPU capabilities at runtime. Choose the former since modifying
forced capabilities out of boot path leaves the system in potentially
inconsistent state.
Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Sometimes, on x86_64, decompression fails with the following
error:
Decompressing Linux...
Decoding failed
-- System halted
This condition is not needed for a 64bit kernel(from commit d5e7caf):
if( ... ||
(op + COPYLENGTH) > oend)
goto _output_error
macro LZ4_SECURE_COPY() tests op and does not copy any data
when op exceeds the value.
added by analogy to lz4_uncompress_unknownoutputsize(...)
Signed-off-by: Krzysztof Kolasa <kkolasa@winsoft.pl>
[Linux commit 99b7e93c95c78952724a9783de6c78def8fbfc3f]
The offending commit in our case is fcc17f96c2 ("LZ4 : fix the data
abort issue").
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
There's no reason to allocate the dec{32,64}table on the stack; it
just wastes a bunch of instructions setting them up and, of course,
also consumes quite a bit of stack. Using size_t for such small
integers is a little excessive.
$ scripts/bloat-o-meter /tmp/built-in.o lib/built-in.o
add/remove: 2/2 grow/shrink: 2/0 up/down: 1304/-1548 (-244)
function old new delta
lz4_decompress_unknownoutputsize 55 718 +663
lz4_decompress 55 632 +577
dec64table - 32 +32
dec32table - 32 +32
lz4_uncompress 747 - -747
lz4_uncompress_unknownoutputsize 801 - -801
The now inlined lz4_uncompress functions used to have a stack
footprint of 176 bytes (according to -fstack-usage); their inlinees
have increased their stack use from 32 bytes to 48 and 80 bytes,
respectively.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
[Linux commit bea2b592fd18eb8ffa3fc4ad380610632d03a38f]
Use {,u}int8_t instead of plain "int" for the tables.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
I clearly went too far there: While the LZ4_WILDCOPY() instances indeed
need prior guarding, LZ4_SECURECOPY() needs this only in the 32-bit case
(where it simply aliases LZ4_WILDCOPY()). "cpy" can validly point
(slightly) below "op" in these cases, due to
cpy = op + length - (STEPSIZE - 4);
where length can be as low as 0 and STEPSIZE is 8. However, instead of
removing the check via "#if !LZ4_ARCH64", refine it such that it would
also properly work in the 64-bit case, aborting decompression instead
of continuing on bogus input.
Reported-by: Mark Pryor <pryorm09@gmail.com>
Reported-by: Jeremi Piotrowski <jeremi.piotrowski@gmail.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Tested-by: Mark Pryor <pryorm09@gmail.com>
Tested-by: Jeremi Piotrowski <jeremi.piotrowski@gmail.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
There's nothing to restore here if there's no FPU in the first place.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Creative Commons is a more common license than GPL for documentation purposes.
Switch to using CC-BY-4.0 to explicitly permit re-purposing and remixing of
the content.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Lars Kurth <lars.kurth@citrix.com>
Release-acked-by: Juergen Gross <jgross@suse.com>
Add model 0x86 to relevant switch() statements, as per SDM 069 Vol 4.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
This only added dead code. Use "if" instead of "depends on" to make
(halfway) clear that other guest options should also go in the same
block. Move the option down such that the shim related options get
presented first, avoiding to ask the question when the answer may end
up being discarded.
While in the neighborhood also bring PV_SHIM_EXCLUSIVE into more
"canonical" shape.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Wei Liu <wl@xen.org>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
It's bogusly non-static. It making the call sites actually less easy to
read, and there being another open-coded use in the file - let's just
get rid of it.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: George Dunlap <george.dunlap@citrix.com>
Introduce vmcb.ei.* to provide names to fields in exitinfo{1,2}. Implement
the task switch names for now, and clean up the TASK_SWITCH handler.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
The type name is poor because the type is also used for the IDT vectoring
field, not just for the event injection field. Rename it to intinfo_t which
is how the APM refers to the data.
Rearrange the union to drop the .fields infix, and rename bytes to the more
common raw. Also take the opportunity to rename the fields in the VMCB to
increase legibility.
While adjusting all call sites, fix up style issues and make use of structure
assignments where applicable.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
The local variable eventinj is set to the value of vmcb->exitintinfo which is
confusing considering that it isn't vmcb->eventinj. The variable isn't
necessary to begin with, so drop it to avoid confusion.
A local rc variable is shadowed in the CPUID, #DB and #BP handlers.
There is a mix of spelling of inst_len and insn_len, all of which are
logically the same value. Consolidate on insn_len which also matches the name
of the emulation functions for obtaining instruction lengths, and avoid
shadowing it in the CPUID and TASK_SWITCH handlers.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
The vmcb is zeroed on allocate - drop all explicit writes of 0. Move
hvm_update_guest_efer() to co-locate it with the other control register
updates.
Move the BUILD_BUG_ON() into build_assertions(), and add some offset checks
for fields after the large blocks of reserved fields (as these are the most
likely to trigger from a mis-edit). Take the opportunity to fold 6 adjacent
res* fields into one.
Finally, drop all trailing whitespace in the file.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
VT-x updates RF before vmexit, so eflags written into the outgoing TSS happens
to be correct. SVM does not update RF before vmexit, and instead provides it
via a bit in exitinfo2.
In practice, needing RF set in the outgoing state occurs when a task gate is
used to handle faults.
Extend hvm_task_switch() with an extra_eflags parameter which gets fed into
the outgoing TSS, and fill it in suitably from the SVM vmexit information.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
The function is init, so can use boot_cpu_data directly.
There is no need to write 0 to svm_feature_flags in the case of a CPUID
mismatch (not least because this is dead code on real hardware), and no need
to use locked bit operations.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
The locking responsibilities have changed and a premature break in
this section now causes the following assertion:
Assertion '!preempt_count()' failed at preempt.c:36
Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Suggested-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com>
Reviewed-by: Paul Durrant <pdurrant@amazon.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
c/s d0a699a389 "x86/monitor: add support for descriptor access events"
introduced logic looking for what appeared to be exitinfo (not that this
exists in SVM - exitinfo1 or 2 do), but actually passed the exit IDT vectoring
information. There is never any IDT vectoring involved in these intercepts so
the value passed is always zero.
In fact, SVM doesn't provide any information, even in exitinfo1 and 2. Drop
the svm struct entirely, and bump the interface version.
In the SVM vmexit handler itself, optimise the switch statement by observing
that there is a linear transformation between the SVM exit_reason and
VM_EVENT_DESC_* values. (Bloat-o-meter reports 6028 => 5877 for a saving of
151 bytes).
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Razvan Cojocaru <rcojocaru@bitdefender.com>
Reviewed-by: Alexandru Isaila <aisaila@bitdefender.com>
Acked-by: Adrian Pop <apop@bitdefender.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
We use the same code structure as we did for Xen.
As starters, detect Hyper-V in probe routine. More complex
functionalities will be added later.
Signed-off-by: Wei Liu <liuwe@microsoft.com>
Reviewed-by: Paul Durrant <pdurrant@amazon.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
We will soon implement Hyper-V support for Xen. Add a framework for
that.
This requires moving some of the hypervisor_* functions from xen.h to
hypervisor.h.
Signed-off-by: Wei Liu <liuwe@microsoft.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
The only user is Xen specific code in PV shim. We can therefore export
the variable directly.
Move __read_mostly to its standard place while at it.
Signed-off-by: Wei Liu <liuwe@microsoft.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Include asm_defns.h because ASM_CALL_CONSTRAINT is defined there.
Include xen/lib.h because we need ASSERT_UNREACHABLE.
No functional change.
Signed-off-by: Wei Liu <liuwe@microsoft.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Xen is able to run as a guest on Xen. We plan to make it able to run
on Hyper-V as well.
Introduce CONFIG_GUEST which is set to true if either running on Xen
or Hyper-V is desired. Restructure code hierarchy for new code to
come.
No functional change intended.
Signed-off-by: Wei Liu <liuwe@microsoft.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
10s is too low for the clang tests, this is the output from a clang
test:
(XEN) [ 6.512748] ***************************************************
(XEN) [ 6.513323] SELFTEST FAILURE: CORRECT BEHAVIOR CANNOT BE GUARANTEED
(XEN) [ 6.513891] ***************************************************
(XEN) [ 6.514469] 3... 2... 1...
(XEN) [ 9.520011] *** Serial input to DOM0 (type 'CTRL-a' three times to switch input)
(XEN) [ 9.544319] Freed 488kB init memory
--- Xen Test Framework ---
Environment: HVM 32bit (PAE 3 levels)
Hello World
Test result: SUCCESS
(XEN) [ 9.610977] Hardware Dom0 halted: halting machine
As can be seen from the output above booting Xen and the XTF test
takes ~10s, without accounting for the time it takes for QEMU to
initialize.
Increase the timeout to 30s to be on the safe side.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wl@xen.org>
Release-acked-by: Juergen Gross <jgross@suse.com>
Enable Xen timestamps in the automated Xen tests, this is helpful in
order to figure out if Xen is stuck or just slow in the automated
tests.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wl@xen.org>
Release-acked-by: Juergen Gross <jgross@suse.com>
When PCID is not available Xen does a full tlbflush by toggling the
PGE bit in CR4. This is not necessary if PGE is not enabled, since a
flush can be performed by writing to CR3 in that case.
Change the code in do_tlb_flush to only toggle the PGE bit in CR4 if
it's already enabled, otherwise do the tlb flush by writing to CR3.
This is relevant when running virtualized, since hypervisors don't
usually trap accesses to CR3 when using hardware assisted paging, but
do trap accesses to CR4 specially on AMD hardware, which makes such
accesses much more expensive.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Linux commit fc5db58539b49351e76f19817ed1102bf7c712d0 says
"Some Coffee Lake platforms have a skewed HPET timer once the SoCs entered
PC10, which in consequence marks TSC as unstable because HPET is used as
watchdog clocksource for TSC."
Follow this for Xen as well. Looking at its patch context made me notice
they have a pre-existing quirk for Bay Trail as well. The comment there,
however, points at a Cherry Trail document. Looking at the datasheets of
both, there appear to be similar issues, so go beyond Linux'es coverage
and exclude both. Also key the disable on the PCI IDs of the actual
affected devices, rather than those of 00:00.0.
Apply the workarounds only when the use of HPET was not explicitly
requested on the command line and when use of (deep) C-states was not
disabled.
Adjust a few types in touched or nearby code at the same time.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Two almost simultaneous mapping requests need to make sure that at the
completion of the earlier one IOMMU mappings (established explicitly
here in the PV case) have been put in place. Forever since the splitting
of the grant table lock a violation of this has been possible (using
simplified pin counts, as it doesn't matter whether we talk about read
or write mappings here):
initial state: act->pin = 0
vCPU A: progress the operation past the dropping of the locks after the
act->pin updates (act->pin = 1, old_pin = 0, act_pin = 1)
vCPU B: progress the operation past the dropping of the locks after the
act->pin updates (act->pin = 2, old_pin = 1, act_pin = 2)
vCPU B: (re-)acquire both gt locks, mapkind() returns 0, but both
iommu_legacy_map() invocations get skipped due to non-zero
old_pin
vCPU B: return to caller without IOMMU mapping
vCPU A: (re-)acquire both gt locks, mapkind() returns 0,
iommu_legacy_map() gets invoked
With the locks dropped intermediately, whether to invoke
iommu_legacy_map() must depend on only the return value of mapkind()
and of course the kind of mapping request being processed, just like
is already the case in unmap_common().
Also fix the style of the adjacent comment, and correct a nearby one
still referring to a prior name of what is now mapkind().
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
The tx/rx fifo flags were not set when the vpl011 is initialized. This
is a problem for certain guests that are operating in polled mode, as a
guest will generally check the rx fifo empty flag to determine if there
is data before doing a read. The result is a continuous spam of the
message "vpl011: Unexpected IN ring buffer empty" before the first valid
character is received. This initializes the flag status register to the
default specified in the PL011 technical reference manual.
Signed-off-by: Jeff Kubascik <jeff.kubascik@dornerworks.com>
Acked-by: Julien Grall <julien@xen.org>
During test, we found a crash on Xen with below trace.
(XEN) Xen call trace:
(XEN) [<ffff82d0802a065a>] R psr.c#l3_cdp_write_msr+0x1e/0x22
(XEN) [<ffff82d0802a0858>] F psr.c#do_write_psr_msrs+0x6d/0x109
(XEN) [<ffff82d08023e000>] F smp_call_function_interrupt+0x5a/0xac
(XEN) [<ffff82d0802a2b89>] F call_function_interrupt+0x20/0x34
(XEN) [<ffff82d080282c64>] F do_IRQ+0x175/0x6ae
(XEN) [<ffff82d08038b8ba>] F common_interrupt+0x10a/0x120
(XEN) [<ffff82d0802ec616>] F cpu_idle.c#acpi_idle_do_entry+0x9d/0xb1
(XEN) [<ffff82d0802ecc01>] F cpu_idle.c#acpi_processor_idle+0x41d/0x626
(XEN) [<ffff82d08027353b>] F domain.c#idle_loop+0xa5/0xa7
(XEN)
(XEN)
(XEN) ****************************************
(XEN) Panic on CPU 20:
(XEN) GENERAL PROTECTION FAULT
(XEN) [error_code=0000]
(XEN) ****************************************
The bug happens when CDP and MBA co-exist and MBA COS_MAX is bigger
than CDP COS_MAX. E.g. MBA has 8 COS registers but CDP only have 6.
When setting MBA throttling value for the 7th guest, the value array
would be:
+------------------+------------------+--------------+
| Data default val | Code default val | MBA throttle |
+------------------+------------------+--------------+
Then, COS id 7 will be selected for writting the values. We should
avoid writting CDP data/code valules to COS id 7 MSR because it
exceeds the CDP COS_MAX.
Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
The tests to check whether the integrated assembler is capable of
building Xen should be performed before testing any assembler
features, or else the feature specific tests would be stale if the
integrated assembler is disabled afterwards.
Fixes: ef286f6778 ('x86: move and fix clang .skip check')
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reported-by: Doug Goldstein <cardoe@cardoe.com>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Previous commit in kdd.c had a small issue which lead to warning/error while compiling
on 32-bit systems due to mismatch of type size while doing type cast from uint64_t to
void *
Signed-off-by: Jenish Rakholiya <rjenish@cmu.edu>
Signed-off-by: Julian Tuminaro <jtuminar@andrew.cmu.edu>
Acked-by: Tim Deegan <tim@xen.org>
Xen used to have single, system-wide limits for the number of grant
frames and maptrack frames a guest was allowed to create. Increasing
or decreasing this single limit on the Xen command-line would change
the limit for all guests on the system.
Later, per-domain limits for these values was created. The system-wide
limits became strict limits: domains could not be created with higher
limits, but could be created with lower limits. However, that change
also introduced a range of different "default" values into various
places in the toolstack:
- The python libxc bindings hard-coded these values to 32 and 1024,
respectively
- The libxl default values are 32 and 1024 respectively.
- xl will use the libxl default for maptrack, but does its own default
calculation for grant frames: either 32 or 64, based on the max
possible mfn.
These defaults interact poorly with the hypervisor command-line limit:
- The hypervisor command-line limit cannot be used to raise the limit
for all guests anymore, as the default in the toolstack will
effectively override this.
- If you use the hypervisor command-line limit to *reduce* the limit,
then the "default" values generated by the toolstack are too high,
and all guest creations will fail.
In other words, the toolstack defaults require any change to be
effected by having the admin explicitly specify a new value in every
guest.
In order to address this, have grant_table_init treat negative values
for max_grant_frames and max_maptrack_frames as instructions to use the
system-wide default, and have all the above toolstacks default to passing
-1 unless a different value is explicitly configured.
This restores the old behavior in that changing the hypervisor command-line
option can change the behavior for all guests, while retaining the ability
to set per-guest values. It also removes the bug that reducing the
system-wide max will cause all domains without explicit limits to fail.
NOTE: - The Ocaml bindings require the caller to always specify a value,
and the code to start a xenstored stubdomain hard-codes these to 4
and 128 respectively; this behavour will not be modified.
Signed-off-by: George Dunlap <george.dunlap@citrix.com>
Signed-off-by: Paul Durrant <pdurrant@amazon.com>
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Release-acked-by: Juergen Gross <jgross@suse.com>
Acked-by: Wei Liu <wl@xen.org>
Acked-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Current implementation of find_os is based on the hard-coded values for
different Windows version. It uses the value for get the address to
start looking for DOS header in the given specified range. However, this
is not scalable to all version of Windows as it will require us to keep
adding new entries and also due to KASLR, chances of not hitting the PE
header is significant. We implement a way for 64-bit systems to use IDT
entry to get a valid exception/interrupt handler and then move back into
the memory to find the valid DOS header. Since IDT entries are protected
by PatchGuard, we think our assumption that IDT entries will not be
corrupted is valid for our purpose. Once we have the image base, we
search for the DBGKD_GET_VERSION64 structure type in .data section to
get information required for handshake.
Currently, this is a work in progress feature and current patch only
supports the handshake and memory read/write on 64-bit systems.
NOTE: This is the Updated version of the previous patch submitted
NOTE: This has currently been only tested when debugging was not enabled
on the guest Windows.
Signed-off-by: Jenish Rakholiya <rjenish@cmu.edu>
Signed-off-by: Julian Tuminaro <jtuminar@andrew.cmu.edu>
Reviewed-by: Tim Deegan <tim@xen.org>
Reviewed-by: Paul Durrant <paul@xen.org>
Andrew Cooper