Commit Graph
38843 Commits
Author SHA1 Message Date
Wei Liu 85578ea686 Run autogen.sh for 4.13
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
2019-03-13 13:40:23 +00:00
Juergen Gross bd61616e94 MAINTAINERS: add myself as maintainer for public I/O interfaces
The "PUBLIC I/O INTERFACES AND PV DRIVERS DESIGNS" section of the
MAINTAINERS file lists Konrad as the only maintainer. Add myself for
helping him to review patches.

Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2019-03-13 11:26:38 +01:00
Jan Beulich 3bf54c9dbf string: fix type use in strstr()
Using plain int for string lengths, while okay for all practical
purposes, is undesirable in a generic library function.

Take the opportunity and also move the function from being in the middle
of mem*() ones to the set of str*() ones, convert its loop from while()
to for(), and correct style.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
2019-03-13 11:25:49 +01:00
Jan Beulich c07186ca66 string: remove memscan()
It has no users, so rather than fixing its use of types (first and
foremost c would need to be cast to unsigned char in the comparison
expression) drop it altogether. memchr() ought to be fine for all
purposes.

Take the opportunity and also do some stylistic adjustments to its
surviving sibling function memchr().

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
2019-03-13 11:25:04 +01:00
Jan Beulich 592b5fcb98 string: avoid undefined behavior in strrchr()
The pre-decrement would not only cause misbehavior when wrapping (benign
because there shouldn't be any NULL pointers passed in), but may also
create a pointer pointing outside the object that the passed in pointer
points to (it won't be de-referenced though).

Take the opportunity and also
- convert bogus space (partly 7 of them) indentation to Linux style tab
  one,
- add two blank lines.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
2019-03-13 11:23:28 +01:00
Andrew Cooper fa6eba8d35 xen/gnttab: Minor improvements to arch header files
* Use XFREE() when appropriate
 * Drop stale comments and unnecessary brackets
 * Fold asm constraints

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Julien Grall <julien.grall@arm.com>
2019-03-12 18:40:24 +00:00
Chao Gao af9a3de69f microcode/intel: use union to get fields without shifting and masking
No functional change.

Signed-off-by: Chao Gao <chao.gao@intel.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
2019-03-12 18:14:25 +00:00
Jan Beulich 19a1c8529b SVM: fix build after "make nested page-fault tracing and logging consistent"
Some compiler versions don't recognize that "mfn" can't really be used
uninitialized in svm_do_nested_pgfault(). To be on the safe side, add an
initializer for p2mt as well.

Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2019-03-12 18:13:10 +00:00
Andrew Cooper 6be613f29b x86/tsx: Implement controls for RTM force-abort mode
The CPUID bit and MSR are deliberately not exposed to guests, because they
won't exist on newer processors.  As vPMU isn't security supported, the
misbehaviour of PCR3 isn't expected to impact production deployments.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
2019-03-12 17:05:21 +00:00
Andrii Anisov 31e67c156f gic-vgic: skip irqs locking in gic_restore_pending_irqs()
This function is called under IRQs disabled already, so drop additional
flags save and restore.

Signed-off-by: Andrii Anisov <andrii_anisov@epam.com>
Reviewed-by: Julien Grall <julien.grall@arm.com>
2019-03-12 16:49:33 +00:00
Wei Liu 9b0bc91b3b README: remove requirement on Python 2
Now that all python scripts are compatible with Python 2.6 and above,
remove the restriction.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
2019-03-12 14:24:53 +00:00
Wei Liu 83a204e695 pygrub/fsimage: make it work with python 3
With the help of two porting guides and cpython source code:

1. Use PyBytes to replace PyString counterparts.
2. Use PyVarObject_HEAD_INIT.
3. Remove usage of Py_FindMethod.
4. Use new module initialisation routine.

For #3, Py_FindMethod was removed, yet an alternative wasn't
documented.  The code is the result of reverse-engineering cpython
commit 6116d4a1d1

https://docs.python.org/3/howto/cporting.html
http://python3porting.com/cextensions.html

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
2019-03-12 14:24:53 +00:00
Wei Liu 0aabd89dcf pygrub: make python scripts work with 2.6 and up
Run 2to3 and pick the sensible suggestions.

Import print_function and absolute_import so 2.6 can work.

There has never been a curses.wrapper module according to 2.x and 3.x
doc, only a function, so "import curses.wrapper" is not correct. It
happened to work because 2.x implemented a (undocumented) module.

We only need to import curses to make curses.wrapper available to
pygrub.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
2019-03-12 14:24:53 +00:00
Wei Liu 660d2dd863 libxl: make python scripts work with python 2.6 and up
Go through transformations suggested by 2to3 and pick the necessary
ones.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
2019-03-12 14:24:53 +00:00
Wei Liu 16cc3362ae build/m4: make python_devel.m4 work with both python 2 and 3
Do the following:

1. Change the form of "print".
2. Use AC_CHECK_FUNC to avoid the need to generate library name.
3. Remove unused stuff.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
2019-03-12 14:24:52 +00:00
Wei Liu b9e1368af1 pygrub: change tabs into spaces
Not sure why Python 2 never complained, but Python 3 does.

Change tabs to spaces.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
2019-03-12 14:24:52 +00:00
Wei Liu e81209fd4e pygrub/fsimage: drop unused struct
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
2019-03-12 14:24:52 +00:00
Wei Liu 72288c1566 Update Python requirement to 2.6
CentOS 5, which was the reason for the 2.4 restriction, is EOL. CentOS
6 ships 2.6.

Bump the version to 2.6 in README. Update configure.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
2019-03-12 14:24:52 +00:00
Andrew Cooper 919ddc3c0e tools/cpu-policy: Add unit tests
These will be extended with further libx86 work.

Fix the sorting of the CPUID_GUEST_NR_* constants, noticed while writing the
unit tests.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
2019-03-12 14:12:31 +00:00
Andrew Cooper f48363c9ca libx86: Introduce a helper to deserialise cpuid_policy objects
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Sergey Dyasli <sergey.dyasli@citrix.com>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
2019-03-12 14:12:27 +00:00
Roger Pau Monné afec08b92f libx86: introduce a helper to deserialise msr_policy objects
As with the serialise side, Xen's copy_from_guest API is used, with a
compatibility wrapper for the userspace build.

Signed-off-by: Sergey Dyasli <sergey.dyasli@citrix.com>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
2019-03-12 14:12:23 +00:00
Andrew Cooper a9a05aeee1 x86/vtd: Don't include control register state in the table pointers
iremap_maddr and qinval_maddr point to the base of a block of contiguous RAM,
allocated by the driver, holding the Interrupt Remapping table, and the Queued
Invalidation ring.

Despite their name, they are actually the values of the hardware register,
including control metadata in the lower 12 bits.  While uses of these fields
do appear to correctly shift out the metadata, this is very subtle behaviour
and confusing to follow.

Nothing uses the metadata, so make the fields actually point at the base of
the relevant tables.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Kevin Tian <kevin.tian@intel.com>
2019-03-12 13:57:13 +00:00
Andrew Cooper 65c165d659 x86/xstate: Don't special case feature collection
The logic in xstate_init() is a rementent of the pre-featuremask days.
Collect the xstate features in generic_identify(), like all other feature
leaves, after which identify_cpu() will apply the known_feature[] mask derived
from the automatically generated CPUID information.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
2019-03-12 13:57:13 +00:00
Jan Beulich 06f04f54ba x86/shadow: sh_{write,cmpxchg}_guest_entry() are PV-only
Move them to a new pv.c. Make the respective struct shadow_paging_mode
fields as well as the paging.h wrappers PV-only as well.

Take the liberty and switch both functions' "failed" local variables to
more appropriate types.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Tim Deegan <tim@xen.org>
2019-03-12 14:45:36 +01:00
Jan Beulich f1f20bb3fa x86/shadow: sh_validate_guest_pt_write() is HVM-only
Move the function to hvm.c, make it static, and drop its sh_ prefix.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Tim Deegan <tim@xen.org>
2019-03-12 14:44:38 +01:00
Jan Beulich 6233b297c9 Arm/atomic: parameterize register modifier macro arguments
Make the abstracting macros take the asm() operand specifier as
argument, in preparation of doing away with the split u64 read/write
definitions.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Julien Grall <julien.grall@arm.com>
2019-03-12 14:43:50 +01:00
Jan Beulich d9bdd36f59 Arm/atomic: drop uniformly used reg macro parameters
There's no point in parameterizing these when all use sites pass the
same arguments.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Julien Grall <julien.grall@arm.com>
2019-03-12 14:43:15 +01:00
Jan Beulich 51ceb1623b Arm/atomic: correct asm() constraints in build_add_sized()
The memory operand is an in/out one, and the auxiliary register gets
written to early.

Take the opportunity and also drop the redundant cast (the inline
functions' parameters are already of the casted-to type).

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Julien Grall <julien.grall@arm.com>
2019-03-12 14:42:17 +01:00
Jan Beulich c8cfbba625 common: avoid atomic read-modify-write accesses in map_vcpu_info()
There's no need to set the evtchn_pending_sel bits one by one. Simply
write full words with all ones.

For Arm this requires extending write_atomic() to also handle 64-bit
values; for symmetry read_atomic() gets adjusted as well.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Julien Grall <julien.grall@arm.com>
2019-03-12 14:40:56 +01:00
Jan Beulich d9195962a6 events: drop arch_evtchn_inject()
Have the only user call vcpu_mark_events_pending() instead, at the same
time arranging for correct ordering of the writes (evtchn_pending_sel
should be written before evtchn_upcall_pending).

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Julien Grall <julien.grall@arm.com>
2019-03-12 14:40:24 +01:00
Jan Beulich a43c1dec24 x86/HVM: don't crash guest in hvmemul_find_mmio_cache()
Commit 35a61c05ea ("x86emul: adjust handling of AVX2 gathers") builds
upon the fact that the domain will actually survive running out of MMIO
result buffer space. Drop the domain_crash() invocation. Also delay
incrementing of the usage counter, such that the function can't possibly
use/return an out-of-bounds slot/pointer in case execution subsequently
makes it into the function again without a prior reset of state.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Paul Durrant <paul.durrant@citrix.com>
2019-03-12 14:39:46 +01:00
Jan Beulich b49225dc9d kexec: suppress bogus warning
Till now "crashkernel=1G-16G:1M" causes

(XEN) crashkernel: '' ignored
(XEN) parameter "crashkernel" has invalid value "1G-16G:1M", rc=-22!

Don't emit the "ignored" warning when there's no placement specification
and the tail of the specified option is actually empty.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
2019-03-12 14:39:13 +01:00
Igor Druzhinin 12c36f577d iommu: leave IOMMU enabled by default during kexec crash transition
It's unsafe to disable IOMMU on a live system which is the case
if we're crashing since remapping hardware doesn't usually know what
to do with ongoing bus transactions and frequently raises NMI/MCE/SMI,
etc. (depends on the firmware configuration) to signal these abnormalities.
This, in turn, doesn't play well with kexec transition process as there is
no handling available at the moment for this kind of events resulting
in failures to enter the kernel.

Modern Linux kernels taught to copy all the necessary DMAR/IR tables
following kexec from the previous kernel (Xen in our case) - so it's
currently normal to keep IOMMU enabled. It might require minor changes to
kdump command line that enables IOMMU drivers (e.g. intel_iommu=on /
intremap=on) but recent kernels don't require any additional changes for
the transition to be transparent.

A fallback option is still left for compatibility with ancient crash
kernels which didn't like to have IOMMU active under their feet on boot.

Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
2019-03-12 14:38:12 +01:00
Jan Beulich 65a510fe51 SVM: make nested page-fault tracing and logging consistent
Don't call __get_gfn_type_access() more than once, to make sure data
recorded for xentrace matches up with what gets logged in case of the
domain getting crashed.

As a side effect this also eliminates a type mismatch reported by
Norbert Manthey, as the first call now also needs to update the local
variable "p2mt".

Do a few cosmetics at the same time: Move a comment up a little, drop
the pointless "case 0" (seeing in particular the comment's wording),
and correct formatting.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2019-03-12 14:36:56 +01:00
Olaf Hering 9d840969ed libxl: prepare environment for domcreate_stream_done
The function domcreate_bootloader_done may branch early to
domcreate_stream_done, in case some error occoured. Here srs->dcs will be
NULL, which leads to a crash.

It is unclear what the purpose of that backpointer is. Perhaps it can be
removed, and domcreate_stream_done could use CONTAINER_OF.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Acked-by: Wei Liu <wei.liu2@citrix.com>
[ wei: fold in comment required by Ian ]
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
2019-03-12 13:02:57 +00:00
Andrew Cooper 58b26fb0b8 xen: Fix XEN_EXTRAVERSION after c/s 100507b34 branching for 4.13
The update to README and SUPPORT.md where correct, but XEN_EXTRAVERSION had an
additional .0 slip in.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
2019-03-12 12:58:01 +00:00
Andrew Cooper a9047a722b tools/xen-foreign: Update python scripts to be Py3 compatible
The issues are:
 * dict.has_key() was completely removed in Py3
 * dict.keys() is an iterable rather than list in Py3, so .sort() doesn't work.
 * list.sort(cmp=) was deprecated in Py2.4 and removed in Py3.

The has_key() issue is trivially fixed by switching to using the in keyword.
The sorting issue could be trivially fixed, but take the opportunity to
improve the code.

The reason for the sorting is to ensure that "unsigned long" gets replaced
before "long", and the only reason sorting is necessary is because
inttypes[arch] is needlessly a dictionary.  Update inttypes[arch] to be a list
of tuples rather than a dictionary, and process them in list order.

Reported-by: George Dunlap <george.dunlap@eu.citrix.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
2019-03-12 12:57:21 +00:00
Juergen Gross 66b4a510b7 tools: add link path flag for local build to pkg-config files
The qemu build process is requiring the link path of Xen libraries
to be specified both with -L and -Wl,-rpath-link. Add the -L flag
to the local pkg-config files.

At the same time let the pkg-config files depend on the Makefile
creating them, too.

Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
2019-03-12 12:57:13 +00:00
Petre Pircalabu d48e183607 vm_event: Add a new opcode to get VM_EVENT_INTERFACE_VERSION
Currently, the VM_EVENT_INTERFACE_VERSION is determined at runtime, by
inspecting the corresponding field in a vm_event_request. This helper
opcode will query the hypervisor supported version before the vm_event
related structures and layout are set-up.

Signed-off-by: Petre Pircalabu <ppircalabu@bitdefender.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Tamas K Lengyel <tamas@tklengyel.com>
2019-03-12 12:57:13 +00:00
Pritha Srivastava 91c3e3dc91 tools/xentop: Display '-' when stats are not available.
Displaying 0 is misleading.

Signed-off-by: Pritha Srivastava <pritha.srivastava@citrix.com>
Signed-off-by: Ronan Abhamon <ronan.abhamon@vates.fr>
Acked-by: Wei Liu <wei.liu2@citrix.com>
2019-03-12 12:57:13 +00:00
Ian Jackson ef15ca08a8 Branch for 4.12: Switch unstable back from specific 4.12 tags
Use master or specific git commits.  The only semantic change is to
pick up qemu-xen master again.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
2019-03-11 14:49:00 +00:00
Ian Jackson 100507b34b Branch for 4.12: change version numbers
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
2019-03-11 14:48:36 +00:00
George Dunlap 4deeaf2a3e README: Document python2 dependency
Much of the tools and configure makefile actually have a python2
dependency; specify this.  It also assumes that `python` points to `python2`;
document how to work around this on systems where this is false.

Also update second version requirement listed to match the first.

Signed-off-by: George Dunlap <george.dunlap@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Release-acked-by: Juergen Gross <jgross@suse.com>
4.12.0-rc5
2019-03-06 14:42:49 +00:00
Jan Beulich eeb31ee522 x86/cpuid: add missing PCLMULQDQ dependency
Since we can't seem to be able to settle our discussion for the wider
adjustment previously posted, let's at least add the missing dependency
for 4.12. I'm not convinced though that attaching it to SSE is correct.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Release-acked-by: Juergen Gross <jgross@suse.com>
2019-03-05 18:04:23 +01:00
Roger Pau Monné 7b653a245f x86/dom0: propagate PVH vlapic EOIs to hardware
Current check for MSI EIO is missing a special case for PVH Dom0,
which doesn't have a hvm_irq_dpci struct but requires EIOs to be
forwarded to the physical lapic for passed-through devices.

Add a short-circuit to allow EOIs from PVH Dom0 to be propagated.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Release-acked-by: Juergen Gross <jgross@suse.com>
2019-03-05 17:41:14 +01:00
Ian Jackson 2215a8b6da tools/libfsimage: Add `XEN' to environment variable name
This library, which is private to Xen and was properly namespaced in
  1a81471188
  tools/libfsimage: Add `xen' to .h names and principal .so name
honours an environment variable to override the directory where
shared objects (ie filesystem plugins) are to be loaded from.

Rename that variable from FSIMAGE_FSDIR to XEN_FSIMAGE_FSDIR, to give
it a proper namespace prefix.

Nothing in xen.git sets this variable.  The three hits for the string
`FSIMAGE_FSDIR' are this getenv, and two references to a compile-time
manifest constant which provides the default value (the -D which sets
it, and the place it is used).

I have also checked the current Debian Xen package in buster and the
variable is not set there either.

CC: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Jan Beulich <JBeulich@suse.com>
CC: George Dunlap <george.dunlap@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Release-acked-by: Juergen Gross <jgross@suse.com>
2019-03-05 16:25:08 +00:00
Jan Beulich fdc2056767 x86/mm: fix #GP(0) in switch_cr3_cr4()
With "pcid=no-xpti" and opposite XPTI settings in two 64-bit PV domains
(achievable with one of "xpti=no-dom0" or "xpti=no-domu"), switching
from a PCID-disabled to a PCID-enabled 64-bit PV domain fails to set
CR4.PCIDE in time, as CR4.PGE would not be set in either (see
pv_fixup_guest_cr4(), in particular as used by write_ptbase()), and
hence the early CR4 write would be skipped.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Release-acked-by: Juergen Gross <jgross@suse.com>
2019-03-05 17:02:36 +01:00
Jan Beulich 329b00e4d4 x86/pv: _toggle_guest_pt() may not skip TLB flush for shadow mode guests
For shadow mode guests (e.g. PV ones forced into that mode as L1TF
mitigation, or during migration) update_cr3() -> sh_update_cr3() may
result in a change to the (shadow) root page table (compared to the
previous one when running the same vCPU with the same PCID). This can,
first and foremost, be a result of memory pressure on the shadow memory
pool of the domain. Shadow code legitimately relies on the original
(prior to commit 5c81d260c2 ["xen/x86: use PCID feature"]) behavior of
the subsequent CR3 write to flush the TLB of entries still left from
walks with an earlier, different (shadow) root page table.

Restore the flushing behavior, also for the second CR3 write on the exit
path to guest context when XPTI is active. For the moment accept that
this will introduce more flushes than are strictly necessary - no flush
would be needed when the (shadow) root page table doesn't actually
change, but this information isn't readily (i.e. without introducing a
layering violation) available here.

This is XSA-294.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Tested-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
2019-03-05 13:54:42 +01:00
Andrew Cooper eccc170053 x86/pv: Don't have %cr4.fsgsbase active behind a guest kernels back
Currently, a 64bit PV guest can appear to set and clear FSGSBASE in %cr4, but
the bit remains set in hardware.  Therefore, the {RD,WR}{FS,GS}BASE are usable
even when the guest kernel believes that they are disabled.

The FSGSBASE feature isn't currently supported in Linux, and its context
switch path has some optimisations which rely on userspace being unable to use
the WR{FS,GS}BASE instructions.  Xen's current behaviour undermines this
expectation.

In 64bit PV guest context, always load the guest kernels setting of FSGSBASE
into %cr4.  This requires adjusting how Xen uses the {RD,WR}{FS,GS}BASE
instructions.

 * Delete the cpu_has_fsgsbase helper.  It is no longer safe, as users need to
   check %cr4 directly.
 * The raw __rd{fs,gs}base() helpers are only safe to use when %cr4.fsgsbase
   is set.  Comment this property.
 * The {rd,wr}{fs,gs}{base,shadow}() and read_msr() helpers are updated to use
   the current %cr4 value to determine which mechanism to use.
 * toggle_guest_mode() and save_segments() are update to avoid reading
   fs/gsbase if the values in hardware cannot be stale WRT struct vcpu.  A
   consequence of this is that the write_cr() path needs to cache the current
   bases, as subsequent context switches will skip saving the values.
 * write_cr4() is updated to ensure that the shadow %cr4.fsgsbase value is
   observed in a safe way WRT the hardware setting, if an interrupt happens to
   hit in the middle.
 * load_segments() is updated to use the VMLOAD optimisation if FSGSBASE is
   unavailable, even if only gs_shadow needs updating.  As a minor perf
   improvement, check cpu_has_svm first to short circuit a context-dependent
   conditional on Intel hardware.
 * pv_make_cr4() is updated for 64bit PV guests to use the guest kernels
   choice of FSGSBASE.

This is part of XSA-293.

Reported-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
2019-03-05 13:54:05 +01:00
Andrew Cooper b2dd00574a x86/pv: Rewrite guest %cr4 handling from scratch
The PV cr4 logic is almost impossible to follow, and leaks bits into guest
context which definitely shouldn't be visible (in particular, VMXE).

The biggest problem however, and source of the complexity, is that it derives
new real and guest cr4 values from the current value in hardware - this is
context dependent and an inappropriate source of information.

Rewrite the cr4 logic to be invariant of the current value in hardware.

First of all, modify write_ptbase() to always use mmu_cr4_features for IDLE
and HVM contexts.  mmu_cr4_features *is* the correct value to use, and makes
the ASSERT() obviously redundant.

For PV guests, curr->arch.pv.ctrlreg[4] remains the guests view of cr4, but
all logic gets reworked in terms of this and mmu_cr4_features only.

Two masks are introduced; bits which the guest has control over, and bits
which are forwarded from Xen's settings.  One guest-visible change here is
that Xen's VMXE setting is no longer visible at all.

pv_make_cr4() follows fairly closely from pv_guest_cr4_to_real_cr4(), but
deliberately starts with mmu_cr4_features, and only alters the minimal subset
of bits.

The boot-time {compat_,}pv_cr4_mask variables are removed, as they are a
remnant of the pre-CPUID policy days.  pv_fixup_guest_cr4() gains a related
derivation from the policy.

Another guest visible change here is that a 32bit PV guest can now flip
FSGSBASE in its view of CR4.  While the {RD,WR}{FS,GS}BASE instructions are
unusable outside of a 64bit code segment, the ability to modify FSGSBASE
matches real hardware behaviour, and avoids the need for any 32bit/64bit
differences in the logic.

Overall, this patch shouldn't have a practical change in guest behaviour.
VMXE will disappear from view, and an inquisitive 32bit kernel can now see
FSGSBASE changing, but this new logic is otherwise bug-compatible with before.

This is part of XSA-293.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
2019-03-05 13:53:32 +01:00